Investigation of the accuracy of a low-cost, portable, autorefractor to provide well-tolerated eyeglass prescriptions: a randomized crossover trial

To compare patient preferences for eye glasses prescribed using a low-cost portable wavefront autorefractor versus standard subjective refraction.

Randomized, cross-over clinical trial

Patients aged 18-40 years presenting with refractive errors to a tertiary eye hospital in Southern India.

Participants underwent subjective refraction (SR) followed by autorefraction (AR) using the monocular version of the QuickSee device. An independent optician, masked to the refraction approach, prepared eyeglasses based on each refraction approach. Participants (masked-to-refraction source) were randomly assigned to use either SR- or AR-based eyeglasses first, followed by the other pair, for a week each. At the end of each week, participants had vision checked and were interviewed about their experience with the eyeglasses.

Proportion of patients preferring eyeglasses prescribed using AR and SR

The 400 participants enrolled between March 26, 2018 and August 02, 2019, had mean (SD) age of 28.4 (6.6) years and 68.8% were women. There was strong correlation between spherical equivalents using SR and AR (r=0.97, p<0.001) with a mean difference of -0.07 diopters (95% limits of agreement: -0.68 to 0.83). Of the 301 (75.2%) patients who completed both follow-up visits, 50.5% (n=152) and 49.5% (n=149) preferred glasses prescribed using SR and AR, respectively (95% CI: 45.7% – 56.3%; p=0.86). There were no differences in demographic or vision characteristics between participants with different preferences (p>0.05 for all).

We observed strong agreement between the prescriptions from SR and QR, and eyeglasses prescribed using SR and AR were equally preferred by patients. Wider use of prescribing based on AR alone in resource-limited settings is supported by these findings.