Myopia
Conditions
Brief summary
The goal of the study is to investigate relationship between the corneal response to a temporary increase in intraocular pressure and corneal mechanical properties.
Detailed description
The preliminary theoretical study in which the corneal geometry at different intraocular pressure (IOP) levels is investigated using a theoretical biomechanical cornea model found changes in both conventional refractive error (sphere and cylinder) and irregular astigmatism i.e. higher order aberrations (e.g. spherical aberration, trefoil and quadrafoil). This is due to the mechanical characteristics of the cornea determined largely by interaction between collagen fibrils organization and extrafibrillar matrix material properties. Corneal geometry and the material properties are the two main factors that contribute to the changes in corneal aberrations with IOP elevation. These aberration changes due to the variation of IOP and the material properties of the cornea can be measured routinely with corneal topography systems (UR) and Brillouin ocular scanner (MGH), respectively and can guide the investigators to study their impact on optical and biomechanical behaviors of the cornea.
Interventions
OTHERInversion
Inversions will be done while the subject is on the inversion table. The subject will be inverted to 135, 150 and 165 degrees. There inversion will not last longer than 3 minutes at a time. The inversion will be terminated if the subject's blood pressure drops below 50 mmHg diastolic or if the subject's blood pressure increases more than 50 mmHg systolic.
Sponsors
University of Rochester
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
A person is eligible for inclusion in the study if he/she: * Is an adult between the ages of 18 and 55. * Is under 250 pounds.
Exclusion criteria
A person will be excluded from the study if he/she: * Is under the age of 18 or over the age of 55 yrs. * Weighs more than 250 pounds. * Has clinically significant dry eye. * Has glaucoma. * Has hypertension. * Has prior CVA. * Has cardiovascular disease. * Has lower extremity joint injury, damage, or replacement. * Has baseline bradycardia. * Has any orthopaedic injuries. * Is pregnant. * Has hiatal and ventral hernias. * Has vertigo. * Has acid reflux (GERD). * Is undergoing myopia control treatment (e.g. atropinisation, Ortho-K, bifocal contact lenses etc.). * Has conditions or has undergone procedures resulting in significant corneal irregularity (e.g. keratoconus, corneal transplant, etc.). This does not include astigmatism and basic refractive errors. * Has any ocular or systemic diseases that, in the opinion of the PI/SI, would interfere with obtaining a measurement.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Corneal Surface Topography Measurement | 6 months | Corneal Surface Topography measurement will be collected at each of the 3-4 study visits at the Flaum Eye Institute. The numerical data generated will be analyzed and compared within each subject as well as across subjects. |
Outcome results
None listed