Klados Nektarios E, Modatsos Emmanouil, Karamaounas Aristotelis, Pallikaris Ioannis
Ophthalmology, Medical School, Institute of Vision and Optics, University of Crete, Heraklion, GRC.
Ophthalmology, 417 Army Equity Fund Hospital, Athens, GRC.
Cureus. 2024 Dec 13;16(12):e75667. doi: 10.7759/cureus.75667. eCollection 2024 Dec.
Scleral cross-linking (SXL) with ultraviolet A (UVA) and riboflavin has already been used in laboratory studies for scleral stiffness increase as a potential treatment for progressive myopia and scleral ectasia. This study aims to investigate whether the regional application of scleral cross-linking (SXL) with ultraviolet A (UVA) and riboflavin in fresh porcine eye globes affects the ocular rigidity as well as its impact on intraocular pressure after an induced acute increase in the volume of intraocular fluid.
The study included two groups of fresh porcine eyes: an experimental group (n=20) that underwent scleral cross-linking (SXL) with riboflavin and UVA applied to the posterior sclera and a control group (n=20) that did not receive SXL treatment. Subsequently, a balanced salt solution (volumes 50, 100, 150, and 200 μL) was administered into porcine globes via a syringe, and, at the same time, the intraocular pressure (IOP) was continuously monitored by a pressure sensor that was cannulated to the vitreous chamber. The relationship between volume and pressure was obtained, and the ocular rigidity coefficient (K) was calculated according to Friedenwald's law. Finally, scleral strips were dissected from the globes and were examined macroscopically.
In the control group, the mean IOP observed entails gradual, statistically significant increases for higher volumes. Specifically, the mean IOP at 0 μL equals 10 mmHg (SD=0), whereas at 200 μL the mean IOP equals 33.83 mmHg (SD=4.060). The differences were statistically significant with p-values <0.001 in all cases. Similarly, the observed gradual IOP increases in the SXL group were statistically significant with p < 0.001 in all cases except for the comparison of volume 0 μL measurements to volume 50 μL, where the p-value equaled 0.003. Specifically in the SXL group, the mean IOP at 0 μL equals 10.00 mmHg (SD=0.000), the mean IOP at 50 μL equals 13.31 mmHg (SD=2.011), whereas the mean IOP at 200 μL equals 32.06 mmHg (SD=3.078). At no additional injected volume, the differences between the control and the SXL groups were statistically significant. The analysis regarding ocular rigidity indicated significantly higher scores in the control group (K50=0.00812, SD=0.03) compared to the SXL group (K50=0.00552, SD=0.027), t=2.844; p=0.007. The difference regards measures of volumes 0 to 50 μL, while all other rigidity measures were found to be non-significant. Interestingly, the ocular rigidity coefficient in the SXL-treated group did not show changes with an increase in IOP. The macroscopic appearance of the scleral strips showed a significantly increased stiffness of the SXL scleras against the control ones.
This study showed that stiffened scleras did not induce substantial change in ocular rigidity and significant IOP elevations. Studying the biomechanical ocular response of laboratory scleral crosslinking applications supports the development of next-generation crosslinking procedures that may constitute potential therapeutic options for severe ophthalmic diseases like pathologic myopia.
采用紫外线A（UVA）和核黄素进行巩膜交联（SXL）已在实验室研究中用于增加巩膜硬度，作为进行性近视和巩膜扩张的潜在治疗方法。本研究旨在探讨在新鲜猪眼球中局部应用紫外线A（UVA）和核黄素进行巩膜交联（SXL）是否会影响眼硬度，以及在眼内液体积急性增加后对眼压的影响。
本研究包括两组新鲜猪眼：实验组（n = 20），对其后巩膜应用核黄素和UVA进行巩膜交联（SXL）；对照组（n = 20），未接受SXL治疗。随后，通过注射器向猪眼球内注入平衡盐溶液（体积分别为50、100、150和200 μL），同时通过插入玻璃体腔的压力传感器连续监测眼压（IOP）。获得体积与压力之间的关系，并根据弗里登瓦尔德定律计算眼硬度系数（K）。最后，从眼球上取下巩膜条并进行宏观检查。
在对照组中，随着注入体积增加，观察到的平均眼压呈逐渐且具有统计学意义的升高。具体而言，0 μL时的平均眼压等于10 mmHg（标准差 = 0），而在200 μL时平均眼压等于33.83 mmHg（标准差 = 4.060）。在所有情况下，差异均具有统计学意义，p值 < 0.001。同样，在SXL组中观察到的眼压逐渐升高在所有情况下均具有统计学意义，p < 0.001，但0 μL与50 μL测量值比较时除外，此时p值等于0.003。具体在SXL组中，0 μL时的平均眼压等于10.00 mmHg（标准差 = 0.000），50 μL时的平均眼压等于13.31 mmHg（标准差 = 2.011），而200 μL时的平均眼压等于32.06 mmHg（标准差 = 3.078）。在任何额外注入体积下，对照组和SXL组之间的差异均无统计学意义。关于眼硬度的分析表明，对照组（K50 = 0.00812，标准差 = 0.03）的得分显著高于SXL组（K50 = 0.00552，标准差 = 0.027），t = 2.844；p = 0.007。差异涉及0至50 μL体积的测量，而所有其他硬度测量均无统计学意义。有趣的是，SXL治疗组的眼硬度系数并未随眼压升高而发生变化。巩膜条的宏观外观显示，与对照巩膜相比，SXL巩膜的硬度显著增加。
本研究表明，巩膜硬化并未引起眼硬度的实质性变化和显著的眼压升高。研究实验室巩膜交联应用的生物力学眼部反应有助于支持下一代交联程序的开发，这些程序可能为病理性近视等严重眼科疾病构成潜在的治疗选择。
