A randomized control study on post-operative iris distortion following small-pupil cataract surgery using B-HEX pupil expander versus Malyugin ring.

Background: The aim of the study was to evaluate postoperative pupil distortion following small pupil cataract surgeries performed using B-HEX and Malyugin rings (MR).

Methods: A randomized control trial was conducted from June 2020 to June 2023 at a tertiary eye-care hospital. The study consisted of 64 participants for cataract surgery with small pupil. There were two groups, one undergoing surgery with the use of B-HEX pupil expander and other with MR intraoperatively and the rest of the surgery was proceeded as per the convention. Areas of preoperative and postoperative images was calculated, put into an online software and pupil distortion was calculated in percentage. Two-tailed t-test was used to see the difference between the two groups.

Results: Mean age at presentation was 70.5 ± 10.12 years. Most common cause for small pupil was tamsulosin therapy. Mean size of small-pupil was 3.0 ± 1.1 mm. With the application of two rings, mean pupillary area preoperatively was 4178.23 ± 1589.46 and postoperatively was 6100.44 ± 2658.28 following the use of MR, respectively and 30,002.93 ± 13,193.40 preoperatively and 37,648.26 ± 15,207.01 postoperatively following the use of B-Hex ring respectively. Comparing baseline area from pupillary area at 1-month follow-up, a significant increase was noted for both the rings. Also, MR caused significantly more pupillary distortion compared to B-HEX ring ( < 0.05).

Conclusion: MR causes significantly more pupillary distortion in the postoperative period compared to B-HEX ring. Though, both the rings cause pupillary distortion, these devices expand the surgical area adequately, ease the procedure, decrease risk of complications achieving good functional visual outcomes.