Ocular surface changes in pterygium

Abstract

Purpose: To evaluate ocular surface abnormalities in eyes with pterygium.

Methods: Impression cytology was performed on 56 pterygia in 50 eyes with primary or recurrent pterygium. Superior, inferior, nasal, and temporal bulbar conjunctivae were evaluated.

Results: The ocular surface morphology directly over the pterygium was found to be abnormal in 100% of cases. This was significant compared with abnormalities in 2.4% in the superior bulbar conjunctiva, 54.5% in the inferior bulbar conjunctiva, and 58.1% in the clinically unaffected interpalpebral conjunctiva. The epithelial cells in pterygium demonstrated squamous metaplasia in 73.2% of cases, with marked enlargement and elongation of the cells and pyknotic changes in the nuclei. Squamous metaplasia was also seen in the inferior conjunctiva (31.7%) and the clinically unaffected interpalpebral conjunctiva (54.8%) but without the advanced changes seen over the pterygium (p < 0.001). A low cellular yield was obtained over the pterygium in 98.2% of cases but only 22.7% in the inferior conjunctiva and 22.6% in the clinically unaffected interpalpebral conjunctiva (p < 0.001). Mucinous hyperplasia signifying increased goblet cell density was observed over the surface of the pterygium in 87.5% compared with 2.4% in the superior conjunctiva, 15.9% in the inferior conjunctiva, and 12.9% in the clinically unaffected interpalpebral conjunctiva (p < 0.001).

Conclusion: The cytology of surface cells in pterygium exhibits squamous metaplasia with increased goblet cell density. A graded series of ocular surface changes exists throughout the bulbar conjunctiva in eyes with pterygium, with the most advanced changes occurring directly over the pterygium surface.