Abstract
Purpose :
Compass is a new device that combines automated perimetry with confocal images of the retina and optical nerve head. Furthermore, the incorporated eye tracking system facilitates identical follow up investigations. The aim of the study was to compare the results of Compass perimetry (Ellex, Germany) with those of Humphrey perimetry (Carl Zeiss Meditec, Germany).
Methods :
A total of 47 subjects (26 control subjects, 21 patients with open angle glaucoma) underwent full perimetric evaluation using the FAP Zest (Compass) and HFA Sita Fast (Humphrey Field Analyzer 3). Only one eye was included into the analysis. Technical specifications of the Compass device are: background luminance: 31,4 asb, maximum luminance: 10000 asb, stimulus size: Goldmann III, stimulus duration: 200 ms and 24-2 grid (54 locations spaced by 6 degrees). HFA parameter are: background luminance: 31,5 asb, maximum luminance: 10000 asb, stimulus size: Goldmann IV, stimulus duration: 200 ms and 24-2 grid (54 locations spaced by 6 degrees). Perimetry specificity and sensitivity were determined using MD, PSD and MD+PSD whereas MD >- 2 and PSD < 6 are used as cutting off values. Spearman correlation coefficient was calculated for MD and PSD.
Results :
Six subjects (1 control, 6 glaucoma) were excluded due to low reliability (fixation loss, false positives). The specificity of Compass and HFA was 100% in the control group for MD, PSD and MD+PSD. The sensitivity of Compass in glaucoma patients was 73,33% for MD, 66,67% for PSD and 66,67% for MD+PSD. The sensitivity of Humphrey in glaucoma patients was 93,33% for MD, 66,67% for PSD and 66,67% for MD+PSD. Compass and HFA showed significant correlation for MD (r=0.87, p=0.00002) and PSD (r=0.89, p<0.00001).
Conclusions :
Based on the current study, Compass provides similar perimetric results compared to the Humphrey device. The difference in MD sensitivity between Compass and HFA might be due to the different stimulus size. As a forefront advantage Compass combines the retinal threshold sensitivity directly with confocal images of the retina.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.