Randomized comparative clinical study of cryoanalgesia versus topical anesthesia in clear corneal phacoemulsification

To compare intraoperative pain scores and objective stress signs during clear corneal phacoemulsification under cryoanalgesia and topical anesthesia.

Hospital Ramón y Cajal, Madrid, and Hospital Universitario Nuestra Sra. de la Candelaria, Tenerife, Canary Islands, Spain.

Eighty-two patients were randomized to have phacoemulsification under cryoanalgesia or topical anesthesia. Uncooperative patients and those with shallow anterior chamber and small pupils were excluded. In case of breakthrough pain during the surgery, a supplemental anesthesia protocol was established. Each patient was asked to grade the severity of pain on a 4-point scale (verbal description score; 0=none, 1=little, 2=some, or 3=much). Immediately after surgery, the general discomfort and pain were evaluated. Surgeon stress was evaluated during surgery. A comparison of the 2 groups was performed using a statistical analysis of variance.

Supplemental anesthesia was required in 1 patient in each group. A total of 95.23% of patients would repeat the same technique under cryoanalgesia versus 97.5% under topical anesthesia. Similar pain levels and surgical stress scores were noted in both groups.

Cryoanalgesia clear corneal phacoemulsification was safe with an acceptable level of pain. It induced a physiological stress response to that of topical anesthesia (blood pressure and heart rate). Cryoanalgesia was preferred over topical anesthesia by some patients. It is a suitable technique for anesthetic allergy cases.