The burden of myopia among Chinese children and adolescents is severe and trending toward younger ages, making control of myopia progression a public health priority. Current mainstream strategies include optical interventions, pharmacologic therapy, and environmental measures. Among these strategies, spectacle designs based on optical defocus-such as defocus-incorporated multiple-segment (DIMS) lenses-have demonstrated efficacy; however, the effect of such designs may attenuate over time because of "defocus adaptation." To address this limitation, D.D.C dual-control spectacles employ a densely staggered microlens layout, a gradient-defocus architecture, and an added peripheral "fogging zone" to disrupt the spatial distribution of defocus cues and reduce contrast, thereby delaying adaptation and enhancing myopia-control efficacy.

The present study therefore proposes a 24-month prospective randomized controlled trial in Guangzhou, enrolling eligible myopic adolescents. The trial will first compare 12-month outcomes between D.D.C-A lenses and single-vision lenses, followed by a crossover and alternating-wear phase, to systematically evaluate the safety and efficacy of the D.D.C technology in slowing myopia progression.

Inclusion Criteria:

• Age between 6 and 14 years;
• Cycloplegic spherical equivalent refraction between -1.50 D and -5.00 D with astigmatism ≥ -1.50 D in both eyes;
• Absolute interocular difference in spherical equivalent refraction ≤ 1.50 D;
• Binocular best-corrected visual acuity ≥ 1.0;
• Intraocular pressure between 10 and 21 mmHg in both eyes;
• Volunteer to participate in this clinical trial with signature of the informed consent form.

Exclusion Criteria:

• History of eye injury or intraocular surgery or ocular trauma;
• Clinically abnormal slit-lamp findings;
• Abnormal fundus examination;
• Presence of ocular diseases such as cataract, glaucoma, fundus pathology, ocular trauma, manifest strabismus, or any other condition affecting visual function;
• Systemic diseases causing low immunity (such as diabetes, Down's syndrome, rheumatoid arthritis, psychotic patients or other diseases that researchers think are not suitable for wearing glasses);
• Participation in a drug clinical trial within 3 months or a device clinical trial within 1 month prior to enrollment;
• Participation in any myopia control clinical trial within the past 3 months and a history of myopia control interventions (e.g., orthokeratology, atropine);
• Only one eye meeting the inclusion criteria;
• Inability to attend regular ophthalmic examinations.