Cure Eye Floaters Naturally
A 63-year-old man with age-related macular degeneration noted a gradual decrease in vision in his left eye. He had undergone indocyanine green enhanced diode laser photocoagulation 15 months earlier for choroidal neovascularization- On examination, his visual acuity in this eye was 20 160. Slit-lamp biomicroscopy (A) revealed an atrophic chorioretinal scar superonasal to the fovea and a neurosensory detachment extending inferotemporally passing beneath the fovea. The sub retinal fluid appeared cloudy with mild subretinal fibrosis.
In contrast to most other paediatric blinding retinal disorders, blindness through retinal detachment is in most cases potentially avoidable if a rationale for the prediction and prevention of retinal detachment could be developed. This goal has been frustrated by a lack of understanding of the factors influencing retinal detachment even in high-risk groups, which are only now beginning to be unravelled. Factors traditionally associated with retinal detachment include refractive error, a positive family history, visible lattice retinopathy and fellow eye involvement, but the nature of these associations is poorly understood. The prevalence of myopia varies enormously and even in Stickler syndrome up to 20 patients may have no significant refractive error. Many patients with retinal detachment have none of the accepted risk features such as lattice retinopathy and, in those that do, retinal tear formation frequently occurs in areas remote from such pathology, so that the associations...
Epidemiology Age-related macular degeneration is the most frequent cause of blindness beyond the age of 65 years. H Laser therapy may be performed in the exudative stage of late age-related macular degeneration in 10 of all patients provided the disorder is diagnosed early. Table 12.6 Stages of age-related macular degeneration (ARM) Stage Characteristics 338 12 Retina Stages of late age-related macular degeneration. a Late age-related macular degeneration Typical signs include drusen (arrow) and geographically central atrophy (arrowhead). c Late age-related macular degeneration The fibrous scar is a typical sign. a Late age-related macular degeneration Typical signs include drusen (arrow) and geographically central atrophy (arrowhead). b Late age-related macular degeneration Intraretinal bleeding (arrow) is a typical sign. c Late age-related macular degeneration The fibrous scar is a typical sign.
Rhegmatogenous retinal detachment can occur in a number of inherited disorders (see Table 12.1), the most common being the Stickler syndromes due to mutations in the genes for type II and type XI collagens, constituents of both vitreous and cartilage. High myopia and retinal detachment are also seen in Marfan syndrome, Ehlers-Danlos syndrome, Smith-Magenis syndrome, Kniest syndrome and spondyloepiphy-seal dysplasia congenita. The detachments are often complex and frequently caused by giant retinal tear. In familial exudative vitreoretinopathy (FEVR),Norrie disease and inconti-nentia pigmenti, there is an underlying retino- vascular abnormality and tractional retinal detachment. Rarely retinal detachment may complicate juvenile X-linked retinoschisis.
Traumatic retinal detachment is a prime example showing how proper (and timely) surgery can improve the prognosis after an injury in one study ambulatory vision was achieved in 75 of eyes undergoing vitrectomy for retinal detachment after open globe injury, as opposed to only 37 of eyes without vitrectomy 56 . There are several types of posttraumatic retinal detachment these may present alone or in combination. During the pre-operative evaluation, it is insufficient to focus on break localization if possible, the type of traction should also be investigated. One of the consequences of retinal detachment is increased uveal aqueous outflow. Removal of the retina is a last resort in lowering the IOP (see Chap. 2.18).
2 The patient suffered a posterior scleral rupture with extensive tissue extrusion, total vitreous hemorrhage, and retinal incarceration his initial vision was NLP. The eye's comprehensive reconstruction was delayed because the only surgeon who agreed to attempt secondary reconstruction was unavailable for almost 3 weeks. When the eye finally underwent vitrectomy and chorioretinectomy, PVR was already present. Several reoperations were performed, the eye is prephthysical, and the recurring PVR-retinal detachment keeps pushing the silicone oil against the cornea, causing zonular opacity. Visual acuity improved to CF, and additional surgeries are planned as needed.
A 75-year-old man with age-related macular degeneration had undergone indocynanine green enhanced diode laser photocoagulation in his right eye eight months earlier for choroidal neovascularization. Slit-lamp biomi-croscopv (A) showed an atrophic laser scar in the center of the macula with no subretinal fluid, hemorrhage, or exudate. The visual acuitv in this eve was 20 100. Flu ores-
Cleotide or with a molecule to adsorb VEGF (VEGF receptor IgG chimera) significantly decreased the neovascular response in the mouse model of ROP 6,61 , indicating that VEGF is a critical factor in retinal neovascularization. VEGF also has been associated with ocular neo-vascularization by other investigators in other animal models, confirming the central role of VEGF in neovascular eye disease 3,18, 47, 72, 76 . These results correspond to what is seen clinically. VEGF is elevated in the vitreous of patients with retinal neovascularization 2, 4 . VEGF was found in the retina of a patient with ROP in a pattern consistent with mouse results 76 . Based on these and other studies an anti-VEGF aptamer is now available to treat neovas-cularization associated with age-related macular degeneration and is in phase III clinical trials for diabetic retinopathy. Clinical trials are planned for evaluation of treatment of the pro-liferative phase of ROP with anti-VEGF injections. VEGF is an...
Effects of Aphakia and Changes in Retinal Permeability and Vitreous Diffusivity on Drug Distribution in the Vitreous
Posterior segment infections that result in endophthalmitis most often occur as a complication following cataract extraction, anterior segment procedures, and traumatic eye injuries (23-25). Vitreoproliferative disease, a disorder in which there is uncontrolled proliferation of nonneoplastic cells, accounts for the majority of failures following retinal detachment surgery (26). A common result of both of these diseases states is inflammation of the retina, which results in a breakdown of the blood-retinal barrier (27). Long-term diabetes is also known to result in a breakdown of the blood-retinal barrier (28). The permeability of the retina will be affected as a result of these disorders and will depend on the extent to which the blood-retinal barrier has been compromised. The retinal permeability of compounds normally unable to cross the blood-retinal barrier will be increased however, the retinal permeability of compounds that are normally actively transported across the retina may...
Although cataract extractions previously involved removal of the entire lens, it is more common today to leave the posterior lens capsule intact in order to reduce postoperative complications such as vitreous changes and retinal detachment (34). To study elimination in an aphakic eye, the human phakic eye model was modified so that the curved barrier formed by the lens (Fig. 7) was replaced by the posterior capsule of the lens (Fig. 13). All of the other tissues of the aphakic eye model were assumed to be in the same
OCT offers an objective test for the quantitative evaluation of patients with central serous chorioretinopathy Longitudinal examinations with OCT are able to track the resolution of the sensory retinal detachment with more sensitivity than slit-lamp biomicroscopy and with a single, permanently recorded measurement 1 * disease may be mistaken for age-related macular degeneration and subretinal neovascularization in older patients 2 . fhe occult form of choroidal neovascularization mav show a similar angiographic appearance to central serous chorioretinopathy when a focal leakage point is present. OCT can provide additional diagnostic information in these cases by confirming the existence of a neurosensory detachment versus abnormalities in the choriocapillaris or pigment epithelium caused by a neovascular membrane, f he serous retinal detachment of central serous chorioretinopathy may be distinguished from a pigment epithelial detachment on OCT by observation of the reflective layer...
