Confidence intervals for change in automated visual fields.

Three successive fields of 136 eyes (86 patients) were extracted from our data base containing over 3000 visual fields performed on the Humphrey visual field analyser with program 30-2. Series of fields in which the second field was depressed relative to the first were selected for analysis to determine how much change between the first two fields was required to predict a downward trend as confirmed by the third field in the series. The data were stratified with respect to initial field damage. Seven regions of the visual field were analysed including the upper and lower temporal and nasal quadrants, the superior and inferior Bjerrum regions, and the whole field. Minimally damaged regions required between 4.7 and 5.6 dB change in mean sensitivity, whereas more damaged regions required between 5.5 and 7.2 dB change in mean sensitivity to have 95% confidence that the negative trend would be confirmed by the third field. The superior Bjerrum region was the most sensitive for the detection of change, and the lower temporal region was the least sensitive. We conclude from this series of data that large changes between two successive fields are required to be sure that the changes are due to disease rather than chance fluctuation. Where any doubt exists, the field should be repeated to confirm the reality of change.

Ghost cell glaucoma in phakic eyes.

We report 3 cases of ghost cell glaucoma all of which occurred in phakic patients with onset between 18 months and 4 years after vitreous haemorrhage. There appears to have been spontaneous disruption of the anterior hyaloid face in all 3 cases. Control of the glaucoma was achieved by medical treatment in one case and by trabeculectomy in two.

Prognostic factors in malignant melanoma of the choroid: a retrospective survey of cases occurring in Northern Ireland between 1965 and 1980.

In Northern Ireland between 1965 and February 1980 one hundred eyes were enucleated following diagnosis of malignant melanoma of the choroid. The pathology of 87 cases was available for re-examination. Data on those patients still alive were examined together with the post-mortem reports of those deceased. A mathematical model was constructed to assess tumour volume more accurately. Survival was analysed using univariate and multivariate methods. Actuarial survival curves were constructed and two multivariate regression models were used--the proportional hazards model and the log-logistic model. In addition person years at risk analysis was used to compare survival with the Northern Ireland population. When the data were examined univariately, the location of the tumour, cell type, degree of invasion and the parameters of size (height, diameter and volume) were all significant prognostic indicators. When multivariate analysis was employed, the degree of invasion did not contribute significantly to the model, this being accommodated by tumour size. Cell type was also shown to be of less importance in the multivariate models. The various prognostic indicators together with the person years at risk analysis are discussed.

Progression of field loss after trabeculectomy: a five-year follow-up.

We report a retrospective study of 60 eyes from 46 patients all with primary open-angle glaucoma who had a trabeculectomy to one or both eyes. A minimum five-year follow-up was available. The percentage pressure reductions at the one and five years postoperatively is shown. In a subgroup of 50 eyes which had Goldman fields documented at least six-monthly for a minimum of five years postoperatively there was a continuation of glaucomatous field loss in 18% of eyes despite postoperative pressures in the normal range. The five-year percentage pressure reduction and the minimum percentage pressure reductions were statistically significant in a comparison between the field loss and no field loss groups. However, in the individual case there seemed no way of predicting which eyes would develop postoperative field loss, and regular postoperative perimetric assessment was found to be essential whatever the pressure measurements recorded.