Assessment of phacoaspiration techniques in clear lens extraction for correction of high myopia.

PURPOSE: To evaluate various phacoaspiration techniques in clear lens extraction for the incidence of intraoperative difficulties and complications.

PATIENTS AND METHODS: This was a prospective study in which bilateral clear lens extraction was performed on 40 eyes of 20 patients, to correct high myopia. The patients were divided into 2 groups: group A underwent supracapsular phacoaspiration; group B were the contralateral eyes of the same patient. These patients were operated on with endocapsular phacoaspiration with the divide and conquer (D and C) technique. Preoperative ocular examination data were recorded and tested for significance. Intraoperative difficulties and complications such as nucleus cracking, capsule rupture and vitreous loss, and repeated chamber collapse were recorded. Postoperative examination data were recorded.

RESULTS: Mean age was 35.65 +/- 5.85 years. Mean follow-up time was 17.1 +/- 8.56 months. In group A mean myopia was -17.3 +/- 5.07 diopters; in group B myopia was -17.9 +/- 4.20 diopters. Mean preoperative uncorrected visual acuity (UCVA) was 0.04 +/- 0.0167, while the mean postoperative UCVA was 0.435 +/- 0.1442. There was a significant difference in pre- and postoperative BCVA within both groups, but not between the two groups. In both groups endothelial cell count (ECC) showed a significant difference between pre- and postoperative data; however, there was no statistically significant difference between both groups in postoperative ECC. The effective phacoaspiration time for group A was 4.6 +/- 1.6 seconds, and for group B 9.90 +/- 2.27 seconds (P < 0.005). No cases of capsule rupture occurred in group A, but 3 cases occurred in group B (15 %) (not significant, P = 0.231). Nucleus cracking did not occur in group A, but in group B 13 cases occurred (65%). Chamber collapse occurred in 4 cases (20%) in group A and 5 cases (25%) in group B (not significant, P = 1.000). Three cases of moderate postoperative iritis were recorded in group B in (15%), in which posterior capsular rupture also occurred. No cases of iritis were recorded in group A (not significant, P = 0.231). Two cases of cystoid macular edema were recorded in group B (10%) and none in group A (not significant, P = 0.487).

CONCLUSIONS: Supracapsular phacoaspiration for clear lens extraction in correction of high myopia seems to present no risk for the posterior capsule, although there is a marginal risk to the ECC.