Myopia, or nearsightedness, is the most common eye disorder, often affecting more than 40% of adults in Europe, Asia and the USA. Severe myopia is associated with an increased risk of developing other eye conditions such as glucoma, cataracts and retinal detachment, which may lead to blindness. Early treatment of myopia in children could help slow the condition and minimize the risk of complications later in life. This study investigates the use of SYD-101, an eye solution, in slowing-down the progression of myopia in children.

This will be a 3-arm, multicentered, randomized, double-masked, vehicle-controlled study conducted in 2 parts.

Part 1 is the primary treatment period of 3 years, during which participants will receive 1 of 3 masked medications.

Part 2 is the randomized withdrawal period of 1 year, during which participants originally receiving Vehicle will receive SYD-101, and participants originally receiving SYD-101 will receive either Vehicle or SYD-101.

Inclusion Criteria:

• Myopia of 0.5 D (diopters) to 6.00 D (inclusive) in both eyes.
• Astigmatism ≤1.50 D in both eyes.
• Anisometropia ≤1.00 D in both eyes.
• If myopia is ≥0.75 D, participant must be wearing single vision eyeglasses or soft, daily-wear, single-vision contact lenses that meet study investigator's criteria.
• BCVA (best-corrected visual acuity) Snellen equivalent of 20/32 or better.

Exclusion Criteria:

• Participants with a history or current evidence of a medical condition predisposing them to degenerative myopia (e.g. Marfan syndrome, Stickler syndrome), or a condition that may affect visual function or development (e.g. diabetes mellitus, chromosome anomaly).
• Current use of a monoamine oxidase inhibitor.
• Evidence of any ocular inflammation or infection in either eye, including blepharitis, conjunctivitis, keratitis, and scleritis.
• Past, present or future plans to use orthokeratology (orthoK), rigid gas-permeable, bifocal, progressive-addition, multi-focal, or other lenses to reduce myopia progression; or the use of atropine, pirenzepine or other anti-muscarinic agent for myopia.
• History or evidence of ocular surgery or planned future ocular surgery in either eye.

Other protocol-defined inclusion/exclusion criteria could apply.