Our experience with strabismus surgery under topical anesthesia performed at a tertiary eye care center.

Sir,

We report our experience of 214 patients (112 males and 102 females), aged 14–70 years [Table 1], who underwent strabismus surgeries under topical anesthesia for exotropias, esotropias, hypertropias, and monocular elevation deficit and dissociated vertical deviations. The patients/patients' parents were briefed about all the pros and cons of topical and peribulbar anesthesia. None of the patients were administered analgesics before the surgery. Children younger than 14 years and those requiring superior oblique procedures or muscle resections were not included in the study.

Table 1

Age and sex distribution

All procedures were performed by one surgeon. A three-step protocol was used first: three drops of 0.5% proparacaine (Sunways (India) Pvt. Ltd.) administered at 5-min intervals, beginning 30-min before surgery, second: lignocaine hydrochloride gel (Neon Laboratories Ltd., India) was placed in the conjunctival sac 30-min before surgery, and third: cotton swab soaked in lignocaine gel was placed on the muscle insertion for 1 min. Additional 0.5% proparacaine eye drops were instilled during the incision of conjunctiva and Tenon's capsule or as needed if the patient complained of discomfort during surgery. The patients were continuously monitored using electrocardiography and pulse oximetry. With a fornix-based limbal incision, muscle was recessions with scleral bites, or hang-back technique for larger recessions or patients with high myopia were done. Conjunctiva was glued back with TISSEEL Fibrin glue (Baxter, India Pvt. Ltd.). Muscle plication techniques were performed using 6-0 vicryl.

Pain severity, pre- and post-operatively, was evaluated by a questionnaire on an 11-point numeric scale where patient-rated pain from 0 to 10 subjectively (0 being no pain and 10 being intolerable pain).

About 99.53% of all cases successfully underwent the surgery under topical anesthesia. One out of 214 cases was unable to tolerate the procedure [Table 2]. Intraoperative bradycardia was observed in 1 patient, and tachycardia in another [Table 3]. There were no incidences of intraoperative pain or excessive bleeding [Table 4]. No patient experienced complications such as unsatisfactory eye alignment, changed refraction, diplopia, scleral perforations, or postoperative infection [Table 5].

Table 2

Percentage of patients who had to have the surgery converted from topical to an alternative form of anesthesia due to pain or fear

Table 3

Percentage of patients showing intra operative bradycardia/tachycardia

Table 4

Grading of intra- and post-operative pain based on verbal pain scale

Table 5

Percentage of patients showing intra operative difficulty due to factors like squeezing of the eye, excessive bleeding

Topical anesthesia for strabismus surgery seems to be an excellent option as evidenced in our series. They are convenient, safe, and provide rapid onset of corneal and conjunctival anesthesia and are not associated with fear of injection or pain on application. The major advantage of the topical anesthesia surgery is that it allows cover test to be performed on the table thus assessing the accuracy of correction on the table and allowing adjustment of the surgical plan if required [Table 6]. In comparison to retro/peribulbar block, the inadvertent paralysis of the muscles which will not be operated on is prevented and also other inherent risks such as ocular penetration and perforation (approximately 1 in 1000), retrobulbar hemorrhage (1%–3%), central nervous depression (1/350–500 cases),[12] and pain with injection necessitating premedication by the anesthetist[12] are prevented.

Table 6

Advantages of topical anesthesia for strabismus surgery

Lidocaine gel appears to be a safe and highly efficacious tool for ocular anesthesia, with high patient and surgeon satisfaction.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.