<prompt> Pterygium is:Vascular anomalyConnective tissue proliferationInflammatory conditionAssociated with Vit. A deficiency  <response>: A pterygium is a proliferation of fibrovascular tissue on the surface of the eye, which extends onto the cornea. The etiology of pterygium is incompletely understood. However, chronic UV exposure is accepted as a causative agent. Treatment options: Pterygia are usually treated only when they interfere with vision. The standard therapy is surgical removal. Pterygia affect astigmatism and are associated with increased rates of macular degeneration; however, it is unclear whether treatment reduces this risk. Eyes with a pterygium or previous pterygium surgery but not pinguecula have a higher risk of incident late age-related maculopathy ARM OR 3.3, 95 CI 1.1-10.3 and early ARM OR 1.8, 95 CI 1.1-2.9. Ref: Chumley H. 2009. Chapter 11. Pterygium. In R.P. Usatine, M.A. Smith, H. Chumley, E. Mayeaux, Jr., J. Tysinger Eds, The Color Atlas of Family Medicine. 