Abstract
Purpose :
To compare glaucoma diagnostic capability of circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in patients with moderate to high myopia before and after RNFL segmentation error correction.
Methods :
The cpRNFLT was measured using spectral-domain optical coherence tomography (OCT) (Nidek; RS 3000, Gamagori, Japan) in myopic eyes with spherical equivalent refractive error worse than -3 diopters. Three circle scans with diameters of 3.45, 4.50 and 6.00 mm were obtained (Fig 1). The OCT software provided 5 parameters: mean global cpRNFLT and mean cpRNFLT for the temporal, nasal, superior, and inferior quadrants. Each OCT scan was reviewed and RNFL segmentation errors were manually corrected. Poor quality OCT scans that could not be manually corrected were excluded from analysis. Receiver operating characteristic (ROC) curves were obtained for all parameters and areas under the curve (AUCs) were calculated before and after segmentation error correction.
Results :
22 myopic healthy eyes and 39 myopic glaucomatous eyes (visual field mean deviation, -10.5±6.9 dB) were included for analysis. Mean age was 57±17 vs. 66±10 years (p=0.013); mean refractive error was -5.0±1.8 vs. -6.5±2.3 diopters (p=0.012); mean axial length was 25.3±1.2 vs. 26.3±1.5 mm (p=0.025) in myopic healthy vs. glaucomatous eyes, respectively. The AUC of mean global cpRNFLT became greater after segmentation error correction in the 3.45-, 4.50- and 6.00-mm scans (0.911 to 0.923, 0.900 to 0.920, and 0.891 to 0.925, respectively), but with no statistical significance (p=0.319, 0.330, and 0.132, respectively; Fig 2). After segmentation error correction, the AUC of mean global cpRNFLT was greatest among the 5 parameters (global and 4 quadrants) in the 3.45-, 4.50- and 6.00-mm scans. The AUCs were similar among circle scans with different diameters (AUC=0.928, 0.920 and 0.925 in the 3.45-, 4.50- and 6.00-mm scans, respectively; p=0.606).
Conclusions :
Correction of cpRNFL segmentation errors may improve glaucoma diagnostic capability for patients with moderate to high myopia. Future studies with a larger sample size are warranted on this subject.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.