(See Figure 11.31.1.)
Critical
Yellow, round, subretinal lesion(s) likened to an egg yolk (lipofuscin) or in some cases to a pseudohypopyon. Typically bilateral and located in the fovea, measuring approximately one to two disc areas in size. Likely present at birth, though may not be detected until examination is performed. Ten percent of lesions are multiple and extrafoveal. ERG is typically normal, while EOG is abnormal, showing severe loss of the light response.
Other
The lesions may degenerate, and patients may develop macular CNV (20% of patients), hemorrhage, and atrophic scarring. In the scar stage, it may be indistinguishable from AMD. Hyperopia is common due to shortened axial length along with angle closure glaucoma; may also have esophoria or esotropia.
Inheritance
Autosomal dominant with variable penetrance and expression. Due to mutation of the BEST1 gene. Carriers may have normal fundi but an abnormal EOG.
There is no effective treatment for the underlying disease. Treatment for CNV is controversial because it may heal without devastating visual loss. In the era of intravitreal anti-VEGF agents, these are now typically first-line agents for CNV, but PDT and focal laser may also play a potential role. Additionally, due to development of subretinal hemorrhage with mild trauma, polycarbonate lenses are recommended at all times and especially while playing sports. See 11.17, NEOVASCULAR OR EXUDATIVE (WET) AGE-RELATED MACULAR DEGENERATION, for detailed treatment options for CNV.
Patients with CNV should be treated promptly. Otherwise, there is no urgency in seeing patients with this disease. Patients are given an Amsler grid (see Appendix 4, AMSLER GRID), instructed on its use, and told to return immediately if a change is noted.