Abstract
Purpose: :
Pilocarpine induced accommodation is frequently used to study the mechanism of accommodation and to test accommodative intraocular lenses in Non-human primates such as Rhesus and Cynomolgus monkeys. However there are no systematic studies that evaluated if topical application of pilocarpine effectively induces accommodation, specifically, in Cynomolgus monkeys. Therefore, the purpose of this study was to determine if topical application of pilocarpine induced accommodative lens changes in adult Cynomolgus monkeys.
Methods: :
All subjects underwent bilateral iridectomies. To facilitate measurements, all subjects were anesthetized. Spectacle plane refractive status was determined for both eyes of 20 monkeys using a custom designed eccentric photorefractor and retinoscopy. Ultrasound biometry was performed to image the natural crystalline lens. Following these baseline measures, two drops of 4 % pilocarpine ophthalmic solution was topically instilled in both eyes of all monkeys twice, at 20 minutes interval. About 40 minutes following pilocarpine instillation, refraction measures and UBM imaging were repeated on all subjects. The change in refractive status of the eye was defined as pilocarpine induced accommodation. The change in the crystalline lens thickness and equatorial diameter were calculated from UBM images through offline analysis.
Results: :
Average pilocarpine induced accommodation measured with photorefraction and retinoscopy were 7.2 ± 3.4 D and 6.9 ± 3.7 D, respectively. The pilocarpine induced dioptric change was associated with a mean decrease in equatorial lens diameter (0.47 ± 0.26 mm) and a mean increase in central lens thickness (0.45 ± 0.20 mm).
Keywords: accomodation • presbyopia