Paediatric ophthalmology Flashcards
What is the definition of amblyopia?
Vision development disorder in which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses; begins during infancy and early childhood, usually only one eye is affected
Which age group is amblyopia unique to?
Children
What is a layman’s term often used to describe amblyopia?
Lazy eye
What does amblyopia lead to if untreated?
irreversible permanent reduction in vision of one or both eyes
What can cause amblyopia?
it is a response to anything that has reduced visual stimulation, but may even occur in the absence of any apparent ocular disease
Why did amblyopia develop evolutionarily?
it is an evolutionary adaptation to prevent complications from one poor eye; if cave child born with squint with one eye in the wrong direction, this would result in intractable double vision, which would be dangerous as couldn’t tell if a sabre tooth tiger was real or false. therefore the brain suppresses vision of the squinting eye and makes it amblyopic.
What are 4 types of amblyopia (based on the cause)?
- Strabismic amblyopia (squint i.e. eyes do not align so one becomes lazy)
- Ametropic amblyopia
- Anisometropic amblyopia
- Form-deprivation amblyopias
What is ametropic amblyopia?
occurs due to large uncorrected refractive errors in the patient’s optic system, but both eyes have a similar refractive error. if severe enough, bot eyes can develop a mild amblyopia
What is anisometropic amblyopia?
there is a significant difference in the refractive error between the two eyes; brain ignores eye producing a less focused image on the retina, and amblyopia develops
What is form-deprivation amblyopia?
usually occurs when here is ocular disease e.g. cataract which prevents good vision, so affected eye becomes amblyopic if cataract not removed
What is the sensitive period during which amblyopia begins?
birth to 9 years old
What are 3 treatment options for amblyopia?
- Treat any identifiable cause e.g. remove cataract, glasses
- Patching of good eye forcing child to use poor eye
- atropic drops to blur good eye
What are 4 possible clues in a history of a baby that can suggest clues as to visual potential/ provide rough visual estimates?
- response to a smile (by 2-3 months of age)
- objects to occlusion: if poor vision in one eye won’t object to it being covered; if cover the single one good eye and have completely taken away sight, they will become agitated and unhappy
- objection to bright lights
- startle response to bright light or sudden surprising visual stimulus
What are 2 ways to perform an objective assessment of infant’s vision?
- Preferential looking
2. simple observation
What is meant by preferential looking in an objective assessment of an infant’s vision?
when given a choice, a baby will look at a more interesting target e.g. more interesting striped card than the blank part; the thinner the stripes, the better the baby’s vision (‘Teller cards’)
Cardiff cards similar but use pictures rather than stripes
What is a limitation of the preferential looking method of visual assessment?
may overestimate vision
What are 5 elements of simple observation when performing an objective assessment of a baby’s vision?
- external examination: large congenital squint (strabismus), buphthalmos
- symmetry between two eyes
- red reflex
- pupil responses
- ophthalmoscopy
What is meant by buphthalmos?
when a pliable infant eye enlarges due to high intraocular pressure of congenital glaucoma
What can be a difficulty with trying to find a baby’s red reflex?
can be hard to do due to wriggling etc.
What simple observation can often give the first indication of pathology in baby’s vision/eyes?
pupil responses
What are three important things that ophthalmoscopy in a baby can show?
optic media, retina, optic nerve
What might poor vision in children be a sign of?
may be a presenting feature of sinister systemic cause
What is often required to diagnose a cause of poor vision in children?
specialist examination and investigaiton i.e. often need to refer to specialist paediatric ophthalmologist
Why is rapid treatment key in loss of vision in children?
the earlier it is treated, the higher chance vision will develop normally and the eye won’t become lazy/amblyopic
What is leukocoria?
name given to the white pupil reflex
What is leukocoria caused by?
opacity of any part of ocular media
What is the management pathway for leukocoria?
urgent referral needed (multiple causes)
What is the most common cause of leukocoria in infants?
congenital cataract
When does congenital cataract appear and what can cause it?
Present at birth, may be associated with ocular or systematic disorders
What are 5 systemic disorders that congenital cataract may be associated with?
- Down’s syndrome
- Toxoplasmosis
- Rubella
- Cytomegalovirus
- Herpes simplex
What is the test for leukocoria?
direct ophthalmoscopy
how many babies per year in the UK have leukocoria?
200
What is there a high risk of if leukocoria is not treated early?
irreversible amblyopia (may be dense and difficult to treat)
What is usually the management plan for leukocoria in babies/children?
urgent referral for prompt surgery