Toris C B, Tafoya M E, Camras C B, Yablonski M E
Department of Ophthalmology, University of Nebraska Medical Center, Omaha 68198-5540.
Ophthalmology. 1995 Mar;102(3):456-61. doi: 10.1016/s0161-6420(95)31000-7.
The mechanism by which apraclonidine, an alpha 2-adrenergic agonist, lowers intraocular pressure (IOP) was evaluated in humans.
In a randomized, double-masked, placebo-controlled study, 0.5% apraclonidine was given topically twice daily for 1 week to one eye in each of 21 ocular hypertensive volunteers. The other eye was treated similarly with vehicle. Before and after 1 week of treatment, aqueous flow, uveoscleral outflow, fluorophotometric outflow facility, intraocular pressure, tonographic outflow facility, episcleral venous pressure, and outflow pressure were either directly measured or mathematically calculated. Values were compared in treated versus contralateral control eyes and on baseline versus day 8 of treatment.
When compared with both contralateral control eyes and baseline day, fluorophotometric outflow facility in the apraclonidine-treated eyes increased by 0.09 to 0.10 microliter/minute/mmHg (P < 0.04), IOP decreased by 3.1 to 5.2 mmHg (P < 0.0001), and outflow pressure decreased by 3.3 to 4.2 mmHg (P < 0.0001). When compared with baseline day only, aqueous flow in the apraclonidine-treated eyes decreased by 0.3 microliter/minute (P < 0.04), and episcleral venous pressure decreased by 1.0 mmHg (P < 0.001). Episcleral venous pressure also decreased in the control eyes compared with baseline day by 1.3 mmHg (P < 0.001). When compared with contralateral control eyes only, uveoscleral outflow in the apraclonidine-treated eyes decreased by 0.47 microliter/minute (P < 0.03). Tonographic outflow facility showed no change when compared with either contralateral control eyes or baseline values.
The apraclonidine-induced reduction in intraocular pressure was associated with an increase in fluorophotometric outflow facility, decrease in aqueous flow and decrease in episcleral venous pressure compared to baseline. The lack of a significant difference in aqueous flow and episcleral venous pressure between treated and contralateral control eyes may represent a contralateral drug effect.
评估α2肾上腺素能激动剂阿可乐定降低人眼内压（IOP）的机制。
在一项随机、双盲、安慰剂对照研究中，21名高眼压志愿者的每只眼睛中，一只眼睛每天局部给予0.5%阿可乐定两次，持续1周。另一只眼睛用赋形剂进行类似处理。在治疗1周前后，直接测量或通过数学计算得出房水流量、葡萄膜巩膜流出量、荧光光度流出易度、眼压、眼压描记流出易度、巩膜静脉压和流出压。比较治疗眼与对侧对照眼以及基线与治疗第8天的值。
与对侧对照眼和基线日相比，阿可乐定治疗眼的荧光光度流出易度增加了0.09至0.10微升/分钟/毫米汞柱（P < 0.04），眼压降低了3.1至5.2毫米汞柱（P < 0.0001），流出压降低了3.3至4.2毫米汞柱（P < 0.0001）。仅与基线日相比，阿可乐定治疗眼的房水流量降低了0.3微升/分钟（P < 0.04），巩膜静脉压降低了1.0毫米汞柱（P < 0.001）。与基线日相比，对照眼的巩膜静脉压也降低了1.3毫米汞柱（P < 0.001）。仅与对侧对照眼相比，阿可乐定治疗眼的葡萄膜巩膜流出量降低了0.47微升/分钟（P < 0.03）。与对侧对照眼或基线值相比，眼压描记流出易度无变化。
与基线相比，阿可乐定引起的眼压降低与荧光光度流出易度增加、房水流量减少和巩膜静脉压降低有关。治疗眼与对侧对照眼之间房水流量和巩膜静脉压缺乏显著差异可能代表对侧药物效应。
