Abstract
Purpose :
Intravitreal injection treatment (IVT) is the most common in-office procedure performed by retina specialists. Rapid growth in the number of IVT procedures is driven by rising incidence of retinal diseases and the continued success of anti-VEGF medications. IVT requires ocular anesthesia, currently administered pharmacologically with lidocaine-based agents. Lidocaine-based anesthesia, however, is time consuming and contributes to corneal decompensation, which leads to post-injection pain and transient vision loss. To improve patient experience and reduce post-injection discomfort, we evaluated tolerability and potential efficacy of a non-pharmacologic, cooling-based method for providing ultra-rapid anesthesia before IVT.
Methods :
A handheld device was developed to provide anesthesia via cooling to a focal area on the surface of the eye immediately prior to intraocular injection. The device is portable and utilizes thermoelectric cooling to rapidly anesthetize a 4 mm x 4 mm area on the surface of the eye. Following IRB approval, subjects receiving bilateral anti-VEGF IVT for either exudative macular degeneration (AMD) or diabetic macular edema (DME) provided informed consent and were enrolled in the study. One eye was randomized to lidocaine-based anesthesia (SOC, 3.5% lidocaine gel) while the fellow eye received ultra-rapid, non-pharmacologic anesthesia. Subjective pain was assessed both (a) at the time of IVT, and (b) 4 hours post-IVT, and responses were recorded via visual analog scale (VAS, 1-10). All eyes were assessed for anterior segment changes via slit lamp examination.
Results :
Ultra-rapid, non-pharmacologic anesthesia was well tolerated prior to anti-VEGF IVT. No ocular toxicity or patient-reported adverse events were seen in the treatment group. Subjective pain scores at the time of injection, as measured by VAS, were 2.9 ± 0.47 for subjects receiving SOC, and 2.7 ± 0.41 in the treatment group (P = 0.7, mean ± SEM). Post-injection pain scores were 1.7 ± 0.5 for SOC and 1.5 ± 0.43 in the treatment arm (P = 0.7, mean ± SEM).
Conclusions :
Ultra-rapid cooling of the eye for non-pharmacologic anesthesia was well tolerated. In addition, patient-reported pain was similar between eyes treated with ultra-rapid cooling and SOC. This first-in-human, proof-of-concept study indicates that ultra-rapid cooling may be useful for ocular anesthesia.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.