Effect of argon laser trabeculoplasty on the glaucomatous diurnal curve.

Daily pressure variation occurs in all individuals. In glaucomatous patients this variation is marked and may exceed 20 mm of mercury. Argon laser trabeculoplasty (ALT) lowers intraocular pressure (IOP). The effect of ALT on the glaucomatous diurnal curve was studied. Incidence and magnitude of post-trabeculoplasty pressure elevation was documented. Twenty-five patients are reported. All patients were treated according to the protocol advocated by Wise. Diurnal curves were obtained 24 hours prior to ALT, and compared to curves obtained 24 hours and 8 weeks after ALT. Eight weeks after surgery the mean IOP fell 22%; the mean peak pressure fell 25%; the mean pressure range fell 30%; and the pressure fluctuations fell 25%. All values were significant at P less than 0.0005. Pressure elevations greater than 5 mmHg occurred in 46% of patients. The effect of ALT on the diurnal curve of glaucomatous patients may be beneficial. Pressure spikes are frequent.