Wollensak Gregor, Spoerl Eberhard
Department of Ophthalmology, Universitätsklinikum CGC, Technical University of Dresden, Dresden, Germany.
Curr Eye Res. 2004 Dec;29(6):413-7. doi: 10.1080/02713680490522498.
Indocyanine green (ICG) has recently been introduced in cataract surgery to stain the anterior lens capsule for better visualization of the capsulorhexis. The aim of the current in vitro study was to examine the effect of ICG staining on the biomechanical strength of the anterior porcine lens capsule.
Two parallel, 8 mm anterior lens capsule strips were prepared from each of 65 porcine postmortem eyes. ICG staining combined with white light exposure of 0.5, 1, 3, and 30 min duration was conducted. Unstained, nonilluminated and 0.1% glutaraldehyde-treated specimens were used as controls. Biomechanical stress-strain measurements were performed using an automated material tester. The absorption spectrum of the 0.5% ICG solution and the emission spectrum of the light source were controlled.
After ICG staining combined with at least 3 min light exposure, a significant increase of stress (31%) at 25% strain and a significant decrease (7%) in ultimate strain was found. Without light exposure, there was no such effect, suggesting a light-dependent process. After 30 min of 0.1% glutaraldehyde treatment, there was a similar increase in stress (322%) at 25% strain and a decrease (47.6%) in ultimate strain.
ICG staining of the lens capsule causes a significant increase in elastic stiffness and a reduction in ultimate extensibility, thereby facilitating a smooth continuous capsulorhexis. The effect is due to a photosensitizing effect of ICG, leading to collagen cross-linking.
吲哚菁绿(ICG)最近已被引入白内障手术,用于对晶状体前囊膜进行染色,以便更好地观察撕囊过程。本体外研究的目的是检验ICG染色对猪晶状体前囊膜生物力学强度的影响。
从65只猪的死后眼球中,每只制备两条平行的8毫米晶状体前囊膜条带。进行ICG染色,并分别给予0.5、1、3和30分钟时长的白光照射。未染色、未照射以及用0.1%戊二醛处理的标本用作对照。使用自动材料测试仪进行生物力学应力-应变测量。控制0.5%ICG溶液的吸收光谱和光源的发射光谱。
ICG染色并结合至少3分钟的光照后,在25%应变时应力显著增加(31%),极限应变显著降低(7%)。未进行光照时,没有这种效应,提示这是一个光依赖过程。经0.1%戊二醛处理30分钟后,在25%应变时应力有类似的增加(322%),极限应变降低(47.6%)。
晶状体囊膜的ICG染色导致弹性硬度显著增加,极限伸展性降低,从而有助于顺利连续地进行撕囊。这种效应是由于ICG的光敏作用导致胶原蛋白交联所致。