Endolaser cerclage is a very reasonable recommendation in eyes undergoing vitrectomy for trauma. The procedure creates a new ora serrata (Fig. 2.9.8) with a very low complication rate80 but offers substantial benefits 63 . This new ora serrata is likely to encompass the entire area where retinal tears develop. It also destroys tissue that may be responsible for the release of inciting agents partially responsible for PVR development. Performing laser cerclage during surgery as a prophylaxis means that subsequent opacification of the media will not interfere with laser delivery if it were to become necessary for a newly developing pathology. Fig. 2.9.8 Endolaser cerclage. Vitrectomy has been performed in this eye for a contusion-related vitreous hemorrhage. A new ora serrata has been created to prevent retinal detachment from a potential (unidentified) retinal break. Such breaks can occur years after the injury but may also be caused by the surgery itself Fig. 2.9.8 Endolaser cerclage....
Personnel in the molecular diagnostics laboratory can assist in assuring that surgical tissue sections are properly identified and uncontaminated. During processing of tissue specimens, microscopic fragments of tissue may persist in paraffin baths (floaters). These fragments can adhere to subsequent slides, resulting in anomalous appearance of the tissue under the microscope. If a tissue sample is questioned, STR identification can be used to confirm the origin of tissue.
Diagnostic considerations Ophthalmoscopy will reveal a serous retinal detachment, usually at the macula. In chronic cases, a fine brown and white pigment epithelial scar will develop at the site of the fluid effusion. Swelling in the central retina shortens the visual axis and produces hyperopia. The site of fluid effusion can be identified during the active phase with the aid of fluorescein angiography (Fig. 12.26a and b).
Chronic inflammation appears an important factor in many of the important diseases of aging. Immunohistochemical evidence for chronic inflammation in affected tissue is seen not only in AD, PD, ALS, and multiple sclerosis but also in other conditions such as atherosclerosis, heart disease, and macular degeneration (Bok, 2005 Kuehn, 2005). Finch (2005), for example, has recently reviewed the remarkable convergence of inflammatory mechanisms in the etiology of cardiovascular disease and Alzheimer disease. The more than 20 epidemiological studies indicating that chronic use of nonsteroidal antiinflammatory drugs (NSAIDs) greatly reduces the risk of AD testifies to the importance of the inflammatory reaction (McGeer & McGeer, 2004a). And recently single epidemiological studies have been published indicating that such use of NSAIDs also reduces the risk of PD (Chen et al., 2003) and macular degeneration (McGeer & Sibley, 2005). Moreover, forms of various inflammatory mediators which favor...
Based on the current understanding it is possible to put the conjunctival scleral pathway for intraocular entry of drugs in perspective vis-a-vis ocular drug delivery. First, the noncorneal penetration pathway involves the permeation of drug across the conjunctiva and sclera and may contribute significantly to drug penetration into intraocular tissues for some drugs. Second, drug entering the eye via the cornea enters the aqueous humor and provides high drug levels to the anterior segment tissues, as described earlier. In contrast, the fraction of drug entering the eye via the noncorneal route may bypass the anterior chamber and access tissues of the posterior segment of the eye, such as the uveal tract, choroid, and retina and, to a lesser extent, the vitreous humor. The differential spatial distribution of drug entering the eye via the corneal versus conjunctival scleral pathway has exciting implications in terms of ocular drug delivery. For example, whereas the corneal route may be...
The findings of high hyperopia ( +7 DS), severe photophobia, poor vision of count fingers (CF) or light perception (LP) in addition to the presence of early peripheral and macular degeneration with bone spicule pigments in the periphery, disc pallor and vessel attenuation has been suggested by Perrault et al. to be pathognomonic of the GUCY-2D mutation 103 . Other groups have, however, reported LCA patients with GUCY-2D mutations who have no significant photophobia, better visual acuity (20 200), and mild to moderate hyperopia 25 .
Retinal perforation or incarceration from penetrating trauma rarely causes acute rheg-matogenous retinal detachment. The associated corneoscleral wound provides access for extrinsic fibroblasts so that combined tractional and rhegmatogenous retinal detachment presents sometimes much later. Vitrectomy and internal tamponade with or without relieving retinectomy may be required as severe proliferative vitreoretinopathy commonly occurs. Traumatic giant retinal tears have been reported to occur in 22 of open globe injuries 34 .
Although most patients with Stickler syndrome were found to have the type 1 vitreous pheno-type, it became clear that a minority of pedigrees had the same classical systemic features and the same risk of retinal detachment but had a different vitreous phenotype. The vitreous was also highly abnormal but instead of the classical membranous anomaly, sparse, irregularly thickened, beaded fibrils were seen throughout an otherwise empty-looking gel (type 2 vitreous phenotype). Linkage to COL2A1 was excluded. Mutations in the gene encoding the ai chain of type XI collagen (COL11A1) on chromosome 1 have been found in seven families 23, 31, 40 and these are, to date, the only mutations associated with the type 2 vitreous phenotype. These pedigrees have a similarly high risk of detachment and giant retinal tear but appear to have a higher prevalence of sensorineural deafness than the type 1 Stickler families 26 .
Spondyloepimetaphyseal dysplasia (SEMD) also forms part of the clinical spectrum of dominant-ly inherited type II collagenopathies. The features include severe dwarfism, pectus carinatum and scoliosis which are usually marked. Cleft palate and retinal detachment are frequently associated, as with SEDC. Disproportionately short limbs and delayed epiphyseal maturation are present at birth. Radiologically, the disorder is indistinguishable from SEDC during infancy but a characteristic mottled appearance created by alternating zones of osteosclerosis and os-teopaenia develops during early childhood.
With the autosomal recessive type VI variant of the Ehlers-Danlos syndromes (EDS VI), also classified as the kyphoscoliotic type, are clinically characterized by neonatal kyphoscoliosis, generalized joint laxity,skin fragility, and severe muscle hypotonia at birth. EDS VI results from mutations in the lysyl hydroxylase 1 gene (PLODi) causing a deficiency of lysyl hydroxylase. This enzyme hy-droxylates specific lysine residues in the collagen molecule to form hydroxylysines, important in collagen cross-linking, which gives collagen its tensile strength. Ocular involvement in EDS VI includes myopia, thin sclera, microcornea and rheg-matogenous retinal detachment. Retinal detachment repair may be complicated by susceptibility to suprachoroidal haemorrhage because of vascular fragility.
Wagner described 13 affected individuals in a three-generation pedigree with autosomal dominant inheritance, low myopia, fluid vitreous, cortical cataract, and variably affected dark adaptation. The cardinal features noted were the complete absence of the normal vitreal scaffolding and preretinal, equatorial, and avascular greyish-white membranes. Rhegmatogenous retinal detachment was not originally reported. There are no associated systemic features. Twenty-eight members of the original pedigree have been examined 16 and four patients had a history of a rhegmatogenous retinal detachment in one eye at a median age of 20 years and 55 of patients older than 45 years had peripheral tractional retinal detachments. Chorioretinal atrophy and cataract increased with the patients' age. Several families with Wagner syndrome, including the original pedigree, have been linked to 5q14.3.
Treatment of the inner ocular tissues and the posterior region of the eye has posed a significant challenge to ophthalmologists. A major tissue to be targeted is the retina, the transparent tissue lining the back of the eye that is responsible for visual acuity, color discrimination, and peripheral vision. Diseases of the retina include retinitis pigmentosa and macular degeneration both result in blindness due to the death of retinal cells. Drugs applied to the cornea usually do not reach the back of the eye. Therefore, direct injection of the drugs into the vitreous is required to target the retina. While this method provides adequate drug levels, it is not without significant risk of retinal detachment, endophthalmitis, vitreal hemorrhage, and or cellular toxicity (65-67). The use of dendrimers to deliver drugs and gene therapy to this area of the eye has great potential.
