Intraocular Pressure Elevation Compromises Retinal Ganglion Cell Light Adaptation

Area of Science:

• Neuroscience
• Ophthalmology
• Vision Science

Background:

• Retinal ganglion cells (RGCs) adapt to ambient light, a crucial function.
• Factors detrimental to RGC health can impact this adaptation.
• Increased intraocular pressure (IOP) is a significant risk factor for glaucoma.

Purpose of the Study:

• To investigate how adaptation-induced changes in RGC physiology are affected by elevated IOP.
• To explore the relationship between IOP and RGC function in the context of glaucoma risk.

Main Methods:

• Wild-type mice underwent 2 weeks of IOP elevation using the bead model.
• RGC responses were recorded using a multielectrode array under scotopic and photopic conditions.
• Spike-triggered averages (STAs) were calculated to compare RGC responses between lighting levels and IOP conditions.

Main Results:

• Low IOP elevation, but not high, diminished adaptation-dependent receptive field (RF) center-surround interactions.
• A higher likelihood of scotopic STAs and increased spontaneous firing rates were observed with low IOP.
• While RGCs showed lighting-dependent changes in RF size and STA peak times, these were not impacted by IOP level.

Conclusions:

• RGCs demonstrate reduced light-dependent adaptation and increased excitability at low, but not high, IOP levels.
• These functional alterations may represent early indicators of glaucoma.
• Identifying these changes could aid in the early diagnosis of glaucoma for more effective treatment.