Pattern electroretinograms during the cold pressor test in normals and glaucoma patients

Area of Science:

• Ophthalmology and Neuroscience
• Visual electrophysiology
• Cardiovascular stress response

Background:

• Pattern electroretinograms (PERG) assess retinal ganglion cell function.
• Glaucoma is a progressive optic neuropathy affecting visual field.
• The cold pressor test (CPT) is a physiological stressor impacting cardiovascular and neurological functions.

Purpose of the Study:

• To investigate the effect of the cold pressor test (CPT) on steady-state PERG in healthy individuals and glaucoma patients.
• To compare PERG responses during CPT in control subjects, ocular hypertension (OHT), normotensive glaucoma (NTG), and high-tension glaucoma (HTG) patients.

Main Methods:

• Steady-state PERGs were recorded in 63 participants (15 healthy, 14 OHT, 20 NTG, 14 HTG).
• PERG amplitudes and latencies were analyzed at baseline, during CPT (ice and warm water), and recovery.
• Blood pressure and heart rate were monitored during the CPT protocol.

Main Results:

• Glaucoma patients (NTG and HTG) exhibited significantly reduced PERG amplitudes compared to controls and OHT patients.
• Normotensive glaucoma (NTG) patients showed a significant decrease in PERG amplitude during the warm water phase of the CPT.
• PERG latencies shortened in control subjects and NTG patients during the warm water recovery phase; blood pressure increased with cold and decreased with warming.

Conclusions:

• The cold pressor test (CPT) demonstrably influences PERG responses, especially in normotensive glaucoma (NTG) patients.
• CPT-induced changes in PERG may offer insights into the pathophysiology of glaucoma and its subtypes.
• Further research could explore the clinical utility of CPT in glaucoma assessment.