White Dot Syndromes
Multiple Evanescent White Dot Syndrome (MEWDS)
Multiple evanescent white dot syndrome (MEWDS) is an acute inflammatory disorder in which patients present with unilateral, multiple, small, white spots at the level of the outer retina and retinal pigment epithelium. Patients typically are young, myopic, and female (75%) and present with symptoms of temporal field loss (enlarged blind spot), blurred vision, and photopsia, often following a flu-like illness. The disorder is typically self-limited with visual recovery over a few to several weeks. During the subacute phase white dots in the fovea may impart a granular appearance; old lesions may fade while new lesions develop in other areas. Vitreous cells and a mild papillophlebitis may occur. Fluorescein angiography (FA) shows early hyperfluorescent dots overlying larger spots (“wreath” pattern) corresponding to the white funduscopic lesions. With indocyanine green (ICG) angiography the dots and spots are hypofluorescent and with fundus autofluorescence the spots are hyperfluorescent and in each case more extensive than seen with color fundus photography or FA. With spectral domain optical coherence tomography (OCT) the spots correspond to loss or discontinuity of the inner segment ellipsoid band and the dots correspond to outer retinal hyper-reflective foci; these resolve briskly with resolution of the illness.
Multifocal Choroiditis (MFC) (Punctate Inner Choroidopathy (PIC), Multifocal Choroiditis and Panuveitis (MCP), Idiopathic Progressive Subretinal Fibrosis Syndrome)
Punctate inner choroidopathy (PIC) and MFC are related, if not identical, entities. Both tend to affect young females (<75%) who are often myopic. These patients develop focal areas of inflammation in the deep retina and choroid that progress into punched-out, atrophic, and pigmented chorioretinal scars. The acute lesions are typically multiple, bilateral, and yellow-white or grayish in appearance. Occasionally, there may be an overlying neurosensory detachment. When these inflammatory spots are small and confined to the posterior pole with minimal vitreous reaction, the entity is typically referred to as PIC. More diffuse disease with larger lesions and associated panuveitis is referred to as MFC. These eyes may present with peripapillary fibrosis and linear clusters of lesions in the peripheral fundus forming curvilinear or concentric streaks (Schlaegel’s line) similar to those seen in the presumed ocular histoplasmosis syndrome (POHS). The presence of uveitis, most commonly anterior and vitreous cells, distinguishes MFC from POHS. Like POHS, both PIC and MFC are frequently associated with secondary choroidal neovascularization (CNV), which can lead to subretinal fibrosis. Rarely, this subretinal fibrosis can be extensive and progressive, in which case it is referred to as the idiopathic progressive subretinal fibrosis syndrome.
Acute Zonal Occult Outer Retinopathy (AZOOR)
Acute zonal occult outer retinopathy (AZOOR) is an idiopathic inflammatory disorder usually affecting young healthy women who develop photopsia and acute progressive visual field loss in one or both eyes due to damage of broad zones of the outer retina. The field abnormality typically begins as enlargement of the blind spot, often described with movements of colors within the scotoma. Funduscopy upon initial presentation may be normal with the exception of mild vitritis. However, in later stages, retinal pigment epithelium (RPE) atrophy, pigment clumping, and arterial attenuation may develop. Approximately one-third of patients develop recurrent disease. Electroretinogram (ERG) testing, autofluorescent imaging, fluorescein and ICG angiography, and OCT localize the abnormality to the photoreceptor–RPE complex. Recently a trizonal appearance on autofluorescence, ICG angiography, and SD-OCT has been described as a defining feature of AZOOR. On SD-OCT this is characterized by normal retina outside of the AZOOR lesion (zone 1) and subretinal drusenoid deposits (zone 2) and RPE and choroidal atrophy (zone 3) within the lesion. On autofluorescence and ICG angiography this trizonal pattern is characterized by a hyperfluorescent line demarcating the AZOOR lesion adjacent to normal retina (zone 1), speckled hyperfluorescence within the AZOOR lesion (zone 2), and hypofluorescence corresponding to choroidal atrophy within the lesion (zone 3).
Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)
APMPPE is a syndrome of multiple, plaque-like, creamy lesions at the level of the RPE that typically affects young healthy men and women in the second and third decade of life. Patients develop rapid visual loss that may be associated with central or paracentral scotomas, photopsia, and metamorphopsia. Most cases are bilateral and the second eye is involved within a few days; however, delayed involvement of the second eye by several weeks can occur. Approximately one-third of the patients report a flu-like syndrome, particularly headaches preceding the visual symptoms. The characteristic clinical finding is the presence of multiple, yellow-white, placoid lesions at the level of RPE, located primarily in the posterior pole. New lesions may develop more peripherally. The size of the lesions varies, but they are usually less than one disc diameter. Associated ocular findings include mild vitritis, papillitis, retinal vasculitis, exudative retinal detachment, and retinal neovascularization and hemorrhage. The active lesions begin to resolve within a few days after the onset of the symptoms and are replaced by RPE atrophy and hyperpigmentation. As the old lesions fade, new active lesions may appear. The visual acuity may return to near normal, but patients may experience prolonged recovery associated with persistent scotomas and more uncommonly even severe vision loss. Rarely stroke and even death have been reported due to central nervous system vasculitis.
Serpiginous Choroiditis
Serpiginous choroiditis is a rare, usually bilateral, recurrent inflammatory chorioretinitis that affects middle-aged men or women. It remains an idiopathic entity; however, recently, many reports have demonstrated an association with tuberculosis exposure in some cases. The acute, grayish-white, subretinal lesions typically originate in the peripapillary region and localize to the outer retina, RPE, and choroid. Over time, there is gradual progression away from the nerve in a helicoid or serpiginous manner, often toward the macula. Chronic lesions show pigmentary changes and fibrous atrophy. New lesions often originate from the margin of older lesions as finger-like extensions. Occasionally, the disorder may originate in the macula, in which case it may be referred to as “macular serpiginous.” CNV is a common complication of serpiginous choroiditis. A vitritis is seen in approximately one-third of cases. Retinal vasculitis and branch retinal artery and vein occlusions have been reported in some cases.