Immediate changes in intraocular pressure after clear corneal micro-incision versus small-incision cataract surgery

We sought to examine changes in intraocular pressure (IOP) in the immediate period after clear corneal micro-incision cataract surgery (MICS) and after small-incision cataract surgery (SICS).

Sixty-eight eyes of 34 patients scheduled for coaxial phacoemulsification were randomized into one of two groups: (a) eyes that were to undergo a 2.0-mm MICS, and (b) a 2.65-mm SICS. At the conclusion of surgery, the IOP was adjusted to the range between 15-40 mmHg with stromal hydration. The IOP was measured using a rebound tonometer preoperatively, at the conclusion of surgery, and at 3, 6, 9, 12, and 15 min postoperatively. The Seidel test and anterior segment-optical coherence tomography were performed at 20 min postoperatively.

Mean IOP at the conclusion of surgery was 27.7 ± 4.7 mmHg in the MICS group and 29.7 ± 5.1 mmHg in the SICS group (p = 0.1239). In both groups, mean IOP decreased to the preoperative level within 9 min postoperatively and did not change significantly for up to 15 min. Mean IOP was similar between the MICS and SICS groups throughout the observation period (p ≥ 0.1239). Hypotony (≤10 mmHg), positive Seidel test, and loss of wound coaptation were not detected in all eyes.

After adjusting the IOP to a relatively high level at the conclusion of surgery, the IOP decreased within 9 min and was stable within 15 min without hypotony. The IOP was comparable between eyes after MICS and SICS, and both incisions virtually closed within 20 min postoperatively.