Vision screening in infants, children and youth

Question 1

What percentage of pre-schoolers have visual problems?

Answer 1

5-10%

Question 2

What is an alternative form of screening vision?

Answer 2

Photoscreening

Question 3

What is amblyopia?

Answer 3

Reduced vision in the absence of ocular disease, which occurs when the brain does not recognize the input from that eye. Two common causes are strabismus and a difference in refractive error.

Question 4

What is a refractive error?

Answer 4

Inability of the eye to focus the image, which is usually correctable with a lens.

Question 5

What is strabismus?

Answer 5

Misalignment of the eye in any direction; may be constant or intermittent.

Question 6

What is pseudostrabismus?

Answer 6

Occurs most often when a broad nasal bridge covers the nasal sclera unequally. This can be determined by the presence of a symmetrical corneal light reflex.

Question 7

What is a cataract?

Answer 7

Opacification of the crystalline lens

Question 8

What are clinically useful normal visual development landmarks?

Answer 8

Face follow: Birth to four weeks of age.
Visual following: Three months of age.
Visual acuity measurable with appropriate chart: 42 months of age.

Question 9

What is the red reflex test?

Answer 9

Reflection of orange-red light from the retina through the pupil, seen at 0.5 m distance through the ophthalmoscope set on ‘2’ diopters. The light should be equal in brightness and colour, and should fill the pupil completely.

Question 10

What is the corneal light reflection?

Answer 10

Small focal bright white reflection of light on the cornea, which should be symmetrically positioned close to the centre of each cornea.

Question 11

What is a fundoscopic examination?

Answer 11

Examination of the posterior segment of the eye using an ophthalmoscope.

Question 12

What is the cover-uncover test?

Answer 12

Performed by covering one eye at a time while the child fixates on a target. The uncovered eye should not move. The covered eye should also not reposition when exposed. If any such movement occurs during this test, providing vision is good (fixation is well maintained), the child should be referred for further assessment.

Question 13

What vision testing methods can be used by what age?

Answer 13

1. Logarithm of the minimum angle of resolution, Lea Hyvärin (LogMAR LH) chart (standardized validated identifiable shapes) from 42 months of age.
2. HOTV chart (four-letter shapes), tumbling E chart or Lea symbols (shapes) from 36 months of age.
3. LogMAR Snellen chart (letters of the alphabet or numbers) after six years of age.
4. The Allen chart (pictograms), previously widely used, is now thought to be too culturally specific to be helpful.

Question 14

What are the recommendations from newborn to 3mo at infant and well-child visits?

Answer 14

1. A complete examination of the skin and external eye structures including the conjunctiva, cornea, iris and pupils.
2. An inspection of the red reflex to rule out lenticular opacities or major posterior eye disease.
3. Failure of visualization or abnormalities of the reflex are indications for an urgent referral to an ophthalmologist.
4. High-risk newborns (at risk of retinopathy of prematurity and family histories of hereditary ocular diseases) should be examined by an ophthalmologist.

Question 15

What are the recommendations from 6-12mo at infant and well-child visits?

Answer 15

Conduct examination as for 0-3mo and:

1. Ocular alignment should be observed to detect strabismus. The corneal light reflex should be central and the cover-uncover test should be normal.
2. Fixation and following a target are observed.

Question 16

What are the recommendations from 3-5yo at infant and well-child visits?

Answer 16

Conduct examination as for 0-12mo and:

Visual acuity testing should be completed with an age-appropriate tool.

Question 17

What are the recommendations from 6-18yo?

Answer 17

1. Screen as above whenever routine health examinations are conducted.
2. Examine whenever complaints occur.

Question 18

What are other recommendations regarding f/u?

Answer 18

1. School-age children who pass visual examination and screening but have reading difficulties should be referred to a reading specialist for further assessment
2. Any infant or child with abnormalities on examination, or who does not pass visual screening, should be referred for further assessment.
3. Infants and children with risk factors, such as developmental delay, should also be fully examined by a well-trained eye care professional
4. Routine comprehensive professional eye examinations of healthy children with no risk factors have no proven benefit
5. It is imperative that access to appropriate professional ophthalmological expertise is readily available and provided by the public health care system of Canada.