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

Aim: 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. Methods: 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. Results: 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. Conclusion: 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.