Amblyopia, characterized by reduced visual acuity, develops in childhood due to insufficient sensory stimulation of the affected eye. It is the leading cause of low vision and loss of stereoscopic vision in both children and adults. Currently, 99 million people worldwide are affected, with recent projections indicating 222 million by 2040. Amblyopia can result from anisometropia (70%), strabismus (30%), or the presence of an ocular pathology (1%). Early management of these conditions (before the age of 7) can prevent the onset of amblyopia. Therefore, screening for these conditions is a major public health challenge to reduce the prevalence and associated costs of visual impairment.

The French-speaking Association of Strabology and Pediatric Ophthalmology (AFSOP) recommends systematic amblyopia screening for 3-year-old children. This screening involves measuring monocular visual acuity in both eyes (LEA chart at 3 meters), checking for strabismus (cover/uncover test), and performing a stereoscopic vision test (e.g., Lang I test).

Amblyopia is currently underdiagnosed for two main reasons: 1) it is often asymptomatic (75% of cases) and therefore cannot be detected without systematic screening; and 2) there is significant difficulty in accessing medical care in certain regions, and thus access to professionals capable of performing this screening (doctors, orthoptists). The difficulty in accessing healthcare professionals capable of screening for amblyopia in children aged 3 to 7 has already been raised.

We believe it would be beneficial to have an alternative screening method that is equivalent to the AFSOP-recommended method and accessible in areas with limited healthcare professionals. An eye-tracking system implemented in a virtual reality (VR) headset has recently been developed for monitoring eye movements. This system has shown effectiveness in rehabilitating visual field impairments in patients with traumatic brain injury. The system allows for remote monitoring of rehabilitation sessions, and data can be downloaded and viewed remotely via Wi-Fi.

The main objective of this study will be to estimate the sensitivity of the new VR-based eye-tracking screening method amblyopia screening method using an eye-tracking system implemented in a virtual reality headset compared to standard screening in children aged 3 to 7 years.

Inclusion criteria:

• Patients aged 3 to 7 years at the time of consent signing.
• Patients followed in the Ophthalmology Department of Strasbourg University Hospital (CHU Strasbourg).
• Holders of parental authority must be affiliated with or beneficiaries of the health insurance system.
• Holders of parental authority must be capable of understanding the objectives and risks related to the research, and able to provide dated and signed informed consent.
• Amblyopic patients must have amblyopia diagnosed by the reference screening method.
• Non-amblyopic patients must have undergone routine screening confirming the absence of amblyopia or any other ocular condition that could lead to amblyopia.
• Screening must be performed in the Ophthalmology Department of CHU Strasbourg, unless a prior screening has been performed according to established guidelines and fully documented in a report by the patient's ophthalmologist (detailed results of the three standard screening tests).
• The screening examination must have been performed within the three months prior to the signing of the informed consent form.

Exclusion criteria:

• Amblyopic children currently undergoing treatment or having previously received treatment for amblyopia (optical correction, strabismus surgery, occlusion therapy, orthoptic rehabilitation).
• Children presenting conditions or states that may cause side effects related to the use of the virtual reality headset (epilepsy, neurological or developmental disorders, autism spectrum disorders, dizziness, nausea, claustrophobia, etc.).
• Inability to provide informed information to the patient or holders of parental authority (emergency situations, difficulties in patient comprehension, etc.).

Children aged 3 to 7 years, including both amblyopic and non-amblyopic patients. All participants are recruited from the Ophthalmology Department of Strasbourg University Hospital (CHU Strasbourg) or referred by their ophthalmologists.