Pediatric Ophthalmology - Overview

Essentials of Pediatric Eye Examination

  1. External inspection of the eye and surrounding structures
  2. Assessment of alignment
    1. Corneal light reflex
    2. following ability - use a light or toy and observe both eyes
    3. Cover test- difficult in infants and toddlers

  3. Red reflex
    redreflex.jpg
  4. Pupillary reaction
  5. Fundoscopic exam
  6. Acuity check-( HOTV , E's, Fixation )
  7. Observation of increased blinking and eye pressing (may indicate decreased vision)

Amblyopia

  1. Reduced vision secondary to visual deprivation or suppression. Normal vision development is dependent on images reaching the retina and failure to stimulate the retina will lead to failure to learn to see. 
  2. Causes
    1. Strabismus- most common
    2. Corneal or lens opacities
    3. Ptosis
    4. unequal refractive errors that leads to use of one eye and suppression of the other
    5. Vitreous or retinal hemorrhages
    6. retinal infections, scars, or tumors
  3. Accounts for about 2% of subnormal vision and early diagnosis necessary to allow attainment of normal vision. 
  4. Diagnosis by recognition of abnormal vision and the underlying conditions associated with development 
  5. Treatment
  6. early detection
  7. elimination of underlying condition
  8. Patching the " good eye"

    amblyopia.jpg

 

Strabismus

  1. Strabismus is a misalignment of the two eyes. It affects about 4% of the population of which 30-50% result in visual loss. Can be in, out, up, or down. 
  2. Leads to amblyopia secondary to suppression which results from the brain ignoring images coming from the crossed eye. The CNS adjusts so child will not have diplopia. |
  3. Loss of depth perception (steriopsis)
  4. Cosmetic problems
  5. Most Common Forms of Strabismus
    1. Visual deprivation- vision interrupted in one or both eyes. Examples would be retinoblastoma or cataract
    2. Infantile esotropia (turning in of the eyes)- idiopathic and may be in one eye or alternating. Usually alternating esotropia will not be associated with amblyopia
    3. Accommodative esotropia- because of refractory error, child must accommodate to see better and convergence results. Usually occurs at later age between 2-4 years but may be in infancy. Amblyopia most common in this condition. 
    4. Exotropia ( turning out of the eye) evident 18 months to 3 years of age. May lead to amblyopia.
  6. Diagnosis
  7. Corneal light reflex
  8. Cover test
  9. Dilated fundus exam
  10. Eliminate underlying cause
  11. Correct amblyopia ( Patching)
  12. Restore ocular alignment (muscle surgery) This is reconstructive and not cosmetic.
  13. Characterized by flat nasal bridge, prominent epicanthal folds. and the absence of nasal sclera which is obscured by the prominent epicanthal folds. Have normal corneal light reflex and cover test.
  14. Treatment
  15. Pseudostrabismus- esotropia
    psuedo 1_0.jpg
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Pediatric Vision Screening

Purpose:

  • To detect conditions that affect visual potential
    • Early detection and prompt treatment may prevent lifelong visual impairment
  • May facilitate detection of neurologic, metabolic, or genetic disorders
  • Children < 3 YO: assess visual behavior
  • Children > 3 YO who are able to follow directions: assess visual acuity

Environment in which to perform the exam:

  • Minimal distractions, dim room for red reflex
  • Infants/Toddlers < 3 YO: hold upright in parent’s arms, assess visual behavior, not acuity

Visual History: 

  • Ask parents questions along these lines to get a baseline of the child’s visual behavior:
  • Does your child see well?
  • Do the eyes appear to cross or wander?
  • Does your child hold things close or squint?
  • Do your child’s eyelids droop?
  • Have your child’s eyes been injured?
  • PMHx or Conditions associated with ophthalmologic findings:
  • Lipid storage disorders, peroxisomal disorders
  • History of prematurity increases risk for developing amblyopia, high myopia (nearsightedness), and strabismus.
  • Among children with severe visual impairment, 70 percent have additional handicaps; 10 percent have impaired hearing
  • Family history of serious childhood eye disease:
  • childhood cataracts, strabismus, amblyopia, glaucoma, retinal problems, nystagmus

Visual Inspection of the Eye:

  • Note the position/spacing of the eyes, width of palpebral fissures, and eyelids
    • Asymmetry of the eyes may be the result of prominent epicanthal folds, a difference in the size of the globes, or ptosis.
    • Widened or narrow palpebral fissures can be part of a syndrome complex
  • Inspect eyelids:
  • Erythematous eyelids à hemangiomas or 2/2 trauma, infection, metastasis, or connective tissue disorders
  • Morgan folds = Small creases of lower eyelid à allergies
  • Edema à hypoproteinemia as part of the nephrotic syndrome.
  • Ptosis à myasthenia gravis, CN III palsy, and ophthalmoplegic migraine.
  • Flaking, erythema, and mild swelling of the eyelid margins à blepharitis 2/2 seborrheic dermatitis of the scalp or face
  • Stye = painful inflam. of hair follicles at lid margin, usually S. aureus
  • Chalazion = nontender, nodular lesion located deeper in the eyelid, à chronic inflammation of a meibomian gland
  • Purulent discharge suggests bacterial conjunctivitis or bacterial keratitis.
  • Tearing may result from a blocked tear duct, presence of a foreign body, allergic reaction, infection, or glaucoma
  • indicate direct trauma to the face or orbit – consider abuse
  • In the cornea - suggests infectious keratitis
    • Raised, grayish branching opacity = herpes simplex keratitis

