Pediatric Opthalmology Flashcards
1
Q
Functional reduction in the visual acuity of an eye, either unilaterally or bilaterally, caused by disuse or misuse during the critical period of visual development
Functional reduction in visual acuity of eye
A
Amblyopia
2
Q
What is the most common cause of pediatric visual impairment
A
Amblyopia
3
Q
What causes amblyopia?
A
- Abnormal vision development in infancy/childhood
- Unilateral or bilateral
- Brain receives poor image from eye and thus does not “learn to see well”
- Vision loss because nerve pathways between brain and eye are not properly stimulated
4
Q
Risk factors for amblyopia
A
- Prematurity
- First degree relative with amblyopia
- Small size for gestational age
- Neurodevelopmental delay
5
Q
Classifications of amblyopia
A
- Strabismus
- Refractive
- Deprivational
6
Q
Misalignment of visual axes of the two eyes
A
Strabismus
7
Q
One or both eyes having refractive error causing imbalance between eyes
A
Refractive
8
Q
Obstruction by a cataract or complete ptosis prevents formation of a formed retina
A
Deprivational
9
Q
What is strabismic amblyopia?
A
- One eye may turn in, out, up, or down
- Described by direction of deviation
- Brain ignores or turns off eye that is not straight and vision drops in that eye
- Foveas of the two eyes are presented with two different and unfusable images
- Visual cortex suppresses image from one eye in order to avoid having diplopia; long term suppression of one eye results in strabismic amblyopia
10
Q
What is refractive amblyopia?
A
- Most commonly due to asymmetric refractive error
- Foveas of two eyes presented with different image clarity d/t unequal uncorrected refractive errors; image in one eye not focused on the fovea at same time as the other
- Brain does not learn how to see wellfrom the eye that has a great need for glasses
- Most commonly in hyperopic (farsighted)
11
Q
When is refractive amblyopia most often detected?
A
- Older age than strabismic amblyopia because children with refractive amblyopia lack obvious external abnormalities and visual functioning appears normal because see well with fellow eye
- Often diagnosed at first vision screening when old enough to identify letters or figures (ages 4 or 5)
12
Q
What is deprivational amblyopia?
A
- Least common form but most severe
- Results from vision deprivation, typically as result of interruption of visual axis or severe distortion of foveal image
- Congenital cataracts, ptosis, congenital corneal opacities, vitreous hemorrhage, and severe refractive errors may cause
- Results in permanent visual impairment if not treated urgently
13
Q
Amblyopia evaluation in pre-verbal child
A
- Fixation reflex
- Differential occlusion objection test
14
Q
What is fixation reflex? How will it present in amblyopic eye?
A
- Testing involving moving visual target to and from child’s visual space, each eye tested by occluding fellow eye
- Amblyopia will rarely maintain fixation with amblyopic eye when both eyes uncovered
15
Q
Differential occlusion objection test
A
- Monitor child’s response to alternate occlusion of eyes
- Children with equal vision respond equally, or not at all
- Children with moderate-to-severe visual impairment in one eye become more irritable when other eye with better vision occluded
16
Q
Amblyopia evaluation in verbal child 3 and older
A
- Allen or Snellen charts for visual acuity
17
Q
How is visual acuity assessed?
A
- Attempt at 3 years of age and older
- Snellen chart measured at 20 ft and marked off
- Begin with 20/40 and if child misses 2 figures in a row, ask child to go up a row and identify all figures
18
Q
Amblyopia referral indications
A
- Failure of visual acuity: worse than 20/40 3-5 yrs old or worse than 20/30 in child greater than or equal to 6
- Visual acuity difference of greater than or equal to 2 lines between eyes in passing range
- Abnormal ocular alignment: strabismus
- Abnormal red reflex
- Asymmetry of vision
- Unilateral ptosis, or other lesions that threaten visual axis, such as hemangioma
19
Q
Amblyopia treatment
A
- Most responsive before age 7, with upper range to be effects 9-10 years
- Elimination of visual obstruction: cataracts, hemangioma
- Correction of refractive error with corrective lenses
- Encourage use of amblyopic eye: patching, corrective lenses, visual blurring, surgery
20
Q
Strabismus
A
Anomaly of ocular alignment of one or both eyes in any direction
AKA: misalignment of the eyes
21
Q
How is strabismus described?
