Short Term Topical Tetracaine is Safe and Highly Efficacious for the Treatment of Pain Caused by Corneal Abrasions

Study Overview
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Brief Summary
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The objective of this study was to show that patients with corneal abrasions would experience more pain relief with short term topical tetracaine than placebo, have similar complication rates, and take less hydrocodone for breakthrough pain.

Detailed Description
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Corneal abrasions are among the most common eye-related injuries seen in the emergency department (ED). Topical anesthetic drops are routinely used prior to slit-lamp examination for diagnosis of corneal abrasions and often provide immediate pain relief. Patients are then sent home with oral analgesics and topical antibiotics. The use of topical anesthetics for outpatient treatment of corneal abrasions is discouraged by most emergency medicine textbooks due to concerns over safety. Case reports of abuse and misuse as well as animal studies have suggested that long term use of topical anesthetics may lead to rare complications. Two clinical trials showed no delayed healing after a short course of topical anesthetics following PRK surgery. Whether this could be applied to nonsurgical patients in the ED was investigated by two small clinical trials that showed similar efficacy and safety but were underpowered to prove a statistical difference. In 2014, a larger randomized trial demonstrated the safety of tetracaine for ED patients with corneal abrasions but failed to show a significant difference in patient visual analogue scale (VAS) pain ratings over time. More recently, a retrospective cohort study of 444 ED patients given tetracaine for 24 hours reported no serious complications or uncommon adverse events. If topical anesthetics could be safely prescribed for short term use in the management of corneal abrasions, it is possible that this would decrease use of systemic opioids for this purpose. The aim of this randomized, double-blind trial was to compare the effectiveness of topical tetracaine versus placebo in ED patients with corneal abrasions as measured by a reduction in the VAS score.

Official Title
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Short Term Topical Tetracaine is Safe and Highly Efficacious for the Treatment of Pain Caused by Corneal Abrasions: a Double-blind Randomized Clinical Trial

Conditions
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Corneal Abrasion

Intervention / Treatment
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* Drug: topical tetracaine hydrochloride 1%
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients aged 18 years to 80 years old presenting to the ED with suspected acute corneal abrasion from mechanical trauma or removal of a foreign body by the physician were included Exclusion Criteria: Patients were excluded if they wore contact lenses, had previous corneal surgery or transplant in the affected eye, presented more than 36 hours after their injury, had a grossly contaminated foreign body or coexisting ocular infection. Additional exclusion criteria were pregnancy, retained foreign body, penetrating eye injury, immunosuppression, allergy to study medication, inability to attend follow up, inability to fluently read and speak English or Spanish, or any injury requiring urgent ophthalmologic evaluation (large or complicated abrasions with significant vision loss, corneal ulcers, corneal lacerations).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Topical tetracaine<br>Topical tetracaine hydrochoride 1% | Drug: topical tetracaine hydrochloride 1%<br>* topical ophthalmologic anesthestic<br>|
| Placebo Comparator: Balanced artificial tear solution<br>Balanced artificial tear solution (Systane) | Drug: Placebo<br>* Placebo<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Visual Analog Scale score | The primary endpoint of the study was the overall post study drop Visual Analog Scale pain score measured at the patients initial follow up Emergency Department visit. Measured on a 0-10 scale with 0 meaning no pain and 10 worst pain. | 48 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual Analog Scale score | Secondary endpoint were the average self-reported post study drop Visual Analog Scale score after each use.Measured on a 0-10 scale with 0 meaning no pain and 10 worst pain. | 1 week | 
| Number of hydrocodone tablets taken |  | 48 hours | 
| adverse events | any adverse events | 1 week |