Despite the known benefits of intravitreal anti–vascular endothelial growth factor (VEGF) drugs, the delivery system for these sight-saving medications has a notable downside: injection pain. But a couple of simple changes in needle design might remedy this, Japanese researchers suggest. Their preliminary study in 140 eyes of 110 people found that a thinner, shorter needle caused less discomfort than did a conventional needle.1
The researchers embarked on their study after receiving complaints about injection pain with anti-VEGF drugs despite the application of topical anesthetic, said coauthor Kotaro Tsuboi, MD, at Aichi Medical University in Nagakute, Aichi, Japan.
Procedure. Patients were randomized to receive either 0.5 mg of ranibizumab or 2 mg of aflibercept. All eyes were anesthetized with 2% lidocaine and sterilized with 5% povidone iodine eyedrops. Injections were performed with a standard, 30-gauge needle (0.3 × 19 mm; Nipro) and the thinner, more flexible 34-gauge needle (0.18 × 8 mm; Pasny).
Immediately after the injections, patients were asked to rate their pain according to a standard 0-to-10 pain scale. In addition, the 2 ophthalmologists who performed the injections rated puncture resistance, reflux, subconjunctival hemorrhage, and ocular movements for the injections on a 0 (undetectable) to 1 (detectable) scale.
Results. The short 34-gauge needle was associated with a significantly lower pain score than the 30-gauge needle, the researchers found. In addition, the surgeons detected meaningful differences in puncture resistance and reflux. There were zero cases of puncture resistance with the 34-gauge needle, versus 45 with the 30-gauge needle. Reflux occurred once with the 34-gauge needle and 22 times with the larger needle.
Subconjunctival hemorrhage and ocular movements did not differ significantly between the 2 groups.
Making the switch. Dr. Tsuboi said he has switched to using a 34-gauge needle for all intravitreal injections and for other procedures that penetrate the sclera. His institution has done this successfully more than 700 times, with few complications, he said.
Nonetheless, further studies of efficacy and safety are needed, Dr. Tsuboi said. Meanwhile, he suggested that ophthalmologists consider using a short, 34-gauge needle for intravitreal therapy in selected cases, as in patients who have a very low tolerance for pain.
1 Sasajima H et al. Ophthalmology. Published online Feb. 28, 2018.
Relevant financial disclosures—Dr. Tsuboi: None.
For full disclosures and the disclosure key, see below.
Full Financial Disclosures
Dr. Brogan None.
Dr. Flynn None.
Dr. Hoehn None.
Dr. Tsuboi None.
||Consultant fee, paid advisory boards, or fees for attending a meeting.
||Employed by a commercial company.
||Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company.
||Equity ownership/stock options in publicly or privately traded firms, excluding mutual funds.
||Patents and/or royalties for intellectual property.
||Grant support or other financial support to the investigator from all sources, including research support from government agencies (e.g., NIH), foundations, device manufacturers, and/or pharmaceutical companies.
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