 

Cataracts

  • Note discharge or excessive tearing
  • Note periorbital ecchymoses, subconjunctival hemorrhage, hyphema, and orbital fractures
  • Note white spots, opacities or foreign bodies

 

Occular Alignment

  • The corneal light reflex
  • Shine a light into the eyes of a patient who is staring straight ahead.
  • Normal eye alignment = symmetric reflex in the center of each pupil.
  • If the light reflex is inwardly displaced = eye is exotropic
  • If outwardly displaced = esotropic
  • If inferiorly displaced = hypertropic
  • Strabismic gaze = a misalignment of the eyes
  • may be normal during the first several months of life
  • Persistent strabismus should be referred to an ophthalmologist

 

Pupil Examination

  • Use a penlight to examine
  • Is the pupil reactive to light?
  • No: Think angle-closure glaucoma if fixed in mid-dilation/unreactive to light. Typically 4 to 5 mm in diameter.
  • Is the pupil small?
  • Yes: consider corneal abrasion, infectious keratitis, or iritis.

 

Red reflex

  • Test in a darkened room
  • Begin at a distance with the beam of light projected onto the upper facial area.
  • From a distance of approximately 18 inches, visualize the fundi are individually and simultaneously (Bruckner test).
  • Viewing the retina obliquely, in addition to straight-on, may improve the detection of retinoblastoma
  • In more darkly pigmented children, the reflex may be more gray than red
  • Children who have an abnormal red reflex (eg, dark spots, markedly diminished reflex, white reflex, asymmetry) should be referred to an ophthalmologist

 

Fundus Examination

  • Clearly visualize the optic disk, blood vessels, and more laterally the macula.
  • Fundus should be pink to red
  • Hemorrhages à suggest abusive head trauma
  • Describe the number, the pattern of distribution, and type
  • Roth Spots (white center) à suggest bacterial endocarditis
  • Papilledema à indication of increased intracranial pressure
  • Takes 12 – 24 hrs to develop in patients with increased intracranial pressure following head injury

 

Visual Behavior

  • Assess in children < 3 YO
  • Goal: determine if the vision is equal between eyes and to check if behavior is “normal”
    • Note the child's ability to see the examiner, to visually track the examiner, and to respond to the examiner's smile.
  • Normal visual behavior:
    • 0-1 month: They turn eyes/head to look at light sources and track objects horizontally. Make eye contact and begin to look at objects that are close to their faces. They appear serious as they fixate.
    • 2 months: Eye contact at 6-8 weeks, vertical and circular tracking. They like mobiles and “lip reading”. Begin to display facial expression as they fixate.
    • 3-4 months: Begin to observe their hands, hold them close to their faces. Watch activity that occurs around them.
    • 6 months: Observe surroundings and recognize favorite people, toys, or foods at a distance. Reaches toward/grasps hanging objects, observes toys falling/rolling away, shifts fixation across midline
    • 7-10 months: Notices small objects, develops pincher grasp, interested in pictures, recognizes partially hidden objects
    • 11-12 months: Looks through windows, recognizes people/pictures, plays hide-and-seek.

 

Fixation reflex

  • A good marker of visual function in most preverbal children
  • Objects with spatial orientation are essential
  • < 3-4 months: The human face is the ideal target
  • > 4 months: Small, colorful toys or stickers placed on the end of tongue depressors are good targets. More than one target may be necessary to keep them interested
  • Objects to avoid:
  • White light from a pen light lacks orientation
  • Targets that make noise provide both visual and auditory cues and distinguishing which cues the child is using to track the object is difficult.
  • How to test:
  • The target is moved to and fro while the child’s head remains still
  • First assess both together, then test separately by occluding one eye at a time
  • Improve accuracy by repeating several times
  • Central-steady-maintained (CSM) method:
  • With one eye occluded, several characteristics of fixation are noted:
  • Is the fixation central (C) or eccentric/noncentral (NC)?
  • Is the fixation held steadily on the target as it is held still and slowly moved (S), or not (US)?
  • Is the child able to maintain fixation with the viewing eye when the other eye is uncovered or through a blink (M), or not (NM)?
  • Fix-and-follow (F + F) method:
  • Test each eye separately
  • Can the child fixate on and follow a target as it is slowly moved through his or her visual space?

