Abstract
Purpose :
For monocular patients who are already blind in one eye, loss of vision in the better-seeing fellow eye can be devastating. This study aims to examine the rate of and risk factors for developing fellow eye blindness among monocular patients followed in an academic ophthalmology and optometry practice.
Methods :
We conducted a retrospective chart review of adult patients seen in the University of California San Francisco optometry and ophthalmology clinics from June 2012 to June 2019 with at least 1 year of visual acuity (VA) data. Demographic information and ocular exam data were collected from the medical record. Patients with monocular status were blind (defined as VA 20/200 or worse) in one eye only. Subjects were excluded if the affected eye was subsequently recorded as having a VA better than 20/200. Monocular patients were categorized into subgroups based on level of fellow eye visual impairment: none (VA better than 20/40), mild (VA 20/40 or worse, and better than 20/80), and moderate (VA 20/80 or worse, and better than 20/200). The proportion of patients developing blindness in the fellow eye was determined using Kaplan-Meier analysis for categorical variables and Cox proportional hazards model for continuous variables.
Results :
Of 22,849 adult subjects with at least 1 year of visual acuity data, 3139 (13.7%) were found to have monocular status within the study period. The length of follow-up did not differ significantly for those with no, mild, or moderate fellow eye visual impairment (p=0.4). Of all monocular patients, 519 (16.5%) went on to develop blindness in the fellow eye. Kaplan-Meier analysis demonstrated a significant difference in the rate of conversion to bilateral blindness based on degree of visual impairment in the better-seeing eye (p<0.01). There was no significant association between fellow eye blindness and age, gender, ethnicity, marital status, smoking status, need for interpreter, or San Francisco residence (all p>0.05).
Conclusions :
At this academic practice, a high percentage of patients were found to have monocular vision. Those with greater visual impairment in the fellow eye were more likely to develop bilateral blindness during the study period, but no risk factors were identified among demographic characteristics. Further aims of this study are to determine the causes of fellow eye blindness in monocular patients, in an effort to prevent this devastating outcome.
This is a 2020 ARVO Annual Meeting abstract.