Purchase this article with an account.
Nadine Solaka, Rahul Modi, Hilary Gaiser, Vitor Pamplona, David Schafran, Ran He, Bruce D Moore; COMPARISON OF A NEW PROTOTYPE OF NETRA-G CELL PHONE-BASED REFRACTION WITH SUBJECTIVE REFRACTION. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2722.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess the performance of a cell phone based refracting device (NETRA-G) phase III. This study investigates the accuracy of a new prototype in determining refractive error (RE) in comparison to subjective refraction (SR) in children.
NETRA-G retrofits a high-resolution mobile phone (Sony Xperia U) by adding a pinhole mask, a film and a lens onto a display. The device is bi-ocular with the fellow eye viewing an object at infinity. The subject aligns red and green lines with the translation on screen proportional to RE. Two NETRA-G devices were used in this study differing only by pupillary distance (#244 having a smaller PD). 24 subjects (mean + SD age 14.67±1.60 yrs) underwent SR and NETRA-G refraction with device #243 and19 subjects (mean + SD age 11.11 +/- 2.92 yrs) underwent the same with device #244. Subjects’ RE ranged from -8.25D to +3.50D sph with 0 to -3.00D cyl for device #243, and from -6.25D to +0.75D sph with 0 to -1.50D cyl for device #244. Exclusion criteria included amblyopia and any ocular pathology.
Compared to SR, the absolute mean differences for sph, cyl and axis were 0.48D±0.66 (p-value=0.59), 0.30D±0.42 (p-value=0.20) and 11 deg±6.59 (p-value=0.08) respectively for device #243, and 0.64D±0.71 (p-value= <0.0001*), 0.36D±0.45 (p-value=0.58) and 18 deg±12.70 (p-value=0.72) respectively for device #244. Orthogonal linear regression showed a slope of 0.90 for sph, 0.95 for cyl, and 1.02 for axis and a y-intercept of -0.34D, 0.06D and 2.98 deg respectively for device #243. It also showed a slope of 0.89 for sph, 0.74 for cyl and 0.77 deg for axis and a y-intercept of -0.68D, -0.10D and 34.13 deg respectively for device #244. 72% of subjects achieved a VA of 20/20 or better and 89% achieved a VA of 20/25 or better with device #243. 66% of subjects achieved a VA of 20/20 or better and 89% achieved a VA of 20/25 or better with device #244.
When both devices were compared to SR, device #244 showed an overestimation of myopic RE more than device #243. Tested variables were not statistically significantly different than SR on both devices except for sph power on device #244 which had a significant p-value of <0.0001 (alpha=0.05). This study shows that NETRA-G is an easy and portable way of measuring RE even in younger populations. This device has a potential to be utilized by non-eye care professionals in areas where access to eye care is limited.
This PDF is available to Subscribers Only