Cain C P, Toth C A, Noojin G D, Carothers V, Stolarski D J, Rockwell B A
TASC, San Antonio, Texas, USA.
Invest Ophthalmol Vis Sci. 1999 Sep;40(10):2343-9.
To evaluate the effects of near-infrared (near-IR) ultrashort laser pulses on the retinas of rhesus monkey eyes and to perform threshold measurements for minimum visible lesions (MVLs) at pulse widths ranging from nanoseconds to femtoseconds.
Near-infrared single laser pulses were placed within the macular area of live rhesus monkey eyes for five different pulse widths (7 nsec; 80, 20, and 1 psec; and 150 fsec). One visible wavelength of 530 nm at 100 fsec was also included in the study. Visible lesion thresholds (MVL-ED50) were determined 1 hour and 24 hours after exposure. Fluorescein angiography thresholds (FAVL-ED50) were also determined using a probit analysis of the dosage. Thresholds were calculated as that dosage causing a 50% probability for damage, and the fiducial limits were calculated at the 95% confidence level.
For all pulse widths, the 24-hour MVL-ED50 was lower than the 1-hour MVL-ED50, and they both decreased with decreasing pulse width. Thresholds at the 1-hour reading decreased from 28.7 microJ at 7 nsec to 1.8 microJ at 150 fsec, whereas thresholds at 24 hours decreased from 19.1 microJ at 7 nsec to 1.0 microJ at 150 fsec. The doubled 1060-nm wavelength of the 530-nm threshold decreased from 0.36 to 0.16 microJ after 24 hours. FAVL-ED50s were much higher than MVL-ED50s, showing that FA was not as sensitive in determining damage levels.
Laser pulse widths less than 1 nsec in the near-IR are capable of producing visible lesions in rhesus monkey eyes with pulse energies between 5 and 1 microJ. Also, the near-IR thresholds for these pulse widths are much higher than for the visible wavelengths. As with visible wavelengths, FA is not as sensitive in determining threshold levels as is visually observing the retina through a fundus camera.
评估近红外（近红外）超短激光脉冲对恒河猴眼睛视网膜的影响，并在从纳秒到飞秒的脉冲宽度范围内进行最小可见损伤（MVL）的阈值测量。
将近红外单激光脉冲置于活恒河猴眼睛的黄斑区域，脉冲宽度分为五种（7纳秒；80、20和1皮秒；以及150飞秒）。该研究还包括100飞秒时530纳米的一个可见波长。在暴露后1小时和24小时确定可见损伤阈值（MVL-ED50）。还使用剂量的概率分析确定荧光素血管造影阈值（FAVL-ED50）。阈值计算为导致50%损伤概率的剂量，并在95%置信水平下计算置信限。
对于所有脉冲宽度，24小时的MVL-ED50低于1小时的MVL-ED50，且二者均随脉冲宽度减小而降低。1小时读数时的阈值从7纳秒时的28.7微焦降至150飞秒时的1.8微焦，而24小时时的阈值从7纳秒时的19.1微焦降至150飞秒时的1.0微焦。24小时后，530纳米阈值的1060纳米波长翻倍后从0.36降至0.16微焦。FAVL-ED50远高于MVL-ED50，表明荧光素血管造影在确定损伤水平方面不那么敏感。
近红外中小于1纳秒的激光脉冲宽度能够在恒河猴眼睛中产生可见损伤，脉冲能量在5到1微焦之间。此外，这些脉冲宽度的近红外阈值远高于可见波长的阈值。与可见波长一样，荧光素血管造影在确定阈值水平方面不如通过眼底相机目视观察视网膜敏感。
