Topical Menthol For Tear Secretion

Official title

Topical Menthol for Tear Secretion

Overview

Tears are the natural way to keep eyes moist, and tears are important for good vision and healthy eyes. Eyes without enought tears get dry and sore. The natural and normal way to stimulate secretion of tears is by turning on cold sensors that are located on the cornea of the eye. Tear are normally released across the eyeball in a finely balanced system that balances out that natural evaporation. But sometimes there is not enough tear secretion to balance out the evaporation of tears and eyes can get sore. The aim here is to test whether menthol in its vapor form may possibly turn on those cold sensors and thus cause secretion of tears. Use of menthol vapors may be like having a switch to release more tears. The aim of this clinical trial is to test the hypothesis that a menthol solution applied onto a cheek will release enough menthol vapor into the air flowing up over the eye's cornea to stimulate cold sensors enough to make a tear flow from the eye. If the hypothesis that menthol safely stimulates tear secretion in healthy people proves to be correct, then this clinical trial may inspire more new research into the use of menthol as an alternative to the use of eye drops for some people.

Detailed description

This is a proof-of-principle clinical trial. It is a double-blind, placebo-controlled, randomized clinical trial. Participants are not being seen by a physician for eye disease, and there is a 50% probability that a participant will receive active treatment, or 50% probability that they will just receive the carrier oil with nothing in it (placebo).

Interventions

• Drug Topical application of 20% menthol solution in MCT oil.
  To facilitate reproducible and correct application of the solution, the subject wears glasses while the product is applied. The solution is rolled onto one cheek by rolling it to an area of about 2cm X 2cm at the cheekbone, underneath the bottom rim of the glasses worn. This method delivers about 12 mg solution, i.e. 2.4 mg menthol to one cheek. Or this method delviers 12 mg of placebo oil. The subject then sits in still air for 5 minutes, at which point tissue is wiped across the skin below the
• Drug Topical Placebo Oil rolled onto the cheek.
  To facilitate reproducible and correct application of the Placebo oil, the subject wears glasses while the product is applied. The Placebo oil is rolled onto one cheek by rolling it to an area of about 2cm X 2cm at the cheekbone, underneath the bottom rim of the glasses worn. This method delivers zero active agent. The subject then sits in still air for 5 minutes, at which point tissue is wiped across the skin below the bottom eyelashes to permit the weighing of secreted tear.

Primary outcome measures

• Objective measure of tear stimulation Yes or No [Time frame: Participant is observed for 5 minutes after application, to record tear-weight data, and the related questions that are asked are completed within 10 minutes after applicaiton.]
• Weight of tear [Time frame: Measured at 5 minutes after dose application.]
• Was there a subjective difference between left and right eyes in terms of sense if moisture [Time frame: 5 to 10 minutes after application]
• Weight of nasal secretion blown into tissue. [Time frame: Within 10 minutes of applying the dose.]

Secondary outcome measures (4)

• Weight of nasal secretion [Time frame: 5 to 10 minutes after application]
• Discomfortable feeling at the treated eye. [Time frame: 10 minutes]
• Degree of cooling or pain at the skin where the dose was applied. [Time frame: 10 minutes]
• Did the procedure increase sense of runny nose? [Time frame: 10 minutes]

Eligibility criteria

Inclusion criteria

• Not under care of an opthalmologist for treatment of dry-eyes

Exclusion criteria

• • Excluded if "Yes" to any of the questions below.

• Are you allergic to menthol or to menthol-containing products like tooth paste or certain cold remedies?
• Are you wearing contact lenses during the time of testing? \_\_\_\_\_\_\_\_
• Are there tears present prior to applying the menthol? \_\_\_\_\_\_\_\_
• Did you use of eye drops during the hour before participation? \_\_\_\_\_\_\_\_
• Do you have broken, irritated, sensitive skin and/or acne at or around application site? \_\_\_\_\_\_\_\_
• Do you have a history of atopy, allergic diseases at the skin of your cheeks?
• Do you have Stevens-Johnson syndrome, which is any known skin response to chemical, thermal, or radiation injury to the application area? \_\_\_\_

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Quadruple blind

Primary purpose

Basic science

Study locations

Canada · 1 center

• Stearacl Incorporated. — Toronto

Identifiers

NCT: NCT07109609 · M240706

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