Eye disease Flashcards
How might visual impairment in an infant or young child present?
Visual impairment may present in an infant or young child with:
- Obvious ocular malformation, e.g. absence of red reflex
- Not smiling responsively by 6wks
- Concerns about poor visual responses, incl poor eye contact
- Nystagmus, roving eye movements
- Squint
What is retinopathy of prematurity?
A potentially blinding vaso-proliferative eye disorder that primarily affects premature low BW infants
Aetiology of retinopathy of prematurity?
The retina has no blood vessels in it until 16wks gestation
- The vessels grow out from the optic disc, only fully reaching the periphery of the eye 1 month after birth
- The incompletely vascularised retina is susceptible to oxygen damage, esp in preterm infants
- Retinopathy of prematurity is a proliferative disorder of this immature retinal vasculature
- Affects developing blood vessels at the junction of the vascularised and non-vascularised retina
Pathophysiology of retinopathy of prematurity?
- Normally, retinal vessels grow in relative hypoxia
- After premature birth, the retina is exposed to increased oxygen → reduced levels of vascular endothelial growth factor (VEGF) → halts vascular growth
- But the eye continues to grow → peripheral area of hypoxic retina à this ischaemia leads to increased levels of VEGF
- This leads to angiogenesis in the retina → the new vessels formed are more tortuous and fragile → increased risk of haemorrhage, retinal detachment, fibrosis and blindness
RFs for retinopathy of prematurity?
- prematurity (esp <32wks),
- low birth weight (<1500g),
- oxygen therapy,
- comorbidities (resp distress, IVH)
Epidemiology of retinopathy of prematurity?
Mostly occurs in extreme low birth weight infants → develops in 16% of all premature births; 35% of very low BW
Signs and symptoms of retinopathy of prematurity?
- Picked up on screening
- Can lead to visual loss and blindness
Ix for retinopathy of prematurity?
- Eyes of susceptible preterm infants (<1500g or <32wks gestation) are screened by an ophthalmologist (with ophthalmoscope)
- Retinal imaging may be done
Mx for retinopathy of prematurity?
Prevention:
- Using reduced concentrations of O2 when ventilating
Mx:
- Laser therapy to ablate new vessels
- Reduces visual impairment
- Intravitreal anti-VEFG (anti-vascular endothelial growth factor) may also be used
Complications and prognosis of retinopathy of prematurity?
Complications:
- Severe visual impairment/blindness; myopia, amblyopia, strabismus
- Complications of treatment: conjunctival haemorrhages, laceration, cataracts
Severe bilateral visual impairment occurs in 1% of very low BW infants
Requires yearly follow-up due to complications
Lower survival rate (due to prematurity itself)
What is strabismus?
Misalignment of the visual axes
Aka squint
Aetiology of strabismus?
Normally both eyes fixate (look at) the object of interest, but in strabismus one eye fixates and the other is deviated Usually caused by refractive error
- Can also be caused by cataracts, retinoblastoma and other intraocular causes à must be excluded
What are the 2 types of strabismus?
-
Concomitant (non-paralytic)
- Common; thought to be a complex genetic trait
- Usually due to a refractive error in one/both eyes à correction of refractive error often corrects squint
- The squinting eye usually turns inward (convergent), but can turn outward (divergent) or vertical
-
Paralytic
- Rare; can be sinister
- Due to paralysis of motor nerves (e.g. by underlying SOL) à squint varies with gaze direction
RFs for strabismus?
- FHx,
- prematurity,
- refractive error
Epidemiology of strabismus?
Common
Transient misalignment is very common up to 3mo
Signs and symptoms of strabismus?
- Eye misalignment
- Amblyopia
- Diplopia (often absent in children due to suppression; if present it only occurs when both eyes are open)
- Intermittent closure of one eye
Ix for strabismus?
-
Red reflexes
- Should be checked in any infant with a squint (rule out retinoblastoma)
-
Corneal light reflex test
- Used by non-specialists to detect squints
- Pen torch is held at a distance to produce reflections on both corneas simultaneously
- If the light reflection does not appear in the same position in the two pupils, a squint is present
-
Cover test
- Child looks at toy/light
- If the fixing eye is covered, the squinting eye moves to take up fixation
- Not appropriate in young children (needs co-operation)
- Child looks at toy/light
-
Further testing by ophthalmology:
- Simultaneous prism and cover test (SPCT) → to measure angle of strabismus
- Vision testing → look for double vision, incomplete eye movements
Mx for strabismus?
Refer all squint persisting >3mo to ophthalmology
-
Treat underlying cause if possible
- Correction of refractive errors with glasses
- Treat amblyopia (see complications)
-
Surgery
- Not usually needed
- Used to strengthen or weaken the functions of muscles
Complications and prognosis of strabismus?
-
Amblyopia
- Potentially permanent reduction of visual acuity in an eye that has not received a clear image
- Affects 2-3% children
- Causes are squint, refractive errors and obstruction to the visual pathway (e.g. cataract)
- May occur in squint when the brain is unable to combine the markedly differing images from each eye à the vision from the squinting eye is ‘switched off’ to avoid double vision
- Treatment is by tackling the underlying condition, and patching the ‘good’ eye for specific periods of the day to force the ‘lazy’ eye to work and therefore develop better vision
- Early treatment is essential → after 7yo improvement is unlikely
-
Psychosocial problems
- Due to cosmetic implications
What is hypermetropia?
