Purpose The purpose of this study was to evaluate the discrepancy between the near visual acuity (VA) measurements using the EyeHandBook smartphone application and the conventional method of using the near vision card. Methods Using similar environmental/ examinational conditions, near VA measurements were obtained and compared using the near vision card and the EyeHandBook app for IPhone 5 from 100 subjects. The obtained data were changed to LogMAR format and the relationship between the two techniques was analyzed by paired sample t-test and scatterplot. Results With a P-value ofo0.0001, our results indicate that the EyeHandBook application running on IPhone 5 overestimates the near VA compared with the conventional near vision card by an average of 0.11 LogMAR unless the measurement done by the near vision card was 20/20. Conclusions Owing to vast utilization of portable high-definition screens in VA measurements, eye-care providers have to be mindful of the potential disparity in VA measurement between different platforms, which in our study was likely secondary to the high contrast and brightness levels of the smartphone's high-definition screen when compared with the near vision card.

Arginase has been reported to reduce nitric oxide bioavailability in cardiovascular disease. However, its specific role in retinopathy has not been studied. In this study, we assessed the role of arginase in a mouse model of endotoxin-induced uveitis induced by lipopolysaccharide (LPS) treatment. Measurement of arginase expression and activity in the retina revealed a significant increase in arginase activity that was associated with increases in both mRNA and protein levels of arginase (Arg)1 but not Arg2. Immunofluorescence and flow cytometry confirmed this increase in Arg1, which was localized to glia and microglia. Arg1 expression and activity were also increased in cultured Muller cells and microglia treated with LPS. To test whether arginase has a role in the development of retinal inflammation, experiments were performed in mice deficient in one copy of the Arg1 gene and both copies of the Arg2 gene or in mice treated with a selective arginase inhibitor. These studies showed that LPS-induced increases in inflammatory protein production, leukostasis, retinal damage, signs of anterior uveitis, and uncoupling of nitric oxide synthase were blocked by either knockdown or inhibition of arginase. Furthermore, the LPS-induced increase in Arg1 expression was abrogated by blocking NADPH oxidase. In conclusion, these studies suggest that LPS-induced retinal inflammation in endotoxin-induced uveitis is mediated by NADPH oxidase-dependent increases in arginase activity.

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