The visual performance and metamorphopsia of patients with macular holes

Background: Most patients attain better visual acuity with the elimination of metamorphopsia after successful closure of a macular hole (MH) by vitrec tomy. Objective: To determine the presurgical visual function of eyes with an MH. Methods: We examined 54 eves of 51 patients with an idiopathic MH using the Amsler chart. We evaluated the types of subjective metamorphopsia and comp ared them with the clinical factors associated with MHs. In a prospective s tudy, we performed a montage test on a separate group of 16 patients with u nilateral idiopathic MHs. The patients were asked to choose, while viewing with their better eye, the computer-modified picture that best matched the unmodified image seen by the eye with the MH. Results: From the results of the Amsler chart test, we divided the subjecti ve changes into 2 types of metamorphopsia: of the 54 eyes, pincushion disto rtion (bowed toward the center) was found in 33 (61%), and unpatterned dist ortion (no specific pattern) was found in 21 (39%). Pincushion distortion w as significantly associated with an MH of shorter duration (less than or eq ual to 6 months) (P = .03) and an early stage (stage 2) of MH formation (P = .02). A scotoma was hard to detect, and patients had difficulty describin g their scotomata and distortions. In the montage test, patients with early MHs chose portraits modified with a pincushion type of distortion. Conclusions: We found concentric pincushion metamorphopsia without subjecti ve scotomata, which we suggest arises from an eccentric displacement of the photoreceptors. This accounts for the main characteristic of the visual pe rformance of patients with idiopathic MHs.