Ocular anesthesia evolves into minimalist technique

The limit of minimal anesthesia has been reached with the arrival of no-anesthesia cataract surgery.

ByEtelvino Teixeira Coelho, MD

For the past 10 years, we have been searching for a more secure and less traumatic way to anesthetize the globe in ocular surgeries such as cataract, glaucoma, strabismus, pterygium and chalazion.

In 1990, the article “Time tested odontologic anesthetic allows sub-Tenon’s local injection” (Ocular Surgery News, September 15, 1990 issue) described our use of prilocaine chlorhydrate plus octapressim (Citanest; Astra), ordinarily used in odontologic blocks, as anesthetic for ocular surgery. The technique used an insulin-type needle containing 0.5 mL of anesthetic injected into the front superior quadrant of the subconjunctival space toward the sub-Tenon’s space.

In 1994, that technique evolved to a sub-Tenon’s injection of prilocaine chlorhydrate using an atraumatic curved cannula, without the use of the needle, in order to avoid the risk of perforation of the globe or intraocular structures. This technique was described in Ocular Surgery News (March 1, 1995 issue) under the title “No-needle anesthesia technique uses atraumatic cannula for infiltration.”

In 1996, we initiated a topical anesthesia technique with pre-surgical instillation of two drops of 5% proximethacaine chlorhydrate (Anestalcon; Alcon) every 5 minutes for five instillations before the patient comes to the operating room, followed by intracameral anesthesia with 0.5 mL of 2% preservative-free lidocaine (Ophtalmos) injected through the side port.

We noticed that the anesthetic level reached using this technique was perfect, although some patients developed corneal edema and folds in Descemet’s membrane. The edema would remain for about 10 days after surgery, delaying the patient’s expected visual recovery.

Intracameral abandoned

In 1998, we abandoned the use of preservative-free 2% lidocaine intracameral injection and introduced a new technique that we have used up to the present, with no side effects to the cornea and excellent anesthetic levels.

We give pre-anesthesia to the patient in the waiting room through the instillation of two drops of 0.5% proximethacaine chlorhydrate (Anestalcon, Alcon) repeated every 5 minutes for five applications. After paraocular disinfection, we then use lidocaine chlorhydrate plus 2% methylcellulose gel (Astra) applied with a cotton swab to the inferior and superior conjunctival sacs. This gel should last for 30 seconds.

After the gel, we apply the lid speculum and initiate phacoemulsification without the least complaint of pain from the patient, even in those situations where, by accident, the iris edge is touched by the phaco tip. Our cataract surgeries usually take about 20 minutes, and we never have complaints from our patients of any kind of pain, neither before nor after the surgery, or even the day after.

Through the use of this technique, we avoid injection of anesthetic substances into the anterior chamber and its possible side effects, providing to our patients a secure and lasting anesthetic level before surgery, as well as a painless and comfortable postoperative course.

No anesthesia

We recently took notice of an article in Focus On Ophthalmology, a Brazilian publication (February-March 1999, vol. 60) under the title “Cataract surgery with no anesthesia, no suture or eye bandage,” by Dr. Virgilio Centurion. In this article, this technique is described as being used in India by our colleague Dr. Amar Agarwal, who says, “What do I really get from using topical anesthesia? Just nothing!” In Brazil, Dr. Centurion first used this technique in February 1999.

The evolution of ocular anesthesia continues, from early topical anesthesia using cocaine, to retrobulbar anesthesia, to peribulbar anesthesia with and without needle, using atraumatic cannulas, to the techniques of topical and intracameral anesthesia, to lidocaine gel, and now to surgery without any anesthesia.

We realize we have seen tremendous progress in surgical techniques, as well as in ocular anesthesia for cataract surgery and other procedures.

Looking back, we can see how little we knew about efficient and secure anesthesia for the globe and appreciate the courage of these surgeons to try to accomplish cataract surgery with no anesthesia at all.

For Your Information:

Etelvino Teixeira Coelho, MD, is director of the Center for Refractive Microsurgery and Excimer Laser in Minas Gerais, Brazil, and the president of the Brasilian Foundation for Visual Rehabilitation in Belo Horizonte – Minas Gerais, Brazil. He can be reached at Rua Guajajaras, 40 #1103, Belo Horizonte, Minas Gerais, Brazil 30-180-910; +(55) 31-224-52-00; fax: +(55) 31-226-92-92; e-mail: etelvinocoelho@excimer.com.br; Web site: www.excimer.com.br. Dr. Coelho has no direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any companies mentioned in this article.