Traustason S, Hardarson S H, Gottfredsdottir M S, Eysteinsson T, Karlsson R A, Stefánsson E, Harris A
Department of Ophthalmology, University of Iceland, Reykjavik, Iceland.
Br J Ophthalmol. 2009 Aug;93(8):1064-7. doi: 10.1136/bjo.2008.148460. Epub 2009 May 4.
To examine whether the addition of dorzolamide to timolol monotherapy influences oxygen saturation in the human retina.
Non-invasive spectrophotometric retinal oximetry was used to measure oxygen saturation in retinal vessels. Twenty patients with open-angle glaucoma (11) and ocular hypertension (9) were recruited. The patients were randomised into receiving timolol monotherapy or dorzolamide-timolol combination for an 8-month test period, followed by a second test period, before which the patients switched treatments. Oximetry measurements were performed at 2-month intervals during each period. Of the 20 patients, 13 followed the study protocol into the second test period, and 10 managed all study visits.
The oxygen saturation in retinal vessels was stable within the test periods. The mean arteriolar saturation was 96 (2)% (mean (SD)) during timolol monotherapy and 97 (2)% during dorzolamide-timolol combination therapy (p = 0.17, all patients pooled, n = 13). Corresponding values in venules were 66 (5)% during timolol monotherapy and 65 (6)% during dorzolamide-timolol therapy (p = 0.13). Patients who started on dorzolamide-timolol combination showed a significant reduction in arteriolar (98 (2)% to 95 (2)%, p<0.01) and venular saturation (69 (5)% to 66 (6)%, p<0.05) when changing to timolol monotherapy.
Adding dorzolamide to timolol monotherapy has a minimal effect, but going from dorzolamide-timolol combination to timolol alone lowered arteriolar and venular oxygen saturation. The retinal oxygen saturation measurements show a high degree of stability over an extended period of time. Previous studies have suggested increased retinal and optic nerve blood flow with dorzolamide. Unchanged oxygen saturation and increased blood flow would indicate increased oxygen delivery to the retina.
研究在噻吗洛尔单一疗法基础上加用多佐胺是否会影响人视网膜的血氧饱和度。
采用无创分光光度法视网膜血氧测定法测量视网膜血管中的血氧饱和度。招募了20例开角型青光眼患者（11例）和高眼压症患者（9例）。患者被随机分为接受噻吗洛尔单一疗法或多佐胺 - 噻吗洛尔联合疗法，为期8个月的试验期，随后是第二个试验期，在此之前患者更换治疗方法。在每个时期，每隔2个月进行一次血氧测定。20例患者中，13例遵循研究方案进入第二个试验期，10例完成了所有研究访视。
在试验期内，视网膜血管中的血氧饱和度保持稳定。噻吗洛尔单一疗法期间，平均小动脉血氧饱和度为96（2）%（均值（标准差）），多佐胺 - 噻吗洛尔联合疗法期间为97（2）%（p = 0.17，所有患者汇总，n = 13）。小静脉的相应值在噻吗洛尔单一疗法期间为66（5）%，在多佐胺 - 噻吗洛尔疗法期间为65（6）%（p = 0.13）。开始接受多佐胺 - 噻吗洛尔联合疗法的患者在更换为噻吗洛尔单一疗法时，小动脉（从98（2）%降至95（2）%，p<0.01）和小静脉血氧饱和度（从69（5）%降至66（6）%，p<0.05）显著降低。
在噻吗洛尔单一疗法基础上加用多佐胺的影响极小，但从多佐胺 - 噻吗洛尔联合疗法改为单独使用噻吗洛尔会降低小动脉和小静脉的血氧饱和度。视网膜血氧饱和度测量显示在较长时间内具有高度稳定性。先前的研究表明多佐胺可增加视网膜和视神经的血流量。血氧饱和度不变而血流量增加表明视网膜的氧输送增加。
