Objective: To determine the prevalence and triggers pterygium in patients treated at the “La Selva” Ophthalmological Clinic, Banda de Shilcayo district. San Martin. Period from July to November 2015. Material and Methods: A descriptive, retrospective and cross-sectional study was carried out, which allowed us to determine the prevalence and triggers pterygium in patients treated at La Selva Eye Clinic. Banda de Shilcayo. San Martin, between July and November 2015. The universe was a total of 1725 patients with several eye diseases, finding a population of 160 patients diagnosed with pterygium in the study period and who met the inclusion criteria. Results: 9.28% of the “La Selva” Ophthalmological Clinic, presents pterygium, with more incidence in age group between 31-50 years (44.4%), with more incidence of females (59.4%); the most affected occupation: Housewife (31.9%); the hig...