Maja Bohac1, Mateja Koncarevic1, Adi Pasalic1, Alma Biscevic1, Maja Merlak2, Nikica Gabric1, Sudi Patel1,3. 1. a School of Medicine, University of Rijeka , Specialty Eye Hospital "Svjetlost" , Zagreb , Croatia. 2. b Department of Ophthalmology , School of Medicine, University of Rijeka , Rijeka , Croatia. 3. c NHS National Services Scotland , Edinburgh , UK.
Abstract
PURPOSE: To report the incidence of postoperative ectasia after laser in situ keratomileusis (LASIK). METHODS: A retrospective case review of 30,167 eyes (16,732 patients) was conducted following LASIK between August 2007 and August 2015. The follow-up was between 2 and 8 years. Tomography was performed after 2 years postop. After identifying cases of ectasia, the charts of these patients were examined to identify any common factors that may have predisposed them to develop ectasia. RESULTS: Ten eyes of seven patients developed post-LASIK ectasia. Eight eyes had been treated for myopia and myopic astigmatism, two eyes for mixed astigmatism. There were no cases of ectasia after LASIK for hyperopia. All 10 cases of ectasia had a flap that was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15 ± 12.88 µm) and refractive error corrected using the Wavelight Allegretto excimer laser. Retrospectively, most prevalent risk factors were thin cornea (≤ 500 µm, 50% of cases), anterior topographic map irregularities (e.g., asymmetric bow tie, 40% of cases), Ectasia Risk Score > 3 (40% of cases), percent tissue thickness alteration ≥ 40% (20% of cases) and low residual stromal bed (≤ 300 µm, 30% of cases). One eye had no identifiable risk factors. In the retrospective chart review 14.97% (4,506) of all the eyes had similar risk factors to the cases that went on to develop ectasia. CONCLUSION: The incidence of ectasia was 0.033% over 8 years. The incidence could be higher as some cases may destabilize beyond this period and some patients were lost to follow-up asymptomatic of any clinical signs. Other intrinsic factors may trigger the development of post LASIK ectasia. The current widely accepted risk factors are not sufficiently rigorous for screening out potential ectasia from developing after LASIK. There is a need to augment accuracy with higher sensitivity and specificity.
PURPOSE: To report the incidence of postoperative ectasia after laser in situ keratomileusis (LASIK). METHODS: A retrospective case review of 30,167 eyes (16,732 patients) was conducted following LASIK between August 2007 and August 2015. The follow-up was between 2 and 8 years. Tomography was performed after 2 years postop. After identifying cases of ectasia, the charts of these patients were examined to identify any common factors that may have predisposed them to develop ectasia. RESULTS: Ten eyes of seven patients developed post-LASIK ectasia. Eight eyes had been treated for myopia and myopic astigmatism, two eyes for mixed astigmatism. There were no cases of ectasia after LASIK for hyperopia. All 10 cases of ectasia had a flap that was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15 ± 12.88 µm) and refractive error corrected using the Wavelight Allegretto excimer laser. Retrospectively, most prevalent risk factors were thin cornea (≤ 500 µm, 50% of cases), anterior topographic map irregularities (e.g., asymmetric bow tie, 40% of cases), Ectasia Risk Score > 3 (40% of cases), percent tissue thickness alteration ≥ 40% (20% of cases) and low residual stromal bed (≤ 300 µm, 30% of cases). One eye had no identifiable risk factors. In the retrospective chart review 14.97% (4,506) of all the eyes had similar risk factors to the cases that went on to develop ectasia. CONCLUSION: The incidence of ectasia was 0.033% over 8 years. The incidence could be higher as some cases may destabilize beyond this period and some patients were lost to follow-up asymptomatic of any clinical signs. Other intrinsic factors may trigger the development of post LASIK ectasia. The current widely accepted risk factors are not sufficiently rigorous for screening out potential ectasia from developing after LASIK. There is a need to augment accuracy with higher sensitivity and specificity.
Authors: Marcus Ang; Damien Gatinel; Dan Z Reinstein; Erik Mertens; Jorge L Alió Del Barrio; Jorge L Alió Journal: Eye (Lond) Date: 2020-07-24 Impact factor: 3.775
Authors: Hon Shing Ong; Mohamed Farook; Benjamin Boon Chuan Tan; Geraint P Williams; Marcony R Santhiago; Jodhbir S Mehta Journal: Clin Ophthalmol Date: 2019-10-14