Abstract
Purpose::
To compare changes in corneal keratocyte density following laser in situ keratomileusis (LASIK) in one eye and photorefractive keratectomy (PRK) in the fellow eye
Methods::
In a prospective, randomized, single-center clinical trial, twenty-five patients underwent laser in situ keratomileusis (LASIK) in one eye and photorefractive keratectomy (PRK) in the fellow eyes. All LASIK flaps were made using the IntraLase FS laser. The mean Manifest Refraction Spherical Equivalent (MRSE) before surgery was -4.18 ± 1.03 D for LASIK eyes and -4.30 ± 1.04 D for PRK eyes. Corneal keratocyte density was measures using the Nidek Confoscan 4 at equivalent stromal zones in both LASIK and PRK eyes. In the LASIK eyes, keratocyte density was measured in the posterior segment of the flap, retroablation zone and mid stromal zone. In the PRK eyes, keratocyte density was measures at the retroablation zone, anterior stromal and midstromal zones. Difference in keratocyte density was measured from pre-op to 1 month, 3 months and 6 months post-op and between LASIK and PRK eyes.
Results::
At 1 month, keratocyte density in the PRK eyes decreased by 32% in the retroablation zone, 17% in the anterior stromal zone and 2% in the midstromal zone, and in the LASIK eyes decreased by 21% in the posterior segment of flap, 14% in the retroablation zone and 4% in the midstromal zone. At 3 month, keratocyte density in the PRK eyes decreased by 35% in the retroablation zone, 19% in the anterior stromal zone and 2% in the midstromal zone, and in the LASIK eyes decreased by 29% in the posterior segment of flap, 21% in the retroablation zone and 4% in the midstromal zone. Six month results will be available by the ARVO meeting and will be presented.
Conclusions::
Keratocyte density decreases in the retroablation zone in both LASIK and PRK eyes. There is a loss of keratocyte density in the LASIK flap. There is no significant change in keratocyte density in the midstromal zone. Six months results will be available by the ARVO meeting and the progression of keratocyte loss will be analyzed and reported.
Keywords: cornea: stroma and keratocytes • refractive surgery: LASIK • refractive surgery: PRK