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PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) performed to correct hyperopia, and hyperopic and mixed astigmatism using wider ablation diameters (optical zone diameter and overall ablation diameter) than those commonly used with the same and other lasers.
METHODS: After flap creation using an Alcon SKBM microkeratome set for a 10-mm flap diameter, 53 eyes (33 patients) with a mean spheroequivalent attempted correction of +2.34 * 2.09 D underwent LASIK (Alcon LADARVision 4000) using a 7-mm optical zone diameter and a 3-mm transition zone for an overall 10-mm total ablation diameter. The nasal hinge was prevented from undesired ablation by the use of proprietary hinge protector software. Eyes were followed for 6 months after surgery.
RESULTS: Six months after surgery, mean spheical equivalent refractive error was -0.22 ± 0.41 D. There were 79.2% of eyes within ±0.50 D, and 98.1% within ±1.00 D of intended correction. Uncorrected visual acuity of 20/20 or better was achieved by 28 eyes (53%) and 20/40 or better by 50 eyes (94.3%). No meaningful visual complaints during nighttime hours, such as haloes or glare, were subjectively reported by patients.
CONCLUSION: The use of larger ablation diameters in LASDX for hyperopia, and hyperopic and mixed astigmatism produced accurate results, early refractive stability, and good visual performance. [J Refract Surg 2003;19:548-554]
Laser in situ keratomileusis (LASIK) is a refractive surgery procedure that involves the use of a microkeratome to create a corneal flap through a lamellar cut, and a laser - usually an excimer laser - to ablate exposed stromal tissue.1,2 The ablation changes the curvature of the central part of the cornea, thus producing a change in refraction. Although the technique was originated to treat high myopic refractive errors3,4, it is currently employed to correct a wide range of refractive errors, mild to high myopia, astigmatism, and hyperopia.5-7
Excimer laser correction of hyperopic refractive errors involves reshaping the anterior corneal surface in order to steepen its curvature above the pupillary entrance, through the removal of a negative meniscus of stromal tissue, thicker at the periphery than at its center. To avoid abrupt steps on the corneal surface, which can lead to refractive regression8, a convenient transition must be provided to connect the central refractive zone...