A refractive error, aka long-sightedness
NB the refractive errors are hypermetropia, myopia, astigmatism (abnormal corneal curvature) and amblyopia
Aetiology of hypermetropia?
Eye has insufficient optical power for its refractive length à light from an object is focussed behind the retina à blurred image
Mild hypermetropia is common in early childhood à overcome through accommodation (changing the shape of the lens of the eye)
- Usually resolves by 3yo
RFs for hypermetropia?
- FHx (but most are sporadic),
- congenital cataracts,
- micropthalmia
Signs and symptoms of hypermetropia?
- Difficulty viewing near objects; distant objects are sharply focussed
- May lead to eye strain (due to extra accommodative effort) and headache
- Young children may rub their eyes, have poor eye contact, squint
- School-aged children may present with behavioural problems
Ix for hypermetropia?
- Orthoptist-led vision screening is done at 4-5yo in UK
-
Tests for visual acuity vary depending on the age of the child
- 6-8wks: face fixation, following a large coloured toy
- 6 months: preferential looking tests of acuity (Keeler/Teller cards - based on preference for patterns)
- 12 months: fixates 1mm crumb
- 1-2yrs: preferential looking tests of acuity (Cardiff cards – assess eye movement to determine if child can see picture)
- 2-3yrs: names or matches pictures in linear array (Kay pictures or Lea symbols)
- 3yrs+: names or matches letters (e.g. Sonksen logMAR, crowded logMAR); older children can do Snellen chart
-
Assessment of refractive error
- Objective refraction: uses retinoscope to determine nature of error
- Doesn’t require input from patient; can be done in young children
- Subjective refraction: uses a series of lenses to measure the error
- Requires patient participation; can’t be done in young children
- Objective refraction: uses retinoscope to determine nature of error
Mx of hypermetropia?
Mild hypermetropia may not need spectacle correction
Convex (plus) lenses
Contact lenses can be used in older children
Laser treatment to the cornea later in life
Complications of hypermetropia?
- Squint
- Amblyopia
- Increased risk of glaucoma
What is myopia?
A refractive error, aka short-sightedness
Aetiology of myopia?
Eyes have excessive optical power for the length of the eyeball à focus the image in front of the retina
- Due to physiological variation in the length of the eye, or an excessively curved retina
RFs for myopia?
- FHx,
- prematurity,
- Marfan’s syndrome,
- Ehlers-Danlos syndrome
Epidemiology of myopia?
Usually presents in adolescence; uncommon in young children (but more common in premature children)
Affects 1 in 4 adults in UK
Signs and symptoms of myopia?
- Distant objects are blurred; close-up objects are in focus
- Rub eyes, squint, behavioural problems
Ix for myopia?
- Orthoptist-led vision screening is done at 4-5yo in UK
-
Tests for visual acuity vary depending on the age of the child
- 6-8wks: face fixation, following a large coloured toy
- 6 months: preferential looking tests of acuity (Keeler/Teller cards - based on preference for patterns)
- 12 months: fixates 1mm crumb
- 1-2yrs: preferential looking tests of acuity (Cardiff cards – assess eye movement to determine if child can see picture)
- 2-3yrs: names or matches pictures in linear array (Kay pictures or Lea symbols)
- 3yrs+: names or matches letters (e.g. Sonksen logMAR, crowded logMAR); older children can do Snellen chart
-
Assessment of refractive error
- Objective refraction: uses retinoscope to determine nature of error
- Doesn’t require input from patient; can be done in young children
- Subjective refraction: uses a series of lenses to measure the error
- Requires patient participation; can’t be done in young children)
- Objective refraction: uses retinoscope to determine nature of error
Mx of myopia?
Concave (minus) lenses
Contact lenses can be used in older children
Laser treatment to the cornea later in life
Complications of myopia?
- Squint
- Amblyopia
- Increased risk of retinal detachment, cataracts, glaucoma
What is retinoblastoma?
A malignant tumour of retinal cells
Aetiology of retinoblastoma?
Can be unilateral or bilateral, familial or spontaneous
All bilateral tumours and 20% of unilateral tumours are hereditary
- The retinoblastoma susceptibility gene is on chromosome 13 (RB1 gene)
- Dominant inheritance but incomplete penetrance à only 10% with hereditary mutations have FHx
- Spontaneous retinoblastoma also involves the RB1 gene (mutation)
RFs for retinoblastoma?
FHx
Epidemiology of retinoblastoma?
Rare (50 new diagnoses/yr in UK)
Accounts for 5% of severe visual impairment in children
Usually presents within first 3yrs of life
Signs and symptoms of retinoblastoma?
- White pupillary reflex (leukocoria) replaces the normal red one
- Strabismus
Ix for retinoblastoma?
