One-piece and three-piece MICS IOLs appear to yield similar PCO rate

This prospective randomized study demonstrated that modifying an acrylic hydrophobic IOL from three-piece to one-piece caused no significant change in posterior capsule opacification (PCO) after one year but did result in a significant decrease in capsular folds.

The study enrolled 40 patients (80 eyes) with age-related cataract. Each patient received a one-piece microincision cataract surgery (MICS) IOL in one eye and a three-piece MICS IOL in the other eye.

The mean regeneratory PCO score and the neodymium: yttrium-aluminium-garnet laser capsulotomy rate were comparably low for both IOLs. However, capsular folds occurred significantly more often in the three-piece IOL group.

The authors say the likely reason for more frequent capsular folds in the three-piece group may be that the poly (methyl methacrylate) haptics of the three-piece IOL are stiffer and less compressible than the single-piece IOL haptics and therefore produce a greater pressure force toward the equator of the capsule, leading to capsular over-tension.

The results show that a slightly higher PCO rate was associated with presence of capsular folds. However, they say that this had no influence on visual acuity, likely because the PCO proceeded from the peripheral area behind the IOL optic-haptic junction and had not yet reached the central region around the visual axis in most cases.

They say that since both IOLs are made of the ssimilar design (optic size, sharp edge, haptic angulation), any possible differences in PCO rate and capsular bag performance could be explained only by the variation of haptic design. But they note that the possible impact of haptic design on PCO prevention is controversial.

They conclude that further follow-up is necessary to prove whether the designs are equally ame hydrophobic acrylic material and have a protective against PCO.