Filling-in phenomenon occurs mostly in patients with bilateral central scotoma

The filling-in phenomenon occurs more frequently in patients with bilateral central scotoma from age-related macular degeneration than in patients with unilateral scotoma, according to a study. It almost always occurs in the patient’s less affected eye, the study authors found.

Salomon Yves Cohen and colleagues in Paris assessed the phenomenon in 16 patients with unilateral central scotoma and 14 patients with bilateral central scotoma using a scanning laser ophthalmoscope. The limits of the scotoma obtained with a point test corresponded to the anatomic edges of the macular lesion. Comparing the point test results to a line test, the investigators were able to determine when the filling-in phenomenon was present.

For patients with bilateral central scotoma, the filling-in phenomenon was observed in 12 of 14 less severely affected eyes, but in only one of the more severely affected eyes. For patients with unilateral central scotoma, the phenomenon was observed in only one of 16 eyes.

The study is published in Graefe’s Archive for Clinical and Experimental Ophthalmology.