Asrani S, Zou S, D'Anna S, Lutty G, Vinores S A, Goldberg M F, Zeimer R
Johns Hopkins University School of Medicine, Wilmer Ophthalmological Institute, Baltimore, Maryland 21287-9131, USA.
Invest Ophthalmol Vis Sci. 1997 Dec;38(13):2702-10.
A new method, laser-targeted photoocclusion, was developed to occlude choroidal neovascularization while minimizing damage to the overlying retina. The ability to occlude normal choriocapillary layer in rats was evaluated as a first test of the feasibility of treating choroidal neovascularization with this method.
A photosensitive agent, aluminum phthalocyanine tetrasulfonate, encapsulated in heat-sensitive liposomes, was administered intravenously along with carboxyfluorescein liposomes. A low-power argon laser (retinal power density of 5.7 W/cm2) locally released a photosensitizer bolus, monitored by the simultaneous release of carboxyfluorescein. A diode laser (operating at 675 nm with a retinal power density of 0.27 W/cm2) activated the photosensitizer with its release.
Vessels in the choriocapillary layer were occluded at day 3 after laser treatment and remained unchanged during the 30-day follow-up. Larger choroidal vessels and retinal capillaries remained perfused. Control experiments excluded possible effects of heat or activation of free photosensitizer. Pilot histologic studies showed no damage to the retinal pigment epithelium.
Laser-targeted photoocclusion caused selective occlusion of normal choriocapillaries while sparing overlying retinal pigment epithelium and retinal vessels. The method has potential as a treatment of choroidal neovascularization that may minimize iatrogenic loss of vision.
开发了一种新方法——激光靶向光闭塞法，用于闭塞脉络膜新生血管，同时将对上方视网膜的损伤降至最低。作为用该方法治疗脉络膜新生血管可行性的首次测试，评估了其闭塞大鼠正常脉络膜毛细血管层的能力。
将包裹在热敏脂质体中的光敏剂四磺基铝酞菁与羧基荧光素脂质体一起静脉注射。低功率氩激光（视网膜功率密度为5.7W/cm²）局部释放光敏剂团块，通过羧基荧光素的同时释放进行监测。二极管激光（波长675nm，视网膜功率密度为0.27W/cm²）在光敏剂释放时将其激活。
激光治疗后第3天脉络膜毛细血管层的血管被闭塞，在30天的随访期间保持不变。较大的脉络膜血管和视网膜毛细血管仍保持灌注。对照实验排除了热或游离光敏剂激活的可能影响。初步组织学研究显示视网膜色素上皮未受损伤。
激光靶向光闭塞法可选择性地闭塞正常脉络膜毛细血管，同时使上方的视网膜色素上皮和视网膜血管免受损伤。该方法有可能成为一种治疗脉络膜新生血管的方法，可将医源性视力丧失降至最低。
