Computer-based real-time analysis in mobile ocular screening

Utilizing minicomputer technology for low-cost photorefraction: a feasibility study

Eccentric photorefraction is an objective technique to determine the refractive errors of the eye. To address the rise in prevalence of visual impairment, especially in rural areas, a minicomputer-based low-cost infrared photorefractor was developed using off-the-shelf hardware components. Clinical validation revealed that the developed infrared photorefractor demonstrated a linear working range between +4.0 D and -6.0 D at 50 cm. Further, measurement of astigmatism from human eye showed absolute error for cylinder of 0.3 D and high correlation for axis assessment. To conclude, feasibility was shown for a low-cost, portable and low-power driven stand-alone device to objectively determine refractive errors, showing potential for screening applications. The developed photorefractor creates a new avenue for telemedicine for ophthalmic measurements.