The cornea in young myopic adults

Aims - To further understand the effect of refractive error on the corneal dimensions and function. Methods - Corneal curvature, corneal thickness, and axial length measuremen ts were performed, as well as specular microscopy and fluorophotometry, on patients with various refractive statuses. 216 subjects, mean age 22.2 (SD 4.2) years, were examined. Patients with previous contact lens wear history , external eye diseases, as well as previous ocular surgeries, were exclude d. Results - The corneas were flatter in eyes with longer axial length (r = -0 .22, p = 0.003). Eyes with more myopic spherical equivalent had longer axia l length (r = -0.90, p < 0.001) as well as less corneal endothelial density (r = 0.20, p = 0.037). Corneal endothelial density decreased in eyes with longer axial length (r = 0.24, p = 0.019); however, it correlated neither w ith corneal thickness (r = -0.06, p = 0.59) nor with corneal curvature (r = -0.07, p = 0.52). The corneas had a mean corneal thickness of S33 (SD 29) mum and were thinner in more myopic eyes (r = 0.169 p = 0.021). The corneas tended to be thinner in eyes with longer axial length. However, the correl ation did not reach statistical significance (r = -0.11, p = 0.14). Besides , there was no significant correlation between the corneal thickness and th e corneal curvature (r = -0.13, p = 0.093) and the endothelial permeability (r = 0.042, p = 0.69). The corneas with higher endothelial density had lar ger corneal transfer coefficient (r = 0.26, p = 0.024) and higher permeabil ity to fluorescein molecules (r = 0.289 p = 0.014). Nevertheless, the corne al endothelial permeability did not correlate significantly with either the axial length (r = -0.18, p = 0.11) or the degree of myopia (r = 0.12, p = 0.26). Conclusion - Changes in the anterior segments as the eyeball elongates in m yopia progression included flatter corneal curvature, decreased corneal thi ckness, as well as decreased endothelial density. These factors should be c onsidered in refractive surgery.