Postoperative intraocular lens rotation: A randomized comparison of plate and loop haptic implants

Abstract

Objective To compare the postoperative rotation of plate and loop haptic implants of spherical power to ascertain the optimal design appropriate for toric intraocular lenses (IOLs). Design Randomized, controlled trial. Participants Forty-eight patients attending for routine cataract surgery by phacoemulsification. Method Patients with cataract as the only ocular disease were randomly implanted with plate or loop haptic implants after uncomplicated phacoemulsification. The baseline position of the IOL was determined from a video frame acquired at the conclusion of surgery. Postoperative IOL position was documented using digital retroillumination images at 2 weeks and 6 months after surgery. Capsular fusion patterns were recorded using slit-lamp biomicroscopy. Correlation of IOL rotation with axial length, capsular contraction, and fusion was attempted. Main outcome measures Early IOL rotation, occurring between surgery and 2 weeks after surgery, was graded as mild (<10°), moderate (10°< to <30°), or severe (>30°) by a semiobjective online comparison of the images. Late IOL rotation, occurring between 2 weeks and 6 months, was measured more precisely using software developed specifically for the study. Results Twenty-three patients were allocated the loop haptic and 25 the plate haptic IOL. The groups were comparable for demographic variables and numbers of patients excluded from analysis ( P > 0.05). Five (24%) of 21 of plate haptic IOLs underwent severe early rotation compared to 2 (9%) of 22 loop haptics ( P = 0.36). The median late rotation was 6.8° for loop haptics compared to 0.6° for plate haptics ( P = 0.0073). Between 2 weeks and 6 months, anticlockwise rotation had occurred in 16 (89%) of 18 loop haptic IOLs compared to 11 (52%) of 21 plate haptic IOLs ( P = 0.0081). Conclusions Plate haptic IOLs show greater rotational stability than do loop haptics made from polypropylene once capsular fusion has taken place. Loop haptics invariably rotate anticlockwise after 2 weeks.