- Regularly screen children if FHx of hereditary retinoblastoma
-
Fundoscopy and examination under anaesthetic
- Appear as a chalky, white-grey retinal mass; often multifocal
- May show retinal detachment and vitreous and/or subretinal seeding
- Appear as a chalky, white-grey retinal mass; often multifocal
-
Ophthalmic USS
- At initial clinical examination or as part of the examination under anaesthesia
-
MRI head/orbit
- Not needed for diagnosis
- Performed to exclude concomitant primitive neuroectodermal tumour in pineal gland (trilateral retinoblastoma) and to detect metastases
-
Molecular testing
- For mutation in RB1 gene
- For family planning and screening for secondary cancers
Mx for retinoblastoma?
Aims to cure, yet preserve vision
-
Chemotherapy
- Esp for bilateral disease, to shrink the tumours
- Followed by laser treatment to the retina
-
Radiotherapy
- May be used for advanced disease; more often used for recurrence
- Enucleation (removal) of the eye may be necessary for advanced disease
Complications and prognosis of retinoblastoma?
-
Vision damage
- E.g. due to intra-retinal haemorrhage from chemotherapy, cataracts after radiation, optic nerve atrophy after carboplatin therapy
-
Second malignancy (esp sarcoma) in survivors of hereditary retinoblastoma
- Chemo/radiotherapy can cause lymphoma and leukaemia
Most patients are cured, but many are visually impaired
What is conjunctivitis?
Inflammation of the conjunctiva (the mucous membrane that covers the front of the eye and lines the inside of the eyelids)
Classified as:
- infectious or non-infectious,
- and as acute, chronic or recurrent
Aetiology of conjunctivitis?
Can be caused by bacteria, viruses, allergic or immunological reactions, mechanical irritation or medicines
-
Bacterial causes:
- S. pneumoniae, S. aureus, Moraxella catarrhalis, H. influenzae
- In neonates: N. gonorrhoeae, Chlamydia
-
Viral causes:
- HSV, adenovirus, VZV, molluscum contagiosum, coxsackie, enteroviruses
- HSV eye disease:
- Can cause blepharitis or conjunctivitis à may extend to cornea to cause dendritic ulceration à corneal scarring and loss of vision
- Viral conjunctivitis is highly contagious
- Mechanical: caused by chronic conjunctival irritation
-
Allergic: can be atopic or non-atopic
- See allergic rhinitis
What is the neonatal presentation of conjunctivitis?
- Sticky eyes are very common, starting on 3rd/4th day of life
- More troublesome discharge with eye redness may be caused by Staph/Strep infection
- Purulent discharge with conjunctival injection and eyelid swelling may be due to gonococcal infection
- Purulent discharge with swelling of eyelids at 1-2wks of age suggests Chlamydia trachomatis
- Can also present shortly after birth
RFs for conjunctivitis?
- exposure to infected person,
- infection in one eye (can spread to other),
- allergen exposure,
- atopy
Epidemiology of conjunctivitis?
Very common
Bacterial conjunctivitis is most common in children (and viral is more common in adults)
Signs and symptoms of conjunctivitis?
-
Red eye and conjunctival injection
- Often bilateral (always bilateral in allergic)
-
Discharge:
- Watery discharge in viral
- Ropy, mucoid discharge in allergic
- Purulent discharge in bacterial
-
Itching
- Most common in allergic
- Eyelids stuck together in the morning
-
Conjunctival follicles
- Round collections of lymphocytes which appear as small dome-shaped nodules, most prominent in the lower eyelid (inferior fornix)
- Seen if caused by viruses, atypical bacteria and toxins
-
Papillae
- Cobblestone appearance of flattened nodules with vascular cores
- Seen in allergic conjunctivitis
Ix for conjunctivitis?
- Clinical diagnosis
-
Identify cause:
- Consider rapid adenovirus assay to identify adenovirus conjunctivitis
- If gonococcal infection suspected: urgent gram stain and culture
- If chlamydial infection suspected: immunofluorescence staining
- If suspicion of HSV: urgent ophthalmic assessment with slip lamp examination of cornea
Mx for conjunctivitis?
Neonatal:
- Sticky eyes: clean with saline or water; resolves spontaneously
- If caused by staph/strep infection: topical antibiotic eye ointment, e.g. chloramphenicol, neomycin
- If caused by gonococcal infection: start treatment immediately (as permanent loss of vision can occur)
- IV cephalosporin (ceftriaxone) (+ topical, e.g. ciprofloxacin ophthalmic)
- If caused by chlamydial infection: oral erythromycin for 2wks (+ topical, e.g. erythromycin ophthalmic)
- Also check and treat mother and partner
Allergic:
- See allergic rhinitis
Bacterial:
- Topical broad-spectrum antibiotics
- E.g. azithromycin, erythromycin for 7-10d
- If moderate-severe or resistant: topical fluoroquinolones, e.g. ciprofloxacin drops
Viral:
- Topical antihistamines and artificial tears for symptomatic relief
Complications and prognosis of conjunctivitis?
Complications:
- Loss of vision (in chlamydial, gonorrhoeal, adenoviral and HSV) if not treated promptly
Bacterial and viral are generally self-limiting over 5-10d
Allergic conjunctivitis usually responds to treatment but usually as seasonal exacerbations
