To compare accelerated corneal crosslinking (CXL) alone, CXL with simultaneous intrastromal corneal ring segments (CXL-ICRS), and CXL with simultaneous topography-guided photorefractive keratectomy (CXL-TG-PRK) in progressive keratoconus, pellucid marginal degeneration (PMD), or laser in situ keratomileusis (LASIK)-induced ectasia.
The Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada.
Prospective nonrandomized interventional study.
Visual and topographical outcomes using a comparative analysis adjusting for preoperative maximum keratometry (Kmax) were evaluated 1 year postoperatively.
Four hundred fifty-two eyes from 375 patients with progressive keratoconus, PMD, or LASIK-induced ectasia that underwent accelerated (9 mW/cm, 10 minutes) CXL alone (n = 204), CXL-ICRS (n = 126), or CXL-TG-PRK (n = 122) were included. Change in logarithm of the minimum angle of resolution uncorrected distance visual acuity was significant with CXL-ICRS (-0.31; 95% CI, -0.38 to -0.24) and CXL-TG-PRK (-0.16; 95% CI, -0.24 to -0.09), but not with CXL alone. No significant differences in change were found between the 3 groups. Change in corrected distance visual acuity (CDVA) was significant in all 3 groups: -0.12 (95% CI, -0.15 to -0.10) with CXL alone, -0.23 (95% CI, -0.27 to -0.20) with CXL-ICRS, and -0.17 (95% CI, -0.21 to -0.13) with CXL-TG-PRK. Improvement in CDVA was greater with CXL-ICRS than with CXL alone (-0.08 ± 0.02; P < .0001) and CXL-TG-PRK (-0.05 ± 0.02; P = .005). Change in Kmax was significant with CXL-ICRS [-3.21 diopters (D); 95% CI, -3.98 to -2.45] and CXL-TG-PRK (-3.69 D; 95% CI, -4.49 to -2.90), but not with CXL alone (-0.05 D; 95% CI, -0.66 to 0.55).
CXL alone might be best for keratoconic patients who meet the inclusion criteria. CXL-ICRS might be more effective for eyes with more irregular astigmatism and worse CDVA and CXL-TG-PRK for eyes requiring improvements in irregular astigmatism but still have good CDVA.