Inclusion Criteria:  primary nasal grade 2 to 3 pterygium based on the clinical stages outlined by Johnston et al (2004) who consented for pterygium excision and conjunctival autograft surgery  Exclusion Criteria:  cornea pathology such as scarring, history of herpetic keratitis, eyelid abnormalities, previous ocular surgery, ocular trauma, and ocular or systemic inflammatory disease Pregnant women and lactating mothers