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Worldwide variations in the use of anesthesia for cataract surgery are underscored in a Chinese meta-analysis of published randomized clinical trials that did not consider the most popular method applied in the United States. A meta-analysis by Li-Quan Zhao, MD, and fellow ophthalmologists at the Shanghai Jiao Tong University School in China evaluated 15 randomized clinical trials comparing the performance of topical and regional anesthesia during phacoemulsification with lens implantation.

Their study, published in the April issue of Ophthalmology, concludes that topical anesthesia falls short of matching the ability of regional anesthesia (including retrobulbar and peribulbar anesthesia) for sparing patients from pain. But overall, the clinical trials indicated the topical approach led to similar clinical outcomes, eliminated injection-related complications, and mitigated patients' fears about needle injections near the eye and orbit.

The finding suggested to coauthor Huang Zhu, MD, professor and deputy director of the Department of Ophthalmology at Xinhua Hospital in Shanghai, that topical anesthesia before cataract surgery is an inevitable trend for ophthalmology as it is practiced in Shanghai, China's largest city (population of 23 million and one of the most prosperous cities in Asia).

He predicted use of topical anesthesia will grow because of improved performance of phacoemulsification machines, better surgical techniques that lead to reduced incision sizes, and effects on the anterior chamber and iris. "Patients feel better than before and do not need regional anesthesia. Topical anesthesia is enough," he wrote in response to questions from Medscape Medical News.

The meta-analysis uncovered several statistically significant differences that generally favored topical anesthesia, including less frequent anesthesia-related complications, such as chemosis, periorbital hematoma, and subconjunctival hemorrhage (P < .05).

By contrast, intraoperative and postoperative pain was higher in the topical anesthesia group, compared with regional anesthesia (P < .05). Additionally, inadvertent intraoperative ocular movement was observed significantly more often among patients who received topical anesthesia than among patients in the retrobulbar group (P < .00001) and those in the peribulbar group (P < .00001).

Compared with patients who underwent regional approaches, those in the topical anesthesia group more often needed an additional intraoperative dose (P < .03). Only 1 of 5 trials that measured procedural duration found a significantly longer surgery time for patients who received topical anesthesia. This finding suggested that the need to administer supplemental anesthesia and the greater incidence of inadvertent eye movement in patients administered topical anesthesia did not have a substantial effect on procedural time.

Still, patients far more often preferred topical anesthesia over other pain-stopping options (P < .00001). The meta-analysis uncovered no significant differences in the surgical complication rate for the topical and injected regional approaches to anesthesia.

These findings may be relevant to ophthalmologic practice in many regions of the world, noted James J. Salz, MD, clinical professor of ophthalmology at the University of Southern California, Los Angeles, but they do not reflect how phacoemulsification is performed in the United States.

The standard of care here has involved topical anesthesia supplemented by intracameral lidocaine for more than a decade, according to Dr. Salz. The protocol calls for the injection of a slightly dilute solution of nonpreserved lidocaine and epinephrine, which facilitates pupil dilation into the anterior chamber immediately after incision to instantly anesthetize the eye internally. The Shanghai group reduced the value of their meta-analysis for US ophthalmologists when they specifically excluded studies of topical anesthesia used in combination with intracameral lidocaine, Dr. Salz said.

Consequently, the relatively greater discomfort patients experience with topical compared with regional anesthesia may have been overstated. "[I]f he had used intracameral lidocaine, there would be virtually no difference in patient discomfort between regional retrobulbar anesthesia and the experience reported for this," he said.

Dr. Salz has rarely heard a patient report discomfort during more than 10 years of experience with the topical intracameral approach, and he has not administered retrobulbar anesthesia in 15 years because of the risk for retrobulbar hemorrhage or globe perforation from the blind injection behind the eye. "You don't get that complication, if you don't stick a needle back there," he told Medscape Medical News.

Peribulbar anesthesia is safer than the retrobulbar approach because the needle is not introduced as close to the eye, but it still occasionally results in complications, he said. Dr. Salz believes his views are consistent with those of other ophthalmologists who in combination perform more than 300 cataract surgeries per month at his clinic. "I don't think any of the 20 doctors here use retrobulbar anymore," he said. "They all use topical, and every one of them uses intracameral lidocaine."

The meta-analysis was supported by grants from the Shanghai Leading Academic Discipline Project and General Program of the Biomedical Division of the Shanghai Science and Technology Commission. Dr. Zhu, the other authors, and Dr. Salz have disclosed no relevant financial relationships.