Morgan Siân R, O'Brart David P S, Huang Jinhai, Meek Keith M, Hayes Sally
School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, UK.
Department of Ophthalmology, Guys and St. Thomas' NHS Foundation Trust, London, UK.
Eye Vis (Lond). 2024 Feb 28;11(1):8. doi: 10.1186/s40662-024-00375-4.
Corneal cross-linking (CXL) using riboflavin and ultraviolet-A light (UVA) is a treatment used to prevent progression of keratoconus. This ex vivo study assesses the impact on CXL effectiveness, as measured by tissue enzymatic resistance and confocal microscopy, of including a pre-UVA corneal surface rinse with balanced salt solution (BSS) as part of the epithelium-off treatment protocol.
Sixty-eight porcine eyes, after epithelial debridement, were assigned to six groups in three experimental runs. Group 1 remained untreated. Groups 2-6 received a 16-min application of 0.1% riboflavin/Hydroxypropyl methylcellulose (HPMC) drops, after which Group 3 was exposed to 9 mW/cm UVA for 10 min, and Groups 4-6 underwent corneal surface rinsing with 0.25 mL, 1 mL or 10 mL BSS followed by 9 mW/cm UVA exposure for 10 min. Central corneal thickness (CCT) was recorded at each stage. Central 8.0 mm corneal buttons from all eyes were subjected to 0.3% collagenase digestion at 37 °C and the time required for complete digestion determined. A further 15 eyes underwent fluorescence confocal microscopy to assess the impact of rinsing on stromal riboflavin concentration.
Application of riboflavin/HPMC solution led to an increase in CCT of 73 ± 14 µm (P < 0.01) after 16 min. All CXL-treated corneas displayed a 2-4 fold greater resistance to collagenase digestion than non-irradiated corneas. There was no difference in resistance between corneas that received no BSS rinse and those that received a 0.25 mL or 1 mL pre-UVA rinse, but each showed a greater level of resistance than those that received a 10 mL pre-UVA rinse (P < 0.05). Confocal microscopy demonstrated reduced stromal riboflavin fluorescence after rinsing.
All protocols, with and without rinsing, were effective at enhancing the resistance to collagenase digestion, although resistance was significantly decreased, and stromal riboflavin fluorescence reduced with a 10 mL rinse. This suggests that a 10 mL surface rinse can reduce the efficacy of CXL through the dilution of the stromal riboflavin concentration.
使用核黄素和紫外线A光（UVA）的角膜交联术（CXL）是一种用于预防圆锥角膜进展的治疗方法。这项体外研究评估了在去上皮治疗方案中加入用平衡盐溶液（BSS）对角膜表面进行UVA照射前冲洗，对CXL有效性的影响，有效性通过组织酶抗性和共聚焦显微镜进行测量。
68只猪眼在进行上皮清创后，在三个实验批次中被分为六组。第1组未接受治疗。第2 - 6组接受16分钟的0.1%核黄素/羟丙基甲基纤维素（HPMC）滴眼液滴注，之后第3组接受9 mW/cm的UVA照射10分钟，第4 - 6组在用0.25 mL、1 mL或10 mL BSS对角膜表面冲洗后，再接受9 mW/cm的UVA照射10分钟。在每个阶段记录中央角膜厚度（CCT）。将所有眼睛的中央8.0 mm角膜纽扣在37℃下用0.3%胶原酶消化，并确定完全消化所需的时间。另外15只眼睛进行荧光共聚焦显微镜检查，以评估冲洗对基质核黄素浓度的影响。
滴注核黄素/HPMC溶液16分钟后，CCT增加了73±14 µm（P < 0.01）。所有接受CXL治疗的角膜对胶原酶消化的抗性比未照射的角膜高2 - 4倍。未用BSS冲洗的角膜与接受0.25 mL或1 mL UVA照射前冲洗的角膜之间的抗性没有差异，但它们的抗性水平均高于接受10 mL UVA照射前冲洗的角膜（P < 0.05）。共聚焦显微镜检查显示冲洗后基质核黄素荧光降低。
所有方案，无论有无冲洗，在增强对胶原酶消化的抗性方面均有效，尽管用10 mL冲洗后抗性显著降低，且基质核黄素荧光减少。这表明10 mL表面冲洗可通过稀释基质核黄素浓度降低CXL的疗效。
