Mid-peripheral pattern electrical retinal responses in normals, glaucoma suspects, and glaucoma patients.

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Current glaucoma diagnosis relies on intraocular pressure, optic nerve changes, and visual field tests, which may detect disease after irreversible damage.
• Pattern electrical retinal responses (PERR) show abnormalities in glaucoma patients, particularly with central visual field stimulation.

Purpose of the Study:

• To investigate the potential of mid-peripheral PERR as an early diagnostic tool for glaucoma.
• To assess if PERR can detect glaucomatous changes before they manifest in visual field tests.

Main Methods:

• PERR were recorded using alternating bar gratings across four visual field quadrants in normal subjects, glaucoma suspects, and glaucoma patients.
• Stimuli were presented at various spatial frequencies, and the onset of peaks (N35, P50) and P50 amplitude were analyzed.
• Age-corrected values were compared across groups and correlated with clinical measures like cup-to-disc ratio.

Main Results:

• Normal subjects exhibited spatial tuning in P50 amplitudes, with age-related amplitude decline.
• Glaucoma patients showed age-corrected reductions in P50 amplitude and earlier implicit times compared to normals.
• Glaucoma suspects displayed intermediate PERR values, and P50 amplitudes weakly correlated with cup-to-disc ratio.

Conclusions:

• Mid-peripheral PERR stimulation appears to be a sensitive method for early glaucoma detection.
• Further research is needed to refine PERR acquisition for clinical use, improving speed and signal quality.