HPMC & sodium hyaluronate cause IOP increases

Sodium hyaluronate 1% and hydroxypropylmethylcellulose 2% (HPMC) can cause significant intraocular pressure (IOP) increases during the first eight hours following cataract surgery, according to a study published in the June issue of Ophthalmology.

Georg Rainer and colleagues from the Medical University of Vienna, Austria enrolled 80 eyes of 40 patients with bilateral age-related cataract. The subjects were randomized to receive either sodium hyaluronate 1% or HPMC 2% during cataract surgery of the first eye. The second eye received an alternative viscosurgical device. IOP was measured preoperatively and 30 minutes, one, two, three, four, six, eight, 20 and 24 hours and one week postoperatively.

The researchers found that the highest mean IOP increase occurred at eight hours postoperatively (5.3±6.4 mmHg) in the sodium hyaluronate 1% group and at two hours postoperatively in the HPMC 2% group (7.8±6.1 mmHg). The mean IOP increase was higher in the HPMC 2%group (r=0.005). IOP spikes (≥30 mmHg) were seen in five eyes (13%) of the sodium hyaluronate 1% group and 13 eyes (33%) of the HPMC 2% group.

It was concluded from the study results that both sodium hyaluronate 1%% and HPMC 2% can cause significant IOP increases during the first eight hours following surgery.