Evaluation of a new perimetric threshold strategy, SITA, in patients with manifest and suspect glaucoma

To evaluate the performance of the new perimetric threshold strategy SITA relative to older methods.

Thirty-two patients with either glaucoma or ocular hypertension performed two threshold visual field tests with each of three threshold strategies, SITA, Humphrey Full Threshold, and Fastpac. Testing was distributed over three visits, and testing order was balanced between strategies to control for order effects.

SITA tests consumed 54% of the time taken by Full Threshold tests on average, and 85% of Fastpac tests; SITA's test times were significantly shorter than those of Full Threshold (p<0.0001) and Fastpac (p=0.0008). Test-retest threshold variability did not differ significantly between strategies. Intertest variability of the pattern deviation analysis was lowest in SITA (p<0.01) relative to both Full Threshold and Fastpac. Both SITA and Fastpac showed higher than expected average sensitivities relative to Full Threshold. SITA and Fastpac showed approximately the same amount of visual field loss. There was a significant relationship between Mean Deviation and the SITA function used to shorten stimulus sequences at points where measurement errors are small (p<0.0001).

Our results suggest that SITA matches the precision of older thresholding methods, consuming considerably and significantly less test time. This indicates that SITA could replace Full Threshold as the standard clinical test used in glaucoma management, without decreasing the quality of test results.