Tomidokoro A, Araie M, Tamaki Y, Tomita K
Eye Clinic, Omiya Red Cross Hospital, Japan.
Invest Ophthalmol Vis Sci. 1998 Feb;39(2):364-71.
To evaluate the use of the laser speckle phenomenon for noninvasive in vivo consecutive measurement of the iridial circulation.
A pigmented rabbit iris was illuminated using a diode laser, and the normalized blur of the resulting laser speckle pattern, NBiris, was determined as a quantitative index of blood velocity in the iridial tissue. The authors compared data on positional variation, reproducibility, and correlation to iridial blood velocity derived with this technique with the blood flow rate simultaneously determined by the microsphere technique. They also evaluated the effects on iridial circulation of ocular perfusion pressure (OPP) change, rectus muscle excisions, and instillation of topical timolol or betaxolol.
The NBiris increased gradually from the pupil margin to the periphery; the coefficient of variation of NBiris was lowest at the center of this area. The coefficient of reproducibility of two NBiris measurements at 5-minute intervals was 8.8%; at 24-hour intervals, it was 14.1%. The NBiris correlated well with the microsphere technique measurements of blood flow rate at several intraocular pressures (IOP) (r = 0.61, P = 0.0002, n = 40) and with the comparison of preinstillation and postinstillation unoprostone (r = 0.93, P = 0.0068, n = 8). The NBiris decreased with OPP reduction, decreased temporarily after excision of the superior or inferior rectus, and showed no significant change after excision of the medial or lateral rectus. Instillation of timolol caused a significant decrease in IOP but did not significantly change the NBiris. Topically applied betaxolol decreased IOP and increased NBiris at 2.5 hours after instillation in an ipsilateral eye.
The laser speckle method permits noninvasive, semiquantitative, consecutive measurement of the iridial circulation, with reasonable reproducibility.
评估利用激光散斑现象对虹膜循环进行无创性体内连续测量的应用。
使用二极管激光照射有色兔的虹膜，并将所得激光散斑图案的归一化模糊度NBiris确定为虹膜组织中血流速度的定量指标。作者将用该技术得出的关于位置变化、可重复性以及与虹膜血流速度的相关性的数据，与通过微球技术同时测定的血流速率进行了比较。他们还评估了眼灌注压（OPP）变化、直肌切除术以及局部滴注噻吗洛尔或倍他洛尔对虹膜循环的影响。
NBiris从瞳孔边缘到周边逐渐增加；该区域中心处NBiris的变异系数最低。每隔5分钟进行两次NBiris测量的可重复性系数为8.8%；每隔24小时测量时，该系数为14.1%。在几个眼内压（IOP）水平下，NBiris与微球技术测量的血流速率相关性良好（r = 0.61，P = 0.0002，n = 40），并且与滴注前和滴注后乌诺前列酮的比较结果相关性良好（r = 0.93，P = 0.0068，n = 8）。NBiris随OPP降低而降低，在上直肌或下直肌切除后暂时降低，而在内直肌或外直肌切除后无明显变化。滴注噻吗洛尔可使IOP显著降低，但对NBiris无显著影响。局部应用倍他洛尔可使IOP降低，并在滴注后2.5小时使同侧眼的NBiris升高。
激光散斑法可对虹膜循环进行无创、半定量、连续测量，且具有合理的可重复性。
