Evaluation of ICL Haptic Location and Optic Tilt in Posterior Chamber Postoperative with ultrasound biomicroscopy

Shen Ye, Jianpin TONG, Xinfang CAO, Yang WANG, Tian'an ZHOU

Objective: To measure the optic tilt and observe the haptic position of the Staar Visian implantable contact lens(ICL) in vivid eyes after ICL implantation by a full-scale 50-MHz ultrasound biomicroscopy(UBM).

Setting: Department of Ophthalmology, First affiliated hospital, College of Medcine, Zhejiang University

Methods: It was a retrospective case series, included 10 patients (20 eyes) with ICL implantation for the correction of high myopia. The lens length was calculated according to the corneal horizontal diameter measured by Orbscan II. Patients were followed preoperatively and postoperatively at 1 day, 1 week, 1 month and every month afterwards. Uncorrected visual acuity, best corrected visual acuity, refraction, intraocular pressure, and slit-lamp examining were observed. The accurate position of the lens and their relationship with adjacent structures were observed by ultrasound biomicroscopy (UBM). ICL tilt and trabecular-iris angle (TIA) were meassured. Observations of preoperative following and the last postoperative following were analyzed by SPSS 16.0 software package.

Results: 1. Mean spherical equivalent refraction was changed from -14.96±3.25 diopters (range -8.38 to -18.75diopters) preoperatively to -0.74±0.63 diopters (range -2 to 0.25 diopters) postoperatively. Statistically significant difference was found (t=-19.225 , P<0.05); 2. The mean logMAR BCVA changed from 0.19±0.18 (range 0 to 0.70) preoperatively to 0.04±0.08 (range 0 to 0.30) postoperatively. It was significantly different (Wilcoxon signed ranks test, p<0.05); 3 The intraocular pressure changed from 15.95±3.61 mmHg to 15.65±3.10mmHg，there was no significant difference between them(t=0.28,P>0.05); 4. The average tilt angle of ICL was 1.33±1.19 degrees, ranged from 0.1 to 5 degrees. There was no correlation between the degree of ICL tilt and Spherical equivalent refraction or logMAR BCVA.; 5.Of the 80 haptics imaged, 26(32.5%) were positioned in the ciliary sulcus, 54(67.5%) were not positioned in the ciliary sulcus; 6. The percentage of trabecular-iris angle(TIA) larger than 30º was 15%,，between 21º and 30º was 50%, between 11ºand 20º was 27.5%, smaller than 10º was 7.5%. No correlation between the haptic location of ICL and related TIA .

Conclusions: More than half the ICL were not implanted in the sulus. The new method we designed for tilt measurement with full-scale 50-MHz UBM is valuable. Minimal tilt(within 5 degree) is safe for postoperative positional stability of ICL.

[Key words] ICL; Ultrasound biomicroscopy (UBM); Haptic location; Optic tilt;