Clinical Trial of Orthokeratology Lens (MCOK-01)

1. Patients with myopia and myopic astigmatism
2. Those who are not willing to wear glasses in daily life
3. Fully understand of the purpose of the clinical trial and agree to sign the informed consent form to participate in clinical trials, based on his/her willingness
4. Those who can visit the institution on scheduled dates
5. Those who can receive guidance and tests as required by the investigator
6. Those who fully understand and follow the instructions of the lenses for this clinical trial

Exclusion Criteria:

\<At screening>

1. Best corrected vision acuity of less than 0.8 with spectacles
2. Subjective refraction test shows spherical power greater than -6.00D，less than -0.50D or astigmatism greater than 1.5D
3. Patients in need of treatment for eye disease other than refractive error (excluding those receiving artificial tears eye drops due to the wearing of corneal contact lenses)
4. The medical history of intraocular surgery that may affect the effect of wearing the lens for this clinical trial (those with corneal transplantation, Retinal detachment, etc.)
5. The medical history of refractive corneal surgery
6. Those in need of a strength out of the scope of lens for this clinical trial
7. Having eye allergic diseases that may cause disorders in wearing the lenses for this clinical trial
8. All Corneal abnormalities including keratoconus, corneal dystrophy, previous history of ocular herpes infections, acute dry eyes, low corneal endothelial cell counts.
9. Pregnant (judgment according to her known information) or those who plan to become pregnant during clinical trial, or those who are breast feeding
10. Those who are participating in other clinical trials or have participated in other clinical trial in the past 30 days
11. Prior experience with use of rigid lenses within the previous 3 weeks or use of soft lenses within the previous 3 days
12. Prior experience with myopia control treatment (e.g. atropine, orthokeratology, multifocal soft contact lenses)
13. Minor/adult subjects who lack mental capacity
14. Other not suitable for this clinical trial at investigator's discretion \<At the beginning of the wearing>

(1) Those who are determined to be unable to obtain good centralized positioning even though changing strength (2) Pregnancy confirmed (3) Those who are difficult in continuing the clinical trial at investigator's discretion