Tear breakup time TBUT This test evaluates the stability of the tear film

Test Fluorescein dye (10 l of a 0.125 fluorescein solution) is added to the precorneal tear film. The examiner observes the eye under 10-20 power magnification with slit lamp and cobalt blue filter and notes when the first signs of drying occur (i) without the patient closing the eye and (ii) with the patient keeping the eye open as he or she would normally. Normal TBUT of at least 10 seconds is normal. Rose bengal test Rose bengal dyes dead epithelial cells and mucin. This test has proven...

Differential diagnosis Two disorders are important in this context

Patients with ocular hypertension have significantly increased intraocular pressure over a period of years without signs of glauco-matous optic nerve damage or visual field defects. Some patients in this group will continue to have elevated intraocular pressure but will not develop glaucomatous lesions the others will develop primary open angle glaucoma. The probability that a patient will develop definitive glaucoma increases the higher the intraocular pressure, the...

Corneal Infections Predisposing Factors Pathogens and Pathogenesis

When certain pathogens succeed in breaching the corneal defenses through superficial injuries or minor epithelial defects, the bradytrophic corneal tissue will respond to the specific pathogen with characteristic keratitis. Predisposing factors that promote inflammation are Infection of the ocular appendages (for example, dacryostenosis accompanied by bacterial infestation of the lacrimal sac). Changes in the corneal epithelial barrier (bullous keratopathy or dry eyes). Topical and systemic...

Dye Examination of the Cornea

Defects in the surface of the cornea can be visualized with fluorescein or rose bengal solution (in either case, administer one drop of 1 solution). Since these dyes are not usually absorbed by the epithelium, they may be used to visualize loss of epithelium over a wide area (such as corneal erosion) and extremely fine defects (as in superficial punctate keratitis). Illumination with a cobalt blue filter enhances the fluorescent effect. Slit lamp examination of the cornea. Slit lamp examination...

Examination Methods

Visual field testing (perimetry) This is the most important test for visual pathway lesions. Because it permits one to diagnose the location of the lesion, it is also of interest from a neurologic standpoint. The visual field is defined as the field of perception of the eye at rest with the gaze directed straight ahead. It includes all points (objects and surfaces) in space that are simultaneously visible when the eye focuses on one point. The examination is performed on one eye at a time. The...

Retinal Vascular Proliferation

Retinal vascular proliferation can occur in retinal ischemia in disorders such as diabetic retinopathy, retinopathy in preterm infants, central or branch retinal vein occlusion, and sickle-cell retinopathy. Growth of this retinal neovascularization into the vitreous chamber usually occurs only where vitreous detachment is absent or partial because these proliferations require a substrate to grow on. Preretinal proliferations often lead to vitreous hemorrhage. Fibrotic changes produce traction...

Retinal Vein Occlusion Definition

Vein occlusion occurs as a result of circulatory dysfunction in the central vein or one of its branches. Epidemiology Retinal vein occlusion is the second most frequent vascular retinal disorder after diabetic retinopathy. The most frequent underlying systemic disorders are arterial hypertension and diabetes mellitus the most frequent underlying ocular disorder is glaucoma. Frequent underlying systemic disorders of retinal vein occlusion include arterial hypertension and diabetes mellitus....

Degenerative Retinal Disorders 337 1245 Age Related Macular Degeneration Definition

Drusen Macular Degeneration Definition

Progressive degeneration of the macula in elderly patients. Epidemiology Age-related macular degeneration is the most frequent cause of blindness beyond the age of 65 years. Pathogenesis Drusen develop in the retinal pigment epithelium due to accumulation of metabolic products. Symptoms Patients notice a gradual loss of visual acuity. Where macular edema is present, patients complain of image distortion (metamorphopsia), macropsia, or micropsia. Findings and diagnostic considerations...

Examination of the Lens

The ophthalmologist uses a slit lamp to examine the lens. The eye can also be examined with a focused light if necessary. Direct illumination will produce a red reflection of the fundus if the lens is clear and gray shadows if lens opacities are present. The examiner then illuminates the eye laterally with a focused light held as close to the eye as possible and inspects the eye through a +14 diopter loupe (see Fig. 1.10). This examination permits better evaluation of changes in the...

Conjunctival Laceration

Epidemiology Due to its exposed position, thinness, and mobility, the conjunctiva is susceptible to lacerations, which are usually associated with sub-conjunctival hemorrhage. Etiology Conjunctival lacerations most commonly occur as a result of penetrating wounds (such as from bending over a spiked-leaf palm tree or from a branch that snaps back on to the eye). Symptoms and diagnostic considerations The patient experiences a foreign body sensation. Usually this will be rather mild. Examination...

Deformities

Paralysis of the levator palpebrae muscle with resulting drooping of one or both upper eyelids (from the Greek ptosis, a falling). The following forms are differentiated according to their origin (see also Etiology) Congenital ptosis (Fig. 2.4). Epidemiology. On the whole ptosis is a rare disorder. Etiology Ptosis may be congenital or acquired. Fig. 2.4 Congenital ptosis of the levator palpebrae muscle causes the upper eyelid to droop usually the deformity is unilateral. Amblyopia will result...

Vertical Deviations Hypertropia and Hypotropia

Like A pattern and V pattern deviations, vertical deviations are also typically caused by anomalies in the pattern of nerve supply to the rectus and oblique muscles. Vertical deviations are usually associated with esotropia or exotropia, for example in infantile strabismus. Primary oblique muscle dysfunction and dissociated vertical deviation are common in this setting. Primary oblique muscle dysfunction is characterized by upward vertical deviation of the adducting eye during horizontal eye...

Diagnosis of Infantile Strabismic Amblyopia Preferential Looking Test

Strabismus occurs most frequently in the newborn and infants and must also be treated at this age to minimize the risk of visual impairment. As the examiner cannot rely on patient cooperation at this age, examination techniques requiring minimal patient cooperation are necessary. The preferential looking test can be used for early evaluation of vision beginning at the age of four to six months. This test cannot reliably detect strabismic amblyopia. However, Teller acuity cards (Fig. 17.7) are...

