<p>Retinal Sensitivity Thresholds Obtained Through Easyfield and Humphrey Perimeters in Eyes with Glaucoma: A Cross-Sectional Comparative Study</p>

Abstract

Objective: To compare global retinal sensitivity thresholds obtained through the Easyfield perimeter (EF) and Humphrey visual field analyzer (HFA). Design: Observational cross-sectional study. Participants: Glaucomatous patients and glaucoma suspects enrolled between October 2018 and April 2019. Materials and Methods: All participants underwent EF (SPARK Precision) and HFA perimetry (SITA-Standard). After inclusion, demographic and ocular data were collected, including measurements of retinal nerve fiber layer (RNFL) thickness obtained from spectraldomain optical coherence tomography (SD-OCT). Global indices (mean deviation, MD; pattern standard deviation, PSD) values were compared between perimeters, and their correlation and agreement were evaluated. We used regression analysis to investigate structure-functional correlations between SD-OCT measurements and MD index of each perimeter. Results: We investigated 111 eyes from 69 patients. Mean MD (mean difference=1.49dB) and PSD values (mean difference=0.42dB) from the HFA were significantly larger than those from the EF perimeter (p<0.001). There were significant linear correlations between EF-MD and HFA-MD (r=0.56), and EF-PSD and HFA-PSD (r=0.38; p<0.001). We found significant non-linear associations between average RNFL thickness and MD values derived from both EF (R 2 =0.41) and HFA (R 2 =0.17) perimeters (p≤0.012). A difference <2dB between EF-MD and HFA-MD was found in 53% of the eyes, while 71% of them had a difference <1dB between EF-PSD and HFA-PSD. Conclusion: While we found a moderate correlation and a small mean sensitivity difference between test results, EF's correlation with structural measurements was at least comparable to that of the HFA. Our findings suggest that although these tests should not be used interchangeably, EF SPARK Precision could be used as an alternative for functional assessment in eyes with mild glaucoma.