 

Visual Acuity Tests

  • Attempt in all children > 3 YO
    • General
      • Improve performance by preteaching children how to do the test
      • Tests are designed to test the vision in each eye individually.
        • If unequal visual acuity - test eye with poorest vision first
        • Retest eye with lower visual acuity
      • Assess vision with and without glasses
      • Standard distance for visual acuity testing =  20 feet.
        • Many children perform better with the test target at 10 if the eye chart is recalibrated for that distance
      • If grossly normal vision, begin with the row of 20/40 and adjust up or down. If they  can identify one figure in a row correctly, the examiner should go to the next row.
      • If the child misses two figures in a row, the examiner should ask the child to identify all of the figures in the previous row.
    • Interpretation
      • Visual acuity for the tested eye = the row above the row in which the child consistently misses two or more figures.
      • Visual acuity varies with the age of the child
        • Kids < 4 or 5 may have acuity of 20/40 or 20/50
        • Kids ~ 4 or 5 should have acuity of at least 20/30
        • Vision should be considered normal if the visual acuity is equal and not severely reduced in the two eyes (ie, better than 20/50).
        • “Perfect” vision = 20/20
      • Most children have better visual acuity than is recorded, but they are not able to maintain attention for the testing of very small letters
  • Optotype tests: assess the child's ability to see and recognize an optotype (eg, figure or letter) and to communicate that recognition to the examiner.
  • The Snellen acuity test (the standard letter test)
  • ** gold-standard **
  • Used for children who can identify letters of the alphabet.
  • The examiner should listen for letters that are consistently misnamed (eg, "E" for "F"); such misnamings may indicate lack of familiarity with the alphabet
  • Picture optotypes
  • used for children who do not know the letters of the alphabet
  • Allen cards: pictures of familiar objects (car, cake, horse, bird)
    • Present child with a single optotype, typically 20/30 size. Begin at near distance and gradually increase distance until the child can no longer identify the figures.
  • Directional optotype tests (eg, the tumbling E game, Landolt rings)
    • require the child to identify the direction the optotype is facing

 

Testing artifacts

  • Squinting
    • "pinhole" effect limits the number of light rays that enter the eye reduces the blur
  • Peeking
  • Occurs frequently. The examiner should sit or stand where they can see both the child and the chart.
  • Ask the child to read the optotypes in reverse or random order.
  • Definition: The achievement of better visual acuity when optotypes are presented in isolation than when they are presented in a row with other optotypes.
  • Consider in children who may have amblyopia
  • Memorization
  • Crowding phenomenon

 

Near Vision Testing

  • Perform in children who have the following complaints:
    • Decline in school performance, reading difficulty
    • Eye strain (asthenopia), headaches
    • Double vision
    • Nystagmus
  • Testing:
  • Use a near vision testing card to present optotypes at a distance of 14 inches.
  • Tested each eye individually

 

Referral indications  Refer to an ophthalmologist if:

  • Abnormal red reflex à may indicate cataract, glaucoma, retinoblastoma, retinal abnormality, or strabismus, or unequal or high refractive error
  • History of prematurity or metabolic or genetic disease
  • Family history of childhood cataract, retinoblastoma, retinal dysplasia, or glaucoma.
  • Should have a formal ophtho exam in the first weeks or months of life
  • Strabismus
  • Pupillary asymmetry of ≥1 mm à suggestive of neurologic condition
  • Corneal asymmetry à suggestive of glaucoma
  • Unilateral ptosis/lesions obstructing the visual axis à may cause amblyopia
  • Eye preference or visual acuity difference of two lines or more between eyes
  • Visual acuity worse than 20/40 in a child 3-5 YO or worse than 20/30 in a child > 6 years
  • Nystagmus.
  • Amblyopia

 

References

  1. American Association for Pediatric Ophthalmology And Strabismus, et al. Red reflex examination in neonates, infants, and children. Pediatrics 2008; 122:1401
  2. American Academy of Pediatrics.  Eye Examination in Infants, Children and Young Adults. Vol 111 April 2003
  3. Bright Futures: Guidelines for Health Supervision of Infants, Children, and Adolescents, 3rd, Hagan JF, Shaw JS, Duncan PM (Eds), American Academy of Pediatrics, Elk Grove Village, IL 2008.
  4. Pediatric ophthalmology, 3rd ed, Nelson, LB, Calhoun, JH, Harley, RD (Eds), Saunders, Philadelphia 1991.
  5. Simon John Commonly Missed Diagnoses in the Childhood Eye Examination  American Family Physician Aug. 15, 2001
  6. Walton, DS., Oski, FA, DeAngelis, CD, Feigin, RD, Warshaw, JB. Eye evaluation in the newborn. Principles and Practice of Pediatrics, Lippincott, Philadelphia 1990. p.468.
  7. Magramm, Irene. Amblyopia: Etiology, Detection, and Treatment- Pediatrics in Review January 1992
  8. Simon John Commonly Missed Diagnoses in the Childhood Eye Examination  American Family Physician Aug. 15, 2001
  9. Baccal and Wilso. Strabismus:  Getting it Straight  Contemporary Pediatrics Feb 2000
  10. American Academy of Pediatrics. Eye Examination in Infants, Children and Young Adults. Vol 111 April 2003
  11. Donahue S. Pediatric Strabismus.  NEJM March 8, 2007
  12. http://www.aao.org/education/ped_vision/index.cfm
  13. NEJM Retinoblastoma. July 19, 2012

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