Peripheral Choroidal Layer Response

Study Overview
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Brief Summary
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The study aims to examine how the vascular layer of the eyeball (choroidal layer) responds when part of the visual field is exposed to specially generated visual stimulus. The study goal will be accomplished by producing specific blur visual stimulus at a particular visual field position and measure any consistent thickness change pattern in the choroidal layer. We propose to test the hypothesis that regional changes in the choroidal thickness may be induced differently after short-term exposure to specific visual stimuli.

Official Title
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Peripheral Choroidal Response to Pure Defocus and Oriented Blur Conditions

Conditions
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Myopia

Intervention / Treatment
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* Device: adaptive optics system


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A person is eligible for inclusion in the study if he/she: Is between the ages of 18 and 40 yrs old Has normal best corrected visual acuity being 20/20 or better Has spherical refractive error between +1.00D and -6.00D. Is capable of fixating on the target. Has no prior ocular surgery. Has no ocular pathology except keratoconus. Can tolerate dilating eye drops Exclusion Criteria: A person will be excluded from the study if he/she: Does not fall within above mentioned age group. Has chronic or systemic eye disease that would interfere with pupil dilation via eye drops. Underwent ocular surgeries or history of ocular trauma Has shallow anterior chamber angle and/or glaucoma. Has clinically significant dry eye. Has signs of any choroidal or retinal pathology, and abnormalities in the visual pathway Has spherical refractive error that exceeds the limits outlined above. Has binocular anomalies (e.g. convergence insufficiency, strabismus, pseudo-myopia, amblyopia). Is an adult unable to consent Is an individual who is not yet adult (infants, children, teenagers) Is a pregnant woman Is a prisoner Is a student for whom you have direct access to/influence on grades Is an economically and/or educationally disadvantaged person

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: normal healthy group<br>Adaptive optics system: this system controls the optical quality of the eye at the peripheral visual field temporarily. | Device: adaptive optics system<br>* the system consists of a wavefront sensor and a deformable mirror that measure and correct (or modify) the eye's optical imperfections (aberrations).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| choroidal thickness | A commercially available optical coherence tomography system will be used to measure changes in choroidal layer thickness before and after manipulating the peripheral optics. | up to 60 mins |