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Jean-Claude Mwanza, Gary C Lee, Joshua L. Warren, John G Flanagan, Paul H Artes, Michael Wall, Thomas Callan, Donald L Budenz; Validation of the Performance of the UNC Optical Coherence Tomography Index for Early Glaucoma Diagnosis.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):705.
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© ARVO (1962-2015); The Authors (2016-present)
To independently validate the performance of the UNC OCT Index,1 which was developed previously and outperforms OCT single parameters in discriminating normal subjects and patients with early visual field loss.
Data of 214 eyes including 118 normal eyes (118 subjects) and 96 eyes (96 subjects) with early glaucoma defined as visual field MD>-4dB from the SITA Size III, V, VI comparison study2 was used in this investigation. Cirrus OCT average and quadrants retinal nerve fiber layer (RNFL); optic disc vertical cup-to-disc ratio (VCDR), cup-to-disc area ratio (CDR) and rim area; and average, minimum and 6 sectoral ganglion cell-inner plexiform layer (GCIPL) measurements were analyzed with the UNC OCT Index algorithm. This algorithm avoids interpretion of lots of different inter-related indices and reduces 16 parameters into a composite of 3 significant parameters (#1: all optic disc; #2: all GCIPL; #3: average, superior and inferior RNFL). The diagnostic performance was assessed using the area under the receiver operator characteristic curve (AROC) and sensitivity. Single parameter AROCs were compared to that of the UNC OCT Index.
Mean age was 60.1±11.0 years for normal subjects and 66.5±8.1 years for glaucoma patients (p<0.001). MD was 0.3±1.0 dB and -1.3±1.4 dB in normal and glaucomatous eyes (p<0.001), respectively. The AROC of the UNC OCT Index was 0.958. The best single metrics when comparted to the UNC OCT Index were VCDR (0.933, p=0.053), average RNFL (0.921, p=0.014) and minimum GCIPL (0.905, p=0.009), as shown in the Figure. The sensitivities at 95% and 99% specificity were 85.4% and 76.0% (UNC OCT Index), 71.9% and 62.5% (VCDR), 64.6% and 53.1% (average RNFL), and 66.7% and 58.3% (minimum GCIPL), respectively. A separate analysis including only 71 glaucomatous eyes with MD>-2 dB (mean: -0.7±0.9 dB) yielded an AROC of 0.949 for the UNC OCT Index compared to 0.922 (VCDR, p=0.064), 0.908 (average RNFL, p=0.03), and 0.896 (minimum GCIPL, p=0.026).
The findings confirm that the UNC OCT Index outperforms single Cirrus OCT parameters and may be a good tool for detection of early glaucoma.1Mwanza JC et al. Combining SDOCT structural parameters for the diagnosis of glaucoma with early visual field loss. IOVS 2013;54:8393-400.2Flanagan JG et al. The influence of perimetric stimulus size on defect detectability in early glaucoma. IOVS 2016;57 (ARVO Abstract).
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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