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J. B. Orr, L. S. Gray, D. Seidel, M. Day, N. C. Strang; The Relationship Between Target Luminance, Pupil Diameter and Accommodation in Emmetropia, Myopia and Hyperopia. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2009. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the relationship between target luminance, pupil diameter and accommodation in emmetropic, myopic and hyperopic subjects
Thirty visually normal subjects (mean ± SD age: 25.36 ± 4.50 years) participated with informed consent in the experiment. Refractive error (MSE) ranged from -10.00D to +4.00D; this was fully corrected using soft daily disposable contact lenses. Subjects viewed a 6/12 Snellen equivalent target, illuminated by a slide projector, in a Badal optical system, at accommodation stimulus levels of 0D and 3D. Subjects with an accommodation response lag/lead >0.5D were excluded. Target luminance levels of 10, 100, 200, 400, 1000, 2000 and 4000 cd/m2 were presented in increasing order of luminance, using slides containing ND filters. One minute of adaptation was allowed before readings were obtained at each luminance level. Continuous recordings of monocular pupil diameter of 1minute duration were obtained from the right eye using the Power Refractor II aligned perpendicularly to the viewing system via a hot mirror.
Mean pupil diameter decreased significantly with increasing target luminance for all refractive groups at both accommodation stimulus levels (ANOVA, p<0.005 for all comparisons). Mean pupil diameter was equivalent between the 0D and 3D accommodation stimulus levels for target luminances 200-4000cd/m2 but significantly smaller at 3D for target luminances 10cd/m2 (ANOVA, F1, 50=3.348, p<0.05) and 100cd/m2 (ANOVA, F1, 50=3.429, p<0.05). Mean pupil diameter was not significantly different between the refractive groups in any of the viewing conditions.
Pupil diameter is independent of refractive error. Pupil diameter is determined by an interaction between the pupillary light response and near-induced miosis. At high luminance levels, near-induced miosis is overridden by the pupillary light response.
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