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A.W. Siu, J.C. Liyu, E.C. Chan, R.S. Li; Absolute Light Detection and Temporal Modulation Sensitivities: Effects of Pupil Diameter . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4095.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Temporal modulation sensitivity (TMS) and absolute light sensitivity (ALS) are two common visual assessment protocols. This study compared the effects of pupil size on TMS and ALS across the central visual field. Methods:ALS and low flickering frequency TMS (6Hz) for the central visual field were measured from the right eyes of 20 young subjects (21.2 ± 1.3 years old) using an automated perimeter (Medmont M600). The measurements were taken under 3 artificial pupils, i.e. 3mm, 4.3mm and 6mm diameter. The sensitivities were grouped and averaged for different retinal eccentricities (3, 6, 10 and 15 deg). Results:TMS and ALS were reduced with increasing retinal eccentricities (p<0.001) and decreasing pupil sizes (p<0.001). TMS collected from all pupil sizes were significantly different from each other (p<0.001). Similarly, ALS of 3mm pupil was statistically different from those of 4.3mm and 6mm (p<0.003). Comparison of the hills of vision showed that pupil size variation resulted in significantly different slopes (p=0.001). The slopes were also found to be significantly different between TMS and ALS (p=0.012). Conclusions: Dilated pupil (6mm) resulted in significantly higher sensitivities than those of smaller pupil for both visual functions. The difference in the slopes of hills of vision also suggested that the variation in retinal illumination affected the visual responses differently for TMS and ALS.
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