Cataract

Question 1

Cataract - def

Answer 1

1. Def = opacification of lens

Question 2

Cataract - causes

Answer 2

Cataracts may be congenital or acquired

Congenital cataracts

1. Hereditary
2. Metabolic (e.g. galactosaemia = rare genetic condition which affects the body’s ability to metabolise galactose)
3. Association with systemic syndromes (e.g. Down syndrome)
4. Congenital infection (e.g. rubella embryopathy)
5. Idiopathic (esp. for unilateral cataracts)

Acquired cataracts

1. Drugs (e.g. long-term steroid therapy)
2. Inflammation (e.g. chronic iritis)
3. Trauma
4. Radiotherapy
5. Infection

Question 3

Cataracts - sx

Answer 3

1. Bilateral congenital cataracts -> poor vision in infancy (abnormal visual behaviour - ?). Unilateral congenital cataracts may go unrecognised as one eye has normal vision
2. Cataracts that involve the anterior portion of the lens can be seen by the unaided eye
3. Detected readily by inspection of red reflex with direct ophthalmoscope - asymmetrical if cataract present

Question 4

Cataracts - ex/ix/dx

Answer 4

1. Ax red reflex using direct ophthalmoscope
2. Complete eye examination by ophthalmologist; may require sedation or general anaesthesia

Laboratory evaluation - may not be necessary if hx and ex reveal a definitive etiology for cataract (e.g. fhx heritable cataracts, associated ocular disease/trauma, obvious syndrome/chromosomal defect)

3. Calcium, phosphate and blood sugar (to exclude metabolic disorders, e.g. DM, hypoparathyroidism); urine for reducing substances after ingestion of galactose-containing milk (galactosaemia)
4. Toxoplasmosis, rubella, CMV, HSV, varicella, syphilis
5. Karyotype and other genetic testing

Question 5

Cataract - mx

Answer 5

1. Refer immediately if newborn cataract (risk of amblyopia increases if dx delayed). Older children to be seen within weeks
2. Mx conservatively if good vision or small cataracts
3. Occlusion therapy for children with incomplete unilateral cataracts and/or amblyopia after cataract extraction
4. Cataract extraction for children with bilateral complete cataracts
5. Need post-op care with eye drops and frequent follow-up