Abstract
Purpose::
To evaluate the change of contractility of ciliary muscle induced by pilocarpine in eyes with presbyopia before and after cataract extraction by ultrasound biomicroscopy (UBM).
Methods::
Clear corneal phacoemulsification with posterior chamber intraocular lens (AcrySof SA60AT, Alcon Laboratories) implantation was performed in 8 eyes of 8 subjects. UBM was performed with and without 2 % pilocarpine instillation, before and 2 months after cataract extraction. Mean (±standard deviation) age was 62.25±6.0 years (range; 58-75 years). At each examination, images of the iridocorneal angle including ciliary muscle at the superior, inferior, temporal, and nasal quadrants were obtained. Axial length of ciliary body (CBAXL) and ciliary process-sclera angle (CPSA) were measured. Images of ciliary muscle were compared visually by Adobe Photoshop 7.0, and measured parameters were analyzed by paired t-test.
Results::
CBAXL value with and without pilocarpine before cataract extraction was 1709±145 µm and 1700±157 µm, respectively, and this increase with pilocarpine instillation was not statistically significant (P=0.665). CBAXL value with and without pilocarpine after cataract extraction was 1774±203 µm and 1634±158 µm respectively, and this increase with pilocarpine instillation was statistically significant (P=0.033). Cataract extraction led to a significant increase of CPSA with and without pilocarpine instillation by 8.0±4.0°and 7.1±4.4°, respectively compared with those before cataract extraction (P=0.001 and P=0.000, respectively). Visually compared configurations of ciliary muscle changes were compatible with the analysis of measured parameters.
Conclusions::
Ciliary muscle moved more forwardly by pilocarpine before cataract extraction, however pilocarpine induced inward movement of ciliary muscle increased after cataract extraction. This finding shows that a lenticular sclerotic component influences the contractility of ciliary muscle, and is related to the presbyopia.
Keywords: presbyopia • ciliary muscle • imaging/image analysis: clinical