Intermittent Exophthalmos

This rare clinical picture characterized by intermittent unilateral or bilateral exophthalmos is caused by varicose dilation of the orbital veins, such as can occur following trauma or in Osler's disease (polycythemia vera). Patients report protrusion of the eyeball of varying severity. Exophthalmos is usually unilateral and is especially prone to occur when the resistance to venous drainage is increased, as can occur when the patient presses, bends over, screams, or compresses the vessels of...

Subconjunctival Hemorrhage

Extensive bleeding under the conjunctiva (Fig. 4.4) frequently occurs with conjunctival injuries (for obtaining a history in trauma cases, see Chapter 18, conjunctival laceration). Subconjunctival hemorrhaging will also often occur spontaneously in elderly patients (as a result of compromised vascular structures in arteriosclerosis), or it may occur after coughing, sneezing, pressing, bending over, or lifting heavy objects. Although these findings are often very unsettling for the patient, they...

Impalement Injuries of the Orbit

Etiology Impalement injuries occur most frequently in situations such as these Intraocular foreign body sustained while working with a hammer and chisel. Fig. 18.8 a The iron splinter is lodged in the lens the cornea has closed spontaneously immediately after the injury (white arrow). A sphincter injury is also present (black arrow). b The iron splinter entered through the sclera and is now lodged in the retina on the posterior wall of the globe, which it has coagulated (white discoloration of...

Color Vision

Color vision defects may be congenital (especially in men as they are inherited and X-linked recessive) or acquired, for example in macular disorders such as Stargardt's disease. Qualitative red-green vision defects are evaluated with pseudoisochromatic plates such as the Ishihara or Stilling-Velhagen plates. They contain numerals or letters composed of small color dots surrounded by confusion colors (Fig. 12.10) that patients with color vision defects cannot read. The Farnsworth-Munsell tests...

Peripheral Retinal Degenerations Definition

Peripheral retinal degenerations refer to degenerative changes that lie parallel to the ora serrata in the peripheral portions of the retina. These include two basic types Harmless retinal changes such as pars plana cysts of the posterior ciliary body or peripheral chorioretinal atrophy (cobblestone degeneration). Precursors of retinal detachment such as local thinning of the retina referred to as snail track or lattice degeneration. Epidemiology The prevalence of the lesions is 6-10 ....

Esotropia

Epidemiology Esotropia is one of the most commonly encountered forms of strabismus. Symptoms and diagnostic considerations There are three forms of esotropia 1. Congenital or infantile esotropia Strabismus is present at birth or develops within the first six months of life. This form is characterized by a large alternating angle of deviation (Fig. 17.4a and b), lack of binocular vision, latent nystagmus (involuntary oscillation of the eyeballs that only occurs or becomes more pronounced when...

Visual Acuity

Visual acuity, the sharpness of near and distance vision, is tested separately for each eye. One eye is covered with a piece of paper or the palm of the hand placed lightly over the eye. The fingers should not be used to cover the eye because the patient will be able to see between them (Fig. 1.4). The general practitioner or student can perform an approximate test of visual acuity. The patient is first asked to identify certain visual symbols referred to as optotypes (see Fig. 1.2) at a...

The Ophthalmic Examination 112 Confrontation Field Testing

Confrontation testing provides gross screening of the field of vision where perimetry tests are not available (see p.391). The patient faces the examiner at a standard distance of 1 m with his or her eyes at the same level as the examiner's (Fig. 1.14). Both focus on the other's opposite eye (i.e., the patient's left eye focuses on the examiner's right eye) while covering their contralateral eye with the palm of the hand. The examiner moves an object such as a pen, cotton swab, or finger from...

Viral Conjunctivitis

Epidemiology The incidence of epidemic keratoconjunctivitis is high in general, and it is by far the most frequently encountered viral conjunctivitis (see Table 4.2). Fig. 4.14 Prominent tarsal follicles and papillae on the upper and lower eyelids. Etiology This highly contagious conjunctivitis is usually caused by type 18 or 19 adenovirus and is spread by direct contact (see also prophylaxis Figs. 4.15 a and b). The incubation period is eight to ten days. Symptoms Onset is usually unilateral....

Examination of the Retinal Nerve Fiber Layer

The retinal nerve fibers have a characteristic arrangement, which explains the typical visual field defects that occur in primary open angle glaucoma. In addition to the early progressive optic nerve and visual field defects, arc-shaped defects also occur in the nerve fiber layer. These defects may be observed in light with red components (Fig. 10.13). Examination of the retinal nerve fiber layer. - Fig. 10.13 The arc-shaped nerve fiber defect (between the arrows) is a sign of an early...

Episcleritis Definition

Circumscribed, usually segmental, and generally nodular inflammation of the episclera (connective tissue between sclera and conjunctiva). Epidemiology Episcleritis is the most common form of scleral inflammation. Lang, Ophthalmology 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. Fig. 6.2 Typical hyperemia and inflammation of the radial Fig. 6.2 Typical hyperemia and inflammation of the radial Etiology Episcleritis is rarely attributable to one of the systemic...

Correction of Refractive Errors 1651 Eyeglass Lenses

Spherical lenses refract light equally along every axis. Toric lenses (known as cylindrical lenses) refract light only along one axis. Spherical and toric lenses can be combined where indicated. The refractive power of the lenses is measured manually or automatically with an optical interferometer. The measured refraction is specified as spherocylindrical combination. By convention, the specified axis of the cylindrical lens is perpendicular to its axis of refraction (Fig. 16.15c and d). The...

Binocular Alignment

Binocular alignment is evaluated with a cover test. The examiner holds a point light source beneath his or her own eyes and observes the light reflections in the patient's corneas in the near field (40 cm) and at a distance (5 m). The reflections are normally in the center of each pupil. If the corneal reflection is not in the center of the pupil in one eye, then a tropia is present in that eye. Then the examiner covers one eye with a hand or an occluder (Fig. 1.6) and tests whether the...

