VASCULITIS

Sarcoidosis

Systemic lupus erythematosus

Clinical Features

Vasculitis consists of inflammation of retinal veins (phlebitis) or arterioles (arteritis). The clinical hallmark of retinal phlebitis or arteritis is a sheathing of the involved vessels, which is typically white, gray, or yellow. This vascular sheathing may be quite subtle or absent on biomicroscopy, but is seen as staining or leakage from the retinal vessels on fluorescein angiography. It is not unusual for the angiographic findings of vascular staining and leaking to be more prominent than the biomicroscopic features. Intraretinal hemorrhages may accompany the distribution of the vasculitis.

Retinal vasculitis may be observed as a primary ocular disease or in association with a variety of systemic and infectious conditions. Individuals may be asymptomatic or complain of visual loss, scotoma, and floaters (when the retinal vasculitis is associated with vitritis or vitreous hemorrhage). Pain and redness may be present in those individuals with anterior segment inflammation. Visual loss may be the result of cystoid macular edema, retinal ischemia, and vitreous hemorrhage in eyes with widespread capillary nonperfusion and neovascularization.

Massive perivascular infiltrates can be seen in frosted branch angiitis, a self-limited condition initially described in healthy, young individuals. A similar clinical picture has been reported in immunocompromised patients with cytomegalovirus (CMV) retinitis and

Behçet’s disease

Cytomegalovirus retinitis with frosted branch angiitis

lymphoma. This outpouring of exudate is thought to be secondary to an immune response.

Differential Diagnosis

Vasculitis associated with systemic disease includes sarcoidosis, Behçet’s disease, Wegener’s granulomatosis, systemic lupus erythematosus, polyarteritis nodosa, inflammatory bowel disease, and multiple sclerosis. Many infectious diseases are associated with retinal vasculitis. These include toxoplasmosis, syphilis, Lyme disease, toxocariasis, tuberculosis, CMV retinitis, and acute retinal necrosis. Primary ocular diseases include birdshot choroidopathy, Eale’s disease, and frosted branch angiitis.

Vasculitides that primarily affect retinal veins include sarcoidosis, pars planitis, Eale’s disease, and frosted branch angiitis. A number of conditions may affect both arteries and veins such as syphilitic chorioretinitis, Behçet’s disease, and primary vasculitis. Behçet’s disease may be associated with retinal infiltrates, branch retinal vein occlusions, and vitritis. Those conditions involving primarily the retinal arterioles include toxoplasmosis, acute retinal necrosis, idiopathic branch retinal artery occlusion syndrome, systemic lupus erythematosus, polyarteritis, and Wegener’s granulomatosis.

The differential diagnosis of vasculitis includes lipemia retinalis, occluded vessels in retinal vein occlusion, and perivascular sheathing (presumably lipid) in patients with diabetic retinopathy.

Best’s disease

Pattern dystrophy

Multifocal Best’s disease

Basal laminar drusen

Clinical Features

Vitelliform, or yellow, lesions in the macula may be single or multiple. Vitelliform lesions refer to deposits of yellow material in the outer retina or retina pigment epithelium (RPE).

Differential Diagnosis

The differential diagnosis of vitelliform lesions includes Best’s disease, pattern dystrophy, or basal laminar drusen. In Best’s disease, a macular dystrophy, the characteristic round, “sunny side up” egg yolk lesion is a unifocal and bilateral finding. Over several years, the yellow material may settle out of the RPE cells and layer into a “pseudohypopyon” under the retina. The yellow pigment will eventually form a patchy or “scrambled” pattern and eventually leave an area of RPE disruption. The presence of a reduced Arden ratio on the electrooculogram (EOG) and a positive family history confirm

the diagnosis of Best’s disease. Multifocal vitelliform lesions may be seen in Best’s disease and in patients with normal EOG findings and no family history.

Multifocal vitelliform macular lesions accompanied by more extensive pigmentary changes on the fluorescein angiogram may signal a pattern dystrophy. These dystrophies appear in adulthood and are often autosomal dominant in inheritance. Pattern dystrophies have a great variety of appearances. The foveomacular dystrophy group, for example, has yellow flecks in the center of the macula and has a vitelliform appearance.

In patients with cuticular or basal laminar drusen, yellow subretinal material may accumulate under the macula in an appearance quite similar to Best’s disease. This vitelliform exudation may or may not be associated with underlying choroidal new vessels and can be quite chronic.