Incontinentia pigmenti is an X-linked domi-nantly inherited disorder usually lethal in males, affecting skin, bones, teeth, the central nervous system and eyes. The characteristic skin lesion begins soon after birth, with a linear eruption of bullae, which resolve to leave a linear pattern of hyperpigmentation. Ocular features are usually apparent within the 1st year of life can occur in up to 77 18 . The main abnormalities are peripheral vascular abnormalities and retinal pigment epithelial defects. Macular vasculopathy with progressive capillary closure has also been described 13 . The affected eye is often microphthalmic and complications can arise from late tractional retinal detachment in up to half of those with eye involvement 18 . Prophylactic cryotherapy or 12.5 Retinal Detachment Complicating Developmental Abnormalities 201
The incidence of early retinal detachment following advanced retinopathy of prematurity (ROP) has been substantially reduced by better screening and prophylactic cryotherapy or photocoagulation. However, the visual results following vitreoretinal surgery for those which do progress to retinal detachment have been very disappointing. The major, and often multiple, surgical challenges need to be carefully weighed against a partial and spontaneous retinal reattachment in up to 10 of cases. Lens-sparing techniques have been advocated for pathology confined posterior to the equator 5 . Preserving the lens whilst gaining surgical access to the vitreous base in the neonatal eye is technically demanding and requires adequate visualization of the pars plicata by using the operating indirect ophthalmoscope or wide-angle viewing systems. Late retinal detachment following treated or untreated retinopathy of prematurity is well-recognized and is more commonly rhegmatoge-nous,but may be tractional...
In one series, 15 of 34 children with rheg-matogenous retinal detachment had a history of inflammatory or infectious disease in the eye with the detachment 44 . Acute retinal necrosis, characterized by anterior uveitis, occlusive retinal vasculitis and progressive peripheral retinal necrosis, occurs primarily in nonim-munocompromised adults as a result of reactivated herpes simplex or varicella zoster virus infection. The risk of retinal detachment is high, reported to be between 25 and 75 and due to retinal breaks, usually following posterior vitreous detachment after the acute phase is over. Although less common, it has been reported to occur in children 6 . Ocular involvement in paediatric AIDS patients has been reported in 50 , 33 having CMV retinitis and 17 retinal detachment 3 . Although uncommon, bilateral serous retinal detachment in Vogt-Koyanagi-Harada may affect young children, and has been reported in children as young as 4 years old 8 . Ocular toxocariasis is a rare cause...
Retinal degeneration leads to impaired function of the photoreceptors and consequently gradual loss of vision., Many types of degeneration are based on genetic factors, e.g., retinitis pigmentosa, a common term for various mutations causing retinal degeneration. In addition to genetic factors, environmental factors (e.g., light exposure) may lead to retinal degeneration. Macular degeneration is the most common type of retinal degeneration, being the leading cause of vision loss in the industrial world. In the following sections we present some genetic and environmental animal models of retinal degeneration.
Therapeutic concepts in oncology such as antiangiogenic or antivascular approaches have reawakened the scientific community's interest in comparative microvascular anatomy and biology. Microvascularity and angiogenesis play a significant role during normal growth, in physiological conditions, and in a variety of pathological conditions such as inflammation, diabetes, macular degeneration, and wound healing. Angiogenesis is thus, not a specific phenomenon in tumors, but instead an integral element of numerous different normal and pathological conditions.
In secondary angle closure glaucoma, iridotrabecular or iridocorneal contact is present. This is most frequently caused by neovascular glaucoma, in which neovascu-larisation with fibrosis of the iris occurs, for example in retinopathy of prematurity. Other causes are end-stage inflammatory disease, retinal detachment, tumours or trauma.
Proliferative vitreoretinopathy (PVR) is found in about 5 of retinal detachments. The cellular evens of PVR include migration of glial cells, pigment epithelial cells, and fibrocytes into the vitreous cavity, where they proliferate and transform and dedifferentiate. The cells may interact with endogenous membranous components of the vitreous. This leads to the formation of vitreal, epiretinal, and subretinal membranes and traction retinal detachment (47). Severe postoperative PVR is the most common cause of failed retinal detachment surgery. Animal models of PVR are based on environmental injuries.
Pigmentosa (RP), one of the better-characterized eye diseases, has been useful in developing excellent natural and transgenic RP models for preclinical testing and for developing pharmaceutics. Progress, however, is slowed for other degenerative diseases leading to blindness, such as macular degeneration, because of their less well-defined etiologies and lack of appropriate animal models. Careful characterization of the genetic and biochemical basis of these degenerations is essential for developing better animal models to study disease progression and to evaluate new treatments.
Macugen (tradename) is the first and thus far only aptamer approved for general medical use. It was approved by the FDA in December 2004. The product is a synthetic PEGylated oligonucleotide with binding specificity for vascular endothelial growth factor (VEGF). It is indicated for the treatment of neovascular ('wet') age-related macular degeneration (AMD). The target indication (age-related neovascular or 'wet' macular degeneration) results from the proliferation of abnormal blood vessels in the eye, which leads to retinal damage and loss of vision. The process of vascularization (angiogenesis) is driven by VEGF. Macugen adopts a three-dimensional shape that allows it to interact specifically with VEGF, thereby inhibiting its activity (the monoclonal antibody-based product Avastin, Chapter 13, achieves a similar effect, but in the context of cancer). The product is administered directly to the site of action by intravitreous injection. Absorption from the eye into the general...
Diseases of the retina are good targets for gene transfer approaches. Visual function hinges on two critical layers of the retina the outer nulcear layer, which contains the photoreceptor cells, and the retinal pigment epithelium, which lies adjacent to the photoreceptors. The relationships between the RPE and photoreceptor cells is critical not only to normal function but also to the pathology of several blinding hereditary diseases, including retinitis pigmentosa, Leber's congenital amaurosis, and macular degeneration.
Angiostatin and endostatin, its efficacy was slightly more potent than those inhibitors. In support of their study, we showed higher concentrations of PEDF in the vitreous of patients with avascular proliferative vitreal retinopathy and diabetic retinopathy when compared to patients with retinal pathologies associated with increased angiogenic activity (228). Based on the clinical data, as well as vivo studies using animal models, it appears that the concentration of PEDF in the eye is important to the vascular state of ocular tissues. These results have stirred much interest in the ophthalmic field and have encouraged several groups to exploit the therapeutic potential of PEDF in ocular diseases, such as age-related macular degeneration, where both cell death and increased angiogenesis contribute to severe visual loss.
Symptoms and findings Collapse of the vitreous body leads to vitreous densities that the patient perceives as mobile opacities. These floaters (also known as flies or cobwebs) may take the form of circular or serpentine lines or points. The vitreous body may detach partially or completely from the retina. An increased risk of retinal detachment is present only with partial vitreous detachment. In this case, the vitreous body and retina remain attached, with the result that eye movements in this region will place traction on the retina. The patient perceives this phenomenon as flashes of light. If the traction on the retina becomes too strong, it can tear (see retinal tears in posterior vitreous detachment, Fig. 11.3 b - c).This increases the risk of retinal detachment and vitreous bleeding from injured vessels. H Floaters and especially flashes of light require thorough examination of the ocular fundus to exclude a retinal tear. 11.3 Aging Changes 283 Retinal tears in posterior...
Importance of the vitreous body for the eye The vitreous body stabilizes the globe although the eye can remain intact without the vitreous body (see vitrectomy). It also prevents retinal detachment. The connections between the vitreous body and retina are generally loose although there may be firm focal adhesions. These firmer focal attachments cause problems during vitreous detachment because they do not permit the vitreous body to become completely detached. The focal adhesions between the vitreous body and retina produce focal traction forces that act on the retina and can cause retinal tears and detachment.
