Systemic supplemental oxygen therapy during accelerated corneal collagen crosslinking for progressive keratoconus; a randomized clinical trial
Kiana Hassanpour1 , Amir Faramarzi 1 *, Baharan Rahmani 1 , Bahareh Kheiri1 , Mohammad-Mehdi Sadoughi1 , Shahin Yazdani1
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences
Abstract: To investigate the potential additive effect of systemic supplemental oxygen
administered during accelerated corneal crosslinking (CXL) for progressive keratoconus (KCN).
Methods: : This study includes eyes with progressive KCN ranodmized to three different CXL
protocols. The first group (OA-CXL) included 19 eyes that underwent an accelerated CXL
protocol (9 mW/ cm2
for 10 minutes) while receiving systemic oxygen at a rate of 5 liters/minute
for 10 minutes. The second group consisted of 14 eyes undergoing the same accelerated CXL
protocol without supplemental oxygen therapy (A-CXL). The third group (C-CXL) was comprised
of 14 eyes undergoing conventional CXL according to the Dresden protocol. All subjects were
followed for at least six months. Visual acuity, keratometry and corneal biomechanical
parameters including corneal hysteresis (CH) and corneal resistance factor (CRF) were
measured preoperatively and 6 months postoperatively.
Results: Reduction in K max was significantly greater in the OA-CXL (P=0.01). At baseline, mean
K max was 54.31 ± 3.64 D in the OA-CXL group, 54.66 ± 4.99 D in the A-CXL group and 56.03 ±
5.28 D in the C-CXL group (P=0.58), which reached 53.58 ± 3.24, 54.59 ± 4.65 and 55.87 ± 4.73
D at six months in the three study groups, respectively (P= 0.115). Mean CRF was increased
significantly only in the OA-CXL group from a baseline value of 6.32 ± 2.12 to 7.38 ± 1.88 mmHg
at 6 months (P=0.009)
Conclusion: This study suggests superior efficacy of an accelerated CXL protocol coupled with
systemic oxygen supplementation as compared to the accelerated CXL protocol and the
conventional protocolin eyes with progressive KCN. . In addition to greater reduction in K max
as the primary outcome, improvement in corneal biomechanics was also observed at 6 months.
