Abstract

EVALUATE THE EFFICACY, SAFETY, CAUSES AND OUTCOMES FOR LENSECTOMY

Dr. Nesmah Qays Mhmood* and Dr. Saba Dhahir Weshaiyh

ABSTRACT

Refractive error includes myopia, hyperopia, astigmatism and presbyopia; these are usually corrected by wearing spectacles or contact lenses. Modifying the shape of the cornea can reduce myopia, hyperopia and astigmatism. Corneal reshaping is achieved in photorefractive surgery using excimer laser ablation and is indicated in the range of refractive error from +6 dioptres (D) of hyperopia to –10 D of myopia, with up to 4 cylinders of astigmatism. This surgery is widely available in the private sector but is not performed as an NHS
procedure unless indicated for therapeutic reasons. Excimer laser refractive surgery techniques in current use include photorefractive keratectomy (PRK), laser epithelial keratomileusis (LASEK) and laser in-situ keratomileusis (LASIK). PRK involves the removal of the corneal epithelium and ablation of the corneal stromal bed. LASEK is a modification of PRK but instead of completely removing the epithelium, dilute alcohol is used to loosen the epithelium, which is lifted from the treatment zone as a hinged sheet and is swept back into place at the end of surgery. In LASIK, a flap is created with a microkeratome, this is lifted, the underlying corneal stromal bed is ablated, and the flap is repositioned. LASIK has been performed in the UK since 1995. Initially it was used to treat higher levels of myopia not suitable for PRK but now it has become the dominant technique for correction of refractive error. Ectasia due to weakening of the cornea is the most serious complication of refractive surgery. Risk factors are high myopia, keratoconus, and a residual cornea\thickness after ablation of less than 250 μm. Assessment for suitability for the procedure requires an appropriate medical, ophthalmological and occupational history followed by a comprehensive ophthalmological examination; in particular to assess the front and back surface of the cornea (corneal topography) and measure of corneal thickness. Other important potential adverse effects of photorefractive surgery include reduced best spectacle corrected visual acuity, infection and problems related to overall visual performance such as glare, halos and difficulties in low light conditions. Methods: This retrospective study recruited eyes of patients who were treated with SMILE after FTAK jule 2019 to jule 2021. Results: This study included 65 eyes from 45 patients. The refraction of all eyes was stable at 4 weeks after.

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