Post-operative changes in the capsulorhexis aperture: a prospective, randomised comparison between loop and plate haptic silicone intraocular lenses

Purpose There is disagreement regarding whether the capsulorhexis aperture always decreases or may increase post-operatively. The aim of this study wa s to settle the controversy concerning loop haptic silicone lenses and to l earn more of the dynamics of the capsulorhexis relating to plate haptic len ses. Methods We performed a prospective randomised study comparing the post-oper ative changes in capsulorhexis aperture in two groups of eyes implanted wit h either plate or loop haptic silicone intraocular lenses. All the surgery was performed, at a teaching hospital in the United Kingdom, by a single su rgeon, using a standard technique of phacoemulsification. Patients were rev iewed at 2 weeks and 6 months post-operatively. Digital retroillumination i mages of the anterior segment were captured. The area of the capsulorhexis aperture was determined by manually detecting its edge on a computer monito r. Results Forty-eight cases were randomised. The groups were comparable for d emographic variables and mean initial aperture size (p > 0.05). There was a n 8.4% mean decrease in aperture size for the loop haptics, contrasting wit h 4.5% expansion for the plate haptics (p < 0.05). Sixty-five per cent of p atients with the plate haptic underwent enlargement of the aperture, contra sting with 25% for the loop haptic lens (p < 0.05). Conclusions Silicone lenses with plate haptics undergo expansion of the cap sulorhexis aperture more frequently than those with Prolene loop haptics.