Injuries to the Lacrimal System

Etiology Lacerations and tears in the medial canthus (such as dog bites or glass splinters) can divide the lacrimal duct. Obliteration of the punctum and lacrimal canaliculus is usually the result of a burn or chemical injury. Injury to the lacrimal sac or lacrimal gland usually occurs in conjunction with severe craniofacial trauma (such as a kick from a horse or a traffic accident). Dacryocystitis is a common sequela, which often can only be treated by surgery (dacryocystorhinostomy). Clinical...

Epikeratophakic Keratoplasty Epikeratophakia

Principle Severe myopia and hyperopia are corrected by suturing specially prepared hyperopic or myopic partial-thickness corneal grafts on to the recipient's cornea. This involves special trephination and preparation of the recipient's cornea. The donor graft is then fitted into the prepared cornea and sutured in place. The donor corneal button is prepared as a frozen section and shaped to the required refractive power these implants can be ordered from eye banks. Indications Any severity of...

Corneal Erosion

Etiology This disorder follows initial trauma to the surface cornea, such as the fingernail of a child carried in the parent's arms, a spiked-leaf palm tree, or a branch that snaps back on to the eye. Properly treated, this epithelial defect usually heals within a short time, i.e., 24 to 48 hours depending on the size of the defect. However, occasionally the epithelial cells do not properly adhere to Bowman's layer so that the epithelium repeatedly ruptures at the site of the initial injury....

Cavernous Sinus Thrombosis Definition

Rare but severe acute clinical syndrome in which the spaces of the cavernous sinus posterior to the orbital cavity become thrombosed, usually in the presence of adjacent purulent processes. This is not an orbital disorder in the strict sense. Etiology These are purulent inflammations that have spread from the middle ear, petrous bone, orbital cavities, or from the facial skin via the angular vein. Symptoms Patients present with an acute clinical picture with headache, stupor, fever, and...

Differential diagnosis

Gonococcal conjunctivitis and inclusion conjunctivitis (see Fig.4.3). Silver catarrh (harmless conjunctivitis with slimy mucosal secretion following Crede's method of prophylaxis with silver nitrate). Treatment During the first few weeks, the infant should be monitored for spontaneous opening of the stenosis. During this period, antibiotic and anti-inflammatory eyedrops and nose drops (such as erythromycin and xylo-metazoline 0.5 for infants) are administered. If symptoms persist, irrigation...

Curvature of Field

This means that the magnification of the image changes as one approaches the periphery. The result is a sharp image with peripheral curvature. Convex or plus lenses produce pincushion distortion concave or minus lenses produce barrel distortion (Fig. 16.23). Fig. 16.22 a Lenses may be regarded as composed of many prisms, which explains many of the optical phenomena of lenses such as dispersion. b A prism refracts a light ray toward its base twice (solid line). However, it appears to the...

Louse Infestation of the Eyelids

This refers to infestation of the margin of the eyelid with crab lice as a result of poor hygienic conditions. The small oval nits frequently hang from the eyelashes (Fig. 2.16), causing inflammation of the margin of the eyelid with severe itching. Mechanical removal with forceps is a time consuming but effective treatment. Application of a 2 mercury precipitate ointment over an extended period of time is also effective. Louse infestation of the eyelids. - Fig. 2.16 Under poor hygienic...

Cataract Definition

A cataract is present when the transparency of the lens is reduced to the point that the patient's vision is impaired. The term cataract comes from the Greek word katarraktes (downrushing waterfall) because earlier it was thought that the cataract was a congealed fluid from the brain that had flowed in front of the lens. General symptoms Development of the cataract and its symptoms is generally an occult process. Patients experience the various symptoms such as seeing only shades of gray,...

Determining Corneal Sensitivity

Non-ophthalmologists may perform a simple preliminary examination of corneal sensitivity with a distended cotton swab (see Fig. 1.11, p. 11). This examination also helps the ophthalmologist confirm the diagnosis in the presence of a suspected viral infection of the cornea or trigeminal or facial neuropathy as these disorders are associated with reduced corneal sensitivity. Ophthalmologists may use an automatic Drager esthesiometer for precise testing of corneal sensitivity and for follow-up...

Other examination methods

CT or MRI to diagnose causes. 14.2 Examination Methods 393 Goldmann hemispheric perimeter and visual field findings. - Humphrey field analyzer and visual field findings. - Fig. 14.3 a In static perimetry, the patient also focuses on a black dot in the middle of the hemisphere. As soon as the patient perceives a light marker, he or she presses a button that triggers an acoustic signal. The result is shown on the monitor on Fig. 14.3 a In static perimetry, the patient also focuses on a black dot...

Arcus Senilis

This is a grayish-white ring-shaped fatty deposit near the limbus that can occur at any age but usually appears in advanced age (Fig. 5.14). Arcus senilis is usually bilateral and is a frequently encountered phenomenon. It occurs as a result of lipid deposits from the vessels of the limbus along the entire periphery of the cornea, which normally increase with advanced age. A lipid-free clear zone along the limbus will be discernible. Patients younger than 50 years who develop arcus senilis...

Seborrheic Blepharitis Definition

This relatively frequent disorder is characterized by scaly inflammation of the margins of the eyelids. Usually both eyes are affected. Etiology There are often several contributing causes. The constitution of the skin, seborrhea, refractive anomalies, hypersecretion of the eyelid glands, and external stimuli such as dust, smoke, and dry air in air-conditioned rooms often contribute to persistent chronic inflammation. Symptoms and diagnostic considerations The margins of the eyelids usually...

Measuring the Diameter of the Cornea

An abnormally large or small cornea (megalocornea or microcornea) will be apparent from simple visual inspection. A suspected size anomaly can be easily verified by measuring the cornea with a ruler. Corneal diameter may be determined more accurately with calipers (usually done under general anesthesia, see Fig. 10.21) or with the Wessely keratometer. This is a type of tube with a condensing lens with millimeter graduations at one end. The examiner places this end on the patient's eye and looks...

