Corneal morphology following use of Malyugin versus B-hex pupil expansion rings in small pupil phacoemulsification

Abstract

The aim of the study is to evaluate changes in corneal parameters following the use of the Malyugin ring (MR) and B-Hex ring (BhR) in small pupil phacoemulsification. A prospective cross-sectional study. 51 eyes with small pupil underwent phacoemulsification with the use of MR and BhR as pupil expansion techniques. Best-corrected visual acuity (BCVA), endothelial cell counts density (ECD), coefficient-of-variation (CV), hexagonality, central corneal thickness (CCT), and intraocular pressure (IOP) were recorded on preoperative day and postoperative day 1 and day 30. Mean age at presentation was 70.9 ± 4.1 years. The most common cause for small pupils was alpha-blockers used in benign prostate hypertrophy, followed by diabetes mellitus and pseudo-exfoliation syndrome. Mean preoperative BCVA (3/60–6/12), IOP (17.12 ± 2.81 mmHg), CCT (530.96 ± 44.47 μ), ECD (2347.96 ± 298.09 cells/mm2), 6A (48.92% ± 6.34%) and CV (39.50 ± 3.49) changed to BCVA (6/9–6/6), IOP (18.69 ± 1.91 mm of Hg), CCT (536.04 ± 37.61 μ), endothelial cell count (2201.15 ± 276.75 cells/mm2), 6A (45.12% ±4.99%), and CV (37.57 ± 3.37) at day 30 postoperatively after use of MR. Similarly, mean preoperative BCVA (3/60–6/12), IOP (16.40 ± 2.42 mmHg), CCT (532.40 ± 36.14 μ), ECD (2433.68 ± 162.01 cells/mm2), 6A (48.84% ± 3.73%), and CV (39.36 ± 3.915) changed to BCVA (6/9–6/6), IOP (17.68 ± 2.75 mmHg), CCT (546.88 ± 31.25 μ), ECD (2322.08 ± 167.97 cells/mm2), 6A (46.36% ± 3.25%) and CV (38.96 ± 4.43) at day 30 post-operatively after use of BhR. The average change was clinically insignificant at day 30. MR and BhRs are safe pupil expansion devices and the corneal parameters are in the acceptable range of any routine phacoemulsification for senile cataracts. Nevertheless, B-hR shows relatively less alteration in corneal parameters, when compared to MR.