Rate of riboflavin diffusion from intrastromal channels before corneal crosslinking

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• 作者：Rebecca McQuaid ; MSc ; ^{rebecca.mcquaid@ucdconnect.ie" class="auth_mail" title="E-mail the corresponding author} ; Michael Mrochen ; PhD ; Brian Vohnsen ; PhD
• 刊名：Journal of Cataract & Refractive Surgery
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：42
• 期：3
• 页码：462-468
• 全文大小：1291 K

文摘

To determine the diffusion of riboflavin from intrastromal channels through the effective diffusion coefficients compared with traditional axial diffusion with epithelium on or off.

Setting

Advanced Optical Imaging Laboratory, University College Dublin, and Wellington Eye Clinic, Sandyford, Dublin, Ireland.

Design

Experimental study.

Methods

The rate of diffusion in whole-mounted porcine eyes was monitored for a 30 minutes using an optical setup with a charge-coupled device camera and a bandpass filter (central wavelength 550 nm and 40 nm bandpass) to image the fluorescence under ultraviolet illumination (365 nm wavelength). For comparison, an isotropic corneal stroma with an annular channel was modeled numerically for different diffusion constants and boundary conditions.

Results

Numerical and experimental results were compared, allowing determination of the effective diffusion coefficient for each case. Experimental results for 6 different riboflavin solutions were in all cases found to be higher than for the common crosslinking (CXL) riboflavin protocol, where the diffusion constant is D₀ = 6.5 × 10⁻⁵ mm²/sec. For the intrastromal channel, 2 isotonic solutions containing riboflavin 0.1% correlated with a diffusion constant of 5D₀ = 32.5 × 10⁻⁵ mm²/sec. Hypotonic solutions and transepithelium had a higher diffusion coefficient approaching 10D₀ = 65.0 × 10⁻⁵ mm²/sec, which is an order-of-magnitude increase compared with the typical diffusion coefficient found in standard CXL.

Conclusions

In this study, riboflavin had a faster stromal diffusion when injected into a corneal channel than when applied as drops to the anterior corneal surface. Further numerical modeling might allow optimization of the channel structure for any specific choice of riboflavin.

Financial Disclosures

Dr. Mrochen has a financial and commercial interest in the products and companies mentioned herein. Dr. Mrochen states interests in other from IROC Innocross/Avedro Inc., outside the submitted work. In addition, Dr. Mrochen has a patent issued and UV devices that were sponsored by IROC Innocross. A PhD grant is also partially financed by IROC Innocross. None of the other authors has a financial or proprietary interest in any material or method mentioned.