| Abstract: |
As refractive surgery gets simpler, safer, more predictable and more effective, it becomes more popular. While cases of simple myopia are usually easy to handle and get satisfactory results when corrected with excimer laser, those with high myopia still represent some challenges.To get the best possible outcome, the surgical plan should be tailored individually to suit each particular case with its peculiar characteristics regarding patients age, activities, visual needs, expectations and of course not the least his own eye parameters.In an attempt to better understand this issue, this study was conducted including ninety eyes of 48 patients, 22 males (45.8 %) and 26 (54.2%) females with a mean age of 40.66±12.03 (range 20 to 63) years and mean spherical equivalent of -12.67±4.64 (range -24 to -7.5) diopters. They were divided into three equal groups.The first group (A) underwent phakic intraocular lens implantation namely Kelman duet lens which is an angle supported anterior chamber phakic lens with rigid tripod haptic and foldable optic that can be injected through a self sealed clear corneal incision of as small size as two mm to be assembled to the previously implanted haptic.The second group (B) under went LASIK after doing the necessary investigations to exclude keratoconus suspects and to make sure that the cornea has enough thickness to allow complete correction of the refractive error in an ablation diameter that matches the scotopic pupil size.The third group (C) underwent clear lens extraction using micro-incision cataract surgery followed by implantation of acrylic foldable posterior chamber IOLs.The mean efficacy index three months postoperatively was 0.99, 0.874 and 0.916 in group A, B and C respectively. UCVA of 0.5 (6/12) or better was achieved in 80%, 93.33%, 63.3% of cases of group A, B and C respectively, while UCVA of 1.0 (6/6) was achieved in 16.67% and 33.3% of cases of group A and B.The mean postoperative safety index was 1.268, 1.03 and 1.249 in group A, B and C respectively. BCVA of 0.5 (6/12) or better was achieved in all cases however, 50%, 60% and 26.67% of cases in group A, B and C respectively achieved postoperative BCVA of 1.0 (6/6)Postoperative spherical equivalent within one diopter of emmetropia was achieved in 76.67%, 86.67%, 70% of cases in group A, B and C respectively. Postoperative defocus equivalent equal to or less than one diopter was achieved in 50%, 80% and 60% of cases group A, B and C respectively.The contrast sensitivity curves improved in the first postoperative month in all spatial frequencies in cases of group A and C without significant change in the subsequent visits. However; in cases of group B the contrast sensitivity curves decreased in the first postoperative month in all spatial frequencies, then improved at the third month visit to the preoperative level to exceed it in the sixth month without significant change in the subsequent ninth month visit.There was transient rise in IOP in cases of group A and C during the first postoperative week however; in group B IOP showed significant decline all through the follow up period.There was statistically significant loss of endothelial cells at one and nine months postoperatively however, the degree of loss varied in different groups. The loss in the mean endothelial cell count from preoperative level to the first month postoperatively was 6.29%, 1.56% and 9.78% and from the first month to the ninth month postoperatively was 0.99%, 1.28% and 0.92% in group A, B and C respectively.Regarding complications; in group (A), 6.67% of cases developed mild intraoperative hyphaema. Pupil ovalization occurred in 6.67% of cases, In 3.33% of cases rotation of the lens occurred due to too short haptics. In group (B), 3.33% of cases had decentered flap 3.33 % had decentered ablation. Interface deposits as well as bleeding to the interface were observed in 6.67%. The incidence of epithelial ingrowth, DLK and flap stria was 3.33% where as that of pseudoDLK was 6.67%. while in group (C), 3.33% of cases had intraoperative iris trauma while developed 6.67% posterior capsule opacification.
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