J Korean Ophthalmol Soc.  2008 Nov;49(11):1723-1728.

Influence of Surface Fluid during Photorefractive Keratectomy Using a 213-nm Solid-State Laser

• Kim KS
• Choi CY
• Tchah H

Abstract

PURPOSE
To investigate the effect of surface fluid on the ablation rate and efficacy of 213-nm solid-state laser during photorefractive keratectomy (PRK). METHODS: Twelve rabbits (24 eyes) underwent myopic PRK for the correction of 10 diopters using 213-nm solid-state laser. Photoablation was performed with removal of corneal surface fluid using the Weckcel(R) sponge every 5 seconds in one eye and without removal of corneal surface fluid in the control eye. The mean central corneal thickness (CCT) was evaluated preoperatively, and at 1 week, 4 weeks postoperatively.
RESULTS
The mean CCT of group 1 (with removal of corneal surface fluid) were 361.3+/-13.9 micrometer preoperatively and 321.4+/-18.5 micrometer at 4 weeks postoperatively. The mean CCT of group 2 (without removal of surface fluid) were 358.7+/-8.9 micrometer preoperatively and 338.4+/-12.0 micrometer at 4 weeks postoperatively. The mean ablation depths were 39.8+/-7.4 micrometer in group 1 and 20.3+/-5.8 micrometer in group 2 at 4 weeks postoperatively p<0.05).
CONCLUSIONS
Induced corneal surface fluid during PRK may influence the ablation efficacy and accuracy of solid-state laser. This result should be considered in clinical trialswith 213-nm solid-state laser, especially in high myopes.

Keyword

213-nm solid-state laser; Ablation efficacy; Ablation rate; Photorefractive keratectomy; Surface fluid

MeSH Terms

Eye
Lasers, Solid-State
Photorefractive Keratectomy
Porifera
Rabbits

Figure

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  Figure 1. The photograph of photorefractive keratectomy using 213-nm solid-state laser in rabbit’s eye.

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  Figure 2. The comparison of ablation depth at postoperative 4 weeks ( P-value<0.05, Mann-Whitney test).

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  Figure 3. Schematic presentation of reflection loss. (A) Experimental model of Geoffrey et al8 (θ=90°). (B) Reflection loss on corneal surface fluid (θ<90°).

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  Figure 4. Schematic presentation of refraction loss in corneal surface fluid.

Reference

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