ORIGINAL RESEARCH

Study of ablated surface smoothness and thermal processes in rabbit cornea treated with MicroScan-Visum and MicroScan-PIC excimer laser systems

About authors

Department for Clinical Research in Ophthalmology,
Clinical Research Center for Otorhinolaryngology, Moscow, Russia

Correspondence should be addressed: Nika Takhchidi
Volokolamskoe shosse, d. 30, str. 2, Moscow, Russia, 123182; ur.ay@ht-akin

Received: 2016-04-11 Accepted: 2016-04-14 Published online: 2017-01-05
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In ophthalmology, excimer lasers are used for treating different refractive disorders. The performance of an excimer laser station can be assessed by a number of criteria, such as cornea surface smoothness after the ablation, differences between the diameter of the postoperative optical zone that received full correction and the diameter of the programmed optical zone, and cornea heating during the surgery. The article presents the results of the assessment of three Russian excimer laser systems: MicroScan-PIC 100 Hz, MicroScan-Visum 300 Hz and MicroScan-Visum 500 Hz (Optosystems, Russia). The smoothness of the ablated surface was measured by New View – 5000 Zygo interferometer (Zygo Corporation, USA). Using PMMA plates, the ablated surface was formed tenfold with each laser as an imitation of the 3.0 D myopia surgical correction, with the optical zone diameter of 6 mm and the transition zone diameters of 2.3 mm for MicroScan-PIC 100 Hz and of 1.9 mm for MicroScan- Visum 300 Hz and MicroScan-Visum 500 Hz. Thermal processes in the cornea were studied in 15 grey chinchillas over 1 year old with a weight of 2–3 kg. With each of the laser systems, phototherapeutic keratectomy was performed on 5 eyes. The smoothest ablated surfaces were formed by MicroScan-Visum 500 Hz. Cornea temperature was the highest here (+3.95 °С by the end of treatment), but still within the range of values acceptable for modern scanning type lasers.

Keywords: excimer laser system, MicroScan-PIC 100 Hz, MicroScan-Visum 300 Hz, MicroScan-Visum 500 Hz, ablation, cornea, error of refraction

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