The rigid scleral contact lens with optical multi-focal design adopted in this study can focus the light in part of the optical area on the front of the retina to form myopic defocus, in order to delay the axial changes in children and adolescents with ultra-high myopia. In this study, RGP was used as a control, and a multicenter, randomized, controlled trial was conducted to verify the safety and effectiveness of multifocal scleral contact lenses for the correction of ultra-high myopia in children and adolescents.

Inclusion Criteria:

1. Be able to understand and sign the informed consent when accompanied by parents or guardians.
2. Age from 8 years old to15 years old.
3. The equivalent spherical lens of both eyes after ciliary muscle paralysis is -5.00D to -20.00D, the astigmatism is ≤-3.50D.
4. Willing to wear hard contact lenses, and able to wear only the hard contact lenses provided by the study as required and ensure adequate wearing duration.

(6) Best corrected visual acuity of both eyes ≥ 0.8.

Exclusion Criteria:

(1) Allergic or intolerant to rigid contact lens or its care products or ciliary muscle paralysis drugs.

Strabismus and/or amblyopia. (3) Those who have worn hard contact lenses in the past 30 days are using atropine, defocus frame lens, bifocal lens or progressive lens, acupuncture, etc. for myopia treatment.

(4) Any clinically significant active eye disease, such as glaucoma, uveitis, chorioretinitis, central retinal artery or vein occlusion, and so on.

(5) Patients with systemic diseases that may affect the wearing of hard contact lenses, such as hyperthyroidism, diabetes, mental illness, and so on.

(6) are using drugs that affect their eye health. (7) History of eye injury or surgery. (8) Incapacitated or unable to follow the visitor as required. (9) Other conditions not suitable for inclusion as judged by the investigator.