The Ability of SWAP and FDT Parameters to Predict Glaucomatous Progression Detected by SAP Guided Progression Analysis

Abstract

Purpose: : To assess whether short-wavelength automated perimetry (SWAP) and frequency doubling technology (FDT) parameters are predictive of progressive glaucomatous visual field loss as assessed by standard automated perimetry (SAP) guided progression analysis (GPA).

Methods: : In the current study, 919 eyes of 621 glaucoma patients and suspects from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS) and African Descent and Glaucoma Evaluation Study (ADAGES) were tested with SAP, SWAP, and FDT Matrix within 3 months. Glaucomatous "likely progression" was determined using GPA. The associations between baseline SWAP and FDT parameters and glaucoma progression on SAP GPA were investigated by Cox regression models. Multivariable models were adjusted for age, intraocular pressure, central corneal thickness and vertical cup-to-disc ratio. The c-index was used to evaluate and compare the predictive abilities.

Results: : Over a 3.7-year average follow-up period, 47 eyes (5.1%) showed progression. In univariable models, SWAP and FDT PSD were predictive of progression [hazard ratios - HR (95% CI); 1.24 (1.08-1.43) per 1 dB and 1.20 (1.01-1.42) per 1dB, respectively]. In multivariable models, SWAP and FDT MD and PSD were not predictive of glaucomatous progression [HR (95% CI); 1.15 (0.99-1.34) per dB, 1.00 (0.94-1.07) per 1 dB, 0.98 (0.91-1.05) per 1 dB, and 1.11 (0.93-1.32) per 1 dB, respectively]. The c-index values for the multivariable models of SWAP and FDT MD and PSD were 0.657, 0.675, 0.662 and 0.666, respectively.

Conclusions: : Univariable models showed that SWAP and FDT are weakly predictive of glaucomatous visual field loss assessed by SAP GPA in glaucoma suspects and patients. Using multivariable models, SWAP and FDT were not suggestive of glaucomatous progression.

Keywords: visual fields • perimetry