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A.A. Abdelkader, S. Esquenazi, W.A. Shihadeh, J. Wood, S. Gill, H. Kaufman; Influence of the Healing Process at the Flap Edge in the Development of Corneal Ectasia After Laser in situ Keratomileusis (LASIK) . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2728.
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Post–LASIK corneal ectasia is a progressive deformation of the gross corneal anatomy that occurs after surgery. However, this is a rare even after deep lamellar keratoplasty. We hypothesize that the sutures that enhance the wound edge healing response give the strength of the lamellar keratoplasty wound. This study compares, in a rabbit model, the stability of previously sutured and unsutured microkeratome flaps.
Unilateral 160 µm thick LASIK flaps using a mechanical microkeratome were performed in 6 rabbit eyes. Animals were then divided in two groups: In group A, the flap was left without sutures. In group B, the flap was sutured with 12 interrupted 10/0 nylon stitches that were removed after 3 weeks under general anesthesia. Slit lamp biomicroscopy was peformed twice a week for the first 3 weeks. Six weeks after surgery all rabbits had corneal topographies performed at their baseline intraocular pressure (IOP) (14 mm Hg) and at 2 artificially increased pressures (25 and 45 mm Hg) using an anterior chamber maintainer implanted in the inferior limbal area.
A statistically significant increase in corneal curvature was observed in group A (unsutured flaps) when the IOP was increased from baseline (14 mmHg) to 25 mm Hg compared with group B (sutured flaps). No further increase in corneal curvature was observed by increasing the IOP from 25 to 45 mm Hg in both groups.
The addition of sutures in the corneal flap after LASIK appears to reduce the amount of corneal steepening when the IOP is artificially increased up to 25 mm Hg in this rabbit model. Our results suggest that corneal ectasia may be related to the clinically observed lack of corneal wound healing at the edge of the flap that allows the cornea to bulge. By stimulating a stronger wound healing response at the edge of the flap the cornea may better resist steepening under increased IOP conditions and improve the long–term stability of LASIK surgery in borderline thin corneas.
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