Optimization of a Photoretinoscopy Method for Determining the Objective Refraction of Children With a Smartphone/add-on Device in India

Inclusion Criteria: * Voluntary, willing to follow the protocol, able to read and understand the information form and give free and informed consent (for parents/guardian of children subjects) and assent (for subjects aged 6-12 years old * At least 6 years old and up to 12 years old at time of informed consent and assent * Average of the equivalent sphere(Sph+Cyl/2) of both eye included in the interval \[-10.00, +8.00\] * Cylindrical refractive error between 0 and 4.00 D on both eyes * Corrected binocular visual acuity in distance vision at least 6/9 Exclusion Criteria: * Incapable of expressing consent * All categories of persons particularly protected by law * Subject in another study which might have an influence on vision or interfere with study assessment * Less than 6 years old, or 13 years old or above at time of informed consent and assent * Amblyopia, Cataract, Strabismus. * Aphakic or pseudophakic (intraocular implant) * Reported severe eye disease involving loss of visual field as in glaucoma, involving loss of acuity and severe discomfort in low or overly bright environments as in retinitis pigmentosa or reported and treated dry eye. * Self-reported neurological deficits, including a history of epileptic pathology or sensory-motor coordination disorders, vestibular or cerebellar pathology (e.g., balance disorders, nystagmus) * Any previous ocular surgery, which might have an influence on vision or interfere with study assessments (e.g. iridectomy, refractive su…