Interaction of laser radiation with matter

Effect of laser radiation wavelength and reepithelization process on optical quality of eye cornea after laser correction of vision

M. S. Kitai, A. V. Semchishen, V. A. Semchishen

Institute on Laser and Information Technologies, Russian Academy of Scienses, Shatura, Moskovskaya obl.

Abstract: The optical quality of the eye cornea surface after performing the laser vision correction essentially depends on the characteristic roughness scale (CRS) of the ablated surface, which is mainly determined by the absorption coefficient of the cornea at the laser wavelength. Thus, in the case of using an excimer ArF laser (λ=193 nm) the absorption coefficient is equal to 39000 cm^-1, the darkening by the dissociation products takes place, and the depth of the roughness relief can be as large as 0.23 mm. Under irradiation with the Er:YAG laser (λ=2940 nm) the clearing is observed due to the rupture of hydrogen bonds in water, and the relief depth exceeds 1 μm. It is shown that the process of reepithelization that occurs after performing the laser vision correction leads to the improvement of the optical quality of the cornea surface.

Keywords: eye cornea, medium darkening due to photochemical reaction, laser ablation, characteristic roughness size, effect of UV radiation, effect of IR radiation.

PACS: 42.66.Ct, 42.66.Lc, 79.20.Eb

Received: 15.12.2014
Revised: 13.05.2015

 English version: Quantum Electronics, 2015, 45:10, 927–932

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