Comparison Of Frequency-Doubling Technology Perimetry, Short-Wavelength Automated Perimetry And Standard Automated Perimetry To Monitor Glaucoma Progression

PurposeDetection of progression is one of the most important and challenging aspects in the clinical management of glaucoma. While both structural and functional changes can occur over time, functional progression correlates more closely with quality of life for glaucoma patients. Early and accurate detection of functional progression is essential to determine the need to modify treatment strategies and also to evaluate the visual prognosis for glaucoma. The standard automated perimetry (SAP) remains the reference standard to detect glaucomatous visual field loss, however, its increasing test-retest variability with visual field severity and eccentricity affects its performance in monitoring progression.Frequency-doubling technology perimetry (FDT) and Short-wavelength automated perimetry (SWAP) are two alternative types of perimetry designed for early detection of visual field loss. The second generation of FDT, the Matrix, increases the spatial resolution by using a 24-2 testing pattern similar to SAP; unlike for SAP, measurement variability doesn’t increase with the deterioration of sensitivity for FDT. In contrast to the full-threshold SWAP, the Swedish Interactive Thresholding Algorithm (SITA) SWAP has shortened test duration and reduced measurement variability. While a considerable number of studies have shown that FDT and SWAP can predict the future onset of visual field loss with SAP, their ability to monitor glaucomatous visual field progression remains unclear. Our goal is to investigate the performance of FDT and SWAP in detection of senescent changes of the normal visual field, monitoring visual field progression in diagnosed and supect POAG eyes in comparison with SAP.METHODS1. FDT, SWAP, and SAP for Detection of Senescent changes of the Normal Visual Field Cross-sectional data of paired FDT, SWAP, and SAP from 207 normal eyes (age, 40-75 years old) enrolled in the DIGS and ADAGES studies were included. The ordinary least squares linear regression of sensitivity (in dB) vs. age (independent variable) was computed for each test location within each test type.2. Comparison of FDT, SWAP, and SAP to Monitor Visual Field Progression in Diagnosed POAGLongitudinal data of paired FDT, SWAP, and SAP from 113 eyes with diagnosed POAG enrolled in the DIGS and ADAGES studies were included. Data from all tests were expressed in comparable units by converting the sensitivity from decibels to unitless contrast sensitivity and by expressing sensitivity values in percent of mean normal (%N) based on an independent dataset of healthy eyes with aging deterioration taken into consideration. Pointwise linear regression analysis was performed and 3 criteria (conservative, moderate, and liberal) were used to define progression and improvement. Global mean sensitivity was fitted with hierarchical linear mixed models. The performance of FDT and SWAP in monitoring visual field progression was investigated in comparison with SAP.3. Comparison of FDT and SAP to Monitor Visual Field Progression in Suspect POAG Longitudinal data of paired FDT and SAP from 121 eyes with suspect POAG (documented glaucomatous optic neuropathy and/or ocular hypertension only) enrolled in the DIGS and ADAGES studies were included. Data from all tests were expressed in comparable units by converting the sensitivity from decibels to unitless contrast sensitivity and by expressing sensitivity values in percent of mean normal based on an independent dataset of healthy eyes with aging deterioration taken into consideration. Pointwise linear regression analysis was performed and 2 criteria (conservative and liberal) were used to define progression and improvement. Global mean sensitivity was fitted with hierarchical linear mixed models. The performance of FDT in monitoring the visual field progression was investigated in comparison with SAP.RESULTS1. The pointwise significant negative relationships were obtained between age and sensitivity for each test type (P< 0.05).2. Based on PLR analysis, no statistically significant difference in the proportion of progressing and improving eyes was observed across tests using the conservative criterion. Fewer eyes showed improvement on SAP compared to SWAP and FDT using the moderate criterion; and FDT detected less progressing eyes than SAP and SWAP using the liberal criterion. The agreement between these test types was poor. The linear mixed model showed a progressing trend of global mean sensitivity over time for SAP and SWAP, but not for FDT. The baseline estimate of SWAP mean sensitivity was significantly lower than SAP by 21.59 %N. FDT showed comparable estimation of baseline mean sensitivity with SAP.3. Based on PLR analysis, no statistically significant difference in the proportion of progressing and improving eyes was observed between FDT and SAP using the conservative and liberal criteria. The agreement between test types was poor to fair. The linear mixed model showed a progressing trend of global mean sensitivity over time for both FDT and SAP without statistically significant difference. The baseline estimate of FDT mean sensitivity was slightly lower than SAP.CONCLUSIONS1. FDT, SWAP, and SAP are all be able to detect senescent changes of the normal visual field.2. For diagnosed POAG eyes, FDT and SWAP do not appear to have significant benefits over SAP in monitoring visual field progression. FDT, SWAP, and SAP may, however, detect progression in different glaucoma eyes.3. For suspect POAG eyes, FDT performs as well as SAP in monitoring the visual field progression. FDT may provide a useful alternative to monitor glaucoma progression in suspect glaucoma eyes.4. The methodology of conversion the sensitivity values from dB scale to the percent of mean normal facilitates the direct comparison of data with different measurements (perimetry vs. perimetry, or perimetry vs. stuctrue), and can provide an useful common scale for the clinical assessments of glaucomatous severity.