No abstract

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.

In a prospective study 82 patients recently diagnosed with simple or capsular glaucoma were randomized to receive primary argon laser trabeculoplasty or pilocarpine treatment. A 2-year follow-up showed a better success rate in the laser group, with less need for additional therapy. The average intraocular pressure and peak pressure was lower and the daytime pressure variation was significantly less in the laser group. The better increase in facility of outflow in the laser group was not statistically significant. In capsular glaucoma, laser treatment resulted in a significantly lower average pressure than with medication. In simple glaucoma the effect was about the same in the two treatment groups. Increase in facility of outflow was significantly better in simple glaucoma than in capsular glaucoma. High initial intraocular pressure gave a significantly lower success rate. Primary argon laser trabeculoplasty as a single glaucoma treatment seems advantageous in comparison to medication with pilocarpine for regulating intraocular pressure.

In 20 eyes (18 patients) with simple or capsular glaucoma in which a first full-circumference argon laser trabeculoplasty resulted in early or late failure, laser trabeculoplasty was repeated. In 12 eyes the second trabeculoplasty was clinically successful. At an average follow-up time of 30 months after second trabeculoplasty, the treatment was still successful in six patients. Early failure after the first treatment seems to be unfavourable for the outcome of secondary treatment. No correlation was found between the accumulated dose of laser energy delivered into the trabecular meshwork and the degree of intraocular pressure reduction after the second trabeculoplasty in this retrospective study.

One hundred and twenty-eight eyes of 113 pre-surgical patients with open-angle glaucoma, treated with 360-degree orgon laser trabeculoplasty, were followed up for 24 months. Success was defined as an intraocular pressure below 23 mmHg as well as an intraocular pressure reduction of at least 20% with the same medical therapy as given before laser treatment, or less. The total success rate was 64%. In 79 eyes with capsular glaucoma the success rate was 76%, whereas in 49 eyes with simple glaucoma it was 45%. The success rate increased in groups with higher degrees of trabecular pigmentation, probably an effect of a higher proportion of eyes with capsular glaucoma in these groups. Baseline intraocular pressure had no influence on the success rate. No correlation was found between the amount of laser energy delivered and the degree of pressure reduction after 6 months. Neither was there any significant difference in laser energy levels between eyes showing successful results and those regarded as failures at the end of the 2-year follow-up period.