Viscosurgical devices can cause significant IOP increases after cataract surgery

Cataract surgery performed using either sodium hyaluronate 1% or hydroxypropylmethylcellulose 2% viscoelastics can cause significant increases in IOP during the first 8 hours postop, according to a randomized study by researchers in Austria.

Georg Rainer, MD, and colleagues at the Medical University of Vienna investigated the natural course of IOP after small-incision cataract surgery using the two viscosurgical devices.

The study included 80 eyes of 40 patients undergoing bilateral surgery for age-related cataract. The researchers randomly assigned the first eye to receive either sodium hyaluronate 1% or hydroxypropylmethylcellulose 2% during surgery. The contralateral eye received the other viscosurgical device, according to the study.

Investigators measured IOP preoperatively, at various intervals beginning at 30 minutes to 24 hours postop and at 1 week follow-up.

The researchers found that, among eyes that received sodium hyaluronate 1%, the highest increase in IOP occurred at 8 hours postop and averaged 5.3 ± 6.4 mm Hg above baseline.

Among eyes that received hydroxypropylmethylcellulose 2%, the highest increase in IOP occurred at 2 hours postop and averaged 7.8 ± 6.1 mm Hg higher than baseline, according to the study.

"Overall, the IOP increase was higher with hydroxypropylmethylcellulose 2% (P = .005)," the authors noted.

IOP spiked to 30 mm Hg or more in five eyes (13%) in the sodium hyaluronate 1% group and in 13 eyes (33%) in the hydroxypropylmethylcellulose 2% group, according to the study.

"A single measurement at 6 hours postoperatively could detect all IOP spikes in the sodium hyaluronate 1% group. In the hydroxypropylmethylcellulose 2% group, a single measurement at 2 hours postoperatively could detect two-thirds of IOP spikes," the authors said.

The study is published in the June issue of Ophthalmology.