Early detection of Best's disease in childhood due to ineffective orthoptic treatment

BACKGROUND: A meticulous fundoscopy is an essential examination before administering an orthoptic occlusion therapy (patching), even in cases with a "clear indication" for patching. In this case of an 8-year-old hyperopic boy the subsequent fundoscopy revealed a bilateral maculopathy that explained the stagnation of the increase of the monocular visual acuity (VA) in spite of a correctly applied patching. HISTORY AND SIGNS: The patient was a boy (8 years old) with a history of ineffective orthoptic treatment for 15 months due to hyperopia. Complete ophthalmological examination, optical coherence tomography (Cirrus HD-OCT, Zeiss, Germany) and electro-oculography (EOG) were performed. No "everyday" symptoms were found. Best corrected VA (hyperopic) on the right was 10 / 20, on the left 8 / 20. Binocular VA was 20 / 20. 15 out of 15 Ishihara plates were identified on both sides. Orthophoria has been seen. Perimetry revealed bilateral nasal-parafoveal microscotoma. Fundoscopy showed a confined and slightly prominent yellow spot on the temporal side of the fovea. OCT revealed a subfoveal accumulation of solid material in the RPE in both eyes. EOG showed normal findings in our case. THERAPY AND OUTCOME: There was no further deterioration of VA in a follow-up time of 12 months. CONCLUSIONS: Ineffective orthoptic treatment (patching) in amblyopic children should prompt the ophthalmologist to a meticulous fundoscopy, even if done so before patching, which is highly recommended. This young patient had no "everyday" visual symptoms. Because mainly the temporal fovea on both sides was affected, he showed normal binocular VA inspite of bilateral VA reduction. The authors think that this effect is due to biretinal summation (retinal filling in).