YAG laser treatment in a series of failed trabeculectomies.

YAG laser treatment was used in 22 consecutive cases of failed or failing trabeculectomy. Seven treatments were considered to be successful with a mean decrease in intraocular pressure of 9.8 mm Hg (6 to 13 mm Hg) over a mean follow-up period of 10.7 months (two to 18 months). In the successful cases the trabeculectomy was the first intraocular surgery that the eye had undergone and the average time from trabeculectomy to YAG laser treatment was relatively short, 6.7 weeks, compared to 1.1 years for the failures. The major complication was an increase in intraocular pressure of 4 mm Hg or more in nine (60%) of the failed cases two hours after laser treatment.

A comparison of experienced clinical observers and statistical tests in detection of progressive visual field loss in glaucoma using automated perimetry.

The visual fields of 30 patients (subjects) with glaucoma were sent to six experienced clinicians (observers). Each subject had at least four visual field examinations on the OCTOPUS 201 automated perimeter spanning at least one year. Each observer was asked to review the visual field data of each subject and determine whether the visual fields were stable, improved, or worse over time. The visual field data were then analyzed using six different statistical models. In only 15 of the 30 subjects did at least five of the six human observers agree on the behavior of the visual field. Agreement among the statistical models was better, with at least five of the six models agreeing on 22 of the 30 subjects. It was concluded that there is, at present, no validated technique for detecting progressive visual field loss in glaucoma using automated perimetry when relatively few visual fields are available for analysis.

Creation of the transformed Q statistic probability distribution to aid in the detection of abnormal computerized visual fields.

This paper describes the creation of a new Q statistic which can be calculated from the threshold data of a single computerized visual field. The Q statistic can then be used to decide, at a given significance level, whether the individual field is normal or abnormal. The Q statistic is constructed to be particularly sensitive to the situation in which only a small subset of the values in the field is depressed, making it particularly useful in the diagnosis of early glaucoma.