The Effect of Lens on the Contractability of Ciliary Muscle

ABSTRACT

There are many factors affecting the outflow facility. Structural changes of aqueous outflow channel by ciliary muscle contraction play major role in the control of outflow facility. Although many studies on the physiology of outflow facility have been done by many authors, the lens effect on the ciliary muscle contractability has not been reported. We performed clear corneal phacoemulsification and foldable intraocular lens implantation in 42 cataract patients and measured intraocular pressure(IOP) pre and postoperatively by Goldmann applanation tonometer and determined outflow facility with and without 2% pilocarpine before and after cataract surgery, respectively. We analysed IOP changes after surgery, and assessed ciliary muscle contractability by analysing outflow facility changes. Statistical analysis was done by Wilcoxon`s signed rank test. IOP decreased by 2.4+/-0.4mmHg(mean+/-SEM)(P<0.001) outflow facility with and without pilocarpine increased by 0.080+/-0.012microliter/min/mmHg(P<0.001) and 0.045+/-0.006microliter/min/mmHg(P<0.01), respectively after lens extraction outflow facility increased 2.8+/-0.4 times by pilocarpine itself after lens extraction(P<0.001). The lens connected to the ciliary muscle muscle by zonnule may have an influence on ciliary muscle contractability.