Sensitivity and specificity of short-duration transient visual evoked potentials (SD-tVEP) in discriminating normal from glaucomatous eyes.

ABSTRACT

PURPOSE: To evaluate the ability of the short-duration transient visual evoked potential (SD-tVEP) to discriminate between healthy eyes and eyes with early to advanced glaucomatous visual field loss. METHODS: We tested 30 eyes of 30 healthy controls and 45 eyes of 35 glaucoma patients. Normal eyes had 20/30 or better visual acuity and normal 24-2 Swedish interactive thresholding algorithm (SITA) Standard visual fields. Glaucoma was staged as mild (mean deviation, MD > -6.0 dB), moderate (MD between -6.0 and -12.0 dB), and severe (MD < -12.0 dB). There were 15 eyes in each group. SD-tVEPs were recorded using the Diopsys NOVA-LX System. Each eye was stimulated with a low (Lc) and a high (Hc) Michelson contrast checkerboard pattern. Each test resulted in an Lc and an Hc SD-tVEP response. Each response was evaluated for overall waveform quality, P100 latency, and P100 amplitude referenced to the N75. The sensitivity, specificity, negative predictor value (NPV), and positive predictor value (PPV) were calculated. RESULTS: Lc latency showed the highest accuracy for discrimination using receiver operating characteristic curves for high and low contrast parameters. The analysis for all subjects resulted in a 91.1% sensitivity, 93.3% specificity, 95.3% PPV, and an 87.5% NPV. Evaluating the mean Lc latency of the mild, moderate, and severe glaucoma patients against controls showed discrimination consistent with the glaucoma severity. CONCLUSIONS: Short-duration transient VEP objectively identified decreased visual function and discriminated between healthy and glaucomatous eyes, and also showed good differentiation between healthy eyes and those with early visual field loss. VEP may be useful for early diagnosis of glaucoma.