Other conditions that may simulate vitelliform lesions include stage 1 macular holes, early cystoid macular edema, hard exudates, and drusen.

VITREOUS HEMORRHAGE

Clinical Features

Vitreous hemorrhage, or red blood cells in the vitreous cavity, may be evenly dispersed or form clumps of cells. Hemorrhage in the formed vitreous initially appears red and, over a period of months, changes in color from red to pink to white. Because of gravity, vitreous hemorrhage tends to be denser inferiorly. The density of blood in the vitreous directly affects visual acuity, which can range from 20/20 to no light perception. A subhyaloid hemorrhage, blood that is trapped between the posterior vitreous surface and inner retina, is more solid and may have a linear or boat-shaped appearance. As the vitreous detaches from the macula, the subhyaloid blood appears more liquid and can move freely under the formed vitreous.

Differential Diagnosis

A common cause of vitreous hemorrhage is posterior vitreous detachment (PVD). At the time of a PVD, the vitreous traction can pull on a retinal blood vessel, creating a vitreous hemorrhage. If the vitreous traction also causes a retinal tear, the torn retinal tissue may bleed into the vitreous cavity. Recurrent vitreous hemorrhage may be due to a bridging vessel between the retinal tear and underlying attached retina. A similar phenomenon may occur in patients with X-linked juvenile retinoschisis. Diabetic retinopathy is a common cause of vitreous hemorrhage. A vitreous hemorrhage in someone with diabetes is presumed to result from neovascularization of the optic disc or retina until proved otherwise. Vitreous hemorrhage following panretinal photocoagulation may be related to persistent neovascularization or vitreous traction on fibrovascular tissue. Other vascular diseases associated with retinal ischemia and neovascularization/ vitreous hemorrhage include branch retinal vein occlusion, sickle cell retinopathy, radiation retinopathy, retinal embolization, and leukemia. Inflammatory disorders with vitreous hemorrhage include Eales’ disease, pars planitis, sarcoidosis, and systemic lupus erythematosus.

Rarely, exudative age-related macular degeneration may be associated with vitreous hemorrhage. This hemorrhage is the result of “breakthrough bleeding” as subretinal blood moves from the subretinal space into the vitreous.

Proliferative diabetic retinopathy

Retinoschisis

Normal vitreous opacities

Vitritis (toxoplasmosis)

Asteroid hyalosis

Amyloidosis

Clinical Features

Nonhemorrhagic vitreous opacities may be due to condensed vitreous, white blood cells, tumor cells, or pigment cells. Large strands of vitreous opacities may represent condensation of the vitreous or vitreous degeneration.

Differential Diagnosis

A commonly seen vitreous opacity is a ring of condensed vitreous, a Weiss ring, noted in front of the optic nerve. This Weiss ring is the hallmark of a posterior vitreous detachment (PVD). In addition, a PVD is accompanied by syneresis, or vitreous contraction, which appears as faint vitreous strands or veils.

Vitritis, or white cells in the vitreous, signals inflammation and possibly infection. In intermediate uveitis, such as pars planitis, vitritis is most prominent in the anterior vitreous. In posterior uveitis. such as multifocal choroiditis, cells are initially seen in the posterior vitreous. Chronic inflammation leads to larger clusters of cells. Early bacterial endophthalmitis is characterized by fine cells in the vitreous, while the clinical feature

suggestive of fungal endophthalmitis is white spheres in the vitreous (described as “cotton balls”) that may be found overlying a chorioretinal abscess.

Clumps of pigment in the vitreous provide clinical suspicion of a retinal tear or detachment. Red blood cells in the vitreous may be due to a retinal tear, trauma, preretinal neovascularization, or subretinal blood that has diffused into the vitreous cavity. Old blood appears white and may be confused with an inflammatory or neoplastic process. Asteroid hyalosis is a common, benign, degenerative condition in which many yellow-white spheres of calcium soaps are seen in the center of the vitreous. Asteroid hyalosis is unilateral in 90% of cases. In amyloidosis, white amyloid material forms cobweb-like opacities in the vitreous and may, if dense, obscure vision.

Clusters of small, white preretinal nodules can be seen in the inferior vitreous cavity in sarcoidosis. A similar type of vitreous opacity is common in pars planitis, in which preretinal “snowballs” form in front of the peripheral retina or pars plana. White tumor cells in the vitreous (identified by vitreous biopsy) may be a presenting sign of ocular-central nervous system lymphoma, and brown tumor cells can be seen in cases of metastatic cutaneous melanoma.