Tilted Disk

An optic nerve that exits the eye superiorly (Fig. 13.5) is referred to as a tilted disk. The superior circumference of the margin of the optic disk will be obscured in a manner similar to oblique entry of the optic nerve. A number of other changes may also be observed, including an inferior crescent, situs inversus of the retinal vessels, ectasia of the fundus, myopia, and visual field defects. These findings may occur in various combinations and are referred to collectively as tilted-disk...

Scleritis Definition

Diffuse or localized inflammation of the sclera. Scleritis is classified according to location Anterior (inflammation anterior to the equator of the globe). Posterior (inflammation posterior to the equator of the globe). Anterior scleritis is further classified according to its nature Non-necrotizing anterior scleritis (nodular or diffuse). Necrotizing anterior scleritis (with or without inflammation). Epidemiology Scleritis is far less frequent than episcleritis. Patients are generally older,...

Exotropia

Exotropia (divergent strabismus) is less common than esotropia. As it is usually acquired, the disorder is encountered more often in adults than in children, who more frequently exhibit esotropia. Exotropia less frequently leads to amblyopia because the strabismus is often alternating. Occasionally what is known as panorama vision will occur, in which case the patient has an expanded binocular field of vision. The following forms are distinguished Intermittent exotropia. This is the most common...

The Intraorbital and Intracranial Portion of the Optic Nerve

The intraorbital portion begins after the nerve passes through a sieve-like plate of scleral connective tissue, the lamina cribrosa. Inside the orbit, the optic nerve describes an S-shaped course that allows extreme eye movements. After the optic nerve passes through the optic canal, the short intracranial portion begins and extends as far as the optic chiasm. Like the brain, the intraorbital and intracranial portions of the optic nerve are surrounded by sheaths of dura mater, pia, and...

Diagnosis of Unilateral and Alternating Strabismus Unilateral Cover Test

Teller Acuity Card

A unilateral cover test can distinguish between manifest unilateral strabismus and alternating strabismus. The patient is requested to fixate on a point. The examiner than covers one eye and observes the uncovered eye (Fig. 17.8a -c). In unilateral strabismus, the same eye always deviates. When the deviating eye is covered, the uncovered eye (the leading, nondeviating eye) remains focused on the point of fixation. When the nondeviating eye is covered, the uncovered deviating eye has to take the...

Basic Knowledge

Anterior Visual Pathway

The anatomy of the visual pathway may be divided into six separate parts (Fig. 14.1) 1. Optic nerve This includes all of the optic nerve fiber bundles of the eye. 2. Optic chiasm This is where the characteristic crossover of the nerve fibers of both optic nerves occurs. The central and peripheral fibers from the temporal halves of the retinas do not cross the midline but continue into the optic tract of the ipsilateral side. The fibers of the nasal halves cross the midline and there enter the...

Astrocytoma Definition

An astrocytoma or astrocytic hamartoma is a benign tumor that develops from the astrocytes of the neuroglial tissue. Epidemiology Astrocytomas are rare. Etiology Astrocytomas belong to the phakomatoses and are presumably congenital disorders that develop from the layer of optic nerve fibers. They may manifest themselves as purely ocular disorders or in association with tuberous sclerosis (Bourneville's disease). Symptoms Patients usually have no ocular symptoms. Calcifying astrocytic hamartomas...

Developmental Anomalies

5.3.1 Protrusion Anomalies 5.3.1.1 Keratoconus Definition Conical, usually bilateral central deformation of the cornea with parenchymal opacification and thinning of the cornea. Epidemiology Keratoconus is the most frequently encountered deformation of the cornea. Occurrence is familial, although women are more likely to be affected than men. Etiology Keratoconus is probably a genetic disorder. It can occur in families with varying paths of hereditary transmission. Occasionally keratoconus is...

Orbital Hematoma

Orbital bleeding is usually post-traumatic but may occur less frequently due to coagulopathy resulting from vitamin C deficiency, anticoagulants, or leukemia. Retrobulbar injections prior to eye surgery and acute venous stasis such as may occur in coughing fits, asphyxia, or childbirth can also cause orbital hematomas. Exophthalmos may be accompanied by monocle or eyeglass hematoma, eyelid swelling, and subconjunctival hemorrhage limited motility is rare. Surgical decompression of the orbital...

AIDSRelated Retinal Disorders Definition

Retinal disorders in AIDS involve either AIDS-associated microangiopathy or infection. Epidemiology Up to 80 of all AIDS patients have retinal disorders as a result of the disease. Other ocular involvement is rare. Pathogenesis The pathogenesis of microangiopathy is still unclear. Opportunistic infections are frequently caused by viruses. Symptoms Microangiopathy is usually asymptomatic. Patients with infectious retinal disorders report loss of visual acuity and visual field defects. Diagnostic...

Electrophysiologic Examination Methods

(electroretinogram, electro-oculogram, and visual evoked potentials see Fig. 12.2a) Electroretinogram (ERG) This examination method uses electrodes to record the electrical response of the retina to flashes of light (Fig. 12.12 a). Photopic (light-adapted) and scotopic (dark-adapted) electroretinograms are obtained. The electroretinogram (ERG) consists of a negative A wave indicating the response of the photoreceptors and a positive B wave primarily indicating the response of the bipolar cells...

Impaired Accommodation 1641 Accommodation Spasm Definition

An accommodation spasm is defined as inadequate protracted contraction of the ciliary muscle. Etiology Accommodation spasms are rare. They may occur as functional impairment or they may occur iatrogenically when treating young patients with parasympathomimetic agents (miotic agents). The functional impairments are frequently attributable to heightened sensitivity of the accommodation center, which especially in children (often girls) can be psychogenic. Rarely the spasm is due to organic...

