This study will evaluate whether augmented reality training is effective and safe for treating unilateral amblyopia after congenital cataract surgery in children.

Children aged 5 to 12 years with unilateral amblyopia after congenital cataract surgery will be enrolled from three eye hospitals in China. Participants will be randomly assigned to one of two groups. One group will receive augmented reality amblyopia training for 2 hours per day for 4 months. The other group will receive conventional patching of the fellow eye for 4 hours per day for 4 months.

The main outcome is the change in best-corrected visual acuity of the amblyopic eye after 4 months of treatment. The study will also evaluate contrast sensitivity, binocular visual function, stereoacuity, vision-related symptoms, quality of life, and adverse events.

This is a multicenter, randomized, parallel-group, superiority clinical trial designed to evaluate the efficacy and safety of augmented reality training for children with unilateral amblyopia after congenital cataract surgery.

The study plans to enroll 88 participants aged 5 to 12 years who have unilateral amblyopia after congenital cataract surgery. Eligible participants will be randomly assigned in a 1:1 ratio to either the experimental group or the control group. The experimental group will receive augmented reality amblyopia training for 2 hours per day for 4 months. The control group will receive conventional patching of the fellow eye for 4 hours per day for 4 months.

The study includes a screening period, a baseline visit, and follow-up visits after 1 month and 4 months of treatment. The primary outcome is the change from baseline in best-corrected visual acuity of the amblyopic eye, measured in logMAR units, at 4 months. Secondary outcomes include contrast sensitivity, suppression status, stereoacuity, and quality of life assessed using the Chinese version of the PedsQL 4.0 Generic Core Scales. Safety outcomes include computer vision symptoms assessed using the CVSS-6 scale and the incidence of adverse events, including dizziness, headache, eye fatigue, blurred vision, and skin allergy.

The purpose of this trial is to determine whether augmented reality amblyopia training provides superior improvement in visual acuity compared with conventional patching, while also assessing its effects on binocular visual function and treatment safety in this patient population.

Inclusion Criteria:

1. Aged 5 to 12 years, male or female.
2. Diagnosed with unilateral amblyopia after congenital cataract surgery.
3. Best-corrected visual acuity (BCVA) of the amblyopic eye ≤0.80 logMAR, BCVA of the fellow eye better than 0.15 logMAR, and interocular BCVA difference ≥0.20 logMAR.
4. Underwent cataract extraction at age ≤5 years and has stable ocular status at least 2 months after intraocular lens implantation.
5. If refractive error is present, optical correction has been worn for at least 3 months.
6. Orthophoria, or if strabismus is present, manifest deviation at distance of 6 m is ≤4 prism diopters after strabismus correction as measured by prism cover test.
7. Able to understand the study procedures, and written informed consent is obtained from the participant and/or legal guardian as required.

Exclusion Criteria:

1. Childhood cataract caused by causes other than congenital cataract, including traumatic, drug-induced, steroid-related, secondary, or metabolic cataract.
2. Other ocular organic diseases that may affect visual acuity assessment or amblyopia treatment evaluation, including but not limited to significant ptosis, corneal or other media opacity, glaucoma or persistent ocular hypertension, optic nerve disease, retinal disease, or cortical visual impairment.
3. Uncontrolled or clinically unstable severe systemic disease that may affect study safety, adherence, or outcome assessment, including active malignancy, severe cardiovascular disease, uncontrolled hypertension, epilepsy, or history of photosensitive epilepsy.
4. Implanted electronic medical devices that may be affected by the study device or may affect safe use of the device, such as a pacemaker or implantable cardioverter-defibrillator.
5. Significant ocular inflammation, photophobia, tearing, eye pain, or other ocular surface or anterior segment disease at screening that may affect visual acuity testing, device wearing, or completion of training.
6. Obvious dizziness, motion sickness, acrophobia, balance disorder, or sequelae of previous brain injury that may affect safe wearing of the augmented reality device or training adherence.
7. Facial trauma, craniofacial deformity, or head and facial structural abnormality that may affect normal wearing, positioning, or safe use of the augmented reality device.
8. Severe psychiatric, cognitive, developmental, or behavioral disorder that may prevent understanding of study procedures, completion of training, or follow-up.
9. Current or planned use of medications that may affect visual acuity, refractive status, pupil status, or visual function assessment, except for short-term cycloplegic agents used for routine ophthalmic examination.
10. Unable to simultaneously perceive binocular stimuli in the device or unable to complete binocular simultaneous vision training after device screening or calibration.
11. Received amblyopia treatment other than spectacle correction within 2 weeks before screening, including patching, atropine penalization, visual training, binocular vision training, or other amblyopia-related interventions.
12. Participation in another drug clinical trial within 3 months or another medical device clinical trial within 1 month before screening.
13. Any other condition that, in the investigator's opinion, makes the participant unsuitable for the study.

This is an open-label study with masked outcome assessment. Due to the obvious differences between augmented reality training and conventional patching, participants, care providers, and investigators cannot be masked to treatment allocation. Outcome assessors will be masked to group assignment when evaluating the primary and relevant secondary outcomes.