What to Assess
For information on specific tests and procedures see: Vision Screening Tools and Tests section
- History — Review risk factors for visual impairment
- External examination — Observe for ptosis and anatomic abnormality
- Monocular distance visual acuity measurement (usually able to assess acuity around 3 years of age, depending on patient cooperation) —
- Use Eye charts to assess for nearsightedness, farsightedness, astigmatism. The Lea symbols, HOTV chart and Tumbling E chart are recommended for preschoolers. Vision testing machines (similar to those at the driver’s licensing departments) can be difficult for younger children to use. It is advisable to have wall charts and picture cards available.
- Eye patches are the only way to be absolutely sure there is no peeking with the other eye!
- Children who wear corrective lenses, should have vision assessment performed while wearing the glasses. If a child requires reading glasses only, remove them for distant visual acuity assessment.
- Eye alignment, motility and tracking — Examine for strabismus and risk for amblyopia (functionally defective development of central visual system), nystagmus (involuntary, rhythmic oscillation of the eyes)
- Unilateral Cover Test /Cover-Uncover Test
- Bruckner test (Red Reflexes from the retinas)
- Pupil exam
- Red Reflex Exam — Assess individual red reflexes and simultaneous red reflex (Bruckner test)
- Stereopsis (binocular depth perception) — e.g. Random-Dot E stereo test
Note: Stereopsis testing is recommended by the Preschool Vision Screening Task Force (Preschool Vision Screening: Summary of a Task Force Report. Pediatrics. 106(5):1105-1112, 2000.), but is not in the AAP guidelines (Eye examination in infants, children and young adults by pediatricians. Pediatrics. 2003.).
- Retinal Exam — Attempt ophthalmoscopy. Success depends on patient cooperation and is possible in 3 to 4 year old children willing to fixate on a toy or other object while being examined with the ophthalmoscope.
Other Potential Assessments
- Instrument-Based Vision Screnning (Photoscreening and Autorefraction): An option – Children younger than 4 years can benefit from this automated vision screening technology which does not depend on behavioral responses of the child. The evaluator must know how to properly apply the technology. It is especially useful in the preverbal, preliterate or developmentally delayed child. Instrument-based screening dies not measure acuity, but assesses for the presence of amblyopia risk factors. It is recommended as an alternative to visual acuity screening with vision charts from 3 to 5 years of age. Visual acuity testing can be used reliably in children older than 4 years of age.
- Color vision Screening to rule out color vision deficiency. Color vision deficits are not sight-threatening.
- A recommendation for color vision screening is included in recommendations of the American Optometric Association but is not in 2003 AAP Policy Statement (see Table 1 in ‘Preschool Vision Screening: Summary of a Task Force Report’. Pediatrics. 106(5):1105-1112, 2000).
Who to Refer for Further Evaluation
- Children with anatomic abnormality, poor visual fixation, eye misalignment, asymmetric or abnormal red reflexes, nystagmus, visual acuity less than 20/40 in either eye are considered to have failed screening evaluation.
- Traumatic injury to the eye
- Additional recommendations from Project Universal Preschool Vision Screening*– See Preschool Vision Screening: Summary of a Task Force Report.Hartmann EE et al. Pediatrics. 2000 Nov; 106(5):1105-1116.
- Children between 36-47 months who pass risk factors and observation but fail visual acuity or stereopsis screening. If responses on visual acuity or stereopsis seem unreliable, re-screening within 6 months using the same tests is indicated. If results on re-screening remain unreliable, referral is recommended.
- Children 48-59 months who pass risk factors and observation, but do not pass visual acuity or stereopsis, must be referred or re-screened within one month. If re-screening is unreliable or not passed, refer immediately.
Results of vision assessments, visual acuity measurements (if performed), eye evaluations and recommendations for follow-up care should be clearly communicated to parents.