Conventional Versus Accelerated Corneal CXL for Keratoconus
Narrative Responses:
Purpose
To evaluate and compare the efficacy and safety of conventional and accelerated cross-linking (CXL) in patients with progressive keratoconus.
Methods
In this prospective comparative study, riboflavin-UVA-induced CXL was performed in 18 eyes according to the conventional epi-off protocol (30 min corneal soaking in 0.1% riboflavin- 20% dextran solution, 30 min 3 mW/cm2 UVA irradiation, 5.4 J), in the other 18 eyes according to the accelerated epi-off protocol (20 minutes corneal soaking in 0.1% riboflavin- 20% dextran solution, 4 min 30 mW/cm2 UVA irradiation, 7.2 J). Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), sphere and cylinder, spherical equivalent (SE), corneal topography, pachymetry and aberrometry were evaluated at baseline and 1,3,6 and at 9 months.
Results
In the conventional CXL group, a significant improvement at month 9 was present for UCVA (-0.11LogMar, p=0.005) and BSCVA (-0.08 LogMar, p=0.039),K1 ( -0.66 D,p= 0.013), Kmax ( -1.57 D, p=0.004), SE (-0.72 D, p=0.018), total RMS (-1.7µm, p=0.001) and for 4 of 7 keratoconic indices [ISV( -8.0), IVA( -0.08), KI ( -0.02), Rmin ( -0.15, all p <0.05). In the accelerated CXL group, UCVA (-0.17 LogMar,p=0.02) and BSCVA( -0.10 LogMar, p=0.007) significantly improved at month 9, whereas no change was observed in any of the tested topographic and refractive parameters (p>0.05). No complications were observed in either group.
Conclusion
Both CXL procedures are safe, and compared to accelerated CXL, conventional CXL seems to be more effective to halt or regress keratoconus.