Etiology Preterm birth and exposure to oxygen disturbs the normal development of the retinal vasculature. Vessel obliteration occurs, followed by proliferative neovascularization. This results in vitreous hemorrhage, retinal detachment, and, in the late scarring stage, retrolenticular fibroplasia as vessels and connective tissue fuse with the detached retina. Findings and symptoms After an initially asymptomatic clinical course, vitreous hemorrhage or retinal detachment will be accompanied by secondary strabismus. Leukocoria can occur in the retrolenticular fibroplasia stage. Table 12.5 shows the classification of the various stages. Stage IV Subtotal retinal detachment Stage V Total retinal detachment 328 12 Retina 12.4 Degenerative Retinal Disorders 12.4.1 Retinal Detachment Definition Retinal detachment refers to the separation of the neurosensory retina (see Fig. 12.2 a) from the underlying retinal pigment epithelium, to which normally it is loosely attached. This can be...
Bleeding from normal retinal vessels as can occur as a result of mechanical vascular damage in acute vitreous detachment or retinal tear. Posterior vitreous detachment with or without retinal tears (38 ). Age-related macular degeneration (2 ). Symptoms Patients often report the sudden occurrence of black opacities that they may describe as swarms of black bugs or black rain. These are distinct from the brighter and less dense floaters seen in synchysis and vitreous detachment. Severe vitreous hemorrhage can significantly reduce visual acuity. Approximately 10 l of blood are sufficient to reduce visual acuity to perception of hand movements in front of the eye. Diagnostic considerations Hemorrhages into the vitreous body itself do not exhibit any characteristic limitations but spread diffusely (the blood cannot form a fluid meniscus in the gelatinous vitreous body) and coagulation occurs quickly (Fig. 11.6). Vitreous hemorrhages require examination with an ophthalmoscope or contact...
Congenital retinal telangiectasia with vascular anomalies that nearly always presents unilaterally and can lead to exudation and eventually to exudative retinal detachment. Pathogenesis Telangiectasia and aneurysms lead to exudation and eventually to retinal detachment. Diagnostic considerations and findings Ophthalmoscopy will reveal telan-giectasia, subretinal whitish exudate with exudative retinal detachment and hemorrhages (Fig. 12.21). changes of telangiectasia (arrow) accompanied by exudative retinal detachment with numerous lipid deposits (arrowheads). changes of telangiectasia (arrow) accompanied by exudative retinal detachment with numerous lipid deposits (arrowheads). Prognosis Left untreated, the disease will eventually cause blindness due to total retinal detachment. Treatment is effective in preventing blindness in about 50 of all patients.
Retinal detachment and retinal dysplasia can occur where primarily posterior embryonic structures persist. The whitish plate of connective tissue will only be visible where anterior changes associated with persistent hyperplastic primary vitreous are also present. The reduction in visual acuity will vary depending on the severity of the retinal changes. Treatment The disorder is not usually treated as neither conservative therapy nor surgery can improve visual acuity. Surgery is indicated only where complications such as progressive collapse of the anterior chamber, secondary increase in intraocular pressure, vitreous hemorrhage, and retinal detachment are present or imminent. The only goal is to save the eye and maintain existing visual acuity. Exudative retinal detachment
Stickler initially described a family with a dom-inantly inherited pattern of high myopia, a high incidence of retinal detachment and abnormal epiphyseal development with premature degenerative changes in various joints. Subsequent analysis of this and other families linked the disorder to COL2A1, the gene for type II col Fig. 12.3. a Type 1 (membranous) vitreous anomaly (arrow) seen in type 1 Stickler syndrome. b Giant retinal tear with radial extensions. c Total retinal detachment due to 360 giant retinal tear Fig. 12.3. a Type 1 (membranous) vitreous anomaly (arrow) seen in type 1 Stickler syndrome. b Giant retinal tear with radial extensions. c Total retinal detachment due to 360 giant retinal tear
The terminating Chapter 15 summarizes in a general way the medicinal chemistry of metal-centered brain diseases and indicates other neurological disorders that may involve metal ions like polyneuropathy, multiple sclerosis, macular degeneration, progressive supranuclear palsy or the restless leg syndrome which are not otherwise covered in the book because knowledge is scarce.
Diagnostic considerations and findings Ophthalmoscopy will reveal intraocular inflammation. Onchocerciasis has been known to be associated with posterior uveitis as well as keratitis and iritis. Histologic examination will demonstrate microfilaria in the retina. Visceral larva migrans, Toxocara canis, or Toxocara cati can cause complications involving endophthalmitis and retinal detachment. Subretinal granulomas and larval inflammation of the retina have been known to occur. The larvae of different species of worms can produce diffuse unilateral subacute neuroretinitis with the typical clinical picture of grayish white intraretinal and subretinal focal lesions. Fly larvae can also invade the subretinal space in ophthalmomyiasis. Retinal detachment, persistent hyperplastic primary vitreous (PHPV), and Coats' disease should also be excluded.
Nontraumatic retinal dialysis (Fig. 12.2) accounts for approximately 10 of all juvenile retinal detachment 17,43 . The male-to-female ratio is 3 2 43 and the majority of patients are hypermetropic or emmetropic 17,33,36 . In 97 of cases, the dialysis affects the inferotemporal quadrant but multiple dialyses occur in one-third and 37 may be bilateral 43 . Detachments associated with dialyses progress slowly, have a low incidence of PVR and characteristically present either as an incidental finding or when the macula becomes detached. They can be managed routinely with buckling techniques Fig. 12.2. Retinal detachment due to nontraumatic retinal dialysis Fig. 12.2. Retinal detachment due to nontraumatic retinal dialysis
Foscarnet (trisodium phosphonoformate) inhibits all human herpes viruses in vitro, including CMV (91), and intravenously administered fos-carnet is currently available for treatment of CMV infections and or retinitis (92,93). The treatment regimen for CMV retinitis consists of an initial induction dose (180 mg kg of body mass per day for 2 weeks) followed by a maintenance dose (120 mg kg day indefinitely) (92,93). Since foscarnet prevents replication of the viral DNA but does not eliminate the virus from the tissues, CMV eventually reactivates and the lesions enlarge so that higher doses of the drug have to be administered. This mode of administering foscarnet may result in serious systemic toxicity (92,93). Intravitreal injection of foscarnet has been reported but also suffers from many of the same complications (endophthalmitis, increased intraocular pressure, retinal detachment, etc.) associated with other modes of ocular injection (94-96). Foscarnet is an ideal candidate for...
Retinal detachment will not be caused by strain (e.g., jogging, lifting weights). Valsalva maneuver, however, may theoretically cause decreased oxygen supply to the eye or lead to necrotic peripheral retinal holes that can lead to retinal detachment in the presence of vitreo-retinal traction or to macular detachment in eyes with optic pit. Valsalva maneuvers should be discouraged2 as should sports with direct or indirect contact (e.g., boxing, judo, parachuting) 4 e.g., presence of an IOFB or retinal detachment. See Chap. 1.8 for further details. If the vitreous hemorrhage is organized and the presence of retinal detachment cannot be ruled out, the surgeon should proceed in a horizontal , layer-peeling fashion to avoid iatrogenic retinal injury Blind cryopexy over a Zone III injury helps prevent retinal detachment To prevent retinal detachment, all posterior retinal breaks should be treated with laser The 3 months is an unscientific, artificial waiting period retinal detachment can...
