Purchase this article with an account.
Sonya Babar Shah, Alberto Omar Gonzalez Garcia, Jeanne Molineaux, Laurie Cox, Jonathan S Myers, L Jay Katz; CORDA and the NOVA-DN VEP protocol in the diagnosis of glaucoma and glaucoma suspects. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4822.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess the ability of a novel OCT analysis method, the CORDA (Color Reflectivity Discretization Analysis, Diopsys, Inc.) HR1 parameter, and a novel visual evoked potential (VEP) protocol, the NOVA DN (Diopsys, Inc.), to differentiate normal, glaucomatous, and glaucoma suspect eyes. CORDA assesses reflectivity of the retinal nerve fiber layer (RNFL) in order to distinguish nerve tissue from glial, vessels and other RNFL constituents. The NOVA-DN VEP protocol is a short-duration, commercially available office test that can assess optic nerve function.
Normal, glaucomatous, and glaucoma suspect eyes underwent peripapillary RNFL imaging using Cirrus SD-OCT (optic nerve head cube 200 x 200 protocol, Carl Zeis Meditec) with post-acquisition CORDA analysis of peripapillary RNFL B-scan images. Eyes then underwent testing with the NOVA-DN VEP protocol. The area under the receiver operating characteristic curve (AUC) was calculated for each method for differentiating eyes with glaucoma, and those that are glaucoma suspect, from normal control eyes.
A total of 136 eyes of 136 subjects (42 healthy eyes, 45 glaucoma suspect eyes and 49 glaucomatous eyes) were tested. The CORDA HR1 parameter discriminated glaucoma patients from normal with the same accuracy as Cirrus mean RNFL thickness (AUC=0.93 for both, p=0.80). For this comparison, the NOVA-DN VEP parameters amplitude low contrast (ALC), amplitude high contrast (AHC), latency low contrast (LLC), and latency high contrast (LHC) had AUC values of 0.76, 0.67, 0.66 and 0.80, respectively. In distinguishing glaucoma suspects from normal, mean RNFL thickness had an AUC value of 0.68, the HR1 parameter AUC value was 0.78 (p=0.02),and the NOVA-DN VEP parameters were less accurate (AUC for ALC = 0.45, AHC =0.47, LLC = 0.47, LHC = 0.44).
The CORDA algorithm shows similar performance to RNFL thickness analysis of Cirrus SD OCT images in differentiating glaucomatous eyes from normal, with possibly better performance vs mean RNFL thickness in distinguishing glaucoma suspects from normal. The NOVA-DN VEP protocol is less accurate in differentiating glaucoma suspects from normal, though the ALC and LHC parameters perform well in distinguishing between normal and glaucomatous eyes.
This PDF is available to Subscribers Only