Binocular interference vs diplopia in patients with epiretinal membrane

IMPORTANCE Patients with epiretinal membrane (ERM) sometimes close 1 eye for improved vision, but associations have not been rigorously studied. OBJECTIVE To evaluate associations with monocular eye closure in patients with ERM, and to report binocular interference (closing 1 eye to improve visual quality). DESIGN, SETTING, AND PARTICIPANTS Retrospective medical record review of an adult strabismus clinic at a tertiary referral center. Patients with ERM referred from retina clinicians between June 2010 and October 2019 who completed the Adult Strabismus (AS)-20 questionnaire, including the question: "I cover or close one eye to see things better."Two groups were identified: (1) patients reporting eye closure sometimes or more, and (2) patients reporting no eye closure (as control patients). MAIN OUTCOMES AND MEASURES Frequencies of (1) central-peripheral rivalry (CPR)-type diplopia (dragged fovea diplopia); (2) binocular interference (monocular eye closure but no diplopia or strabismus); and (3) other, associated with monocular eye closure. Visual acuity, metamorphopsia, aniseikonia, and AS-20 quality of life domain scores (self-perception, interactions, reading function, and general function) compared between binocular interference, CPR-type diplopia, and control patients. RESULTS A total of 124 patients with ERM (58 of 124 were women [47%]; mean [SD] age, 70 [9] years) reported monocular eye closure. Associations were binocular interference in 36 (29%; 95%CI, 21%-38%), CPR-type diplopia in 34 (27%; 95%CI, 20%-36%), and other (primarily strabismus) in 54 (44%). Compared with control patients with ERM (n = 11), patients with ERM and binocular interference had worse quality of life on AS-20 reading function (95 vs 62; mean difference, 22 points; 95%CI, 7-27 points; P = .007) and general function (89 vs 68; mean difference, 23 points; 95%CI, 13-34 points; P = .01) domains. Compared with CPR-type diplopia, patients with binocular interference had poorer worst-eye visual acuity (median 0.50 vs 0.30 logMAR [20/63 vs 20/40]; mean difference, 0.13 logMAR; 95%CI, 0.00-0.25 logMAR [20/20 to 20/35]; P = .03), and a larger interocular difference (0.46 vs 0.19 logMAR [20/58 vs 20/30]; mean difference, 0.15 logMAR; 95%CI, 0.03-0.28 logMAR [20/21 to 20/38]; P = .004). CONCLUSIONS AND RELEVANCE Study findings suggest that binocular interference, manifesting as monocular eye closure (without diplopia or strabismus), is a distinct entity affecting quality of life in patients with epiretinal membrane.