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S.R. Kasthurirangan, A. Glasser; Age Related Changes in the Near Pupil Response . Invest. Ophthalmol. Vis. Sci. 2005;46(13):719.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: With increasing age, accommodative amplitude decreases and the near pupil response increases. These age related changes have not been systematically compared and quantified in the past. This study explores static and dynamic aspects of changes in the accommodative pupil response with age. Methods: Accommodation and accommodative pupillary responses to 10–15 cycles of step accommodative stimulus demands from 1D to 6D in 1D steps were measured with a PowerRefractor at 25 Hz in 60 subjects (ages: 14 – 41 years, mean ± SD: 25.85 ± 5.67 years). The accommodative and pupil responses for each stimulus were averaged after removing latency and were fitted with exponential functions to obtain amplitudes, peak velocities and time constants. The accommodative amplitude of each subject was measured objectively with a Hartinger coincidence refractometer with a push–up task. Results: Accommodative amplitude decreased linearly with age (slope: –0.26 D/year; p < 0.05). Amplitude of pupil constriction increased linearly with accommodation in 60% of subjects, and in this 60%, the slope of this relationship, (pupil constriction per diopter of accommodation) increased with age (slope: 0.02 mm/D/year; p < 0.05). The amplitude of pupil constriction for a 5D stimulus did not change with age (p = 0.89). The latency of pupil constriction did not change with age (p = 0.34). The peak velocity of pupil constriction was invariant with amplitude of pupil constriction in 87% of subjects. The individual mean peak velocity of pupil constriction did not change with age (p = 0.62; overall mean: 5.86 mm/sec). Time constants increased linearly with amplitude of pupil constriction in 48% of subjects and in this 48%, the slopes of the time constant vs amplitude relationships did not change with age (p = 0.63). Time constant increased linearly with amplitude of pupil constriction for the combined data of all 60 subjects (slope: 0.13 sec/mm; p < 0.05). Conclusions: In the age group 14 – 41 years, an increase in the amount of pupil constriction with age per diopter of accommodative response, but not stimulus amplitude, suggests that the effort to accommodate remains the same while the accommodative response is reduced. The dynamics of the near pupil response do not change over this age range.
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