Fixation elements on plate intraocular lens: large positioning holes to improve security of capsular fixation.

OBJECTIVE

This study aimed to evaluate in rabbit eyes the effects of large positioning holes in one-piece silicone plate-haptic intraocular lenses (IOLs) with respect to security of capsular bag fixation. Mechanical strength of capsular fixation is correlated with the histologic findings of regenerating lens material and fibrous tissue ingrowth through the positioning holes on silicone plate IOLs, comparing capsules implanted with large-hole style plate IOLs to fellow capsules implanted with small-hole style plate IOLs.

DESIGN

The study design was a prospective, randomized, experimental study.

PARTICIPANTS

A total of 40 fellow capsular bags from 20 New Zealand white rabbits were examined. Capsules implanted with conventional small-hole silicone plate IOLs were used as the control in all pairs of fellow capsules.

INTERVENTION

Phacoemulsification and implantation of a silicone plate IOL with small positioning holes in one eye and implantation of a silicone plate IOL with large positioning holes in the fellow eye were measured. All rabbits were killed at 2 months. The force required to extract the IOLs from the capsular bag was measured. All capsular bags underwent histopathologic analysis.

MAIN OUTCOME MEASURES

Extraction force measurements and histopathologic examination, comparing capsules implanted with small-hole plate IOLs with fellow capsules implanted with large-hole plate IOLs, were measured.

RESULTS

The large-hole style IOL required significantly more force to extract from the capsular bag compared to the conventional small-hole style (P = 0.003). Histologically, proliferating lens epithelial material and fibrous tissue were observed growing through all of the large positioning holes (synechia formation) but not through any of the small positioning holes.

CONCLUSIONS

Silicone plate IOLs with large positioning holes become affixed more firmly within the capsular bag compared to conventional small-hole plate IOLs. These findings suggest that large holes in silicone plate IOLs allow for superior capsular bag fixation. This should reduce the rates of decentration and dislocation.