Comparison of accelerated corneal collagen cross-linking under normal and increased oxygen concentrations: A pilot...

To evaluate the role of local oxygen supplementation in accelerated collagen cross-linking (CXL) in human subjects.

Patients with progressive keratoconus were enrolled and randomized to undergo accelerated CXL in either local oxygen supplementation (Group 1, Cases, n = 10) or room-air oxygen (Group 2, Controls, n = 10). Baseline uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent (MRSE), corneal tomographic parameters, corneal biomechanics, and wavefront analysis were documented. Patients were followed up at 1 week, 1 month, 3 months, and 6 months.

Twenty eyes of 20 patients (Group 1, Cases, n = 10; Group 2, Controls, n = 10) were enrolled. At 6 months, both groups exhibited significant flattening of steepest keratometry, increased corneal optical densitometry, and reduced thinnest pachymetry. No eye had keratoconus progression in either group. There was no significant change in UDVA, CDVA, and MRSE in both groups. No intergroup significant differences were found in UDVA, CDVA, MRSE, steepest keratometry (Kmax), or corneal astigmatism. Demarcation line depth was comparable between groups at 6 months.

Accelerated CXL is a useful modality to manage progressive keratoconus. However, in short term, local oxygen supplementation does not seem to have any additional benefit over room-air oxygen. Larger studies with longer follow-up period are required to further investigate the same.