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  • LASIK with a large ablation zone effective for high hyperopia

    Refractive Mgmt/Intervention

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    This retrospective study evaluated treatment of high hyperopia using LASIK with an aberration-neutral profile and large ablation zone.

    Study design

    The study included 77 patients (146 eyes) with hyperopia greater than +5 D (average +6.6 D). All patients were treated with the Amaris 750S excimer laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) using an aberration-neutral profile, a 6.7-mm optical zone, and a large 9.2-mm total ablation zone. Flaps were created with a mechanical microkeratome. Three-fourths of the corneal vertex offset with respect to pupil center was used through the asymmetric offset centration of the system. The location of the corneal vertex and offset values were obtained using videokeratoscopy. Refractive results, predictability, safety and efficacy were evaluated at 6-months postoperatively.

    Outcomes

    At 6 months, the mean manifest refraction spherical equivalent (SEq) and cylinder were −0.06 D and 0.42 D, respectively. Eyes tended to be within ±0.50 D of the attempted SEq correction and achieved an uncorrected distance visual acuity of 20/20 or better. Overall, 10% of eyes lost 1 line of corrected vision while 4% gained a line; none lost more than 2 Snellen lines.

    Loss of CDVA correlated with steeper postoperative keratometry (0.028 lines worse/D of keratometry). Postoperative keratometries steeper than 47 D lost an average of −0.16 lines of CDVA compared with flatter postoperative keratometries (−0.11 lines vs. +0.06 lines, P<0.0005). The eyes that gained lines had -1 D flatter keratometries than the eyes that lost lines (P<0.05). Eyes with a correction higher than 6 D SEq lost, on average, -0.14 lines of CDVA compared with lower corrections (P=0.005).

    Limitations

    This study evaluated visual acuity and refractive outcomes, but did not evaluate higher order aberrations or contrast sensitivity. Since some studies suggest that significant regression can occur within the first 12 months after LASIK, the authors would need a longer follow-up period to support their conclusions.

    Clinical significance

    LASIK for high hyperopia using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability and visual outcomes.