[Study of corneal morphological changes and light scattering rate in keratoconus]

The paper gives the results of studying the rate of light scattering by different corneal layers in keratoconus from confocal microscopy data. The study was conducted using a Confoscan-4 confocal microscope (Nidek, Japan). The rate of light scattering was estimated from the results of analyzing the densitometric curve, by applying a Z-scanning system. A total of 77 patients (136 eyes) with stages 1-4 keratoconus and 20 healthy individuals at the age of 16 to 20 years were examined. Confocal microscopy revealed corneal changes that were characteristic of different stages of keratoconus and a cause of its optical heterogeneity. As an epithelial lesion progressed, there was an obvious tendency towards increases in the scattering of light waves and in the range between their minimum and maximum values. Examination of corneal stromal layers revealed no statistically significant differences between the minimal level of light scattering in health and that in keratoconus in its different stages. However, there was an increase in the maximum level of light scattering due to the appearance of compact tissue portions with a higher reflectivity. The range between the minimum and maximum values was also increased. Comparison of the levels of light scattering by the posterior corneal epithelium established no statistically significant differences. Overall, increased light scattering by individual corneal microstructures and a distorted ratio between its minimum and maximum levels may be considered as a morphological component of aberrations that reduce the resolution of the eye optical system.