Visual developmental abnormalities affect 10 to 15% of the population under 6 years of age and leads to amblyopia in 30% of cases if left untreated. Untreated amblyopia in adulthood has consequences on the quality of life of individuals but will also represent a cost to society due to the increased risk of visual impairment.

The screening protocol for this study recommends that a screening examination for amblyopia and amblyogenic factors be routinely performed by an orthoptist in children between 3 and 4 year old. This examination should include, as a minimum, a standardised measurement of visual acuity, a cover test and a measurement of refraction by photoscreener. In the event of a positive screening, the child must then be referred to an ophthalmologist so as to complete an ophthalmological examination.

The aim of this protocol is to propose screening tests usually performed with a high specificity, in order to avoid congestion of ophthalmological services (i.e. by avoiding excessive or unnecessary referral of children to the ophthalmologist) without losing sensitivity by combining several tests.

The orthoptists' role in this screening protocol is to facilitate an extensive screening coverage of the population in this age group, as they are more easily accessed by the patients and more equitably spread in the community than ophthalmologists.

Therefore, by initially screening and then referring less children to the ophthalmologist, the aim is to reduce waiting times in the access of ophthalmological services which could be detrimental in terms of treatment success rates for patients acutely needing care.

Based on the referral of children between 3 and 4 years of age by the orthoptist to an ophthalmologist, the analysis of the data from the standard screening protocol used in our centre will enable us to validate it scientifically. The referral thresholds can thus be secondarily adjusted for each test if the initial objectives are not achieved (specificity > 90% and sensitivity > 87%). The aim of this study is also to observe a change in the patient flow by reducing the volume of consultations with the ophthalmologist currently required based on the present referral rate. The efficiency of the screening protocol by calculating the probable economic gain linked to the modification of the screening circuit will be secondarily studying in this protocol

Inclusion Criteria:

• Children from 3 to 4 years old consulting for a screening of visual disorders,
• Patients registered with French social security scheme,
• Not participating in any other clinical study,
• Consent obtained from one of the two parents or the legal representative.

Exclusion Criteria:

• Children whose parent or legal representative is vulnerable according to article L1121-6 of the CSP,
• Children whose parent or legal guardian is under guardianship or trusteeship or under legal protection,
• Children, whose parent or legal guardian is unable to give consent, or is protected by law.

Children from 3 to 4 years old, girls or boys, with a medical reason for consultation (paediatric orientation) or parent's request (child's complaint)