How Accurately Does the Diopsys Visual Evoked Potential (VEP) Vision Testing System Detect Glaucoma?

Sensitivity and Specificity of the NOVA-DN VEP Protocol and a Novel Analysis of Optical Coherence Tomography Images for Glaucoma Diagnosis

Evaluate sensitivity and specificity of NOVA-DN visually evoked potentials (VEP) protocol and new software method (Corda) for glaucoma detection using optical coherence tomography (OCT) images to differentiate between normal subjects and glaucoma suspects.

The aim of this study was to evaluate the ability of NOVA-DN VEP protocol and Corda parameters to discriminate between healthy eyes and eyes with early to moderate glaucomatous visual field loss. We will evaluate measurements of the NOVA-DN VEP protocol, Corda software and Cirrus spectral domain (SD) OCT software in order to compare and correlate.

Hypotheses is that NOVA-DN VEP protocol and Corda analysis results in a high sensitivity, specificity and area under the Receiver Operating Characteristic (ROC) curves (ROC area) for glaucoma detection. Second hypothesis is NOVA-DN VEP protocol and Corda parameters can differentiate between normal and glaucoma suspects.

Inclusion Criteria:

Group 1: Healthy Subjects

• intraocular pressure less than 22 millimeters of mercury (mmHg)
• normal appearing optic discs and retinal nerve fiber layer (RNFL)
• normal optical coherence tomography (OCT) RNFL thickness
• normal visual field (VF) results in both eyes.

Group 2: Glaucoma Suspects

• glaucomatous appearance of optic discs and/or RNFL in at least one eye
• normal OCT
• normal VF results in both eyes.

Group3: Glaucoma Patients

• Glaucomatous optic disc appearance (cup to disc ratio, rim thinning or RNFL defects)
• Repeatable intraocular pressure (IOP) of 23 mmHg or more, in at least one eye
• Repeatable abnormal VF tests

Exclusion Criteria:

• inability to perform reliable VF or OCT
• visual acuity worse than 20/40
• refractive error greater than +/-5.00 diopters sphere, greater than +/- 3.00 diopers cylinder