Evaluating the Ectasia Risk Score System in Cancelled Laser In Situ Keratomileusis Candidates

Abstract

Purpose: To evaluate the ectasia risk score system in cancelled laser in situ keratomileusis (LASIK) candidates at an academic hospital.
 Methods: LASIK candidates who had been cancelled by a surgeon considering the patient age, preoperative central corneal thickness, residual stromal bed thickness, or preoperative manifest refraction spherical equivalent were retrospectively reviewed, and their Randleman ectasia risk score system score was calculated.
 Results: The mean ectasia score of 194 eyes (97 patients) was 4.5 ± 2.67; 40 (20.6%), 46 (23.7%), and 108 (55.7%) eyes were classified as low-, moderate-, and high-risk eyes, respectively. The topography was abnormal in 69% of the patients. The mean manifest refraction spherical equivalent, central corneal thickness, and estimated residual stromal bed thickness were 4 (+0.50 to –15.50) diopters, 520 (439 to 608) μm, and 312.38 (61.5 to 424.12) μm, respectively. The main cause of cancellation in low- and moderate-risk patients (86 eyes) was the presence of unstable refractive error in the past year.
 Conclusion: Although promising, some other criteria, such as stable refraction, should be added to this scoring system to achieve greater practicality since a main cause of cancelling LASIK candidates in this study was the presence of unstable refraction.

Ectasia risk score system and practical subjective scoring system in screening of keratorefractive surgery candidates

“…In the current study, there were 49 male patients and 65 female patients, there were no significant differences between the studied groups as regard age and gender. P value was 0.69, and this was in agreement with (3) study in which a total of 97 patients Abnormal preoperative topography remains the greatest independent risk factor for post-LASIK ectasia, although corneas with normal topographies preoperatively have also been reported to develop ectasia after LASIK (8).…”

“…In (3) study, the mean RSB thickness of cancelled patients was 312 μm above the widely accepted 250 μm. Moreover, in (8) study, the average RSB was >250 μm.…”

“…The study (3) The study (10) study, demonstrated a highly prevalent risk factor that was suspected and abnormal topographic patterns were found in approximately 64% of patients. This was consistent with former reports.…”

“…Histologic findings suggest that post-LASIK keratectasia results in collagen fibril thinning and a decreased interfibrillar distance within the residual stromal bed (RSB) (3).…”

Post-LASIK keratectasia in the context of a thicker than intended flap detected by anterior segment optical coherence tomography

“…5,6 Several risk factors that predispose to the occurrence of corneal ectasia after refractive surgery have been described, such as high myopia, forme fruste keratoconus, and low residual stromal bed thickness (RSBT), but cases with mild myopia, normal topography, and residual stromal bed more than 300 μm may also develop ectasia. [5][6][7][8][9][10][11][12][13][14] Although the upper limit of myopia suitable for treatment by LASIK has been arbitrarily set as less than 12.00 dioptre (D), keratectasia after LASIK has been reported in cases treated for much lower degrees of myopia from 4.00 to 7.00 D. 15 Inferior corneal steepening was noted in some of these cases preoperatively. In the absence of refractive instability or slit-lamp microscopic features of keratoconus, these corneal changes have been called forme fruste keratoconus.…”