Trochlear nerve palsy

Causes The commonest cause is trauma less common causes include vascular disease (diabetes mellitus, hypertension, and arteriosclerosis). Trochlear nerve palsy is a relatively common phenomenon. Effects The superior oblique is primarily an intorter and a depressor in adduction. This results in upward vertical deviation of the paralyzed eye in adduction and vertical strabismus (see Fig. 17.16). Patients experience vertical diplopia the images are farthest apart in depression and intorsion....

Radiation Injuries Ionizing Radiation

Etiology Ionizing radiation (neutron, or gamma x-ray radiation) have high energy that can cause ionization and formation of radicals in cellular tissue. Penetration depth in the eye varies with the type of radiation, i.e., the wavelength, resulting in characteristic types of tissue damage (Fig. 18.13). This tissue damage always manifests itself after a latency period, often only after a period of years (see also Symptoms and clinical picture). Common sites include the lens (radiation cataract)...

Treatment

U An acute glaucoma attack is an emergency, and the patient requires immediate treatment by an ophthalmologist. The underlying causes of the disorder require surgical treatment, although initial therapy is conservative. Medical therapy. Goals ofconservative therapy Decrease intraocular pressure. Allow the cornea to clear (important for subsequent surgery). Time factor in reducing intraocular pressure Principles of medical therapy in primary angle closure glaucoma (see Fig. 10.3) Osmotic...

Tumors of the Lacrimal

Epidemiology Tumors of the lacrimal sac are rare but are primarily malignant when they do occur. They include papillomas, carcinomas, and sarcomas. Symptoms and diagnostic considerations Usually the tumors cause unilateral painless swelling followed by dacryostenosis. Diagnostic considerations The irregular and occasionally bizarre form of the structure in radiographic contrast studies is typical. Ultrasound, CT, MRI, and biopsy all contribute to confirming the diagnosis. Differential diagnosis...

Subjective Refraction Testing for Eyeglasses

While the patient looks at vision charts, the examiner places various combinations of lenses in front of the patient's eye. The patient reports which of two lenses produces the sharper image. The better of the two is then compared with the next lens. This incremental method identifies the optimal correction. It is expedient to use the patient's objective refraction as the starting point for subjective testing. Refraction testing is performed either with a series of test lenses from a case or...

Conjunctival Nevus

Birthmarks can occur on the conjunctiva as on the skin. They are usually located near the limbus in the temporal portion of the palpebral fissure, less frequently on the lacrimal caruncle. These benign, slightly raised epithelial or subepithelial tumors are congenital. Fifty percent of nevi contain hollow cystic spaces (pseudocysts) consisting of conjunctival epithelium and goblet cells. Conjunctival nevi may be pigmented (Fig.4.24a) or unpigmented (Fig. 4.24b), and they may increase in size as...

Arteritic Anterior Ischemic Optic Neuropathy Definition

An acute disruption of the blood supply to the optic disk due to inflammation of medium-sized and small arterial branches. Epidemiology The annual incidence is approximately three cases per 100000.The disorder occurs almost exclusively after the age of 60. Women are affected slightly more often than men, accounting for 55 of all cases. Fifty per cent of all patients suffer from ocular involvement within a few days up to approximately three months of the onset of the disorder. Etiology Giant...

Superficial Punctate Keratitis Definition

Superficial punctate corneal lesions due to lacrimal system dysfunction from a number causes (see etiology). Epidemiology and etiology Superficial punctate keratoconjunctivitis is a very frequent finding as it can be caused by a wide variety of exogenous factors such as foreign bodies beneath the upper eyelid, contact lenses, smog, etc. It may also appear as a secondary symptom of many other forms of keratitis (see the forms of keratitis discussed in the following section). It can also occur in...

Position structure and nerve supply of the lacrimal gland The lacrimal

Krause Gland

Gland is about the size of a walnut it lies beneath the superior temporal margin of the orbital bone in the lacrimal fossa of the frontal bone and is neither visible nor palpable. A palpable lacrimal gland is usually a sign of a pathologic change such as dacryoadenitis. The tendon of the levator palpebrae muscle divides the lacrimal gland into a larger orbital part (two-thirds) and a smaller palpebral part (one-third). Several tiny accessory lacrimal glands (glands of Krause and Wolfring)...

Problems with Contact Lenses

Aroused Female Genital

Etiology These problems occur either with poorly seated rigid contact lenses that rub on the surface of the cornea or from overwearing soft contact lenses. Giant papillae from contact lens incompatibility. Giant papillae from contact lens incompatibility. Fig. 5.12 Wartlike protrusions of connective tissue on the pal-pebral conjunctiva due to contact lens or preservative incompatibility (with simple eversion of the upper eyelid). Fig. 5.12 Wartlike protrusions of connective tissue on the...

Corneal Dystrophies Definition

This term refers to a group of corneal metabolic dysfunctions that always lead to bilateral opacification of the various layers of the cornea (see Classification below). Epidemiology Corneal dystrophy tends to be rare. The most frequent form is Fuchs' endothelial dystrophy, followed by dystrophy in the corneal stroma. Etiology The various corneal dystrophies are genetic disorders. They usually manifest themselves in the first or second decade of life except for Fuchs' endothelial dystrophy,...

Posterior Uveitis Due to Toxoplasmosis Definition

Focal chorioretinal inflammation caused by infection. Epidemiology This clinical syndrome is encountered frequently. Pathogenesis The pathogen, Toxoplasma gondii, is transmitted by ingestion of tissue cysts in raw or undercooked meat or by oocysts from cat feces. In congenital toxoplasmosis, the child acquires the pathogen through transplacen-tal transmission. Symptoms and diagnostic considerations As a general rule, a negative complement-fixation test does not exclude Toxoplasma infection...

Blepharospasm Definition

This refers to an involuntary spasmodic contraction of the orbicularis oculi muscle supplied by the facial nerve. Etiology In addition to photosensitivity and increased tear production, blepharospasm will also accompany inflammation or irritation of the anterior chamber. (Photosensitivity, epiphora, and blepharospasm form a triad of reactive clinical symptoms.) Causes of the disorder include extrapyramidal disease such as encephalitis or multiple sclerosis. Trigeminal neuralgia or psy-chogenic...

