Department of Clinical Sciences, Faculty of Veterinary Medicine, Liège University, Liège, Belgium.
Equine Vet J. 2011 Jan;43(1):69-73. doi: 10.1111/j.2042-3306.2010.00118.x.
There is a clinical impression that tetracaine hydrochloride (THCl) eyedrops is a suitable topical anaesthetic in horses.
To determine the duration of corneal anaesthesia following instillation of multiple doses and 2 concentrations of THCl in 10 healthy horses.
The corneal touch threshold (CTT) was determined, in both eyes, before (basal CTT) and after application of one drop of 0.5% THCl, 2 drops at a 1 min interval of 0.5% THCl or one drop of 1% THCl. CTT was measured in mm every 5 min until complete recovery of the basal CTT. Treatments were separated by an interval of at least one week.
Corneal sensitivity was significantly reduced from baseline values for 30, 60 and 50 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively. Mean maximal anaesthetic effects, corresponding to a CTT of 0 mm, lasted 5.5, 16 and 15.25 min and maximal anaesthetic effect was present in 55, 90 and 80% of eyes, 5 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively.
The application of a second drop or the use of more concentrated eyedrops significantly increases duration of both anaesthesia and maximal anaesthetic effect.
Duration of corneal anaesthesia following tetracaine instillation was established enabling a better use when performing diagnostic and therapeutic procedures. Comparison of tetracaine with other ocular anaesthetics needs to be published in the future.
临床上有一种印象，认为盐酸丁卡因（THCl）滴眼剂是一种适合马的局部麻醉剂。
确定 10 匹健康马单次和两种浓度的 THCl 滴眼后角膜麻醉的持续时间。
在应用 0.5%THCl 滴眼剂 1 滴、0.5%THCl 滴眼剂 2 滴（间隔 1 分钟）或 1%THCl 滴眼剂 1 滴之前，分别测量双眼的角膜触阈值（CTT）。在 5 分钟内，每 5 分钟测量一次 CTT，直到恢复基础 CTT。每种治疗方法之间间隔至少一周。
与基线值相比，应用 0.5%THCl 滴眼剂 1 滴、0.5%THCl 滴眼剂 2 滴和 1%THCl 滴眼剂 1 滴后 30、60 和 50 分钟，角膜敏感性显著降低。最大麻醉效果的平均时间（对应 CTT 为 0mm）分别为 5.5、16 和 15.25 分钟，应用 0.5%THCl 滴眼剂 1 滴、0.5%THCl 滴眼剂 2 滴和 1%THCl 滴眼剂 1 滴后 5 分钟，最大麻醉效果分别出现在 55%、90%和 80%的眼中。
应用第二滴眼剂或使用更浓缩的滴眼剂可显著增加麻醉持续时间和最大麻醉效果。
确定了滴入丁卡因后角膜麻醉的持续时间，以便在进行诊断和治疗操作时更好地使用。未来需要发表丁卡因与其他眼部麻醉剂的比较。
