Background: Myopia a refractive error that is a major contributor to visual disability across combined age groups all over the world. Aim of the work: To detect changes in the corneal endothelial cells parameters among high myopic patients versus emmetropic individuals in different age groups aiming at proper identification of the endothelial cells behavior; hence we can predict more precise results after phaco refractive surgeries and implantable collamer lens (Icl) implantation. Patients and methods: This case-control research, performed on 168 eyes of 84 participants allocated into two groups:  Group I (42 cases, 84 eyes): individuals with high myopic eyes, and Group II (42 cases, 84 eyes): individuals with healthy emmetropic eyes as a control group at Outpatient Clinic, Ophthalmology Department, Suez Canal University Hospital, Ismailia, Egypt for a period of six months from February 2021 to July 2021. (NIDEK CEM-530) specular microscope was utilized to determine the central corneal thickness (CCT) of the participants. Results: The study observed no significant variance in CoV% among high myopic and emmetropic eyes, but there was a significant variation in ECD (Endothelial Cell Density) and HEX% (Hexagonality) among the two groups. The mean ECD in high myopic eyes was 2533.79±315.37 cells/mm², while in emmetropic individuals, it was 2706.65±313.50 cells/mm². Conclusion: The research found that corneal endothelial cell density and morphology significantly vary among different age groups, indicating a significant effect of age on corneal endothelial function.