Performance of a temperature-controlled shape-memory pupil expander for cataract surgery.

PURPOSE: To perform ex vivo and in vivo validation of a manufactured, optimized shape-memory pupil expander and compare its performance to that of existing devices.

SETTING

National University of Singapore and SingHealth Academy.

DESIGN

Prospective randomized blinded assessment.

METHODS

Shape-memory expanders were manufactured by overmolding and were inserted into ex vivo porcine eyes and in vivo monkey eyes for validation. The shape-memory expander was compared to the Malyugin ring, OASIS iris expander, and iris hook. After insertion and removal of the devices, the eyes were fixed, and the iris images were analyzed.

RESULTS

The shape-memory was successful in pupil expansion for both in vivo and ex vivo experiments. Subsequent ex vivo device comparison revealed iris pigment epithelial loss in 36.4% of eyes for the iris hooks, 30.8% for the iris expander, and 20.0% for the Malyugin ring. Sphincter tears were observed in 27.3% of eyes for the iris hooks and 10.0% for the Malyugin ring. No observable tissue irregularities were observed in the shape-memory expander.

CONCLUSION

The shape-memory expander was optimized to minimize stress exerted onto the iris tissue. The in vivo and ex vivo experimental validation demonstrate efficacy in engineering design and further highlight the translational potential of smart materials in implant development to improve patient healthcare.