Accommodation In The Primate Eye Following Intraocular Lens Implantation

Abstract

Abstract: : Purpose: To evaluate the accommodative potential in 3 rhesus monkeys (Macaca mulatta) eyes following implantation of an experimental flat silicone disk intraocular lens (IOL) in one eye (8.5mm diameter, n=1; 9.0mm, n=2) and either a SI40NB or SI30NB (standard clinical IOLs) in the opposite eye. Methods: The function of the ciliary body (CB) and lens (natural and IOL) was evaluated by Scheimpflug photography, color slit–lamp photography, ultrasound biomicroscopy (UBM) and goniovideography (GV) in rhesus monkeys (6 to 9 years old) before and after IOL insertion and before and during pharmacological stimulation (CARB; 40% carbachol intontophoresis 2x15 sec) of the ciliary muscle to induce accommodation. Refraction (Hartinger coincidence refractometer) and anterior chamber (AC) depth (A–scan) were also measured before and after CARB. Results: Following all IOL insertions, signs of inflammation included AC cells and fibrin that subsided after one month. No significant change in refraction occurred in the two animals with the 9.0 mm silicone disk IOL and the SI40NB IOL. In the animal that received the 8.5 mm silicone disk (OD), CARB induced 3.25 and 2.9 Diopters (D) of accommodation at 3 and 12 months post IOL insertion respectively. In the opposite (SI30NB IOL) eye, CARB induced 2.00 D, 1.45 D, and 1.83 D of accommodation at 3, 11 and 12 months respectively. Conclusions: Approximately 1 D more accommodation was attained with the 8.5 mm silicone disk IOL vs. the standard clinically used IOL, but the amplitudes were small compared to normal phakic eyes. That accommodation was attained with the 8.5 mm silicone disk IOL but not the 9.0 mm silicone disk may be due to a more precise fit of the 8.5 mm silicone disk IOL inside the capsular bag.

Keywords: aging: visual performance • reading • refraction