Retinal detachment in buphthalmic eyes following trabeculotomy has been reported with a frequency of 3 over a mean follow-up period of 9 years 31 . This demonstrates the general susceptibility to retinal tears in the stretched and highly myopic buphthalmic eye rather than a special postoperative risk of any one surgical method. Even after goniotomy, Rice 46 reported several cases of retinal detachment with congenital glaucoma. Long-standing postoperative hypotony may sometimes lead to retinal detachment. In eyes with Peters anomaly, the risk of postoperative complications is especially high. In a retrospective study of 34 eyes in 19 patients who had undergone trabeculectomy, trabeculotomy, goniotomy, Molteno shunt implantation, cyclo-dialysis, or cyclocryotherapy, a graft failure was observed in 26 eyes (76 ), cataract in six eyes (18 ), inoperable retinal detachment with phthisis in 12 eyes (35 ), and phthisis alone in six (18 ). Finally, there was no light perception in 12 eyes (35...
Figure 2-10, OCT tomograms of a neurosensory retinal detachment (A), and a serous detachment of the retinal pigment epithelium (B). Both detachments exhibit an elevation of the retina over an optically clear space corresponding to serous fluid accumulation. In the pigment epithelial detachment, however, the red band defining the posterior sensory retina boundary is also elevated and the detached RPE severely shadows the reflections from the choroid below. Neurosensory detachments may occasionally be confused with severe retinal edema on OCT, since in many cases the fluid accumulation and reduced back-scattering which occurs with edema is preferentially seen in the outer retinal layers. It is important in these cases to identify a smooth and continuous fluid-retina boundary to establish the diagnosis of a sensory retinal detachment.
A brief resume of the functional food potential of these various Mediterranean biomolecules reveals obvious benefits. Tomatoes are rich in many useful nutrients, but of greatest interest in recent years is the almost unique occurrence in tomatoes of the non-provitamin A carotenoid, lycopene. Lycopene is a potent antioxidant that exhibits a strong inverse relationship with cancers of the prostate gland, lung, and stomach (177). It may be of some comfort to those who have a pizza-and-baked-beans-rich diet that processed tomato products are also a good source of lycopene. Tomatoes also contain other carotenoids such as j-carotene, lutein, and zeaxanthein. A diet high in lutein may reduce age-related macular degeneration. In humans, the pigment lutein is concentrated in the macula of the eye (part of the retina where the sharpest vision is rendered). Lutein works by neutralizing free radicals. What is interesting are the conflicting reports of the health benefits of carotenoids
One of the more important signs of an intraocular tumor in children is leukocoria, or a white pupillary reflex (Fig. 8.1). There are many causes of leukocoria in children 33-35 . The more common ones include congenital cataract, retinal detachment due to retinopathy of prematurity, persistent hyperplastic primary vitreous, and congenital retinal telangiectasia with exudation (Coats disease). Retinoblastoma is probably the most serious condition to cause leukocoria in children. Any child with leukoco-ria should be referred promptly to an ophthalmologist for further diagnostic evaluation.
Familial exudative vitreoretinopathy (FEVR) is a bilateral, clinically and genetically heterogeneous condition that is characterized by a failure of peripheral retinal vascularisation. It has a remarkable similarity to retinopathy of prematurity but occurs in full-term infants who are otherwise healthy and have not been treated with oxygen in the neonatal period. The changes may be mild with a peripheral retinal avascular zone, detectable with certainty only by fluorescein angiography, or may slowly progress to cause peripheral neovascularisation and exudative or tractional retinal detachment and vitreous haemorrhage. Rhegmatogenous retinal detachment may also occur. Progression of fundus changes and threat to vision is rare after age 20 years. There is a high incidence of myopia, anisometropia and amblyopia, especially in asymmetric disease. Progressive disease may be treated with peripheral photocoagulation or cryotherapy. Vitreoretinal surgery may be challenging because of adherent...
Intravitreal injection is the most direct approach for delivering drug to the vitreous humor and retina however, this method of administration has been associated with serious side efects, such as endophthalmitis, cataract, hemorrhage, and retinal detachment (59). In addition, multiple injections are usually required, further increasing the risk. Nevertheless, intravitreal injection continues to be the mode of choice for treatment of acute intraocular therapy.
OC r can cross-sectionally image the morphological changes in non-exudative age-related macular degeneration. Soft drusen cause a modulation in the highly reflective band defining the posterior boundary of the neurosensory retina consistent with the ac- OCT images of exudative macular degeneration and choroidal neovascularization may aid in the diagnosis and management of this pervasive disease. Many eves with choroidal neovascularization (CNV)
The cornea is so badly damaged that even the color of the iris may be impossible to determine at the slit lamp (Fig. 2.2.14). The condition of the cornea may be due to the presence of multiple wounds with excessive edema and or blood staining. The lens, if present at all (Fig. 2.12.2), is rarely clear. The vitreous hemorrhage is usually very severe, and the retina is often incarcerated in the wound. Early retinal detachment and the development of PVR are frequent complications. The visual acuity is typically in the NLP to HM range. The treatment should not be based on whether the visual acuity is NLP or greater (see Chap. 1.8).
A 42-year-old man with human immunodeficiency virus (HiV) was referred for decreasing vision, flashes, and floaters in his right eye over the past month. On examination, the visual acuity in this eye was 20 100, Slit-lamp biomicroscopy (A) showed mild macular edema and a yellow subretinal lesion involving the fovea. Several other chorioretinal lesions were identified in the mid-periphery. A clinical diagnosis of progressive outer retinal necrosis was established.
Coronary heart disease, as in non-diabetic patients with heart disease, exercise may theoretically precipitate angina, myocardial infarction, arrhythmias or even sudden death. As with other patients with coronary heart disease, physical activity is contraindicated in the presence of unstable angina. High intensity aerobic exercise and isometric exercise are contraindicated in the patient with proliferative retinopathy because of an increased risk of developing retinal or vitreous hemorrhages and retinal detachment. However, moderate intensity aerobic exercise, such as walking, is an acceptable modality of treatment. Patients with peripheral neuropathy should not engage in exercise which may traumatize the insensitive foot (such as jogging). In addition, properly fitted footwear and checking of the feet for injury after exercise are recommended precautions. Data evaluating the potential problem of exercise-induced hypo-glycemia in type-2 diabetes patients taking oral agents or insulin...
Clinical course and prognosis Visual acuity improves in approximately one-third of all patients, remains unchanged in one-third, and worsens in one-third despite therapy. Complications include preretinal neovascularization, retinal detachment, and rubeosis iridis with angle closure glaucoma.
Some of the difficulty George and Nancy experienced understanding what Dr. Michaels told them about Nancy's condition is that older adults do not learn new information about a familiar disease such as breast cancer and an unfamiliar disease such as acromegaly as readily as younger adults (Brown & Park, in press). For George and Nancy, the familiar disease was Nancy's diabetes-related vision problems. An explanation for this counterintuitive finding may be that it is difficult for older adults to learn information inconsistent with or disconfirming what they already believe. Because Nancy Mullen had macular degeneration for some time and believed she knew the nature of that condition, it may have been particularly difficult for her to learn the new information about how serious that medical condition had become.
X-linked retinoschisis is an uncommon cause of retinal detachment in childhood accounting for 2.5-5 of all paediatric retinal detachments. Most affected children have a characteristic foveal schisis and peripheral retinoschisis is seen in 70 (Fig. 12.5) 12 . Highly elevated, bullous retinoschisis involving the macula may occur in infancy and eventually reattach spontaneously, leaving pigment demarcation lines 11 . Haemorrhage may occur within the schisis cavity or the vitreous. Retinal detachment may occur in up to 16 12 . A full thickness retinal break occurring de novo or a communication between outer and inner leaf defects in the schisis wall may lead to rhegmatogenous retinal detachment. Full thickness breaks may be effectively managed by scleral buckling procedures. Where communication exists between inner and outer leaf breaks, an internal approach may be required. The gene causing X-linked retinoschisis has now been identified and molecular genetic diagnosis in affected males...
