Postoperative intraocular lens rotation - A randomized comparison of plateand loop haptic implants

Objective: To compare the postoperative rotation of plate and loop haptic i mplants 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 b y phacoemulsification. Method: Patients with cataract as the only ocular disease were randomly imp lanted with plate or loop haptic implants after uncomplicated phacoemulsifi cation. The baseline position of the IOL was determined from a video frame acquired at the conclusion of surgery. Postoperative IOL position was docum ented using digital retroillumination images at 2 weeks and 6 months after surgery. Capsular fusion patterns were recorded using slit-lamp biomicrosco py. Correlation of IOL rotation with axial length, capsular contraction, an d fusion was attempted. Main Outcome Measures: Early IOL rotation, occurring between surgery and 2 weeks after surgery, was graded as mild (<10 degrees), moderate (10 degrees < to <30 degrees), or severe (>30 degrees) by a semiobjective online compar ison of the images, Late IOL rotation, occurring between 2 weeks and 6 mont hs, was measured more precisely using software developed specifically for t he study. Results: Twenty-three patients were allocated the loop haptic and 25 the pl ate haptic IOL, The groups were comparable for demographic variables and nu mbers of patients excluded from analysis (P >0.05), Five (24%) of 21 of pla te haptic IOLs underwent severe early rotation compared to 2 (9%) of 22 loo p haptics (P = 0.36). The median late rotation was 6.8 degrees for loop hap tics compared to 0.6 degrees for plate haptics (P = 0.0073). Between 2 week s 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 lo op haptics made from polypropylene once capsular fusion has taken place. Lo op haptics invariably rotate anticlockwise after 2 weeks.