The effect of phenylephrine on the cornea

Area of Science:

• Ophthalmology
• Corneal Physiology
• Pharmacology

Background:

• Phenylephrine hydrochloride is a commonly used ophthalmic vasoconstrictor.
• The corneal epithelium serves as a critical protective barrier.
• Potential adverse effects of ophthalmic drugs on corneal structure require investigation.

Purpose of the Study:

• To investigate the effects of phenylephrine hydrochloride on corneal thickness and ultrastructure.
• To determine the role of the corneal epithelium in mediating phenylephrine-induced ocular changes.

Main Methods:

• Rabbit corneas with intact or denuded epithelium were treated with phenylephrine hydrochloride.
• Corneal thickness was measured before and after treatment.
• Ultrastructural analysis was performed using scanning and transmission electron microscopy.

Main Results:

• Phenylephrine caused significant corneal edema and vacuolation in keratocytes and endothelial cells when the epithelium was absent.
• Corneas with intact epithelium showed no significant change in thickness and minimal ultrastructural alterations.
• Cytotoxicity was observed in endothelial cells and keratocytes in denuded corneas, with less severe, epithelium-limited damage in intact corneas.

Conclusions:

• The corneal epithelium is crucial in protecting against phenylephrine hydrochloride-induced corneal edema and cellular damage.
• Phenylephrine hydrochloride can exhibit cytotoxic effects on corneal endothelium and keratocytes when the epithelial barrier is compromised.