Glaucomatous visual fields. FASTPAC versus full threshold strategy of the Humphrey Field Analyzer

This study examined how FASTPAC, a fast strategy for the Humphrey Field Analyzer (HFA), compares to the standard 4/2-dB full threshold strategy in patients with glaucoma.

The author tested one eye each of 50 patients with glaucoma (23 with only relative defects, 27 with at least one absolute defect; age range, 25 to 79 years; median age, 61.5 years) with both strategies using program 30-2 of the HFA (stimulus size III). Global visual field indices as calculated by Statpac, unweighted mean sensitivity, and examination time were compared. In addition, a point by point analysis of the sensitivity values was performed.

Between the two strategies, no significant differences were found for indices directly related to the sensitivity values (mean sensitivity [MS], mean deviation [MD]) or for the actual thresholds. For the entire population, FASTPAC showed higher mean short-term fluctuation (SF; P = 0.018), lower mean pattern standard deviation (PSD; P = 0.006), and mean corrected PSD (CPSD; P < 0.001) values and a time reduction of more than 30% (P < 0.001) compared to the standard strategy. These differences between the strategies were found to be independent of the amount of field loss, except for PSD (P = 0.001). No age influence was present. Statistically significant linear regression (r > 0.70, P < 0.001) was found between the FASTPAC values of MS, MD, PSD, CPSD, and the corresponding values determined with the standard strategy. No correlation exists for SF (r < 0.46, P > 0.030).

FASTPAC provides a considerable time reduction at the cost of higher threshold fluctuation. This may lead to problems in detecting relative defects or changes in differential light threshold in follow-up examinations.