2018-19 TOW #42: Vision screening

The eyes are the window to the soul, as the saying goes. If that’s the case, we get to see all kids’ souls in clinic! There is good evidence that we have a role in early identification of vision problems through vision screening, so it’s recommended by the US Preventive Services Task Force.

Materials for this week:

Take-home points for vision assessment and problems:

  1. What are recommended vision screening guidelines? US Preventive Services Task Force recommends children <5 be screened to detect amblyopia, strabismus, and visual acuity defects. AAP guidelines include screening at all well visits, from newborn to age 3 using history, vision assessment, external exam, eye movements, pupil exam, and red reflexes. For ages 3 to 5, the AAP recommends adding age-appropriate visual acuity and direct ophthalmoscopy.
  2. Visual system development occurs throughout infancy and childhood and represents a “critical period” of vision development. Early on, we can test visual acuity by testing fix and follow for each eye by covering one at a time. By age 3-4 (up until 60 months), children should be able to see 20/40 on an age-appropriate eye chart, and by age 5 (60 months), should be 20/20. The visual system development is complete by age 8-10.
  3. Reasons for early referral: 1) persistent ocular deviation at 4 months of age; 2) asymmetry on the simultaneous red reflex test; 3) unexplained torticollis; 4) any witness of lack of ocular alignment or parental concern about ocular alignment (even if it’s “just when tired”), and lack of visual acuity in each eye for age (refer if 20/30 or worse in either eye after age 5).
  4. Amblyopia or “lazy eye” is decreased vision in one or both eyes due to abnormal development of visual pathways in childhood. It is the leading cause of vision loss among children with a prevalence of 1-4%. Causes include deprivation (e.g., cataracts), strabismus (misalignment), and refractive error (nearsightedness, farsightedness or astigmatism (abnormal curvature of the lens)). Early treatment is important, but there is some evidence that treatment can help up to age 14. Treatment includes correcting refractive errors with glasses and patching to strengthen the weaker eye. Patching may start to improve vision within a few weeks, but usually lasts months.
  5. Strabismus – eye misalignment is present in about 4% of kids. It can be identified via Corneal Light Reflex and Cover-Uncover test. For the corneal light reflex, when shining a light directly onto both eyes, if the light reflex is displaced nasally, this finding indicates an exotropia (the eye is turned out). When the light reflex is displaced temporally, this finding indicates an esotropia (the eye is turned in). The cover-uncover test should be performed while the child fixates on a small, interesting target, such as a small toy or sticker on a tongue depressor. (NOTE: a bright beam of a light may not provide as comfortable a target and does not adequately stimulate accommodation/focusing). As the child attends to the target, each eye is alternately covered. A shift in an eye’s alignment as it assumes fixation onto the target is a possible indication of strabismus.

TOW #42: Vision problems

The eyes are the window to the soul, as the saying goes. If that's the case, we get to see all kids' souls if we are doing our jobs! We have a critical role in helping ensure that children's vision is developing appropriately, and intervening early when problems are detected. There is good evidence that we have a role in early identification of vision problems through vision screening, so it's recommended by the US Preventive Services Task Force.

Materials for this week:

Take-home points for vision assessment and problems:

  1. What are recommended vision screening guidelines? US Preventive Services Task Force recommends children <5 be screened to detect amblyopia, strabismus, and visual acuity defects. AAP guidelines include screening at all well visits, from newborn to age 3 using history, vision assessment, external exam, eye movements, pupil exam, and red reflexes. For ages 3 to 5, the AAP recommends adding age-appropriate visual acuity and direct ophthalmoscopy.
  2. Visual system development occurs throughout infancy and childhood and represents a "critical period" of vision development. Early on, we can test visual acuity by testing fix and follow for each eye by covering one at a time. By age 3-4 (up until 60 months), children should be able to see 20/40 on an age-appropriate eye chart, and by age 5 (60 months), should be 20/20. The visual system development is complete by age 8-10.
  3. Reasons for early referral: 1) persistent ocular deviation at 4 months of age; 2) asymmetry of appearance on the simultaneous red reflex test; 3) unexplained torticollis; 4) any witness of lack of ocular alignment or parental concern about ocular alignment (even if it's “just when tired”), and lack of visual acuity in each eye for age.
  4. Amblyopia or "lazy eye" is decreased vision in one or both eyes due to abnormal development of visual pathways in infancy or childhood. It is the leading cause of vision loss among children with a prevalence of 1-4%. Causes include deprivation (e.g., cataracts), strabismus (misalignment), and refractive error (nearsightedness, farsightedness or astigmatism (abnormal curvature of the lens)). Early treatment is important, but there is some evidence that treatment can help up to age 14. Treatment includes correcting refractive errors with glasses and patching to strengthen the weaker eye. Patching may start to improve vision within a few weeks, but usually lasts months. 
  5. Strabismus – eye misalignment is present in about 4% of kids. It can be identified via Corneal Light Reflex and Cover-Uncover test. For the corneal light reflex, when shining a light directly onto both eyes, if the light reflex is displaced nasally, this finding indicates an exotropia (the eye is turned out). When the light reflex is displaced temporally, this finding indicates an esotropia (the eye is turned in). The cover-uncover test should be performed while the child fixates on a small, interesting target, such as a small toy or sticker on a tongue depressor. (NOTE: a bright beam of a light may not provide as comfortable a target and does not adequately stimulate accommodation/focusing). As the child attends to the target, each eye is alternately covered. A shift in an eye’s alignment as it assumes fixation onto the target is a possible indication of strabismus.