Effect of TrueTear Corneal Surface Imaging

Study Overview
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Brief Summary
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This study will evaluate the utility of TrueTear™ to improve anterior corneal surface imaging quality before cataract surgery, refractive lens exchange, or laser refractive surgery.

Detailed Description
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Corneal imaging will be repeated before and after TrueTear use during a single patient visit. Image quality measures will be compared.

Official Title
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Effect of TrueTear Use on Anterior Corneal Surface Imaging Quality

Conditions
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Myopia, Cataract

Intervention / Treatment
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* Device: TrueTear


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled to undergo routine imaging for cataract surgery, refractive lens exchange or laser refractive surgery Exclusion Criteria: A cardiac pacemaker, implanted or wearable defibrillator, or other implanted metallic or electronic device (e.g. cochlear implant) in the head or neck Chronic or frequent nosebleeds, a bleeding disorder (e.g. hemophilia), or another condition that can lead to increased bleeding A known hypersensitivity (allergy) to the hydrogel material that comes into contact with the inside of the nose during use of the TrueTearTM device Pregnancy Presence of any ocular disease or condition which in the investigator's opinion would confound the study results

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: TrueTear<br>Use of TrueTear device to stimulate tear production | Device: TrueTear<br>* Ues of TrueTear neurostimulator<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Surface Asymmetry Index (SAI) Assessed With Corneal Topography | Surface asymmetry index (SAI) is an index that indicates an average value of the corneal power differences between the points spatially located at 180° from 128 equidistant meridians. A radially symmetrical surface has a value of zero, and this value increases as the degree of asymmetry is greater. Higher values are worse, but there is no set maximum value and no unit of measure. | Change from baseline SAI at 5-10 minutes after using the TrueTear device. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Surface Regularity Index (SRI) Assessed With Corneal Topography | Surface Regularity index (SRI) is a local descriptor of surface regularity in a central 4.5 mm diameter area of the cornea. It correlates well with the value of visual acuity (p = 0.80, P <0.001), assuming the cornea is the only limiting factor for vision. A normal cornea presents SRI values below 0.56 (the SRI would be 0 in a perfectly regular cornea). SRI values increase with increasing irregularity of the corneal surface. Higher values are worse, but there is no set maximum value and no unit of measure. | Change from baseline SRI at 5-10 minutes after using the TrueTear device. |