Comparative morphology of epicorneal conjunctival membranes in rabbits and human pterygium

Area of Science:

• Ophthalmology
• Veterinary Pathology
• Comparative Pathology

Background:

• A rare ocular lesion in rabbits is described.
• The lesion presents as a progressive, non-adherent conjunctival membrane advancing towards the corneal center.
• It shares clinical similarities with human pterygium but exhibits key differences.

Purpose of the Study:

• To present and characterize a rarely described ocular lesion in rabbits.
• To differentiate this rabbit lesion from human pterygium based on clinical and microscopic findings.
• To propose a potential etiology for the observed lesion.

Main Methods:

• Observation of four clinical cases of the ocular lesion in rabbits.
• Clinical examination to assess the lesion's progression, adherence, and origin.
• Microscopic examination of the conjunctival fold to determine its composition.

Main Results:

• The lesion is a conjunctival membrane originating from the entire limbal circumference with symmetric growth.
• The membrane advances progressively towards the cornea without adherence and does not penetrate corneal layers.
• Microscopic analysis revealed the fold consists of fibroblasts and collagen, suggesting a collagenous dysplasia.

Conclusions:

• The described lesion in rabbits is a unique conjunctival dysplasia.
• It differs from human pterygium due to its free nature, symmetric limbal origin, and lack of corneal penetration.
• Further investigation into collagenous dysplasia as a potential cause is warranted.