Authors: AC Viswanathan, FW Fitzke, RA Hitchings.

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

Purpose: To compare the performance of PROGRESSOR (pointwise linear regression) and Statpac 2 (comparison with baseline values) in detecting early deterioration in the visual fields of normal-tension glaucoma (NTG) patients.

Methods: Visual field series from 19 untreated NTG eyes which were deteriorating on clinical grounds were analyzed by PROGRESSOR and Statpac 2. Progression criteria for PROGRESSOR were 1) inner points: slope < -1 dB / yr, p < 0.05 and 2) edge points: slope < -2 dB / yr, p < 0.05. Criteria for Statpac 2 were p < 0.05 change probability for any point on 3 consecutive fields. Detection time was defined as the time interval between the initial field and the first field in which at least one progressing point was identified. Detection times produced by the two techniques were compared.

Results: PROGRESSOR and Statpac 2 agreed on progression in all 19 eyes. Mean detection time for PROGRESSOR was 1.077 years (s.d. 0.985 years) and for Statpac 2 was 2.161 years (s.d. 1.357 years). PROGRESSOR detected progression sooner than Statpac 2 in 18 eyes (p < 0.01, Wilcoxon Matched-Pairs Signed-Ranks Test). PROGRESSOR detected progression earlier by a mean of 1.085 years (s.d. 0.936 years).

Conclusions: PROGRESSOR consistently detected progression earlier than Statpac 2. The PROGRESSOR software is a useful tool for the early detection of visual field deterioration in normal-tension glaucoma.

(Presented at the ARVO Meeting, Fort Lauderdale 1996)