A
- Direction of deviation
- Conditions under which presents
- Whether changes with position or gaze
22
Q
What is strabismus related to?
A
- Family history
- Low birth weight
- Prematurity
23
Q
How is strabismus described?
A
- Nasal/inward –> eso
- Temporal/outward –> exo
- Upward –> hyper
- Downward –> hypo
24
Q
What should be in strabismus differential?
A
- Ocular instability of infancy
- Pseudostabismus
25
Q
What is ocular instability of infancy
A
- Unsteady ocular alignment often sporadically present in newborns until first few months of life
- Usually resolves around 3 months of age after child is able to fix and follow
26
Q
What is pseudostrabismus?
A
- Apparent esotropia in children with wide nasal bridge or large epicanthal folds during first few years of life
- Not true strabismus: rather optical illusion in which wide nasal bridge or epicanthal folds cover nasal sclera making eye appear esotropic, particularly when child looks in lateral gaze
27
Q
History in strabismus
A
- Developmental hx
- Family hx
- How long present
- Head or eye trauma
- Genetic or neuromuscular medical issues
- Exposure to toxins
- Headache, diplopia, or abnormal head posture
28
Q
Physical exams in strabismus
A
- Corneal light reflex
- Cover test
- Cover/uncover test
- Bruckner Red Reflex
29
Q
Corneal light reflex
A
- Primary screening technique
- Small toy used as accommodation targe with opthalmoscope standing several feet from child
- Hold light and toy in same hand and use light to reflect on both eyes at same time
- Normal test reveals light refects off same position in each eye
30
Q
Cover test
A
- Child asked to visually fixate on a target at distance or near
- Examiner briefly covers one eye while observing opposite eye for movenet
- No movement when covering either eye if normal ocular alignment
- Strabismus present if eye that is not occluded with cover test shifts to re-fixate on target when fellow, previously fixating eye covered
31
Q
Cover/uncover test
A
- Child asked to visually fixate on target at distance or near
- Cover placed over one eye for a few seconds and then rapidly removed
- Eye that was under cover observed for refixation movement
- If strabismus, previously covered eye will shift back into straight-ahead position to re-establish sensory fusion with other eye
- Positive test when cover rapidly removed and affected eye deviated and realigns after cover removed to fixate on object
32
Q
Bruckner Red Reflex
A
- Opthalmoscope with largest diameter light positioned 18-20 inches from child’s face and used to visualize both red reflexes at same time
- Light positioned just around skin of child’s eyes and child should be looking directly at ophthalmoscope
- Should be equal in size, shape, color, and hue
33
Q
Complications of strabismus
A
- Amblyopia
- Diplopia
- Secondary contracture of extraocular muscles, limiting extraocular motility and binocular vision fields
- Psychosocial and vocational consequences
34
Q
A
35
Q
Strabismus referral indications
A
- Constant strabismus at any age
- Intermittent strabismus after 6 months of age
- Positive corneal light reflex test or cover or cover/uncover
- Positive bruckner test
- Deviations that change with gaze
- Torticollis not explained by muscle spasm
- Complaints of eye fatigue
- Prematurity/genetic disorder/metabolic disorder
- Parenteral concern
36
Q
Treatment of strabismus
A
- Corrective lenses: address vision impairment caused by amblyopia, refractive error correction with glasses
- Patching: refractive error correction with patching
- Surgery: recession or resection
37
Q
What is recession surgery?
A
- Repositioning of muscle insertion posterior to original insertion on sclera which weakens effect on globe position
38
Q
Resection surgery
A
- Shortening muscle which permits it to act as a passive restraint, effectively increasing its effect on globe position
