Comparison of the anesthetic effect of different dosages of tetracaine 0.5% ophthalmic solution on corneal sensatio

Phase 4

Completed

• Conditions: Corneal sensation; Eye - Normal eye development and function; Anaesthesiology - Anaesthetics

• Registration Number: ACTRN12621001289808
• Lead Sponsor: niversidad Autónoma de Yucatán

Brief Summary

1. Research question. What is the effect of different dosages of tetracaine 0.5% ophthalmic solution on corneal sensation? 2. Background information. Tetracaine hydrochloride ophthalmic solution is a long action aminoesther local anesthetic. It is used widely on ophthalmology at a 0.5% solution. The recomended dosage depends on the manufacturer and goes from a single drop to 5 drops applied at 5 minutes intervals, and there are trials assessing the security and efficacy on different settings. Nevertheless, we did not find any trial comparing the efficacy of different dosages on humans. 3. Participants characteristics. Healthy subjects 18 years old or older. 4. Key results. The Duration of the maximal anesthetic effect was longer when tetracaine was applied at a greater dosage. The duration of corneal anesthesia was similar in the three groups. The degree of the maximal anesthetic effect was greater with a greater dosage. Baseline corneal sensation was similar in males and females. There were no severe adverse events derived from the use of Cochet-Bonnet or tetracaine. Limitations. 5. Limitations. Balanced salt solution as placebo does not cause a burning sensation like tetracaine, thus probably affecting the blinding. Cochet Bonnet anesthesiometer measures superficial touch sensitivity, and the results may vary when transposed to a surgical setting. We did not measure sensation beyond 63 minutes, affecting the results regarding the duration of corneal anesthesia.

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Completion: 2019-12-28
• Study Start: 2021-09-23
• Last Update Posted: 27 September 2021

Recruitment & Eligibility

• Status: Completed
• Sex: All
• Target Recruitment: 81

Inclusion Criteria

Healthy subjects.
18 years old or older.

Exclusion Criteria

•Any known systemic disease.
•Any known ophthalmic disease.
•Contact lens wear.
•Previous ophthalmic surgery.
•The presence of symptoms or signs of any ophthalmic disease.

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Corneal sensation measured with a handheld Cochet-Bonnet aesthesiometer.[Corneal sensation was measured at baseline, and every 3 minutes after intervention until minute 63. Primary timepoint is minute 63 after drug administration.]

Secondary Outcome Measures

Name	Time	Method
Presence of any adverse event described in association with the use of tetracaine: chemosis, lacrimation, transient conjunctival hyperemia, burning and photophobia. Assessed at slitlamp after recovery of baseline sensation. [After recovery of baseline sensation, or after 63 minutes from drug administration.];Presence of an epithelial defect greater than 1mm. assessed at slit-lamp using the cobalt blue filter, after the instilation of fluoresceine sodium drop (from an ophthalmic strip and a drop of balanced salt solution). Defect size was measured by silt beam.[After recovery of baseline sensation, or after 63 minutes from drug administration.]