Optic Neuritis Definition h

Optic neuritis is an inflammation of the optic nerve that may occur within the globe (papillitis) or posterior to it (retrobulbar optic neuritis). Epidemiology Optic neuritis occurs most frequently in adults between the ages of 20 and 45. Women are more frequently affected than men. Twenty to forty per cent of all patients with optic neuritis develop diffuse encephalitis (multiple sclerosis). Fig. 13.10 c Functional findings. The enlarged blind spot (indicated by hatching) is an early...

Neonatal Dacryocystitis

Etiology Approximately 6 of newborns have a stenosis of the mouth of the nasolacrimal duct due to a persistent mucosal fold (lacrimal fold or valve of Hasner). The resulting retention of tear fluid provides ideal growth conditions for bacteria, particularly staphylococci, streptococci, and pneumococci. Symptoms and diagnostic considerations Shortly after birth (usually within two to four weeks), pus is secreted from the puncta. The disease continues subcutaneously and pus collects in the...

Orbital Cavity 1551 Orbital Cellulitis Definition

Acute inflammation of the contents of the orbital cavity with the cardinal symptoms of limited motility and general malaise. H Orbital cellulitis is the most frequent cause of exophthalmos in children. Etiology Acute orbital inflammation posterior to the orbital septum is usually an inflammation that has spread from surrounding tissue. Over 60 of all cases (as high as 84 in children) may be classified as originating in the sinuses, especially the ethmoidal air cells and the frontal sinus. In...

Bacterial Keratitis

Epidemiology Over 90 of all corneal inflammations are caused by bacteria. Etiology The pathogens listed in Table 5.1 are among the most frequent causes of bacterial keratitis in the urban population in temperate climates. Table 5.1 The most common bacterial pathogens that cause keratitis Table 5.1 The most common bacterial pathogens that cause keratitis Typical characteristics of infection Infection progresses slowly with little pain. As in Staphylococcus aureus infection. Typical serpiginous...

Optic Disk Drusen

Optic Disc Drusen

Drusen are yellowish lobular bodies in the tissue of the optic disk that are usually bilateral (in 70 of all cases). Ophthalmoscopy can reveal superficial drusen but not drusen located deep in the scleral canal. In the presence of optic disk drusen, the disk appears slightly elevated with blurred margins and without an optic cup (Fig. 13.9). Abnormal morphologic signs such as hyper-emia and nerve fiber edema will not be present. However, bleeding in lines along the disk margin or subretinal...

Oculomotor nerve palsy

Complete oculomotor nerve palsy Every intraocular and almost every extraocular muscle is affected, with loss of both accommodation and pupillary light reaction. The failure of the parasympathetic fibers in the oculomotor nerve produces mydriasis. Ptosis is present because the levator pal-pebrae is also paralyzed. The paralyzed eye deviates in extorsion and depression as the function of the lateral rectus and superior oblique is preserved. Patients do not experience diplopia because the ptotic...

Blepharophimosis

This refers to shortening of the horizontal palpebral fissure without pathologic changes in the eyelids. The palpebral fissure, normally 28-30 mm wide, may be reduced to half that width. Blepharophimosis is a rare disorder that is either congenital or acquired (for example, from scar contracture or aging). As long as the center of the pupil remains unobstructed despite the decreased size of the palpebral fissure, surgical enlargement of the palpebral fissure (by canthotomy or plastic surgery)...

Intraocular Portion of the Optic Nerve

The intraocular portion of the optic nerve is visible on ophthalmoscopy as the optic disk. All the retinal nerve fibers merge into the optic nerve here, and the central retinal vessels enter and leave the eye here. The complete absence of photoreceptors at this site creates a gap in the visual field known as the blind spot. Shape and size The optic disk (Fig. 13.2) is normally slightly vertically oval with an average area of approximately 2.7 mm2 and a horizontal diameter of approximately 1.8...

Herpes Zoster Keratitis Definition

Keratitis due to endogenous recurrence of chickenpox (caused by the varicella-zoster virus see herpes zoster ophthalmicus). Etiology Proceeding from the trigeminal ganglion, the virus reinfects the region supplied by the trigeminal nerve. The eye is only affected where the ophthalmic division of the trigeminal nerve is involved. In this case, the nasociliary nerve supplying the interior of the eye will also be affected. Hutchinson's sign, vesicular lesions on the tip of the nose, will be...

Chlamydial Conjunctivitis

Chlamydia are Gram-negative bacteria. 1 See Appendix for side effects of medications Lang, Ophthalmology 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. Table 4.2 Overview of infectious conjunctivitis Table 4.2 Overview of infectious conjunctivitis Staphylococcal Subacute Purulent discharge, conjunctivitis blepharitis, superficial punctate keratitis, thickening of the conjunctivitis at the lim-bus Staphylococci Gram-posi-tive cluster form Streptococcal...

Retrochiasmal Lesions

Etiology Retrochiasmal lesions may result from a wide variety of neurologic disorders such as tumors, vascular insults, basal meningitis, aneurysms of the posterior communicating artery, abscesses, injuries (such as a contrecoup injury to the occipital lobe), and vasospasms (in an ocular migraine). Symptoms, diagnostic considerations, and clinical picture Visual field testing in particular will provide information on the location of the lesion. Perimetry is therefore a crucial diagnostic study....

Surgical Treatment Vitrectomy Definition

Fundus Drawing

Surgical removal and replacement of the vitreous body with Ringer's solution, gas, or silicone oil. Indication The primary indications include Unabsorbed vitreous hemorrhage. Tractional retinal detachment. Proliferative vitreoretinopathy. Removal of intravitreal displaced lenses or foreign bodies. Severe postoperative or post-traumatic inflammatory vitreous changes. Procedure The vitreous body cannot simply be aspirated from the eye as the vitreoretinal attachments would also cause retinal...

