Astigmatism and surface phenomena in pterygium.

Area of Science:

• Ophthalmology
• Corneal Science

Background:

• Pterygium is a wing-shaped fibrovascular growth on the conjunctiva that can extend onto the cornea.
• Its impact on corneal topography and cellular changes is not fully understood.

Purpose of the Study:

• To investigate the effects of pterygium on corneal astigmatism and ocular surface characteristics.
• To evaluate the efficacy of different vital stains in visualizing pterygium tissue.

Main Methods:

• Examination of 39 eyes with pterygium and 17 control eyes.
• Measurement of astigmatism and assessment of tear film stability (Break Up Time).
• Application of vital stains (tetrazolium, rose bengal, fluorescein, alcian blue) and cytologic analysis.

Main Results:

• Increased "with the rule" astigmatism was observed in 46% of pterygium eyes (≥4 D in 13%) without vision impairment.
• Tetrazolium and rose bengal intensified staining over the pterygium, unlike fluorescein or alcian blue.
• Stocker's line was present in 46% of cases; corneal thickness and tear film stability were normal.

Conclusions:

• Pterygium frequently induces astigmatism, primarily "with the rule", but typically does not compromise visual acuity.
• Certain vital stains effectively highlight pterygium tissue, aiding in its assessment.
• The ocular surface and corneal structure show minimal significant changes directly attributable to the pterygium itself.