[Local anesthesia in glaucoma's surgery].

EDITORIAL There are a number of questions about the type of anesthesia to be applied and if it should be different depending on the type of surgical technique. The use of topical anesthesia in cataract surgery is a routine procedure (1) due to the advantages of its application and the elimination of risks derived from loco-regional technique (retrobulbar hemorrhage , perforation, miotoxicity) as well as providing adequate analgesia, facilitating quick visual recovery and avoiding any type of occlusion. For glaucoma surgery it should be the ideal technique because we must add to the above advantages the absence of IOP modifications determined by retrobulbar anesthesia secondary to the injection of anesthetic in the muscular cone and the application of Honan's balloon, as well as the absence of sub-conjunctival hemorrhage (which may appear in sub-tenon anesthesia). This reduces the risk of failure of the anesthesia. However, in spite of all these advantages , its use is not widespread because glaucoma surgery is generally longer. In addition it involves specific surgical steps which exhibit an increased sensitivity to pain such as cauterization, scleral incision , conjunctival manipulation and suture. As regards the surgical technique, cryocycloco-agulation is very painful, rendering topical anesthesia insufficient and justifying the use of loco-regional techniques. In trabeculectomy and EPNP many surgeons talk about the utilization of topical anesthesia (2). However, in many cases this anesthesia is not isolated because it is followed on many occasions by intravenous sedation (propofol, midazolan, fen-tanyl) which give rise to increased analgesia as well as exhibiting possible side effects such as disorien-tation, confusion and respiratory depression. On other occasions, topical anesthesia is accompanied by subconjunctival anesthesia in the area where the scleral flap will be performed. The utilization of topical anesthesia in isolation requires a previous selection of patients, who must collaborate and have low anxiety levels (to avoid discharge of catecholamines which increase blood pressure during surgery) and also requires greater skill by the surgeon due to the increased probability of sudden ocular movements and more blinking than with other anesthesia techniques. Its application in drops (tetracaine, oxibuprocaine, lidocaine) is initiated 20-30 minutes before surgery at five-minute intervals, thus increasing its absorption by tissue and achieving greater analgesia. After the surgery and before suture more drops added to reduce the patient's pain. Lidocaine has also been added in the form of gel, achieving greater efficacy due to its longer and larger contact surface …