Some factors affecting the intraocular pressure reduction after argon laser trabeculoplasty in open-angle glaucoma

One hundred and thirty-five eyes in 120 patients with open-angle glaucoma were treated with argon laser trabeculoplasty and followed up for 6 months. The mean reduction in intraocular pressure in the whole material was 10.9 mmHg. 13.1 in eyes with capsular glaucoma and 7.2 in eyes with simple glaucoma. The possible influence of the degree of trabecular pigmentation, the pre-treatment intraocular pressure level and the presence of exfoliative material on the amount of pressure reduction was analysed. The presence of some trabecular pigmentation was a prerequisite for the effect of ALT, but the degree of pigmentation did not influence the pressure-reducing capacity of argon laser trabeculoplasty. The pressure reduction was found to be correlated to the pre-treatment intraocular pressure level without influence of the presence of exfoliative material. Eyes with capsular glaucoma had higher pre-treatment intraocular pressures and seldom had non-pigmented trabecular meshwork, which may explain the greater pressure reduction in this group.