Abstract
Purpose :
To report the distribution of disc area measured with the Monaco, a combined ultra-widefield scanning laser ophthalmoscope (UWF-SLO) + spectral domain OCT (SD-OCT) in a large, mixed-race population of healthy eyes. Additionally, to compare the disc area measurement of 43 glaucomatous eyes imaged on both Cirrus and Monaco devices.
Methods :
Optic disc scans were obtained from one randomly selected eye of 861 normal, healthy subjects using the Monaco device only and 43 glaucoma patients using both Monaco and Cirrus devices. Images were reviewed for quality. Scans with low signal strength or artifact affecting the disc measurement area were excluded. For the healthy eyes, we report the mean, standard deviation, and cut off points of 33% and 66% to characterize the values for ‘small’, ‘average’ and ‘large’ optic disc grouping. For the glaucomatous eyes, regression analysis and Bland Altman plots were used to determine the agreement of optic disc area measurements between devices.
Results :
The mean disc area of normal eyes was 1.96 mm2 ± 0.41 (range = 1.2 to 3.1 mm2). Split evenly into thirds, the small group is < 1.77 mm2, the average group is 1.77 – 2.1 mm2, and the large group is > 2.1 mm2. There was a strong correlation between the optic disc area from the Monaco and Cirrus devices. The Pearson correlation coefficient was r = 0.97. The mean optic disc area for Monaco was 2.18 mm2 ± 0.44 and for the Cirrus it was 2.01 ± 0.40 mm2, with a mean difference of - 0.18.
Conclusions :
Disc area measurements are highly correlated but differ between the Monaco and Cirrus devices by around 8%. Knowing the distribution of disc area for a particular device can aid in the clinical assessment of the optic nerve by considering the relative disc area and its effect on the neuroretinal rim and C/D ratios.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.