Ultraviolet-A absorbance analysis in thin porcine corneas pre-and post-crosslinking

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Science

Background:

• Corneal crosslinking (CXL) is a standard treatment for progressive keratoconus.
• Standard CXL protocols may require adjustments for corneas thinner than 400 μm.
• Understanding ultraviolet-A (UVA) radiation absorption by corneal tissue is vital for CXL efficacy and safety.

Purpose of the Study:

• To determine the ultraviolet-A (UVA) absorbance coefficient of porcine corneal lamellas at different thicknesses.
• To investigate the relationship between corneal thickness and UVA absorbance at 365 nm.
• To inform the optimization of UVA application in corneal crosslinking procedures.

Main Methods:

• In vitro study using 12 porcine corneal lamellas.
• Corneal lamellas separated into 180, 300, and 360 μm thickness groups.
• UVA (365 nm) absorbance measured using a spectrophotometer before and after crosslinking (Dresden protocol).

Main Results:

• Obtained α-coefficients for UVA absorbance were 12.85, 76.55, and 120.27 for 180, 300, and 360 μm groups, respectively.
• Statistical analysis revealed a significant linear correlation between stromal lamellar thickness and UVA absorbance.
• A theoretical formula was derived to predict UVA absorbance based on corneal thickness.

Conclusions:

• Corneal thickness demonstrates a linear correlation with UVA spectral absorbance.
• Findings support personalized UVA energy delivery for corneal crosslinking, especially for corneas <400 μm.
• Optimized UVA application can enhance the safety and efficacy of CXL treatments.