Ocular hypothermia: anterior chamber perfusion

Area of Science:

• Ophthalmology
• Physiology
• Medical Research

Background:

• Maintaining stable intraocular temperature is crucial for ocular health and surgical procedures.
• Hypothermic interventions are explored for various medical applications, but their effect on ocular tissues requires detailed investigation.

Purpose of the Study:

• To investigate the impact of cooled fluid perfusion on intraocular temperature in rabbit eyes.
• To determine how perfusion rate and temperature influence ocular tissue cooling.
• To assess the duration of temperature changes post-perfusion.

Main Methods:

• Anterior chambers of 27 rabbit eyes were perfused with balanced salt solution at controlled temperatures (25°C or 11°C) and flow rates (4.8 or 8.5 ml/min).
• Intraocular temperatures were monitored using a thermocouple probe in the anterior chamber, anterior, mid, and posterior vitreous, and on the retinal surface.
• Temperature changes were recorded during perfusion and for 4 minutes after cessation.

Main Results:

• Perfusion with cooled fluid significantly reduced temperatures in the anterior chamber, anterior vitreous, and retina.
• Higher perfusion rates and lower perfusion temperatures amplified the cooling effect.
• Intraocular temperatures returned to baseline levels approximately 4 minutes after perfusion stopped.

Conclusions:

• Cooled fluid perfusion effectively lowers intraocular temperatures in rabbit eyes, impacting even the retina.
• Both increased perfusion rate and decreased perfusion temperature enhance hypothermic effects.
• The observed hypothermia is transient, with temperatures normalizing shortly after perfusion cessation.