Olo

Non-Proliferative Diabetic Retinopathy A 62-year-old man was examined approximately two months after focal laser photocoagulation treatment for background diabetic retinopathy and clinically significant macular edema in both eyes. Fundus examination (A) of his right eye, which had a visual acuity of 20 100, revealed scattered dot and blot hemorrhages throughout the macula, hard exudate, and laser scars. A vertical OCT image (B) through the macula showed a diffuse increase in retinal...

Epiretinal Macular Membranes

Macular Pseudohole Macular Edema Retinal Traction Current diagnostic techniques for epiretinal macular membranes include slit-lamp biomicroscopy and fluorescein angiography. OCT images are useful in confirming the diagnosis of faint, diaphanous membranes, and in providing a cross-sectional assessment of factors contributing to vision loss, such as membrane opacity, retinal distortion or fractional detachment, and macular edema. The amount of foveal distortion, detachment, or edema provides an...

Chorioretinal Inflammatory Diseases

Case 9-12, Chorioretinal Scar from Previous Toxoplasmosis A 23-year-old man had a history of toxoplasmosis in both eyes. The left eye (A) was notable for an atrophic and hyperpigmented chorioretinal scar involving the central macula. The visual acuity in this eye was 20 80. An OCT image (B) taken through the scar displayed a complete loss of neurosensory retinal tissue consistent with an old, focal necrotizing retinitis. Increased reflectivity was observed from the retinal pigment epithelium...

Optic Disc Pitting Papilledema

As in glaucoma, OCT is also useful for cross-sectional profiling of the optic nerve head and retinal nerve fiber layer (NFL) in neurological diseases of the optic nerve. Radial tomograms through the optic disc provide information on the disc contour. Optic nerve pits, for example, appear as focal excavations in the nerve head. Quantitative measurements such as cup and disc diameter may be directly extracted from the tomograms, which may be useful in evaluating optic nerve atrophy. The extent of...

Choroidal Neovascularization

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- cumulation of material within or beneath Bruchs membrane Ml. The apparent elevation of the RPE is similar in appearance to a serous pigment epithelial detachment (PED) however, unlike a PED, soft drusen display shallow margins and mild...

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Case 9-11- Healed Cytomegalovirus Retini A 36-year-old HIV+ man with a history of cytom lovinis (CMV) retinitis over the past two years no tic continued loss of his peripheral vision in the right eye several months prior to examination. His best corre visual acuity on examination was 20 60. Dilated fui examination (A) of this eye showed healed CMV reti superiorly affecting almost half the retina. A vertical OCT image (B) through fixation der strated a well-defined region of retinal atrophy sup*...

Transverse Scan

Visual Acuity

Figure 1-6, Image measurement using Optical Coherence Tomography. Tomographic images are constructed by performing rapid, successive axial (longitudinal) measurements at different transverse points. Each axial measurement represents optical reflection and backscatter from microstructures which are intercepted by the optical beam. By scanning the beam transversely while performing axial measurements, a two dimensional set of data may be measured which is a cross-sectional map of the reflection...

Operculum Retina

Dilated fundus examination D) of the patient's right eye revealed mild mottling of the retinal pigment epithelium and an apparently attached vitreous, A subtle cyst or pseudohole was observed in the fovea. The patient's visual acuity in this eye was 20 25. Fluorescein angiography (E) appeared normal OCT examination (F) demonstrated an elevation of the inner retina above an optically clear space consistent with a cvst direct v in the fovea. The minimally reflective band corresponding to the...

Layer Poj 2 Medicine For Which Purpose

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. fected by abnormalities in the cornea,...

Interpretation Of Oct Images

The evaluation of OCT tomograms depends on the ability of the observer to identify both differences in the relative reflectivity of different tissue layers and morphological changes in tissue structures 8 . In some cases, because of the high axial resolution of the OCT images, small changes in morphology may be difficult to assess by direct observation of the images. In these cases, automated computer image processing tools may be used to extract precise quantitative measurements from the...

Qva

OCT images comparing an idiopathic full-thickness macular hole (A), a macular pseudohole due to an epiretinal membrane (B), and a lamellar or partial-thickness hole (C), The full-thickness hole displays a complete loss of retinal tissue in the fovea and surrounding retinal edema. The pseudohole and lamellar hole, however, exhibit an intact photoreceptor layer in the fovea. The pseudohole is characterized by a steepened fovea 1 pit contour due to traction by the epi retinal...

Diabetic Retinopathy

Examination of the patient s left eve (E) showed a large foveal cyst and clinically significant macular thickening. Corresponding late leakage of fluorescein dye was observed in the central macula on angiography (F). The visual acuity in this eye was 20 40. OCT (G) demonstrated macular thickening with a large central cystic space extending to the inner limiting membrane and smaller surrounding cysts. he foveal thickness was 460 j.m. Focal laser photocoagulation was performed and the patient...

Macular Degeneration

The patients left eye had a visual acuity of counting fingers associated with a serous neurosensory retinal detachment and subretinal neovascularization (C), OCT (D) showed a large elevation of the retina over an optically clear cavity The reflection from the choroid was not attenuated beneath the cavity consistent with a neurosensory detachment. The lack of a continuous, highly q reflective thin band corresponding to a normal retinal pigment epithelium and choriocapillaris suggested the...