Childhood Vision Screening

Childhood vision screening identifies amblyopia, strabismus and significant refractive error in children before the age at which these conditions become difficult to treat. It includes age appropriate visual acuity testing, the cover test, stereopsis, and examination of the red reflex in infancy.

The screen aims to identify children who need specialist assessment, not to diagnose every eye condition.

Usage. It is used in routine screening at fixed ages, and in infants whenever a red reflex abnormality or squint is noticed.

Indications. Routine vision screening at scheduled ages, parental concern about squint or vision, and red reflex examination at birth and during infant review.

Preparation and technique. Visual acuity is tested with age appropriate methods, such as preferential looking in infants and symbol or letter charts in older children. The cover test detects strabismus. Stereopsis is tested with stereo targets where the child is old enough. The red reflex is examined in a darkened room with an ophthalmoscope, and the reflex is compared between the two eyes.

Contraindications and precautions. Uncooperative children may need repeat testing or specialist assessment. Mental impairment or neurodevelopmental disorder requires adapted testing.

Interpretation.

• An absent or asymmetric red reflex requires urgent referral, since it may indicate cataract, retinoblastoma or other serious pathology.
• A squint that is constant or intermittent requires referral for orthoptic assessment.
• Visual acuity under the age specific threshold, or a significant difference between the two eyes, requires referral.
• Refractive error is confirmed by cycloplegic refraction in specialist settings.

Causes of reduced acuity. Amblyopia, refractive error, strabismus, cataract, optic nerve disease, and retinal disease.

Critical values and findings needing immediate action.

• An absent red reflex in any eye requires same day referral.
• Sudden loss of vision or a new squint with other neurological signs requires urgent medical review.

Limitations and artefacts. Screening sensitivity is limited in young children who do not cooperate. Uncorrected refractive error is a common cause of false positive referral. Amblyopia is more likely to be missed when testing is delayed beyond the sensitive period.

Follow up tests. Orthoptic assessment, specialist ophthalmic examination, cycloplegic refraction, and retinal assessment where indicated.

Special groups. Preterm infants require specialist retinal screening depending on their gestational age and birth weight, as part of a separate specialist service. Children with neurodevelopmental disorders need adapted screening tools.