PERG and spectral sensitivity in ocular hypertensive and chronic open-angle glaucoma patients

Pattern electroretrinography (PERG) was performed in 33 patients with chronic open-angle glaucoma (COAG), 18 ocular hypertensive (OH) patients, and 24 normal subjects. COAG patients exhibited significantly lower PERG amplitudes than did normal subjects (P8rps = 0.025; P16rps less than 0.0001). The OH patients fell into two distinct groups: those with normal PERG scores and those with lower than normal scores. OH patients with PERG scores significantly lower than control values demonstrated significantly larger cup-to-disc ratios (P = 0.002) and higher initial intraocular pressures (IOPs) than did OH patients with normal PERG scores (P = 0.021). In the 11 OH patients in whom spectral sensitivity measurement was available, statistically significant correlations were found between the blue-cone sensitivity loss and the PERG amplitude (r8rps = 0.772, P8rps = 0.0053 and r16rps = 0.699, P16rps = 0.0167, respectively. Our results demonstrate reduced PERG amplitude in high-risk OH patients and further illustrate the correlation between PERG amplitude and blue-cone spectral sensitivity in OH subjects. Confirmation of the roles of PERG and spectral sensitivity in the detection of early glaucoma requires longitudinal study.