Objective: To analyze the long-term safety of implantation of iris-fixed phakic intraocular lens (IOL) Verisyse for the treatment of high myopia.
Methods: One hundred and eighteen eyes of 59 cases implanted Verisyse for high myopia in Eye Center of Tongren Hospital from Jan. 2005 to Jan. 2007 were followed up for 48 to 72 months, mean time period was (56.2 ± 16.9) months. There were 32 male cases (64 eyes) and 27 female cases (54 eyes). Age ranged from 22 to 39 years old, mean (26.6 ± 7.5) years. The uncorrected vision acuity was 0.02 - 0.08, and the best corrected vision acuity was 0.3 - 1.0. The visual acuity, refraction, intraocular pressure, corneal endothelium and the distance between Verisyse to corneal and lens was measured separately, and the complications were also observed. The results were treated with analysis of paired-samples t test and Fisher exact probability test. A difference at P < 0.05 was considered to be statistically significant.
Results: The complications included the dislocation of Verisyse into anterior chamber in 8 cases (8 eyes, 6.78%), retina detachment in 2 cases (2 eyes, 1.69%), corneal endothelium lost more than 1000/mm(2) in 6 cases (7 eyes, 5.93%), corneal edema in 1 case (1 eye, 0.84%). Pre-operative mean corneal endothelium density was (2821 ± 117)/mm(2), and it was (2249 ± 654)/mm(2) after surgery. There was no significant difference (t = 1.112, P = 0.09) between pre- and post-operative data. Post-operative uncorrected vision improved 5 to 8 lines than that of pre-operation. Post-operative corrected vision improved 1 to 3 lines than that of pre-operation except 1 case (1 eye) developed corneal decompensation and 2 cases (2 eyes) developed retina detachment. SE showed no significant difference in long-term after operation compared with 3 months after surgery (t = 0.641, P = 0.21). The mean intraocular pressure was (16.4 ± 3.4) mm Hg (1 mm Hg = 0.133 kPa). The distance between anterior surface of IOL and endothelium was (2.468 ± 0.342) mm, distance between posterior surface of IOL and lens was (0.652 ± 0.176) mm, and distance between edge of IOL and peripheral endothelium was (1.728 ± 0.213) mm except eyes occurred Verisyse dislocation. Verisyse dislocation occurred more commonly when the iris was not perfectly crapped in the loop, and the difference was significant (P = 0.000). No glaucoma occurred.
Conclusions: Implantation of Verisyse can correct high myopia effectively. But it damages corneal endothelium in some cases. This complication may be related to the unstable position of Verisyse in the anterior chamber. So we should pay more attention to the safety of this kind of phakic IOL clinically.