Argon laser trabeculoplasty in progressive low-tension glaucoma.

Twenty-two phakic eyes with progressive low-tension glaucoma had a 360-degree argon laser trabeculoplasty (ALT). Seven of these eyes had diurnal curves performed pre- and two months postlaser treatment to measure the effect of ALT on diurnal pressure variation. Sixteen of the 22 eyes (73%) were clinical successes with a 4.9 mm Hg decrease at 12 months in the successful group. However there was a decreasing pressure lowering effect with time with a mean follow-up of 21.6 months. The diurnal curve data showed a 6.2 mm Hg decrease between the mean pressure pretreatment and two months postlaser treatment. The mean peak pressure posttreatment was 13.29 mm Hg, a 6.17 mm Hg decrease from the prelaser mean peak pressure. The finding of 24-hour pressure control and a reduction in the mean peak pressure confirms the usefulness of ALT in progressive low-tension glaucoma and we recommend that it be utilized as the step in between maximally tolerated medical therapy and filtering surgery.