Key Takeaways
- A cooling anesthesia device reduced pain during intravitreal injections, with the lowest pain scores observed using a -15°C application for 10 seconds.
- Mild, transient punctate epithelial erosions were reported in 35.7% of eyes treated with the -15°C, 10-second regimen, while no cases occurred in the -15°C, 15-second group.
A cooling anesthesia device reduced pain associated with intravitreal injections in a multicenter clinical trial, with the lowest pain scores observed when the device was applied at -15°C for 10 seconds.
The open-label, dose-escalation study enrolled 80 patients who had previously received at least 3 intravitreal injections and had used subconjunctival lidocaine for anesthesia. Participants were assigned to 1 of 4 cooling regimens applied to the conjunctiva at the injection site, ranging from -10°C for 20 seconds to -15°C for 20 seconds.
Pain during intravitreal injection was assessed using a 0-to-10 visual analog scale. Patients treated with cooling anesthesia at -15°C for 10 seconds reported significantly lower pain scores than those treated at -15°C for 15 seconds (2.2 vs 3.6; P = 0.0255). Mean pain scores in the 10-second group ranged from 1.0 to 2.9 across study visits, compared with 3.2 to 5.2 in the 15-second group.
Researchers also found that pain scores declined over time, with treatment order associated with a 0.10-unit reduction in pain per visit (P = 0.0002).
Punctate epithelial erosions were reported in 20 of 56 eyes (35.7%) treated with the -15°C, 10-second regimen, while no cases were reported in the -15°C, 15-second group.
Reference
Khanani AM, Patel SN, Wykoff CC, et al. Long term evaluation of the safety and efficacy of local cooling anesthesia during intravitreal injections: The COOL-2 Trial. PLoS One. 2026 Jun 10;21(6):e0349554. doi: 10.1371/journal.pone.0349554. PMID: 42268873.
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