Posterior optic buttonholing appears to reduce IOP peaks after cataract surgery

This prospective randomized study compared postop IOP measurement between traditional in-the-bag IOL implantation and a technique that involves buttonholing the IOL through the posterior capsulorhexis. They conclude that the posterior optic buttonholing (POBH) significantly reduces the risk of postoperative IOP peaks, and is equivalent to in-the-bag IOL implantation in terms of surgical challenge, length of surgery and safety.

The study included 30 consecutive patients who underwent bilateral cataract surgery. After performing a primary posterior capsulorhexis (PPC), one eye also underwent POBH, while the fellow eye had in-the-bag IOL implantation.

Standardized IOP measurements by Goldmann applanation tonometry were performed throughout the first  24 hours after surgery, as well as one week and one month postoperatively.

During the first 24 hours after surgery, all IOP measurements were significantly lower in eyes with combined PPC/POBH compared to the PPC only group (p<0.001). IOP measurements were highest in the first postoperative hour in both groups. However, in the combined group, no IOP peaks of more than 27 mmHg were observed, whereas in the PPC only group seven patients had an IOP peak of more than 27 mmHg and four IOP peaks of more than 30 mmHg. At one week postop, IOP was similar in both groups (p>0.05). All patients achieved a BCVA of Snellen 6/6 or better four weeks after surgery, and no intra- or postoperative complications were observed.

The authors conclude that this technique would be especially advantageous in pediatric cataract cases since the primary opening of the lens capsule is mandatory in these patients. They also believe it has the potential to become a routine alternative to standard in-the-bag IOL implantation because it offers significantly reduced postoperative anterior movement of the IOL, which results in increased predictability and stability of postoperative refraction.