Best's disease
 

Vitelliform stage. Pseudohypopyon stage.

The macula contains well circumscribed, rounded macular lesion measuring about 1 to 2 disc diameter. The lesion  contains yellowish substance show at the inferior half of the lesion (pseudohypopyon). The condition is bilateral  (although the macula may show different stages of Best's disease). Other examination: look outside the macula for smaller lesion Note: Best's disease evolves through five stages. Most patients are over the age of 20 have vitelliform eruptive or  end stages. The end stage may be indistinguishable from age-related macular degeneration. In young patient with  macular atrophy or fibrosis always consider Best disease in your differential diagnosis.

Questions:

1. How is Best's disease inherited?

Answer
Autosomal dominant with variable penetrance. The abnormal chromosome is located in chromosome 11.

2. What are the various stages of Best's macular dystrophy?

Answer
In chronological order the five stages are:
Stage 1 (pre-vitelliform) characterized by an abnormal EOG in an symptomatic patient with no detectable fundus lesion
Stage 2 (vitelliform) shows ill-defined yellow spots at the level of the retinal pigment epithelium due to accumulation of lipofuscin granules.
Stage 3 (pseudohypopyon) occurs when part of the lesion becomes absorbed.
Stage 4 (vitello-eruptive) in which the egg yolk begins to break up and assume a scrambled egg appearance. At this point, the patient usually develops visual impairment.
Stage 5 (end-stage) is characterized by a moderate to severe impairment of visual acuity associated with one of the following macular lesions: a hypertrophic scar or a vascularised fibrous scar with SRNVM or an atrophic lesion.

3. List some of the common hereditary macular disorders.

Answer
Autosomal dominant
cone-rod dystrophy
Best's disease
central areolar choroidal dystrophy
cone dystrophy
Autosomal recessive
Stargardt's disease
degenerative myopia
X-linked recessive
juvenile retinoschisis
cone dystrophy

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