Authors: AC Viswanathan, FW Fitzke, RA Hitchings.

Institute of Ophthalmology, Bath Street, London, UK and Moorfields Eye Hospital, City Road, London, UK.

Purpose: To determine whether increasing the interval between visual field tests affects the ability to detect progressive glaucomatous field loss.

Methods: 119 retinal locations which were deteriorating significantly by more than1dB/year (untreated normal tension glaucoma patients: 6 eyes) were studied. Analysis was repeated using ‘thinned’ data: 1 field per year instead of the full 3 per year over 4 years.

Results: The ‘thinned’ data only identified 45.4% of the deteriorating points over the 4 year period. Furthermore, there was a mean delay of 1.10 years (p<0.01) in detection.

Conclusion: Less frequent visual fields detect fewer progressing locations and detect them later.

(Presented at the American Academy of Ophthalmology Annual Meeting, Atlanta 1995)