Vision Screening (& Myopia)
also Vision Development

Eye exam: cover-uncover, alternate cover, phorias vs tropias, pupillary afferent defect

• most common ophthalmologic problem in young children is myopia or near-sightedness.
• By age 40, most people have lost the ability to read at near distance and begin to use reading glasses.

Birth to 3 years:

• physical exam
  • eyelids and orbits for symmetry and function
  • external evaluation of the conjunctiva, sclera, cornea, and iris
  • assessment of ocular motility and muscle balance with the corneal light reflex
  • examination of the posterior segment of the eye with the red reflex.
  • testing fixation: CSM, must be Central, Steady, Maintained. the unilateral cover test is useful in infants and toddlers who are able to fixate on an object. Cover one eye and note if looks steadily at target. Uncover the eye. In the normal child, there will be no change in fixation. A strabismic patient who strongly prefers the just-uncovered eye will switch fixation. A child with poor vision in absence of strabismus will react strongly/get fussy when the better eye is covered.
  • In patients with large angle esotropia and equal visual acuity, cross fixation may be seen: Looks like an apparent diminished ability to abduct either eye and a pseudoparesis of the lateral rectus muscles. This is because children find it more convenient to look at an object in the right field with the esotropic left eye, and vice versa. Temporary occlusion of either eye or rotating the baby in a chair on an adult's lap will usually demonstrate that abduction is present
  • Evaluate the ability to fix and follow. If poor fix/follow is noted, when do you refer? 2 months!

• PE as above + 2 other things:
  • Ophthalmoscopic examination may be possible in very cooperative 3- to 4-year-old children.
  • Distance vision acuity testing should begin at age 3:
    • Testing distance of 3 m (10 ft) is recommended for all visual acuity tests.
    • Measure acuity w/ binocular vision, since this is the norm for the patient
      • children w/ latent nystagmus may see much better binocularly
      • in the binocular state, compensatory face positions may be appreciated i.e nystagmus with a null zone, paralytic strabismus; in fact, occluding one eye may eliminate the compensatory position, distinguishing ocular from nonocular torticollis
    • Allen card test may be attempted as early at 2.5 yo, definitely try by age 3
      • commonly used symbols of a truck, house, birthday cake, bear, telephone, horse, and tree.
    • Tumbling e's: used for children > 4 yo, child indicates direction of the arms of the E
    • HOTV: Used for children 3-5 years-old.
      • Used to check for visual acuity in children who do not know the alphabet (uses only the letters HOTV)
      • Children are preconditioned.
      • Child matches up letters on the wall chart with response cards.
      • Chart is placed 10 feet from the child.
    • Snellen testing: Alphabet letters; used for children >4 years-old; The best test for school-aged children
    • other than an unusual child with accomodative insufficiency, there are no conditions in which a child with normal distance acuity will have subnormal near acuity. So, near acuity testing at 14 inches is not essential, if far acuity is done
  • Complete evaluation of a child should be attempted by age 3 and repeated in 6 months if not initially successful. If the repeat examination also is unsuccessful, the child should be referred to a pediatric ophthalmologist for testing.
  • Reasons for referral for age 3-5 years:
    • Out of six items. if 3 or more errors at 10 feet, when looking at 20 foot line (i.e <10/20 or <20/40). Pass = 4/6 correct.  (15-foot line for children six years and older)
    • when visual acuity is 20/50 or worse in any eye. E.g. A normal 4 yo has 20/40 vision.
    • two line difference between eyes even within the passing range
  • Ocular alignment: unilateral cover test at 3 m. Refer for any eye movement.

• annual eye exam, should be tested annually due to the high frequency of refractive errors noted in this age group
• Distance visual acuity: same tests as above. Now start testing monocular vision.
• Refer for:
  • monocular: 3 or more errors with either eye tested at 3 m (10 feet) when looking at the 15 foot line (i.e. <10/15 or 20/30) (20-foot line for children age 3-5)
  • two line difference between eyes, even within passing range (i.e. 10/10 and 10/15 or 20/20 and 20/30)
  • visual acuity 20/40 or worse in any eye . E.g. A normal 6 yo has 20/20 vision.
• Ocular alignment: unilateral cover test at 3 m (10 ft). Refer for any eye movement.

>10 years old: q2-3 years

References:
American Academy of Pediatrics Committee on Practice and Ambulatory
Medicine, Section on Ophthalmology. Eye examination and vision
screening in infants, children, and young adults. Pediatrics.
1996;98:153-157
American Academy of Pediatrics Committee on Practice and Ambulatory
Medicine. Recommendations for preventative pediatric health care.
Pediatrics. 2000;105:645-646
Calhoun JH. Consultation with the specialist. Eye examinations in
infants and children. Pediatr Rev. 1997;18:28-31
http://www.eyetec.net/ce/M5S2.htm
Harley's Pediatric Ophthalmology, 4th edition
CHLA Board Review 2005