Eye Disease in a Child Flashcards
Define conjunctivitis.
Purulent discharge from the eye.
Define hypermetropia.
: Long-sightedness. Light focusses at a point behind the retina.
Define myopia.
Short-sightedness. Light focuses on a point in front of the retina.
Define strabismus.
Abnormal alignment of both eyes. As a result, the eyes look in different directions and do not focus simultaneously on a single point.
Define retinopathy of prematurity.
Vaso-proliferative disorder of the retina affecting premature infants.
Define retinoblastoma.
Primary tumor of the immature cells of the retina. Autosomal dominant.
Explain the aetiology/risk factors for conjunctivitis.
Infection:
- Staph aureus, strep pneumoniae, strep viridans
- Chlamydia trachomatis: Vertical transmission most common (serovars A-C)
- Neisseria gonorrhoeae: Opthalmia neonatorum
- Viral: adenovirus; exclude HSV.
Allergy: Vernal keratoconjunctivitis; chronic allergy, history of atopy
Explain the aetiology/risk factors of hypermetropia.
Genetic factors
Age
Structural: Abnormal shape of cornea, weak ciliary muscle, low converging power of eye lens.
Explain the aetiology/risk factors for myopia.
Genetic factors
Structural factors: Long eyeball diameter, thick cornea.
Endocrine: Acromegaly
Environmental factors (not yet established): Too little time outdoors, excessive close work.
Explain the aetiology/risk factors for strabismus.
Non-paralytic: refractive error in one or both eyes.
Paralytic: Squinting eye could be caused by motor nerve paralysis or SOL.
Explain the aetiology of retinopathy of prematurity.
During intrauterine development of the retina, retinal vessels should grow out from the optic disc as a wave of mesenchymal spindle cells. The growth of the blood vessels is related to the level of oxygen. In pre-term infants there is earlier exposure to oxygen. In hyperoxic extrauterine situations normal retinal vessel maturation stops causing atrophy of the vessels and leads to ischamia. This in turn causes angiogenic factors to be released leading to angiogenesis in the retina. The new vessels formed are more tortuous and fragile increasing the likelihood of haemorrhage.
What are the risk factors for retinopathy of prematurity?
Low birth-weight
Low gestational age at delivery
Prolonged exposure to high oxygen levels
Acidosis
Explain the aetiology/risk factors for retinoblastoma.
Genetic defect in chromosome 13q14. Alters RB1 gene (tumour suppressor) or MYCN gene.
Summarise the epidemiology of conjunctivitis.
1% live births.
Summarise the epidemiology of myopia.
One in 5 teenagers.
Summarise the epidemiology of hypermetropia.
10%
Summarise the epidemiology of strabismus.
4% of children