The Effect of Malyugin Ring in Phacoemulsification Surgery of Cataract with Small Pupil

Abstract

Objective: To assess the effect of Malyugin rings in phacoemulsification surgery of cataract in eyes with small pupils. Methods: This was a prospective case-control study. Twenty-seven microcoria cataract cases (32 eyes) were enrolled and divided into two groups. In Group I (21 eyes), the pupils were dilated by with two instruments. In Group II (11 eyes), the pupils were dilated by Malyugin ring insertion. Clear corneal incisions of 3.2 mm were used in the phacoemulsifications. All cases were followed up postoperatively at 1 week and at 1, 3, and 6 months. Pre- and postoperative values were compared for best corrected visual acuity (BCVA), intraocular pressure, corneal endothelial cell counts, and pupil size. Independent-samples t-tests were used in the analyses. Results: All surgery was completed successfully by the same doctor. All intraocular lenses were implanted within the capsule, and no complications occurred. Measurements for the following pre- and 6-month postoperative parameters were compared: BCVA (LogMAR): Group I, 1.15±0.75 vs. 0.30±0.21 and Group II, 1.42±1.16 vs. 0.30±0.31; IOP (mmHg): Group I, 14.7±4.6 vs. 14.1±6.4 and Group II, 16.1±5.1 vs. 12.4±2.2; Average corneal curvature (diopter, D): GroupI, 44.55±1.83 vs. 44.94±2.70 and Group II, 44.72±1.55 vs. 45.37±1.25; Corneal endothelial cell density (cells/mm2): Group I, 2 490±498 vs. 1 486±612 and Group II, 2 620±989 vs. 2 089±729; Pupil diameter (mm): Group I, 2.0±0.6 vs. 3.3±1.2 and Group II, 2.2±0.8 vs. 3.5±1.2. The parameters of the corneal endothelial cells were statistically different (t=-2.352, P=0.038) after surgery between the two groups, and no statistical difference was found in the other parameters. Conclusions: Use of the Malyugin ring in microcoria cataract phacoemulsification does not affect the 6-month postoperative visual acuity, intraocular pressure, or average corneal curvature. The pupils were enlarged before surgery. Malyugin ring can help reduce the loss of corneal endothelial cells in surgery. Key words: cataract; small pupil; Malyugin ring