Use of visual field tests in glaucoma detection by optometrists in England and Wales.

This paper is based on a survey of 241 optometrists (5% of the national total) in England and Wales, which covered many aspects of glaucoma detection. There were 45 optometrists (19%) who did not use a field screener. Of the 196 who did, 173 reported their criteria for deciding which patients to test: 17 (estimated at 8% of the original sample) used a field screener routinely in patients over 40 years; 40 (19%) selectively tested all patients with intraocular pressure > 20 mmHg, together with most others in whom any glaucoma risk factor was present, (this required a visual field test in only one in five patients aged over 40 years and may be relatively cost-effective); the remaining 116 (55%) on average tested less than one in ten of their patients with a field screener, practice which is shown to contribute little to the number of glaucomas detected. Routine field testers had the highest glaucoma detection rates, and those of the selective testers were not significantly lower.