[Posterior chamber phakic intraocular lens for correction of extreme myopia]

Abstract

Objective: To evaluate the efficacy, safety and stability of posterior chamber phakic intraocular lens implantation for the correction of extreme myopia.

Methods: This study included 216 eyes of 113 patients with a mean age of 30 years (18 approximately 49) from January 1997 to December 2005. An implantable contact lens (ICL V2 and V4, Staar Surgical Inc.) was inserted. Patients were examined preoperatively and followed at 1 day, 1 week, 1, 3, 6, 12, 24, and 36 months postoperatively. The examination content included the uncorrected visual acuity, best corrected visual acuity (BCVA), slitlamp examination, refraction, intraocular pressure, endothelial cell morphometry, etc. Spherical equivalent was (17.78 +/- 3.88) diopters before the operation. Surgical implantation was performed through a 3.2 mm clear corneal sutureless incision using paraocular anesthesia. The mean follow-up period was 18.2 months (ranged 6 to 24 months) for refractive data and 24.3 months (ranged 6 to 36 months) for the complications.

Results: Successful implantation was achieved in all patients. Postoperatively, all eyes had a significant increase in uncorrected visual acuity. The mean spherical equivalent refraction at the last examination was (-1.00 +/- 1.40), within +/- 1.00 D of the targeted refraction in 191 eyes (88.4%) and within +/- 0.50 D in 165 eyes (76.4%). In eyes in which the preoperative myopia was less than 20.00 D (n = 151), the achieved refraction was within +/- 1.00 D of the intended refraction in 145 eyes (96.0%) and within +/- 0.50 D in 128 eyes (84.8%). The refraction remained stable with a statistically insignificant change (P > 0.05) at each interval during the follow-up. The best corrected visual acuity (BCVA) improved by 1 or more lines in 168 eyes (77.8%) at 1 year after the operation. Four eyes (1.85%) lost 1 line of BCVA. Pupillary block glaucoma requiring surgical intervention occurred in 4 eyes (1.85%). Three eyes (1.39%) developed cataract 1 year after ICL (V2) implantation, all ICLs in these eyes were removed, and the refractive errors were corrected by lensectomy and implantation of low-power posterior chamber IOLs. BCVA was mentioned in all of these eyes.

Conclusion: Posterior chamber phakic intraocular lens implantation appears to be an effective, safe and reliable method for the correction of extreme myopia.