Paragon CRTEvaluation of Orthokeratology Lenses With a 5MM Optic Zone Diameter

Inclusion Criteria:

A person is eligible for inclusion in the study if they:

1. Are 6- 35 years of age
2. If under 18 years old they are accompanied by a parent or legal guardian who is able to read, understand and sign the parental information and permission document
3. Have had a self-reported visual exam in the last two years
4. Are able to read (or be read to), understand and sign the assent document if under 18 years old or are able to read, understand and sign the consent document if aged 18 or older
5. Are willing to comply with the wear schedule (approximately 8 hours per night for every night, while sleeping)
6. Are willing to comply with the visit schedule
7. Have a refractive spherical component of their prescription between -0.50 and up to -6.00 diopters (inclusive) AND a refractive cylinder of no more than -1.75 diopters
8. Have a refractive spherical component ≥ cylinder component
9. Have a minimum visual acuity of +0.20 logMAR with each eye, when refracted at the Screening visit
10. Have clear corneas and no active ocular disease.
11. Have no medication, medical condition, or ocular conditions that contraindicate contact lens wear OR are expected to affect lens comfort or vision across the 1-month study duration, in the opinion of the investigator
12. Can be shown to have stable keratometry for at least the previous 1 month, if they have previously worn orthokeratology lenses.

Exclusion Criteria:

1. Present at screening visit with the presence of ocular or systemic disease or report the use medications which might interfere with orthokeratology contact lens wear, such as keratoconus, diabetes mellitus, steroid eye drops
2. Have a post-treatment predicted flat K value ≤38.00D (e.g. Patient baseline flat keratometry value = 40.00, patient has 2.00D of myopic refractive error. 40.00-2.00= 38.00D)
3. Have a known sensitivity to the diagnostic sodium fluorescein to be used in the study
4. Are pregnant, planning a pregnancy or lactating
5. Have amblyopia
6. Have presbyopia or has dependence on spectacles for near work over the contact lenses
7. Present at screening visit with the presence of clinically significant (grade ≥3; ISO scale) anterior segment abnormalities.
8. Present at screening visit with slit lamp findings that would contraindicate orthokeratology contact lens wear such as:

1\. Pathological dry eye or associated findings 2. Pterygium, pinguecula, or corneal scars within the visual axis 3. Neovascularization > 0.75 mm from of the limbus 4. Giant papillary conjunctivitis (GPC) worse than grade 1 5. Anterior uveitis or iritis (past or present) 6. Seborrheic eczema, Seborrheic conjunctivitis 7. History of corneal ulcers or fungal infections 8. Poor personal hygiene 9. Aphakia