الفهرس 
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Abstract
Abstract : The corneal endothelium is formed by a single layer of cells on the posterior corneal surface and transports water from the stroma into the anterior chamber to preserve the corneal dehydration and its transparency. In the past, assessment of the corneal endothelium was limited to biomicroscopic evaluations for guttae, folds, and keratic precipitates, and it was quite difficult to assess the endothelial cell characteristics and functional reserve. The introduction of advanced evaluation techniques, including specular microscopy, fluorophotometry, and pachymetry, has enabled evaluation of the corneal endothelial cell density and function. In some species, the endothelium can regenerate after injury. On the contrary, humans exhibit a cell repair mechanism characterized by enlargement of the endothelial cells. In the absence of the ability of endothelial cells to proliferate, the endothelial cover of the posterior corneal surface is maintained by a gradual increase in the size of the remaining cells, which result in increased cellular pleomorphism and a decrease in the percentage of hexagonal cells with age. Specular microscopy is used to establish and compare normative data for corneal endothelium parameters among different ethnic groups and between men and women. Due to the existence of variations in endothelial parameters in Indian, Filipino, Iranian, Thai, Chinese, Japanese, and American populations, knowledge of normative data on the corneal endothelium is important. Data gathered may help in the assessment of the functional endothelial reserve of individuals and may even aid in understanding corneal disease in people of different genders, ages, and ethnic groups. This cross-sectional study was conducted at Mansoura University Ophthalmology Center aiming to determine the effect of age and gender on corneal parameters as corneal endothelial cell density (CED), central corneal thickness (CCT), average cell size, coefficient of variation in cell size (CV), and percentage of regular hexagonal cells in normal healthy Egyptian population. We included a total of 150 subjects who were subjected to complete history taking, slit lamp biomicroscopic examination, visual acuity assessment, in addition to IOP measurement. Moreover, a non-contact specular microscope was used to assess corneal morphological parameters including corneal endothelial density, average cell size, CV, and central corneal thickness. Our study showed the following findings : The mean age of the included cases was 37.68 years (range, 10 – 66). We included 76 males (50.7%) in addition to 74 females (49.3%). The mean value of visual acuity was 0.69, whereas BCVA had mean value of 0.85. The mean values of sphere, cylinder, and axis were -0.42, -0.67, and 82.6 respectively. IOP had mean value of 15.41 (range, 11.5 – 19.6). Corneal endothelial density had mean value of 2559.47 cells/mm2, while average cell size had mean value of 398.08 μm. CV had mean value of 39.33% (range, 26 – 60). The mean value of central corneal thickness was 511.07 μm. No significant difference was detected between males and females regarding UCVA, BCVA, IOP, and refractive parameters, apart from sphere which was significantly different between the two genders. Corneal endothelial density, average cell size, and central corneal thickness did not show significant differences between the two genders. However, CV was significantly higher in females (40.33 vs. 38.36%). Age had a significant negative correlation with UCVA, BCVA, sphere and cylinder. On the other hand, both axis and IOP failed to show a significant correlation with age. No significant correlation was detected between age and either of corneal endothelial density, CV, average cell size and central corneal thickness.