Monocular Eye Closure May Be Underreported by Patients with Epiretinal Membrane

Patients with epiretinal membrane (ERM) do not always tell their ophthalmologist that they tend to cover their affected eye for better vision, according to recent research. This monocular eye closure may negatively impact their quality of life in measures of reading and general function, according to the study published in JAMA Ophthalmology. The investigators looked into the prevalence and consequences of this behavior. 

Researchers conducted a retrospective medical record review of 124 patients with ERM who reported monocular eye closure. As part of their initial examination at an adult strabismus clinic, patients responded to the Adult Strabismus-20 (AS-20) questionnaire on aspects of health-related quality of life including; self-perception, general function, reading function, and interactions. 

Researchers applied the term “binocular interference” to describe closing one eye to improve vision, even in the absence of strabismus or central peripheral rivalry (CPR)-type diplopia, and assert that binocular interference is a distinct clinical entity, and a symptom associated with ERM.

“Of the 36 patients with binocular interference, 4 (11%) expressed concerns regarding closing 1 eye by history, as documented in the medical record,” according to the investigators. “Interestingly, for the other 32 patients, there was no mention of closing 1 eye by history, but the symptom of monocular eye closure was elicited using the AS-20 questionnaire.”

Subjects with binocular interference and CPR-type diplopia attained lower mean scores than the control group on the AS-20  in the “reading function” domain (P =.007) and “general function” domain (P =.01).

Due to negative effects of binocular interference on reading and general function, the researchers conclude that treatment options (nonsurgical or surgical) merit investigation to improve or relieve binocular interference. 

“To eliminate or decrease the interference from the macropsia subsequent to the ERM, one needs to filter out the distorted central image of the affected eye,” explains Peter J. Shaw, an associate professor at the School of Optometry and Vision Science, University of Waterloo, Canada. “Adding plus or minus 1.50 D to the affected prescription will blur the central vision such that it makes it easier for the patient to stop trying to fuse the disparate images and focus, so to speak, solely on the central vision information supplied by the unaffected eye.”

Shaw adds that peripheral vision is tolerant of refractive blur, and ERM typically does not cause macropsia in peripheral regions. He cautions that when adding power to a lens, there is a potential for optical aniseikonia when there are different lens powers left to right.

Limitations of the JAMA Ophthalmology study include a small sample size, and a lack of visual acuity and contrast sensitivity data. 

Researchers explained that monocular eye closure was previously studied in relation to cataracts, but “eye closure does not appear to have been previously reported in patients with retinal disease.” 

Peter J. Shaw, OD is CEO, CTO of Shaw Lens Inc., a lens design software company.

Reference

Hatt S, Leske D, Iezzi R, Holmes J. Binocular interference vs diplopia in patients with epiretinal membrane. JAMA Ophthalmology. Published online September 10, 2020. Accessed October 21, 2020. doi: 10.1001/jamaophthalmol.2020.3328.