Maximum human objectively measured pharmacologically stimulated accommodative amplitude

Andrzej Grzybowski,^1,2 Ronald A Schachar,³ Magdalena Gaca-Wysocka,² Ira H Schachar,⁴ Barbara K Pierscionek<sup>5

1</sup>Institute for Research in Ophthalmology, Foundation for Ophthalmology Development, Poznan, ²Department of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland; ³Department of Physics, University of Texas, Arlington, TX, ⁴Byers Eye Institute of Stanford University, Palo Alto, CA, USA; ⁵School of Science and Technology, Nottingham Trent University, Nottingham, UK

Purpose: To measure the maximum, objectively measured, accommodative amplitude, produced by pharmacologic stimulation.
Methods: Thirty-seven healthy subjects were enrolled, with a mean age of 20.2±1.1 years, corrected visual acuity of 20/20, and mean spherical equivalent refraction (SER) =–0.83±1.60 diopters. For each subject, the right pupil was dilated with phenylephrine 10%. After 30 minutes, the pupil was measured, the left eye was patched, and the right eye was autorefracted. Pilocarpine 4% was then instilled in the right eye, followed by phenylephrine. At 45 minutes after the pilocarpine, autorefraction and pupil size were again measured.
Results: Mean pupil size pre- and postpilocarpine was 8.0±0.8 mm and 4.4±1.9 mm, respectively. Pre- and postpilocarpine, the mean SER was –0.83±1.60 and –10.55±4.26 diopters, respectively. The mean pilocarpine-induced accommodative amplitude was 9.73±3.64 diopters. Five subjects had accommodative amplitudes ≥14.00 diopters. Accommodative amplitude was not significantly related to baseline SER (p-value =0.24), pre- or postpilocarpine pupil size (p-values =0.13 and 0.74), or change in pupil size (p-value =0.37). Iris color did not statistically significantly affect accommodative amplitude (p-value =0.83).
Conclusion: Following topically applied pilocarpine, the induced objectively measured accommodation in the young eye is greater than or equal to the reported subjectively measured voluntary maximum accommodative amplitude.

Keywords: maximum, accommodative amplitude, objective, pilocarpine