Zaidi SBH, et al. - Researchers conducted this descriptive cross-sectional prospective study to determine the difference in mean corneal endothelial cell density (CECD) between the healthy and diseased eyes of the patients with unilateral pterygium with different morphology patterns by using a non-contact specular microscope (SP2000: Topcon Corporation, Japan), as well as to see whether there was a connection between pterygium severity and daily sunlight exposure with the CECD loss. This investigation was performed at Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan from January 21, 2019, to January 22, 2020. Two hundred eyes (n= 100 patients) with unilateral pterygium between the ages of 18 and 68 were chosen. There was no evidence of a connection between sunlight exposure and CECD loss. Using a non-contact specular microscope, the authors found that the mean corneal endothelial cell density in patients with unilateral pterygium was 2411.61 ± 143.64 cells/mm ².