Validation of an affordable handheld wavefront autorefractor

Rubio M, Hernandez CS, Seco E, Perez-Merino P, Casares I, Dave SR, Lim D, Durr NJ, Lage E
Optometry and Vision Science 96:10 2019
[Journal Link]

Abstract

Significance: There is a critical need for tools that increase the accessibility of eye care to address the most common cause of vision impairment:  uncorrected refractive errors. This work assesses the performance of an affordable autorefractor which could help reduce the burden of this healthcare problem in low-resource communities.

Purpose. To validate the commercial version of portable wavefront autorefractor for measuring refractive errors.

Methods. Refraction was performed without cycloplegia using (1) a standard clinical procedure consisting of an objective measurement with a desktop autorefractor followed by subjective refraction (SR), and (2) with the handheld autorefractor. Agreement between both methods was evaluated using Bland-Altman analysis and by comparing the visual acuity (VA) with trial frames set to the resulting measurements.

Results. The study was conducted on 54 patients (33.9 ± 14.1 years of age) with a Spherical Equivalent (M) refraction determined by SR to range from -7.25 to 4.25 D (-0.93 ± 1.95 D, mean ± standard deviation). Absolute average differences between the portable autorefractor and SR were 0.31 ± 0.27 D, 0.10 ± 0.10 D, and 0.07 ± 0.10 D for M, J₀, and J₄₅, respectively. The device agreed within 0.5 D of SR in 87 % of the eyes for spherical equivalent power. The average VA achieved from trial lenses set to the wavefront autorefractor and SR results was 0.02 ± 0.015 and 0.015 ± 0.042 LogMAR units, respectively. VA resulting from correction based on the device was the same as that achieved by SR in 87 % of the eyes.

Conclusions. This study found excellent agreement between the measurements obtained with the portable autorefractor and the prescriptions based on SR, and only small differences between the VA achieved by either method.