H Fluorescein angiography is used to diagnose vascular retinal disorders such as proliferative diabetic retinopathy, venous occlusion, age-related macular degeneration, and inflammatory retinal processes. Where the blood-retina barrier formed by the zonulae occludentes is disturbed, fluorescein will leakfrom the retinal vessels. Disorders of the choroid such as choroiditis or tumors can also be diagnosed by this method in these cases indocyanine is better than fluorescein.
Retinal capillary hemangioma is a reddish pink retinal mass that can occur in the peripheral fundus or adjacent to the optic disc 49 . The tumor often has prominent dilated retinal blood vessels that supply and drain the lesion (Fig. 8.13). Untreated lesions can cause intraretinal exudation and retinal detachment. Fluorescein angiography shows rapid filling of the tumor with dye and intense late staining of the mass. Patients with retinal capillary hemangioma should be evaluated for the von Hippel Lindau syndrome, an autosomal dominant condition characterized by cerebellar hemangioblastoma, pheochromocytoma, hypernephroma, and other visceral tumors and cysts. If the tumor produces macular exudation of retinal detachment, it can be treated with methods of laser photocoagulation, cryotherapy, photodynamic therapy, plaque radiotherapy, or external beam radiotherapy. The gene responsible or this syndrome has been localized to the short arm of chromosome 3.
During the past few years, the cellular mechanisms regulating microvascular morphogenesis have come under close scrutiny. In consideration of the important role that cell-to-cell and cell-to-matrix interactions play in regulating these developmental and disease-related processes, researchers have taken advantage of the technology and approaches founded in genetics and cell biology in their efforts aimed at revealing the molecular mechanisms controlling developmental and pathologic angiogenesis. Although significant inroads have been made with regard to the molecular and cellular details that govern endothelial seeding of early organ primordia or the regulatory role that pericytes play in microvascular physiology, there is currently little knowledge regarding the molecular and cellular events regulating vascular morphogenesis, including the signals regulating the recruitment and local differentiation of pericytes. Presumably, the early inductive events that stimulate vascular...
Retinal neovascularization, the second phase of ROP, is hypoxia-induced 11, 45 and occurs between roughly 32 and 34 weeks PMA. The neovascularization phase of ROP is similar to other proliferative retinopathies such as diabetic retinopathy. The new blood vessel formation occurs at the junction between the nonvascular-ized retina and the vascularized retina. These new vessels are leaky and can cause tractional retinal detachments leading to blindness. If we could allow the normal growth of blood vessels after preterm birth, the second destructive phase would not occur. Alternatively, if we could attenuate the rapid proliferation of abnormal blood vessels in the second phase and allow controlled vascularization of the retina, retinal detachments could be prevented.
The retreatment rate was similar with both treatment regimes, i. e., 35 vs 37 , but near confluent laser progression to retinal detachment was observed only in 3.6 compared to 29.4 in the scatter group. In their series, Fallaha et al. had applied confluent laser spots in all patients, although some variability was in fact present, as photocoagulation was performed by six different ophthalmologists, with some using rather near confluent laser than confluent laser spots. Interestingly, a similar rate of adverse outcomes was observed in both treatment groups, i. e., approximately 30 in zone I and posterior zone II disease, and roughly 16 in anterior zone II disease. The same group had reported earlier that with confluent laser ablation there may be a higher risk for phthisis bulbi 13,30 .
Retinal artery occlusions may result from orbital infections (e.g., angioinvasive aspergillosis or mu-cormycosis) or in acute orbital trauma (e.g., retro-orbital hemorrhage with elevated intraorbital and intraocular pressure). Intraocular inflammation (e.g., exudative retinal detachment, vitreous cells, retinal in
Prerequisites for effective prevention of severe visual handicap in premature children are adequate screening and correct interpretation of the findings. National evidence-based guidelines have been developed from multicenter studies. Because of increasing knowledge with the natural course of the disease and the anatomical and functional outcome with actual treatment regimes, new treatment recommendations have recently evolved that eventually may modify actual guidelines. Because of late sequelae such as ametropia, amblyopia, strabismus, secondary glaucoma, and secondary retinal detachment, life-long ophthalmological examinations are mandatory.
These nerves can be assessed fairly rapidly. The olfactory nerve is not commonly assessed formally unless the patient complains of a recent alteration in sense of smell. The integrity of cranial nerve II should be checked by assessing the visual fields. Bitemporal hemianopia (tunnel vision) suggests a lesion at the optic chiasm, commonly a pituitary tumor. Homonymous hemianopia indicates a post-chiasmal lesion opposite the side of the visual defect. An upper and outer defect suggests a lesion of the opposite cortex in the temporal region, while central visual loss indicates a retrobulbar problem, usually multiple sclerosis. Sudden total visual loss, usually in one eye, may occur in retinal detachment, retinal venous or arterial occlusion, glaucoma, or vitreous hemorrhage.
The choroid lacks autoregulation, that is, it lacks metabolic regulation. We have found that when neonatal dogs are exposed to 100 percent oxygen for 4 days the choroidal vasculature does not constrict. In cat the Po2 in choroid is normally around 70 mmHg, whereas in hyperoxia it increases to 250 mmHg 5 . As a consequence, systemic hypoxia and elevated intraocular pressure lead to decreases in choroidal Po2. The choroidal vasculature supplies oxygen to outer retina while retinal vasculature supplies oxygen to inner retina. From the measurements and modeling of Linsenmeier's lab 5 , the photoreceptors live at the edge. The retina consumes more oxygen per gram of tissue than many other tissues, including brain, barely receiving enough oxygen for maintenance of its normal metabolic function. All of the oxygen for photoreceptor metabolism is supplied by the choroidal vasculature in light conditions and 90 percent of the oxygen consumed by photoreceptors in the dark 5 . As a consequence,...
Being able to preoperatively determine whether the blood is under or in front of the RPE would be very helpful to the ophthalmologist. If the hemorrhage is sub-RPE, evacuation is probably not necessary if it is under the neuroretina, removal is indicated. The OCT may be helpful in some cases, but the exact location of the blood is more difficult to determine in the context of large traumatic hemorrhage than in a small one caused by age-related macular degeneration. If the retina is detached over a large area because of the blood, this must be considered a hemorrhagic retinal detachment (see below).
A retinal break (see above) is present, which may have been caused by the injury or by the surgeon (see Chap. 2.7). The time from injury to retinal detachment development varies from hours to years, depending on the type, location, and size of the break as well as whether vitreous hemorrhage is also present. Regarding treatment, even in the presence of a retinal break, the most important factor in the development of a retinal detachment is traction. Unless the vitreoretinal traction is addressed, therapy is likely to fail. Vitrectomy for retinal detachment should always be complete if vitreous (i.e., traction) is left behind, there is now more room for intraocular fluid movement (currents) and for vitreous movement (dynamic traction). The fluid can then easily enter through the retinal break, which is held open by the residual traction force.
