Corneal crosslinking effects on macular microvasculature in progressive keratoconus cases: A prospective single-arm study.

OBJECTIVE

To evaluate the macular microvascular changes after corneal collagen crosslinking (CXL) in progressive keratoconus (KCN) cases

DESIGN

Single-arm prospective interventional study

PARTICIPANTS

Thirty eyes of 25 cases with progressive KCN are included in this study to undergo a corneal epi‑off CXL procedure.

METHODS

All included eyes underwent an epi‑off CXL procedure with Dresden protocol and were followed up for 6 months. All patients were examined at four visits: before the CXL procedure, one week, one month, and 6 months after the CXL procedure. Patients underwent a macular optical coherence tomography angiography (OCTA) before, 1 month, and 6 months after the CXL procedure.

MAIN OUTCOME MEASURES: The vessel density (VD) in the foveal, parafoveal, perifoveal, whole image, superior-Hemi, and inferior-Hemi regions was evaluated in both superficial and deep capillary plexus (SCP and DCP).

RESULTS

The study enrolled 12 Males and 13 Females with a median age of 24.0 (IQR:21.0-26.5). Foveal VD in DCP was lower than the baseline at 1 and 5-6 months after the procedure. The mean difference (MD) between the baseline and the follow-ups was 4.34 % (95 %CI:0.25-8.42) and 6.21 % (95 %CI:2.20-10.35), respectively. The SCP VD showed a significant decrease in the superior segment of the macular OCTA 5-6 months after CXL (MD: 3.44 % (95 %CI:1.28-5.60)). Other macular SCP and DCP parameters showed no statistically significant change 5-6 months after CXL, although numerically, they seem lower at the last follow-up compared to the baseline.

CONCLUSION

The corneal CXL procedure may alter the macular microvasculature, lasting even 6 months after the procedure, despite its overall presumed safety regarding the patients' vision and retinal function.