FLECKED RETINA SYNDROMES

Clinical Features

The flecked retina syndromes consist of a diverse group of disorders characterized by the presence of fleck-like lesions at the level of the retinal pigment epithelium (RPE) or retina. True flecks have a triradiate, fish tail, or “pisciform” configuration. The flecks are located at the level of the RPE and may be found in the macula and/or midperipheral retina. They tend to be bilateral and symmetric, although the size and shape of individual flecks may vary. The flecks tend to fade over time. Flecks must be differentiated from round or oval lesions consistent with drusen, several of the congenital stationary night blindness conditions, or the inflammatory white dot syndromes.

Differential Diagnosis

Identifying the location of the fleck-like lesions is important to determine the etiology of a given condition. Stargardt disease/fundus flavimaculatus is the most common flecked retinal syndrome involving the RPE. Other conditions include drusen, fundus albipunctatus, the flecked retina of Kandori, retinitis punctata albescens, Alport’s syndrome, and vitamin A deficiency.

Several retinal toxicities may mimic the flecked retina syndromes; these abnormalities are usually found within the retina. They include canthaxanthin, talc, and tamoxifen retinopathies. Other conditions associated with retinal crystals include sickle cell retinopathy, idiopathic juxtafoveal retinal telangiectasis, Bietti’s crystalline retinal dystrophy, cystinosis, and oxalosis.

Stage I macular hole

Diabetic retinopathy with macular edema

Central serous chorioretinopathy

Solar retinopathy

Clinical Features

The macula is recognized clinically as the region within the temporal vascular arcades. Histologically, the macula is defined as having the following: two or more layers of ganglion cell nuclei; taller and more pigmented retinal pigment epithelial cells; and xanthophyll pigment. Under normal circumstances, the foveal depression limits the visibility of the yellow xanthophyll pigment. Loss of the foveal depression is accompanied by anterior displacement of the xanthophyll pigment. This condition is manifest clinically as a yellow spot or ring in the fovea.

Differential Diagnosis

A stage 1 macular hole is the most notable condition characterized by the presence of a yellow spot (or yellow ring) in the fovea. A prominent xanthophyll reflex also may be detected in association with subretinal or intraretinal fluid in the fovea. Conditions include central serous chorioretinopathy, choroidal neovascularization, toxemia of pregnancy, uveal effusion syndrome, optic disc edema, diabetic retinopathy, and cystoid macular edema. Other conditions simulating a prominent xanthophyll reflex include solar retinopathy and pattern dystrophy.

Clinical Features

Intraretinal hemorrhages vary in appearance based on their location within the retina. Flame-shaped hemorrhages are superficial, bright red, fan-shaped hemorrhages located in the nerve fiber layer. Dot/blot hemorrhages are small, round, dark red hemorrhages located in the deeper, more vertically oriented layers of the retina. Both flame-shaped and dot/blot intraretinal hemorrhages result from disruption of the retinal capillaries and breakdown of the blood-retinal barrier. Individuals with intraretinal hemorrhages may be asymptomatic or have significant visual loss depending on the etiology.

Differential Diagnosis

Intraretinal hemorrhages are associated with a variety of retinal vascular diseases including diabetes mellitus, hypertension, branch and central retinal vein occlusions,

leukemia, anemia, radiation retinopathy, ocular ischemia, retinal macroaneurysms, and sickle cell disease. Intraretinal hemorrhages may be seen with epiretinal membrane contraction. Intraretinal hemorrhages may

be observed in inflammatory diseases including human immunodeficiency virus, cytomegalovirus retinitis, sarcoidosis, and Behçet’s disease and other conditions associated with vasculitis. They may result from direct or indirect ocular trauma (contusion injury, shaken baby syndrome, childbirth, Valsalva retinopathy, Terson’s syndrome, Purtscher’s retinopathy). They may occur following acute posterior vitreous separation, in areas of persistent vitreoretinal traction, and with acute retinal tears. Intraretinal hemorrhages have been described following bone marrow transplantation and in association with high-altitude sickness.

Diabetic retinopathy

Coat’s disease

Branch retinal vein occlusion

Retinal arterial macroaneurysm

Clinical Features

Lipid exudates have been referred to as “hard exudates.” This description reflects the relatively discrete, yellow, refractile nature of the deposits. The lipid deposits are either intraretinal or subretinal, depending on the etiology. Lipid exudates tend to be localized around a given area of pathology forming a round or “circinate” pattern. However, large amounts of lipid exudation may accumulate at sites distant from the abnormality. For example, individuals with Coat’s disease or a peripheral retinal capillary hemangioma may present with visual loss as

a result of subretinal fluid and lipid exudation in the macula.

Lipid exudates must be distinguished from intraarterial emboli, retinal crystals, drusen, and the flecked retina syndromes.

Differential Diagnosis

Lipid exudation is usually associated with retinal vascular leakage or abnormal vascular proliferation from either the choroidal or retinal circulation. Retinal vascular leakage may result from congenital vascular abnormalities (Coat’s disease, idiopathic juxtafoveal retinal

telangiectasis type 1) or acquired retinal vascular disorders (diabetic retinopathy, hypertensive retinopathy, venous occlusive disease, macroaneurysms, radiation retinopathy). In the case of diabetic retinopathy, retinal lipid exudate may be associated with systemic hyperlipidemia. Lipid exudation may occur as an unusual complication of retinitis pigmentosa and chronic retinal detachment.

Lipid exudation from vascular proliferation may be seen in patients with age-related macular degeneration (AMD) and other causes of choroidal neovascularization (CNV). Lipid exudation is associated with choroidal melanoma and retinal capillary hemangiomas.