Effect of previous argon laser trabeculoplasty on the ocular hypotensive action of latanoprost.

PURPOSE: To study the effect of previous argon laser trabeculoplasty (ALT) on the hypotensive activity of latanoprost in primary open-angle glaucoma (POAG).

METHODS

This was a prospective, observer-masked study. We measured the intraocular pressure (IOP) before and after 3 months of monotherapy with latanoprost in 43 eyes that had undergone a previous ALT, and in a control group (not treated with ALT) of 43 IOP-matched eyes with POAG.

RESULTS

Latanoprost induced a 17.4+/-16.6% IOP decrease in the study group (ALT-treated eyes) and a 25.8+/-17.2% IOP reduction in the control eyes (P=0.02, unpaired Student's t-test).

CONCLUSIONS

Latanoprost is less effective in ALT-treated eyes than in eyes with POAG not treated with ALT.