Validation of Near Eye Tool for Refractive Assessment (NETRA) – Pilot Study

Abstract

Background: Uncorrected-refractive-error (URE) is the leading cause of global vision impairment (VI); 122.5 million people are estimated VI from URE. NETRA is a $30USD clip-on application for smartphones. Purpose: To validate the NETRA as an alternative to subjective refraction for potential use in resourcepoor countries. Methods: NETRA uses a pinhole mask attached to a smartphone displaying a spatially resolved pattern to the subject. Refractive error is estimated by the patient subjectively aligning patterns by a touchscreen interface on the smartphone. NETRA was compared to subjective refraction in 34 eyes.Results: The mean Subjective Spherical Equivalent (SSE) was -0.65D (std 2.79, 95%CI ±0.97) Twosided T-test showed that mean SSE is not statistically significantly different (two sided t-test; t=1.6742 p=0.1036, 95% CI±0.29) from the mean NETRA Spherical Equivalent (NSE) . Mean difference of Spherical Equivalents (NSE -SSE) was 0.24D (Std 0.84, 95%CI ±0.29). And NETRA produced a mean VA improvement of 0.44LogMAR (Std 0.52, 95%CI±0.18), or four Snellen lines. Conclusion:In settings where access to a trained refractionist is not possible, NETRA has the potential to estimate refractive error closely enough to render an individual no longer VI from URE. NETRA is potentially a cost-effective tool in meeting the VISION2020 goals to eradicate avoidable blindness and warrants further testing in resource-poor settings.

Design and Clinical Evaluation of a Handheld Wavefront Autorefractor

“…However, in a recent study on 34 eyes, the M measured with the mobile phone refractometer was found to agree within 0.25 D of the SR in only 15% of the measured eyes. 23 There are several areas in which the QS could be improved. The range of the current prototype is limited to subjects with an M of greater than or equal to j6.0 D of myopia.…”

Paradoxes in Eye Health Care in Low-Income Countries and Design Strategies for Mobile Health Technology to Overcome them

“…Smartphones are also being utilized for retina imaging with an indirect lens and the built-in camera [26]. Assessment of refraction with a pinhole adopter attached to a smartphone is also another example to mention [27].…”

Шляхи Розвитку Мобільної Медицини

“…Так, у світовому масштабі рефракція залишається основною причиною всіх порушень зору. Для вирішення цієї проблеми, в рамках виконання програми NETRA (Near Eye Tool for Refractive Assessment) був розроблений оптичний пристрій, пристосований для використання із смартфоном, щоб дозволити виконувати суб'єктивне автоматич-не дослідження [32].…”