Several authors do not recommend trabe-culectomy as a primary procedure in congenital glaucoma, as they have attained only moderate success rates associated with severe intra- and postoperative complications such as vitreous loss, endophthalmitis, retinal detachment, scle-ral collapse, subluxation of the lens, and uveitis as possible risks. Shallow anterior chamber and
Seeding of the retinal surface in the macula by proliferative cells42 leads to wrinkling of the ILM. Collagen production by these cells then results in focal traction with partial- or full-thickness folds, and (cystoid) macular edema. Traumatic EMP usually occurs after contusion, and it is more common after vitreous hemorrhage, retinal detachment, or incomplete vitrec-tomy (i.e., if PVD was not achieved). Inflammation is another contributing factor. The risk of EMP is lower in patients over 50 years of age. The condition may take years to develop.
Medulloepithelioma of the ciliary body. a Mass is visible peripheral to the lens on scleral depression. b Following enucleation in another case, the mass is seen in the ciliary body with total retinal detachment occurs in association with ipsilateral facial nevus flammeus or variations of the Sturge-Weber syndrome. Ipsilateral congenital glaucoma is a frequent association. Secondary retinal detachment frequently occurs. Affected children often develop amblyopia in the involved eye.
A single D YAG laser pulse was applied that day to open the posterior hyaloid and facilitate clearing of the hemorrhage. The patient returned for a follow-up examination one month later with no improvement in visual acuity and continued floaters in his vision. Slit-lamp biomicroscopy (D) displayed old, gray subhyaloid hemorrhage in the inferior macula and trace epiretinal membrane centrally,
Eighty percent of patients with type 1 Stickler syndrome are myopic. The myopia is congenital and usually of high degree. The 20 who are emmetropic, or even hypermetropic, do in fact have an increased axial length which is refrac-tively compensated by cornea plana. The term congenital megalophthalmos or cryptomy-opia has been used to encompass both states. Lens opacities, often wedge-shaped cortical opacities peculiar to Stickler syndrome, may be seen. Pigmented radial paravascular lattice is a characteristic feature but the fundus appearances can be deceptively normal. The vitreous phenotype, however, is pathognomonic. A vestigial amount of gel behind the lens is bordered by a distinct folded membrane, termed the membranous or type 1 vitreous anomaly (Fig. 12.3A) 39 . This membrane is congenital and should not be confused with the posterior hyaloid membrane, which differs in its position, its movement and the degree of surface crinkling. The lifetime risk of retinal detachment,...
Once the diagnosis of Stickler syndrome has been established, a coordinated multidiscipli-nary approach may be needed to manage myopia and retinal detachment, combined conductive and sensorineural deafness, cleft palate and joint problems.Although intelligence is normal, patients of school age may face considerable educational difficulties because of combined visual, hearing and speech impairment. Prophylactic retinopexy should be offered to reduce the risk of retinal detachment 38 and because of the lifetime risk of detachment, all patients require long-term follow-up. Parents and other siblings should also be examined so that affected members of the family are identified, offered prophylaxis and genetic advice.
Kniest syndrome is an autosomal dominant disorder that shares many similarities with Stickler syndrome. Mutations are found in the same gene as for Type 1 Stickler syndrome (COL2A1), but result in dominant-negative effects rather than haploinsufficiency with consequently more severe arthropathy. It typically presents at birth with shortened trunk and limbs, congenital megalophthalmos and flattened nasal bridge. The joints are often large at birth and the fingers long and knobbly. Motor milestones can be delayed because of joint deformities and muscle atrophy may result from disuse. Both conductive and sensorineural hearing loss may be present as with the Stickler syndromes. The intellect is normal and myopia, retinal detachment and giant retinal tear are the major ophthalmic complications.
Tachment, vitreous haemorrhage and bilateral retrolental masses. The retinal detachments are usually of early onset and have been diagnosed in utero. Most cases progress to an extensive vitreoretinal mass and bilateral blindness. The gene for Norrie disease has been identified on Xpii.4. Norrin,the product of the Norrie disease gene, is a secreted protein important for normal retinal vascularization and regression of hyaloid vessels and also regulates the interaction of the cochlea with its vasculature.
The most common eye finding in patients with congenital toxoplasmosis is chori-oretinal scars, which were present in 79 of the patients. The classic location is the macula (Fig. 13.1) however, the most common location was in the periphery (64 ). If you consider the total surface area of the retina, there was a predisposition for the macular area (58 ). In addition, active retinitis was seen in 11 and retinal detachment in 10 49 . Retinal detachment Numerator represents number of patients with finding denominator is the total number, unless otherwise specified. Patients with bilateral retinal detachment in whom the location of scars was not possible were excluded from the denominator. Number in parentheses is total number of patients with findings Numerator represents number of patients with finding denominator is the total number, unless otherwise specified. Patients with bilateral retinal detachment in whom the location of scars was not possible were excluded from the...
The first moment to make the decision for enucleation is immediately or within a day or two following the injury. The globe is ruptured, massive intraocular bleeding is present and there is evidence that repair will not restore visual function. To lower the risk of sympathetic oph-thalmitis, the eye will be enucleated at an early phase. A wide range of foreign bodies can be found in these eyes. The inflammation is usually mild or absent. The most important mission for the pathologist is to confirm the irreparable damage. The lens is often absent or prolapsed through the corneal wound, a retinal tear shows the side of penetration, the vitreous is haemorrhagic, papilloedema is present and the retina can show exudative detachment (Fig. 10.18).
Nal or choroidal vessels, like inflammatory or neoplastic disorders. In rhegmatogenous detachment, passage of fluid from the vitreous cavity to the subretinal space is present. It occurs through a hole in the retina, caused by degeneration or a minor trauma. Enucleated eyes with retinal detachment usually show many signs of previous surgical intervention. The most important information for the surgeons is whether the retina survived the separation and reattachment or not and if a reason for surgical failure can be found.
A proliferative vitreoretinopathy model was generated in albino rabbits by combing some factors that probably cause the disease. The eyes were injected with platelet-rich plasma, and in addition they underwent cryother-apy or vitrectomy or both procedures. Total retinal detachment and giant holes were obtained more often in experimental eyes than in controls. Microscopic investigation showed intravitreal or preretinal proliferation of fibroblast-like cells (54). Another combination model involves retinotomy with removal of vitreous, cryotherapy, and platelet-rich plasm injection. This is an efficient model of PVR retinal detachments were produced in 100 of rabbit eyes (55).
Free radical formation has been implicated in a number of conditions, including cataracts, dry eye, and macular degeneration. The retina seems to be more susceptible to this damage than other tissues. Some studies suggest that the intake of antioxidant vitamins may help to delay the formation or slow the progress of these conditions. These relationships were extensively studied in a major multicenter clinical trial known as the Age-Related Eye Disease Study (AREDS). It was sponsored by the National Eye Institute, one of the federal government's National Institutes of Health. The AREDS set out to determine the natural history and risk factors of age-related macular degeneration (AMD) and cataract and to evaluate the effect of high doses of antioxi-dants and zinc on the progression of AMD and cataract. Results from the AREDS showed that high levels of antioxidants and zinc significantly reduce the risk of advanced age-related macular degeneration (AMD) and its associated vision loss....
Clinical trials have also been conducted to study the effect of the antioxidants on the progression of age-related macular degeneration (AMD) and vision loss. The Age-Related Eye Disease Study Research Group recommends supplements of zinc and antioxidants for adults at risk for developing AMD. However, the group
Weakness, fatigue, decreased thyroid function, and blurred vision. Too much zinc can lead to anemia. Smokers should avoid the use of beta-carotene. However, antioxidant therapy offers hope to patients with conditions (such as macular degeneration) that have very few preventative or therapeutic measures. Studies suggest that vitamin therapy is useful in slowing the development of cataracts, macular degeneration, and dry eye.