Parasitic Retinal Disorders Definition

Leukocoria

Inflammation of the retina caused by infection with parasites such as Onchocerca volvulus (the pathogen that causes onchocerciasis), Toxocara canis or Toxocara cati (nematode larvae that are normally intestinal parasites of dogs and cats), Taenia solium, (pork tapeworm), and other parasites. Epidemiology Onchocerciasis, like trachoma and leprosy, is one of the most frequent causes of blindness worldwide. However, like the other parasitic diseases discussed here, it is rare in Europe and North...

Asteroid Hyalosis

These usually unilateral opacities of the vitreous body (75 of all cases) are not all that infrequent. They are thought to be linked to diabetes mellitus and hypercholesterolemia. The disorder is characterized by white calcific deposits that are associated with the collagen fibers of the vitreous body and therefore are not very mobile. Most patients are not bothered by these opacities. However, the examiner's view of the fundus can be significantly obscured by snow flurries of white opacities....

Degenerative Retinoschisis Definition

Afrequently bilateral split in an inner and outer layer of the retina. The split is usually at the level of the outer plexiform layer (Fig. 12.25). Epidemiology About 25 of all people have retinoschisis. The tendency increases with age. Pathogenesis Idiopathic retinal splitting occurs, usually in the outer plexi-form layer. Symptoms Retinoschisis is primarily asymptomatic. The patient will usually notice a reduction of visual acuity and see shadows only when the retinal split is severe and...

Concomitant Strabismus Definition

Concomitant strabismus differs from paralytic strabismus in that the angle of deviation remains the same in every direction of gaze. The deviating eye follows the normal fellow eye at a constant angle. Epidemiology Concomitant strabismus occurs almost exclusively in children. Approximately 5.3-7.4 of all children are affected. In 60-70 of all cases, the disorder initially manifests itself within the first two years of life. Etiology Vision at birth is neither focused nor binocular, and both...

Examination Methods Visual Acuity see Chapter 1 1221 Examination of the Fundus

Mirror Fundus

Direct ophthalmoscopy (Fig. 12.4a see also Fig. 1.13) A direct ophthalmoscope is positioned close to the patient's eye. The examiner sees a 16-power magnified image of the fundus. Advantages. The high magnification permits evaluation of small retinal findings such as diagnosing retinal microaneurysms. The dial of the ophthalmoscope contains various different plus and minus lenses and can be adjusted as necessary. These lenses compensate for refractive errors in both the patient a Direct...

Developmental Anomalies of the Lens

Lentiglobus

Anomalies of lens shape are very rare. Lenticonus is a circumscribed conical protrusion of the anterior pole (anterior lenticonus) or posterior pole (posterior lenticonus). A hemispherical protrusion is referred to as lentiglobus. Symptoms include myopia and reduced visual acuity. Some patients with Alport's syndrome (kidney disease accompanied by sensorineural hearing loss and anomalies of lens shape) have anterior lenticonus. Posterior lenticonus may be associated with a lens opacity (Fig....

Treatment and Avoidance of Strabismic Amblyopia

Strict occlusion therapy by eye patching or eyeglass occlusion is the most effective method of avoiding or treating strabismic amblyopia. Primarily the leading eye is patched. 478 17 Ocular Motility and Strabismus Occlusion therapy of amblyopia. - 478 17 Ocular Motility and Strabismus Occlusion therapy of amblyopia. - Fig. 17.11 The leading eye is patched for several hours or days at a time to improve visual acuity in the deviating amblyopic eye. Fig. 17.11 The leading eye is patched for...

Staphyloma and Ectasia

Staphyloma refers to a bulging of the sclera in which the underlying uveal tissue in the bulge is also thinned or degenerated. By far the most common form is posterior staphyloma in severe myopia, a bulging of the entire posterior pole of the eyeball (Fig. 6.1). Staphyloma can also occur secondary to scleritis (see Fig. 6.4). Ectasia is a thinning and bulging of the sclera without uveal involvement, as can occur secondary to inflammation. Both staphyloma and ectasia are secondary or incidental...

Epithelial Conjunctival Tumors 4531 Conjunctival Cysts

Cyst Blood Vessel Wrist

Conjunctival cysts are harmless and benign. Occurrence is most often postoperative (for example after surgery to correct strabismus), post-traumatic, or spontaneous. They usually take the form of small clear fluid-filled inclusions of conjunctival epithelium whose goblet cells secrete into the cyst and not on to the surface (Fig. 4.21 ). Cysts can lead to a foreign-body sensation and are removed surgically by marsupialization (removal of the upper half of the cyst). 106 4 Conjunctiva...

Disadvantages of Contact Lenses

Contact lenses exert mechanical and metabolic influences on the cornea. Therefore, they require the constant supervision of an ophthalmologist. Mechanical influences on the cornea can lead to transient changes in refraction. Spectacle blur can result when eyeglasses suddenly no longer provide the proper correction after removing the lens. Contact lenses require careful daily cleaning and disinfection. This is more difficult, time-consuming, and more expensive than eyeglass care and is...

Disorders of the Lower Lacrimal System 331 Dacryocystitis

Inflammation of the lacrimal sac is the most frequent disorder of the lower lacrimal system. It is usually the result of obstruction of the nasolacrimal duct and is unilateral in most cases. Epidemiology The disorder most frequently affects adults between the ages of 50 and 60. Etiology The cause is usually a stenosis within the lacrimal sac. The retention of tear fluid leads to infection from staphylococci, pneumococci, Pseudomonas, or other pathogens. Symptoms Clinical symptoms include highly...

Vitritis and Endophthalmitis Definition

This refers to acute or chronic intraocular inflammation due to microbial or immunologic causes. In the strict sense, any intraocular inflammation is endophthalmitis. However, in clinical usage and throughout this book, endophthalmitis refers only to inflammation caused by a microbial action that also involves the vitreous body (vitritis). On the other hand, isolated vitritis without involvement of the other intraocular structures is inconceivable due to the avascularity of the vitreous...

