The comparison of manual vs automated disc margin delineation using spectral-domain optical coherence tomography.

AIMS: To examine the impact of manual vs automated disc margin delineation on optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters using spectral-domain optical coherence tomography (SDOCT). METHODS: A prospective cohort study consisting of normal, glaucoma suspect (GS) and glaucoma patients who underwent ONH and RNFL measurements using SDOCT technology (RTVue; Optovue Inc.). The retinal pigment epithelium/Bruch's membrane (RPE/BM) complex end points were automatically determined first, and were manually redefined subsequently. Analysis of variance, coefficient of variation (COV), concordance correlation coefficient (CCC), and Bland-Altman plots were used for the analyses. RESULTS: Ninety-nine eyes of 50 subjects (age 68±10 years) consisting of 36 glaucoma, 56 GS, and 7 normal eyes were included. The RNFL thickness measurements were similar (P>0.05) between the two methods of demarcation, except for the inferior-nasal sector (P=0.04). For the ONH measurements, the cup-to-disc (C/D) ratio and rim area showed significant differences between the two methods (P<0.001). COV/CCC values for the ONH parameters were as follows: cup area 17.6%/0.88; cup volume 7.4%/0.91; average C/D ratio 18.1%/0.78; rim area 25.3%/0.69; and rim volume 42.6%/0.71, respectively. CCC/COV values for the RNFL parameters were as follows: average 2.1%/0.98; inferior-temporal quadrant 8.1%/0.79; inferior-nasal quadrant INQ quadrant 12.6%/0.67; SNQ quadrant 7.8%/0.83; and STQ quadrant 7.8%/0.88, respectively. CONCLUSION: An overall high agreement and moderate-substantial concordance was observed between the demarcation methods. Automated disc margin delineation of SDOCT can be used reliably in clinical practice.

Detection of progressive macular thickness loss using optical coherence tomography in glaucoma suspect and glaucomatous eyes.

AIMS: To examine the rate of macular thickness loss using time-domain optical coherence tomography (OCT) in functionally progressing versus non-progressing eyes, determined by standard automated perimetry (SAP). METHODS: Glaucoma suspects (GS) and glaucomatous (G) eyes underwent SAP and OCT imaging every 6 months. Functional progression was determined using pointwise linear regression, defined as 2 contiguous locations losing ≥1.0 dB/year at P<1.0% in the same hemifield. The annual rate of macular thickness loss was calculated from inner and outer regions of the macular map. RESULTS: 72 eyes (43 GS and 29G) with ≥30 months of follow-up were enrolled. Fourteen eyes demonstrated SAP progression. The annual rate of macular thickness loss (µm/year) in progressing eyes was faster (all P<0.05) than non-progressing eyes in temporal outer (-1.90±2.97 vs 0.33±2.77), nasal inner (-1.70±2.66 vs 0.14±2.76), superior inner (-2.15±4.57 vs 0.51±2.99), temporal inner quadrants (-2.58±5.05 vs -0.38±2.34), and the average of inner macular quadrants (-1.84±2.90 vs 0.03±2.10). The rate of loss in the nasal inner (P=0.02) and temporal outer (P=0.02) macular regions was associated with optic disc haemorrhage. CONCLUSIONS: Eyes with SAP progression have significantly greater rates of macular thickness loss consistent with glaucomatous retinal ganglion cell atrophy, as compared with non-progressing eyes.