First Author: S.M.Dsouza INDIA
Co Author(s): R. Battu R. Shetty B. Shetty 0 0 0 0 0 0 0 0 0
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Bests vitelliform dystrophy is characterized by abnormal deposition of lipofuschin between the sub-RPE layer and bruchs membrane. Typical manifestations and progression of Best disease through different clinical stages based on ophthalmoscopic appearance . Adult onset foveo-vitelliform macular dystrophy (AOFVD) is a dominantly inherited macular disorder. Characterized by mild visual loss, onset in midlife, and various patterns of unilateral or bilateral foveal yellowish deposits in the pigment epithelium. Despite numerous clinical studies, AOFVD is still considered difficult to classify. The various descriptions do not make for an easy diagnostic approach, and this disease is often confused with other pigment epithelium alterations.
The study was done at Narayana Superspeciality eye hospital Bangalore which is a tertiary care referral centre.
we describe the pattern and evolution of vitelliform alterations ranging from stage 0, with a normal fundus, to stage4, with fibrosis or atrophy. In three cases complete ophthalmic evaluation, Fluorscein angiography, ERG, EOG and spectralis OCT was done.
In the first patient right eye had the previtelliform stage and the left eye had the vitelloeruptive stage with CNVM. High resolution spectralis OCT showed revealed a normal appearance of all major intra-retinal layers until the external limiting membrane (ELM). The central retinal thickness, defined as the distance from the internal limiting membrane (ILM) to the photoreceptor outer segment layer (PR OS), was normal. The other 3 patients had the “pseudohypopyon stage” in the right eye and the “scrambled egg stage” in the left eye, wherein OCT demonstrated that the lipofuscin accumulated in a cystic space underneath the retinal pigment epithelium in the “pseudohypopyon stage” of Best’s disease and the disruption of the photoreceptor layer in the “scrambled egg”stage.In the pseudohypopyon” stage, lipofuscin accumulates in the subretinal pigment epithelium cystic space, at least in the early stages, and that in the later stages it could increase in height to cause photoreceptor dysfunction and visual loss.
The high backscattering signal reflected at the inner and outer photoreceptor segment interface showed a slight loss of continuity as well as less reflectivity in the center of the macula. Additionally, the highly reflective signal band, indicating the retinal pigment epithelium/photoreceptor complex that is located right underneath the OS PR, appears thinner and less reflective, probably because of melanin changes in the retinal pigment epithelium or deposits in or underneath the retinal pigment epithelium. Further characterization of microstructural alterations on optical coherence tomography can help in monitoring the stability of the disease
We think these new OCT findings would help in better understanding of Best’s disease. Lipofuscin accumulates in the subretinal pigment epithelium cystic space, at least in the early stages, and that in the later stages it could increase in height to cause photoreceptor dysfunction and visual loss. The compression of the neurosensory retina overlying the pigment epithelium lesion most likely accounts for degeneration and resultant metamorphopsia typically occurring in this condition. High resolution OCT is a non-invasive intervention that provides insight into the morphology of Best’s dystrophy.