Clinical validation of a novel wavefront autorefractor in a base hospital and vision center in rural India

Methods : Participants were recruited from patients scheduled for a general refraction at Aravind Eye Hospital (base hospital, N=506; and satellite vision center, N=202). Patients were prescribed eyeglasses via subjective refraction (L_SR) by an ophthalmic technician with over four years of refraction experience. Consenting patients that were within the range of the autorefractor (-6D to +10D) were enrolled in the study. Participants were then prescribed eyeglasses with an autorefractor (L_AR) that was an alpha prototype of the QuickSee wavefront aberrometer. The QuickSee is handheld, binocular, open-view, intended to be low-cost, and was operated by a technician with no formal eye care training. The VA and prescription preferences for trial lenses set to L_SR and L_AR were evaluated by a refractionist blinded to the prescription source. The right-eye VA for each patient was converted to LogMar values and analyzed with a paired t-test. Prescription preferences were determined with a survey.

Results : The mean age of participants was 35 ± 13 years (range: 15-70). Of the 708 participants, 220 had presbyopia, 75 had an immature cataract, 21 had conjunctivitis, and 1 had keratoconus. Mean VA was 0.29 ± 0.36, -0.04 ± 0.11, and -0.01 ± -0.15 LogMar units before correction, with L_SR, and with L_AR, respectively. VA was significantly better after correction from both prescription methods (p < 0.01). VA from L_SR was also significantly better than L_AR (p < 0.01). A total of 47%, 91%, and 85% of patients had 20/20 vision or better, before correction, with L_SR, and with L_AR, respectively. Survey results showed 25% of participants had no preference of eyeglasses, 42% preferred L_SR, and 33% preferred L_AR.

Conclusions : Our study shows a small benefit to eyeglasses prescribed by subjective refraction versus a novel autorefractor. Participants using eyeglasses prescribed by the autorefractor achieved a VA that was only approximately one letter worse than using eyeglasses prescribed by a refractionist. More than half of the participants either had no preference or preferred eyeglasses prescribed by the autorefractor. However, the required training to perform autorefraction is considerably shorter compared to subjective refraction.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.