The effect of 2% pilocarpine on depth of field in different time intervals among presbyopic subjects

Purpose: The aim of this study was to determine the effects of 2% pilocarpine ophthalmic solution on the depth of field and the pupil size of human eye in the presbyopic population. Settings and Design: Prospective experimental study. Methods: The prospective study included 120 presbyopic people aged between 40 and 55. All willing subjects underwent a comprehensive eye examination that included measuring the visual acuity for distance and near, retinoscopy, refraction, anterior and posterior segment examination, depth of field, and pupil size in room illumination. Following a preliminary examination, 2% pilocarpine ophthalmic solution was instilled in both eyes, and after various intervals of 15, 30, and 45 min, the depth of field and the pupil size were measured. Results: Before instillation of 2% pilocarpine solution, the mean pupil size was 0.34 mm with a standard deviation (SD) of +/- 0.37. After instillation, the mean pupil size changed to 2.20, 1.91, and 1.57 mm with SD of +/- 0.43, +/- 0.27, and +/- 0.34 mm, respectively, in 15, 30, and 45 min time intervals. Initial mean depth of field also changed from 1.76 D (SD +/- 0.20) to 1.72, 1.65, and 1.59 D with SD of +/- 0.20, +/- 0.16, and +/- 0.22 D, respectively, in 15, 30, and 45 min time intervals. Conclusion: The study concludes that pupillary miotics create a pinhole effect after the instillation of 2% pilocarpine ophthalmic drop, extending the depth of field. The effect was highly clinically significant at 45 min with a P value <0.001.