engleski

Short-term effect of conventional and accelerated corneal cross-linking protocol on corneal stability and visual acuity

Purpose: To determine the 6-month effect of conventional (CXL30) and accelerated crosslinking with UVA intensity of 9mW/cm2 (CXL10) on corneal stability and visual function and to investigate whether there was a difference in ABCD grading system parameters regarding the two procedures. Setting: Prospective study. Methods: Twenty-seven eyes of 25 patients with a documented diagnosis of keratoconus (KN) progression defined by the instructions from the Global Consensus on Keratoconus and Ectatic Diseases were included. Patients were selected to undergo either CXL 30 or CXL 10 procedure. After epithelial debridement, soaking the cornea with riboflavin 0.1%/hydroxypropyl methylcellulose 1.1% for 10 min. at 2-minute intervals, the surgeon decided to proceed with UVA irradiance of 3mW/cm2 or 9mW/cm2 . At the baseline visit and the follow-up visits after one month (mo.) (V1), three (V2), and six mo. (V3) postoperatively, all the patients underwent complete ophthalmic examination, including uncorrected visual acuity (UDVA), best- corrected visual acuity (BCVA), and corneal tomography (Pentacam HR ; Oculus, Wetzlar Inc, Germany). Results: In the CXL 30 group, all the parameters from ABCD grading system significantly changed from baseline visit to V3 ; parameter A decreased (2.5 vs. 2.6 vs. 2.4 vs. 2.5, p= 0, 048), B increased (4.66 vs. 4.54 vs. 5.03 vs. 4.99, p=0.01), C increased (1.52 vs. 2.09 vs. 2.36 vs. 2.14, p <0.001), and D decreased (2.33 vs. 2.49 vs. 1.99 vs. 1.87, p <0.001). While in the CXL 10 group, there were no significant changes in parameters A (4.7 vs. 4.6 vs. 4.4 vs. 4.3, p=0.247) and B (6.92 vs. 7.18 vs. 7.05 vs. 7.01, p=0.933), while parameter C increased (2.51 vs. 2.98 vs. 2.95 vs. 2.86, p=0.001) and D decreased (2.82 vs. 2.84 vs. 2.35 vs. 2, 24, p <0.001). After an initial decline after one mo., BCVA recovered on V2 and V3 in both groups (p <0.001). Similarly, after an initial increase after one mo., maximal keratometry readings (Kmax) significantly decreased in both groups on V2 and V3, with higher significance in the CXL 30 group (p=0.001 vs. p=0.035 ). In the CXL 30 group, there were significant changes in other monitored parameters ; index of surface variance – ISV ( p=0.011), index of height decentration (p=0.001), minimum sagittal curvature – Rmin (p <0.001), average pachymetric progression index (p <0.001), Ambrósio relational thickness maximum – ARTmax (p=0.008), front and back mean keratometry (p <0.001), pachymetry apex – PA (p <0.001), and front elevation (p=0.042). While in the CXL 10 group, there were significant changes only in ISV (p=0, 002), Rmin (p=0.043), ARTmax (p=0.019), and PA (p <0.001), no other parameters significantly changed in CXL 10 group. Conclusion: Both CXL protocols showed similar short-term efficacy in improving visual acuity and Kmax and halting the progression of keratoconus. Also, both protocols changed various corneal parameters on Pentacam in a similar fashion ; however, the conventional protocol resulted in more significant short-term changes in the cornea. Disclosure of Interest: None declared

Corneal crosslinking ; Accelerated protocols ; Dreseden protocol ; corneal tomography

nije evidentirano