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K. R. Seger, M. Crandall, L. Nan, B.-C. Jiang; The Effect of a Customized Add on Near Work Induced Transient Myopia. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3976.
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A formulation has been developed by Jiang et al (2008) to determine the optimal add which would create the least error in accommodative and vergence responses. In this study we tested whether the calculated optimal add reduces near work induced transient myopia (NITM).
We measured the accommodative error and the near phoria at 40 cm under fully corrected conditions for 19 young adults. Using the formula derived previously we calculated the optimal add power for each of our 19 subjects, consisting of 10 stable myopes (SM), defined as existing myopia which has not progressed more than 0.25D within the last 2 years, and 9 progressive myopes (PM), defined as existing myopes with at least 0.50D increase in myopia within the last 2 years. NITM was obtained by comparing their refraction as determined by a COAS aberrometer immediately before and after performing continuous basic computer work at 40cm for an hour. This was done on two separate occasions, with and without the optimal add, in a randomized order.
For SM without an add, average NITM was 0.154±0.056 (D); with the optimal add NITM was 0.027±0.109 (D). For PM without an add, average NITM was 0.212±0.062 (D); with the optimal add NITM was 0.128±0.101 (D). Comparing the overall groups by ANOVA there is a significant difference in the NITM response between SM and PM (p=.0066). For all the subjects combined there is a significant difference in the NITM response between with an add and without an add (p=.0024). Further analysis with Fisher’s LSD test showed a significant decrease (p<.01) in the NITM response for the SM group with an add compared to the NITM without an add. The decrease in the NITM response with and without an add for PM was not statistically significant. There was not a significant difference between the NITM response without an add when comparing the SM to the PM group. The NITM response with an add showed a significant difference for the SM group compared to the PM (p<.05).
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