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Postoperative intraocular lens rotation: a randomized comparison of plate and loop haptic implants
C K Patel1, S Ormonde, P H Rosen
1Oxford Eye Hospital, Radcliffe Infirmary, England. ckpatel@ukgateway.net
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 degrees), moderate (10 degrees < to <30 degrees), or severe (>30 degrees) 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 degrees for loop haptics compared to 0.6 degrees 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.