Histomorphological changes in the cornea of the rat following monocular eyelid closure

Objectives: The aim of this study was to describe structural changes in the cornea of the rat after monocular eyelid closure. Methods: Twenty-six Rattus norvegicus male rats aged three months were used. The rats were randomly assigned into baseline (2), experimental (16) and control (8) groups. Unilateral eyelid closure was performed on the experimental animals by suture tarsorrhaphy. At experiment days 5, 10, 15 and 20, four rats from the experimental group and two rats from the control group were euthanized, their eyeballs harvested, and routine processing was done for paraffin embedding, sectioning and Masson’s trichrome staining. The photomicrographs were taken using a digital photomicroscope. Results: In the closed eyes, there was a time-dependent reduction in the stratification of the corneal epithelium with subsequent disintegration, and an increase in distribution of stromal keratocytes while the corneal endothelial cells showed slight enlargement from squamous shape. The contralateral and control eyes did not exhibit any significant changes through the experimental period. Conclusion: Monocular eyelid closure causes structural changes in the corneal epithelium, stroma and endothelium of the tarsorrhaphy eye. Therefore, tarsorrhaphy should not be prolonged due to risk of corneal diseases and diminution of vision as a result of the structural changes. Keywords: cornea; eyelid closure; rat; tarsorrhaphy