Direct Comparison of SVOne Obtained Refraction to Subjective Manifest Refraction

Study Overview
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Brief Summary
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The purpose of the study is to compare the final glasses prescription based on refraction obtained with SVOne device to the final prescription obtained via subjective manifest refraction.

Detailed Description
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Uncorrected refractive error is the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting 1 in 90 individuals (1). In the US population approximately 14 million individuals aged 12 years or older have visual impairment (defined as distance visual acuity of 20/50 or worse), of which more than 11 million individuals (2) could have their vision improved to 20/40 or better with refractive correction. Uncorrected refractive error impacts all aspects of life, including, but not limited to, loss of employment opportunities, inability to care for family, and inability to receive an education. SVOne is smartphone-based autorefractor, powered by wavefront aberrometry, due to its portability and accuracy it presents as an effective and accessible method of detecting refractive error and dispensing spectacles for better vision (3). In this study, for each patient, a single clinician will determine final prescription through manifest refraction, while a different clinician will determine final prescription using SVOne exam protocol. Sphere, cylinder and axis will be converted to power vectors and compared by linear regression analysis.

Official Title
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Direct Comparison of SVOne Obtained Refraction to Subjective Manifest Refraction

Conditions
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Refractive Errors

Intervention / Treatment
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* Diagnostic Test: Refraction


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects must be 12 (under 18 with parental consent) years of age and older up to 65 years of age. No known ocular pathology from previous clinical exams that may limit best corrected visual acuity. Exclusion Criteria: Refractive error greater than +/- 14.00 diopters, or astigmatism greater than -7.00 diopters. Known ocular (corneal, lenticular, vitreal, or retinal) pathology that may limit BCVA. Best corrected visual acuity with spectacles of 20/25 or worse. Any previous surgical or laser procedures that may limit BCVA 11 years of age and younger

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 65 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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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Refraction|Refractive error measurement|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sphere, cylinder and axis measurement for each patient | the outcome includes sphere, cylinder and axis measurement (in diopter) by using both SVOne wave-guided autorefractor and subjective manifest refraction | 4 months | 
| Comparison of two measurements on the same patient | the outcome will include comparison of two sphere, cylinder and axis measurements (in power vectors) for each patient obtained with SVOne wave-guided autorefractor and subjective manifest refraction. | 4 months |