Q Fig. 2.9.2 Vitreoretinal configuration and the risk of retinal detachment. a The vitreous is completely attached. Even if there are areas with abnormally strong vitreoretinal adhesion, there is no risk of retinal break and subsequent detachment development formation since the vitreous gel is stable it is unable to shift position1 even with major and abrupt eye or head movement. b The vitreous is completely detached (true PVD). Although there is now room for the vitreous to shift with eye or head movement, it represents no risk for retinal break development lacking vitreoretinal adhesion.2 c Partial PVD, the only condition carrying a significant risk of retinal break formation. With eye or head movement, vitreous movement follows, exerting traction at the point of adhesion (arrow). In principle, there are two therapeutic approaches to surround the area of adhesion with (laser) scars to overcome the traction force or to perform vitrectomy to eliminate the traction.3 d Vitreoschisis....
Optic disk changes in orbital disease optociliary shunts (arrows) in (A) and (D) and optic nerve atrophy with retinal infarction (B) in optic nerve meningioma (C). (S, sclera RD, retinal detachment CH, choroid.) FIGURE 6.4. Optic disk changes in orbital disease optociliary shunts (arrows) in (A) and (D) and optic nerve atrophy with retinal infarction (B) in optic nerve meningioma (C). (S, sclera RD, retinal detachment CH, choroid.)
Retinal detachment due to blunt trauma is almost always rhegmatogenous and most commonly caused by a disinsertion at the ora serra- ta (dialysis) (Fig. 12.1A), usually occurring in older children. Bilateral retinal detachment due to traumatic dialysis has been described as a rare presenting feature of nonaccidental injury 14 . Sudden antero-posterior compression associated with a corresponding coronal expansion typically causes avulsion of the pars plana epithelium, which can be seen as a characteristic irregular ribbon within the vitreous cavity (Fig. 12.1 B). The superior quadrant is more often involved in contrast to the usual lower temporal quadrant involvement in nontraumatic dialysis 17, 33 . The disinsertion may involve more than 90 of the circumference and superficially resemble a giant retinal tear. However, the vitreous gel remains attached to the posterior flap so that there is no independent mobility characteristic of a giant retinal tear. Further distinguishing features...
If fungus is suspected (usually begins approximately 3 months after surgery Candida is the most commonly encountered organism), consider amphotericin B 5-10 lg at time of vitrectomy. Amphotericin B has been reported to have retinal toxicity in animal studies. Therefore, if air-fluid exchange is performed for concurrent retinal detachment, the dose of amphotericin should be reduced by a third to one half.
Childhood leukemias can occasionally exhibit tumor infiltration in the retina, optic disc, and uveal tract. It is characterized by a swollen optic disc and thickening of the retina and choroid, often with hemorrhage and secondary retinal detachment. Intraocular leukemic infiltrates are generally responsive to irradiation and chemotherapy, but they generally portend a poor systemic prognosis.
Age-Related Macular Degeneration The choroidal vasculature is at the heart of age-related macular degeneration. There are many forms of AMD, but the two major types are exudative or wet and nonexudative or dry AMD. In nonexudative AMD eyes, there are macular drusen and sharply defined focal areas of RPE atrophy, which are associated with varying degrees of loss of the choriocapillaris. Drusen is a form of deposit on Bruch's membrane, which is believed to be incompletely digested material from the RPE that cannot traverse Bruch's membrane for removal by the choriocapillaris. One hypothesis states that the deposit of the debris on Bruch's membrane is a result of choriocapillaris insufficiency. Alternatively, debris may accumulate on Bruch's membrane and choriocapillaris atrophy results since it is not needed any more. Drusen appear as refractile structures when viewing the ocular fundus, and the ophthalmologist refers to them as hard drusen when they are sharply demarcated and highly...
Eyes with ocular colobomas are at a significantly increased risk of detachment and account for approximately 0.5 of paediatric retinal detachments 25 . Giant retinal tears are seen in association with lens colobomas 19 and rheg-matogenous detachment may develop in eyes with choroidal coloboma, when small retinal breaks may be found in the hypoplastic retina
The success of the RPE and IPE transplants in animal models has prompted several pilot studies in AMD and RP patients. A surgical team of ophthalmologists at the Johns Hopkins Medical Institute recently attempted a Phase 1 clinical trial aimed at restoring vision with fetal human neural retinal transplants (36). Patients selected for the transplant had advanced cases of retinitis pigmentosa and neovascular age-related macular degeneration. The objective of the pilot study was to determine the safety of the surgical procedure, the patient's tolerance for the grafted tissue, and the visual outcome. The procedure involved surgically grafting small healthy fragments of fetal human neural retina sheets into the subretinal space of eight patients with RP and one with AMD. Recipients of the allografts were not given postoperative systemic immunosuppressive drugs. Several criteria were used to assess visual 2. Surgical and mechanical considerations During surgical...
Figure 4 Patients with retinitis pigmentosa and macular degeneration become blind when the rods and cones degenerate and no longer convert incoming light into electrical impulses. While other parts of the retina remain healthy, the brain stops receiving impulses required to provide vision. The retinal prosthesis is designed to bypass the lost rods and cones and directly stimulate the surviving ganglion cells that are connected to the brain through the optic nerve. Specially designed glasses capture the visual scene and transmit this information into the eye through an invisible laser beam. The laser strikes a solar panel (photodiode array) located within the pupil to generate internal power. An ultra-thin electrode array carries the power to the retinal surface, where it stimulates the ganglion cells. (Courtesy of Dr. Joseph F. Rizzo, Harvard University, USA.) Figure 4 Patients with retinitis pigmentosa and macular degeneration become blind when the rods and cones degenerate and no...
Marfan syndrome is a dominantly inherited disorder of fibrillin production with a prevalence of approximately one in 20,000 and features skeletal, cardiovascular and ocular abnormalities. The fibrillins are high-molecular-weight extracellular glycoproteins, and mutations in the fibrillin gene on chromosome 15 (FBN1) cause Marfan syndrome and dominant ectopia lentis. Fibrillin has been found to be widespread in lens capsule, zonules, iris, ciliary body, choroid and sclera 45 . In a study to correlate genotype with phenotype 35 , it was noted that, whereas large-joint hyper-mobility is more common in those with premature termination codon mutations, lens dislocation and retinal detachment are less common. The association of rhegmatogenous retinal detachment with Marfan syndrome is well recognized and approximately 75 occur below 20 years of age 24 . Retinal detachment due to giant retinal tear formation is reported to occur in 11 37 . Although there is a significant association with...
The miotic nature of these drugs must be also be taken into account. In patients with cataracts, miosis can markedly decrease vision. Historically, miotics have been said to increase the risk of retinal detachment and cataracts, though this has not been conclusively established. Systemic adverse effects are similar with all cholinergic drugs and include sweating, salivation, stomach and digestive upset, and decreased heart rate. Miotic therapy has proven efficacy and is an inexpensive option. However, with the possible exception of the gel and sustained-release systems (to be discussed shortly), miotic therapy is usually associated with poor compliance a result of patient discomfort and the frequent administration required (often 4 times a day).
Direct Cholinergic Local Brow ache, breakdown of blood aqueous barrier, angle closure (increases pupillary block and causes the lens iris diaphragm to move anteriorly), decreased night vision, variable myopia, retinal tear detachment, and possibly anterior subcapsular cataracts. Systemic Rare. Indirect Cholinergic Local Retinal detachment, cataract, myopia, intense miosis, angle closure, increase bleeding post surgery, punctal stenosis, increase formation of posterior synechiae in chronic uveitis. Systemic Diarrhea, abdominal cramps, enuresis, increases effect of succinylcholine.
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