New fixation device for photorefractive surgery and its effect on corneal epithelial wound healing

Abstract

PURPOSE: A new eyeball fixation device during photorefractive surgery was designed and tested. The device fixates the eyeball by means of a suction ring, and is then fixated to the headrest of the patient's chair via clipper and metal frames.

METHODS: Photorefractive keratectomy (PRK) was performed on PMMA contact lenses placed over the patient's cornea (n=6) to evaluate smoothness of the ablated surface and on rabbit (n=24) and patient (n=30) corneas for evaluation of wound healing time. Decentration with fixation was examined using videokeratography after PRK.

RESULTS: After fixation, only small amounts of corneal movement from the patient's pulsating heart were noted. The mean smoothness (root mean square) of the PMMA contact lens ablated surface was 0.43 +/- 0.16 microm in non-fixated eyes and 0.26 +/-0.05 microm in fixated eyes. Mean epithelial healing rate was 47.93 +/- 21.80 microm/hr in non-fixated rabbit eyes and 66.49 +/- 20 microm/hr in fixated rabbit eyes. Mean epithelial healing time was 3.47 +/- 1.11 days in non-fixated human eyes and 2.53 +/- 0.51 days in fixated human eyes. Mean decentration after PRK was 0.30 +/- 0.28 mm in fixated human eyes.

CONCLUSION: Fixating the eyeball allows less movement of the eye and achieves a smoother ablation surface for more rapid epithelial healing after PRK.