A Study to Test the Potential of Brillouin Microscopy for Biomechanical Properties Measurements in Human Cornea

Study Overview
=================
Brief Summary
-----------------
The purpose of this research study is to find out if the new Brillouin Ocular Scanner can measure the variation (difference) of the corneal elastic changes involved in the onset of corneal ectasia, induced by LASIK surgery and cornea collagen crosslinking (CXL) treatment. Ectasia refers to the thinning and bulging of the cornea and results in severe vision degradation (loss), which may occur because of a progressive disease (keratoconus) or because of LASIK surgery. It is believed that the structural weakening of the cornea plays a major role in developing ectasia. CXL is a treatment that is able to halt the progression of ectasia. The Brillouin Ocular Scanner is a technique based on the principles used in the laser speed measuring of a car (radar gun). When laser light illuminates a moving sample, a portion of the light slightly changes color. In our body, e.g in eye and corneal tissue, very weak sound waves are naturally present and they can induce a similar color shift. Measuring this color shift with a sensitive light color meter (spectrometer), we will measure the sound speed in the tissue.

Official Title
-----------------
A Study to Test the Potential of Brillouin Microscopy for Biomechanical Properties Measurements in Human Cornea

Conditions
-----------------
Pellucid Marginal Corneal Degeneration, Keratoconus, Keratectasia

Intervention / Treatment
-----------------
* Device: Brillouin Ocular Scanner


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Subjects with healthy cornea Patients with mild, moderate, or advanced keratoconus Subjects diagnosed with PMD Patients before and after LASK surgery Patients with keratoconus before and after collagen crosslinking treatment Exclusion Criteria: Normal volunteer group: presbyopia and/or cataract Keratoconus subjects group: corneas with scars developed, received any ocular surgery, such as laser vision correction surgeries or CXL treatment Subjects diagnosed with PMD: excludes corneas received any ocular surgery, such as laser vision correction or CXL treatment Patients before and after LASK surgery Corneas received priori ocular surgeries, taking any ocular medications except season allergy medicine such as artificial tears

Ages Eligible for Study
-----------------
Minimum Age: 15 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Normal healthy subjects<br>Healthy subjects with normal appearing corneas respecting all the general inclusion/exclusion criteria. Multiple axial measurements with the Brillouin Ocular Scanner on the cornea will be carried out. | Device: Brillouin Ocular Scanner<br> <br> |
| Active Comparator: Keratoconus subjects<br>Subjects classified as patients with mild, moderate, or advanced keratoconus. Multiple axial measurements with the Brillouin Ocular Scanner on the cornea will be carried out. | Device: Brillouin Ocular Scanner<br> <br> |
| Active Comparator: Subjects diagnosed with PMD<br>Subjects with Pellucid marginal corneal degeneration (PMD). Multiple axial measurements with the Brillouin Ocular Scanner on the cornea will be carried out. | Device: Brillouin Ocular Scanner<br> <br> |
| Active Comparator: Patients before and after LASK surgery<br>Healthy subjects who are scheduled to undergo LASIK surgery. Multiple axial measurements with the Brillouin Ocular Scanner on the cornea will be carried out. | Device: Brillouin Ocular Scanner<br> <br> |
| Active Comparator: Patients with keratoconus before and after CXL<br>Subjects who are scheduled to undergo collagen crosslinking treatment. Multiple axial measurements with the Brillouin Ocular Scanner on the cornea will be carried out. | Device: Brillouin Ocular Scanner<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Brillouin frequency shift of corneal stroma | Brillouin frequency shift of corneal stroma in normal corneas and corneas diagnosed with keratoconus and pellucid marginal degeneration | at time of measurement | 
| Change of Brillouin frequency shift from base line in corneas received LASIK surgery | Brillouin frequency shift in corneas before and after receiving LASIK surgery | 1 day and 4-8 weeks | 
| Change of Brillouin frequency shift from base line in corneas received crosslinking treatment | Brillouin frequency shift in corneas before and after receiving crosslinking surgery | 3 days, 1 month, 3 months, 6 months |