Schwarz Christina, Sharma Robin, Fischer William S, Chung Mina, Palczewska Grazyna, Palczewski Krzysztof, Williams David R, Hunter Jennifer J
Center for Visual Science, University of Rochester, Rochester, NY, USA.
Flaum Eye Institute, University of Rochester, Rochester, NY, USA.
Biomed Opt Express. 2016 Nov 16;7(12):5148-5169. doi: 10.1364/BOE.7.005148. eCollection 2016 Dec 1.
Two-photon ophthalmoscopy has potential for assessment of function of normal and diseased retina. However, light safety of the sub-100 fs laser typically used is a major concern and safety standards are not well established. To test the feasibility of safe two-photon excitation fluorescence (TPEF) imaging of photoreceptors in humans, we examined the effects of ultrashort pulsed light and the required light levels with a variety of clinical and high resolution imaging methods in macaques. The only measure that revealed a significant effect due to exposure to pulsed light within existing safety standards was infrared autofluorescence (IRAF) intensity. No other structural or functional alterations were detected by other imaging techniques for any of the exposures. Photoreceptors and retinal pigment epithelium appeared normal in adaptive optics images. No effect of repeated exposures on TPEF time course was detected, suggesting that visual cycle function was maintained. If IRAF reduction is hazardous, it is the only hurdle to applying two-photon retinal imaging in humans. To date, no harmful effects of IRAF reduction have been detected.
双光子眼科检查法在评估正常和患病视网膜的功能方面具有潜力。然而，通常使用的亚100飞秒激光的光安全性是一个主要问题，且安全标准尚未完善确立。为了测试人类光感受器的安全双光子激发荧光（TPEF）成像的可行性，我们在猕猴身上使用了多种临床和高分辨率成像方法，研究了超短脉冲光的影响以及所需的光照水平。在现有安全标准范围内，唯一因暴露于脉冲光而显示出显著影响的指标是红外自发荧光（IRAF）强度。对于任何一种暴露情况，其他成像技术均未检测到其他结构或功能改变。在自适应光学图像中，光感受器和视网膜色素上皮看起来正常。未检测到重复暴露对TPEF时间进程有影响，这表明视觉循环功能得以维持。如果IRAF降低是有害的，那么这是在人类中应用双光子视网膜成像的唯一障碍。迄今为止，尚未检测到IRAF降低的有害影响。
