Cooling Anesthesia for Intravitreal Injection: Results of the Prospective Open-Label, Dose-Ranging COOL-1 Trial

Abstract

Purpose To evaluate the safety and efficacy of a novel medical device to provide cooling anesthesia to the eye as local anesthesia for intravitreal injections. Study Design First in human, open-label study of 43 subjects assessed at three different doses: −10°C for 20 seconds (group 1), −15°C for 15 seconds (group 2), and −15°C for 20 seconds (group 3). Main outcome measures were safety and pain of injection using a numeric rating scale (NRS). Results Cooling anesthesia did not result in any serious ocular adverse events. One grade 1 adverse event was a vasovagal response during cooling administration which resolved immediately after cooling. Mean NRS scores at the time of injection for each group ranged from 2.5 to 4.3 There was a statistically significant difference between pain scores of the 3 groups at injection in aggregate but not in pairwise comparisons ( P value = 0.047). There was a statistically significant decrease in pain from injection to 5 minutes post injection in all groups ( P value = 0.00008, 0.003, 0.0005 for groups 1, 2, 3, respectively) as well as from 5 minutes to 24–48 hours ( P value = 0.00001, 0.018, and 0.0545 for groups 1, 2, 3, respectively). Conclusion The rapid cooling anesthesia device was well tolerated for achieving local anesthesia among patients receiving intravitreal injections with no serious ocular adverse events.

Cooling Anesthesia for Intravitreal Injections – A Review

“…The primary outcome measure was to assess subjective pain (24 to 48 hours after the injection) using a Numeric Rating Scale (NRS), the range being 0 to 10, 0 being the least and 10 being severe/unbearable pain and adverse events as measured by complete slit-lamp examination (both anterior and posterior segment examination after 30 minutes of having the injection). 25 , 26 …”

“…The secondary outcome measure was to measure the response of the patient to needle penetration during IVT injection and the time taken from the beginning of anesthesia to IVT injection. 25 , 26 …”

“…The inclusion criteria include: 26 Men and women >18 years old. Those who are undergoing IVT injections in one or both eyes with ranibizumab or aflibercept using a 30-gauge needle as part of their normal standard of care.…”

“…The exclusion criteria include: 26 Presence of scleromalacia. Presence of conjunctival, episcleral or scleral defects.…”

“…Each study of two study sites assessed 2/3 treatment doses, with a common dose of −10°C for 20 seconds between the two sites. 25 , 26 …”