Koelbl Philipp Simon, Klante Pia, Koch Frank, Lingenfelder Christian, Werner Jens Ulrich, Enders Christian, Hessling Martin
Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Albert-Einstein-Allee 55, D-89081, Ulm, Germany.
Clinic of Ophthalmology, Goethe University, Theodor-Stern-Kai 7, D-60590, Frankfurt, Germany.
Graefes Arch Clin Exp Ophthalmol. 2017 Nov;255(11):2185-2198. doi: 10.1007/s00417-017-3758-y. Epub 2017 Aug 5.
For diaphanoscopy or transscleral laser applications, the transmission of the sclera is an essential property. The study aimed to determine the pressure dependent transmission of human sclera from anterior to posterior.
Pressure dependent transmission measurements were performed by a pressure inducing setup at the range of 60-2058 kPa. The transmissions were measured within spectral range of 350-1100 nm. Specimens of human sclera were taken from corneo-scleral transplants. Those compounds were obtained at pars plicata residual sclera tissue. For an anterior to posterior examination of transmission, samples were taken from halved eye globes, which were formerly fixed in formalin.
The pressure dependent transmission increased with rising load at all measured wavelengths for human sclera samples. The highest increase was observed for short wavelengths. With rising pressure, the increase of transmission aimed for a steady state. This behavior was fitted by a limited growing function. With an inducing burden of 2058 kPa, the steady state was already reached and exhibited an increase in transmission factor of 4.1 at 400 nm and 1.8 at 1000 nm. The anterior to posterior measurements of human sclera fixed in formalin were not corresponding to the results of the other human samples. For the porcine samples, the transmission increased from anterior to the equator of the eye globe. Further posterior the transmission decreased and rose again to N. opticus. With rising pressure, the transmission increased at all wavelengths and all locations. Posterior from the equator, with higher pressure the transmission became superior compared to anterior.
The results of human sclera fixed in formalin could be related to formalin-induced cross-linking between the collagen fibers. Because of doubt about the physiological behavior of formalin-fixed samples, formalin-free porcine postmortem eye globes were also probed having a very similar thickness and histological structure as human sclera, so the results could be set in relation to human probes. These results can now be used to create an eye-map to determine maximum possible retina irradiation or illumination durations for transscleral applications in eye surgery.
对于透照检查或经巩膜激光应用而言，巩膜的透射率是一项基本特性。本研究旨在确定人巩膜从前到后的压力依赖性透射率。
通过压力诱导装置在60 - 2058 kPa范围内进行压力依赖性透射率测量。在350 - 1100 nm光谱范围内测量透射率。人巩膜样本取自角膜 - 巩膜移植片。这些样本取自睫状褶残余巩膜组织。为了从前到后检查透射率，样本取自曾固定于福尔马林中的半球形眼球。
对于人巩膜样本，在所有测量波长下，压力依赖性透射率随负荷增加而升高。在短波长处观察到最高的增加幅度。随着压力升高，透射率的增加趋向于稳定状态。这种行为符合有限增长函数。在2058 kPa的诱导负荷下，已达到稳定状态，在400 nm处透射率因子增加4.1，在1000 nm处增加1.8。固定于福尔马林中的人巩膜从前到后的测量结果与其他人体样本的结果不相符。对于猪的样本，透射率从眼球前部到赤道处增加。再往后透射率降低，然后在视神经处再次升高。随着压力升高，在所有波长和所有位置透射率均增加。在赤道后方，压力越高，透射率相比前部越高。
固定于福尔马林中的人巩膜的结果可能与福尔马林诱导的胶原纤维之间的交联有关。由于对福尔马林固定样本的生理行为存在疑问，还对死后的无福尔马林猪眼球进行了探测，其厚度和组织结构与人类巩膜非常相似，因此可以将结果与人类样本相关联。这些结果现在可用于创建一个眼图，以确定眼科手术中经巩膜应用时视网膜的最大可能照射或照明持续时间。