Retinal Arterial Occlusion Definition

Retinal Image Meaning

Retinal infarction due to occlusion of an artery in the lamina cribrosa or a branch retinal artery occlusion. Epidemiology Retinal artery occlusions occur significantly less often than vein occlusions. Etiology Emboli (Table 12.2) are frequently the cause of retinal artery and branch retinal artery occlusions. Less frequent causes include inflammatory processes such as temporal arteritis (Horton's arteritis). 12.3 Vascular Disorders 321 Table 12.2 Causes of embolus in retinal artery occlusion...

Normal and Abnormal Fundus Findings in General

Normal Fundus Photo

Normal fundus The retina is normally completely transparent without any intrinsic color. It receives its uniform bright red coloration from the vascula-ture of the choroid (Fig. 12.8). The vessels of the choroid themselves are obscured by the retinal pigment epithelium. Loss of transparency of the retina is a sign of an abnormal process (for example in retinal edemas, the retina appears whitish yellow). The optic disk is normally a sharply defined, yellowish orange structure (in teenagers it is...

Examination of the Cornea

The cornea is examined with a point light source and a loupe (Fig. 1.10). The cornea is smooth, clear, and reflective. The reflection is distorted in the presence of corneal disorders. Epithelial defects, which are also very painful, will take on an intense green color after application of fluorescein dye corneal infiltrates and scars are grayish white. Evaluating corneal sensitivity is also important. Sensitivity is evaluated bilaterally to detect possible differences in the reaction of both...

Other causes for exposure keratitis without facial nerve palsy include

Uncompensated exophthalmos in Graves' disease. Insufficient eyelid closure following eyelid surgery to correct ptosis. Insufficient eye care in patients receiving artificial respiration on the intensive care ward. Symptoms Similar to superficial punctate keratitis (although usually more severe) but unilateral. Diagnostic considerations Application of fluorescein dye will reveal a typical pattern of epithelial lesions (Fig. 5.11 i). Treatment Application of artificial tears is usually not...

Neonatal Conjunctivitis

Gonococcal Conjunctivitis Newborn

Epidemiology Approximately 10 of the newborn contract conjunctivitis. Etiology (Table 4.3) The most frequent pathogens are Chlamydia, followed by gonococci. Neonatal conjunctivitis is less frequently attributable to other bacteria such as Pseudomonas aeruginosa, Haemophilus, Staphylococcus aureus and Streptococcus pneumoniae, or to herpes simplex. The infection occurs at birth. Chlamydia infections are particularly important because they are among the most common undetected maternal genital...

Herpes Simplex of the Eyelids Definition

Herpes The Eyelid

Acute, usually unilateral eyelid disorder accompanied by skin and mucous membrane vesicles. Etiology Infection of the skin of the eyelids results when latent herpes simplex viruses present in the tissue are activated by ultraviolet radiation. The virus spreads along sensory nerve fibers from the trigeminal ganglion to the surface of the skin. Symptoms Typical clustered eruptions of painful vesicles filled with serous fluid frequently occur at the junction of mucous membranes and skin (Fig....

Xanthelasma Definition

Milia Millium Testiculos

Local fat metabolism disorder that produces lipoprotein deposits. These are usually bilateral in the medial canthus. Fig. 2.20 The round cysts of the glands of Moll are usually located in the angle of the eye. The weight causes temporary ectropion. Fig. 2.20 The round cysts of the glands of Moll are usually located in the angle of the eye. The weight causes temporary ectropion. Epidemiology Postmenopausal women are most frequently affected. A higher incidence has also been observed in patients...

Forms of retinitis pigmentosa

Retinal Neovascularization

Rod-cone dystrophy (classic retinitis pigmentosa, by far the most frequent form). 2. Cone-rod dystrophy (inverse retinitis pigmentosa). 3. Sectoral retinitis pigmentosa. 4. Retinitis pigmentosa sine pigmento (form without pigment). 5. Unilateral retinitis pigmentosa. 6. Leber's amaurosis (form occurring in early childhood). 7. Retinopathy punctata albescens (punctate retinitis). 8. In combination with other disorders in syndromes and metabolic disorders such as mucopolysaccharidoses, Fanconi's...

Stargardts Disease Definition

This is a macular dystrophy that proceeds from the retinal pigment epithelium. Inheritance Autosomal recessive disorder. Epidemiology Stargardt's disease is rare. Symptoms Progressive loss of visual acuity occurs between the ages of 10 and 20 years. Findings and diagnostic considerations Initial findings are slight with white fleck lesions in the macular region (Fig. 12.29), which may occur in combination with lesions in the entire fundus (fundus flavimaculatus). The electroretinogram and...

Evaluation of Tear Drainage

Stenosis Lacrimal Punctum

Conjunctival fluorescein dye test Normal tear drainage can be demonstrated by having the patient blow his or her nose into a facial tissue following application of a 2 fluorescein sodium solution to the inferior fornix. Probing and irrigation These examination methods are used to locate stenoses. After application of a topical anesthetic, a conical probe is used to dilate the punctum. Then the lower lacrimal system is flushed with a physiologic saline solution introduced through a blunt cannula...

Conjunctiva Inclusion Conjunctivitis

Epidemiology Inclusion conjunctivitis is very frequent in temperate countries. The incidence in western industrialized countries ranges between 1.7 and 24 of all sexually active adults depending on the specific population studied. Etiology Oculogenital infection (Chlamydia trachomatis serotype D-K) is also caused by direct contact. In the newborn (see neonatal conjunctivitis), this occurs at birth through the cervical secretion. In adults, it is primarily transmitted during sexual intercourse,...

Eye 63 Diopters

16.1.1 Uncorrected and Corrected Visual Acuity Uncorrected visual acuity This refers to the resolving power of the eye without corrective lenses. Corrected visual acuity This refers to the resolving power of the eye with an optimal correction provided by corrective lenses (determined by visual acuity testing). Both uncorrected visual acuity and corrected visual acuity provide information on how far apart two objects must be for the eye to perceive them as distinct objects (minimum threshold...