Impact of intraocular pressure regulation on visual fields in open-angle glaucoma.

OBJECTIVE: To investigate the correlation of different parameters of intraocular pressure (IOP) to visual field decay in open-angle glaucoma. DESIGN: Analysis of visual field decay during a prospective, randomized clinical trial comparing primary laser trabeculoplasty with medication. PARTICIPANTS: Of a total of 82 included eyes in 82 patients with newly detected high-pressure open-angle glaucomas, 76 (55 capsular, 21 simple) fulfilled the 2-year follow-up with the stated number of reliable visual field examinations and were included in this analysis. INTERVENTION: Automated perimetry and a daytime IOP curve were taken every second month during the 2-year follow-up. MAIN OUTCOME MEASURES: Six IOP parameters were evaluated and correlated to visual field outcome. The subgroups with the two types of glaucoma (capsular and simple) were analyzed separately. RESULTS: Visual field decay showed greater correlation to IOP variation (range and peak) and mean IOP than IOP at start or degree of IOP reduction. The relation between mean IOP and visual field decay in the whole group was not quite linear, with more decay at higher IOP levels. The association between IOP regulation and visual field decay was most pronounced in capsular glaucoma, whereas the results in the small group of simple glaucomas were inconclusive. CONCLUSIONS: Visual field prognosis in high-pressure open-angle glaucoma, essentially capsular glaucoma, is better in patients with smaller IOP variation and poorer in patients with high mean IOP.

Primary argon laser trabeculoplasty vs pilocarpine. III. Long-term effects on visual fields.

In a prospective randomized study on primary argon laser trabeculoplasty vs pilocarpine in 82 newly detected open-angle glaucoma patients, visual field changes were analysed for absolute changes over 2 years on automated threshold perimetry and manual Goldmann perimetry. Regression analysis was also performed using the threshold perimetry examinations taken every second month. Analyses based on automatic perimetry were corrected for eventual bias due to cataract and induced miosis. There was significantly less decay of visual field in the group treated with laser. This was even more pronounced for eyes with capsular glaucoma, especially in the early stage. For the smaller group with simple glaucoma no significant advantage of laser could be shown. Successful intraocular pressure reduction significantly improved the visual field outcome. Laser trabeculoplasty is therefore recommended as primary therapy in capsular glaucoma.

Primary argon laser trabeculoplasty vs pilocarpine. IV. Long-term effects on optic nerve head.

In a prospective, randomized study on primary argon laser trabeculoplasty vs piloparpine in 82 newly detected open-angle glaucomas the progress of optic nerve head damage is presented. In 70 patients reliable stereo photographs could be analysed. In the laser treated group a progression of glaucoma damage after 24 months was seen in 6/37 eyes (16%) and in the pilocarpine-treated group 16/33 (49%) (p = 0.0048). There was a statistically significant favourable outcome if intraocular pressure was regulated in terms of peak and range of pressure, but not average pressure. This was even more pronounced in capsular glaucoma, but not significant for simple glaucoma. Pilocarpine increased the risk for further damage to the optic nerve head 6.4 times compared to laser trabeculoplasty. Thus, laser is recommended as the primary therapy in high tension glaucoma, especially in capsular glaucoma.

Primary argon laser trabeculoplasty vs pilocarpine. II: Long-term effects on intraocular pressure and facility of outflow. Study design and additional therapy.

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.

Primary argon laser trabeculoplasty vs. pilocarpine. Short-term effects.

This is a prospective study of 82 newly discovered patients with simplex or capsular glaucoma from two centres, collected between 1984 and 1989 and selected at random for primary treatment by either laser or pilocarpine. Preliminary two-year follow-up shows that primary laser treatment gives a significantly higher number of patients where the intraocular pressure is successfully controlled. Primary argon laser trabeculoplasty has been carried out in 40 patients. The first treatment was given to either the upper or to the lower half of the trabecular meshwork. In the second treatment after one month the other half was treated. In both groups the first treatment gave the highest pressure reduction. The somewhat higher pressure reduction after upper treatment versus lower was insignificant. The degree of trabecular pigmentation did not influence the two month follow-up result, neither did the type of glaucoma. Of the eyes treated with laser, peripheral anterior synechiae could be seen in 18%. Acute intraocular pressure rises greater than 5 mmHg occurred in 21% of the eyes after the first treatment and in 37% after the second treatment. Pressure rises greater than 10 mmHg occurred in 5% after the first and in 10% after the second treatment. No pressure-lowering substances were given. Considering that 16% of the eyes had an intraocular pressure that was higher than baseline pressure even 6 h after either first or second treatment, it is recommended that a pressure-lowering medication on the day of treatment should be administered.

Intraocular pressure reduction after argon laser trabeculoplasty in open-angle glaucoma. A two-year follow-up.

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.

Repeated argon laser trabeculoplasty.

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.

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.