developmental cataract 9
TRANSCRIPT
Developmental cataract
Definition
Congenital cataract: - Cataract present at birth- Involves embryonic or fetal nucleus Developmental cataract:- Occurs from infancy to adulthood- May involve infantile or adult
nucleus, deeper layers of cortex or the capsule
Etiology Heredity: - Accounts for 1/3rd of congenital
cataracts- Dominant pattern- Common cataracts which are
inherited are: cataracta pulverulenta, zonular cataract, coronary cataract, total cataract
Maternal factors: - Malnutrition- Infections: TORCH- Drugs: thalidomide, corticosteroids- Radiation exposure
Fetal or infantile factors:- Deficient oxygenation due to placental
haemorrhage- Metabolic disorders: hypocalcemia,
storage disorders, galactosemia, neonatal hypoglycemia
- Other congenital syndromes: Lowe’s, myotonica dystrophica, etc
- Birth trauma- Malnutrition Idiopathic
Clinical types Punctate cataract:- Commonest form- Blue dot cataract (cataracta coerulea):
tiny blue dots seen on oblique illumination- Sutural cataract:opacities involving Y
sutures- Cataracta centralis pulverulenta: powdery
fine opacities within embryonic or fetal nucleus
Zonular cataract- Constitutes 50% of all visually significant
cataract- Development is affected at a later stage and a
zone surrounding embryonic nucleus (usually fetal nucleus) becomes opacified, its extent depending on the duration of inhibiting factor
- Sharply demarcated opacity with area within and surrounding the opacity being clear
- Linear spoke like opacities running towards equator: “riders”
- Usually bilateral- Etiology: genetic (dominant inheritance),
environmental (malnutrtion late fetal or early infantile life, vitamin D deficiency)
Fusiform cataract- Also called as spindle shaped
cataract/ axial or coralliform cataract- Anteroposterior spindle shaped
opacity, sometimes with off-shoots giving an appearance resembling a coral
- Etiology: genetic
Nuclear:- Results when development of lens
is inhibited at an early age, so that the central nucleus remains opaque- embryonal nuclear cataract
- Progressive form of nuclear cataract- rubella
Coronary cataract: - Development affected around puberty,
thereby involving deep layers of cortex and most superficial layers of adolescent nucleus
- Club shaped opacities near the periphery of the lens, axial region remaining clear: vision usually not affected
- Non progressive
Anterior polar cataract:- Involves the central part of anterior capsule
and the adjacent cortex- Etiology: delayed formation of anterior
chamber during development (congenital), perforation of corneal ulcer in ophthalmia neonatorum resulting in contact of cornea with anterior lens capsule (acquired)
- May also result in formation of anterior pyramidal cataract (white plaque projecting forwards into the anterior chamber)
Sometimes an anterior cortical cataract may form (due to opacification of underlying cortex)
Reduplicated cataract/ imprint cataract: when subcapsular epithelium grows between the capsular and cortical opacities, clear lens fibres separate the 2 opacities forming an imprint cataract (buried opacity)
Usually non progressive, do not interfere with vision
Posterior polar cataract:- Due to persistence of posterior
part of vascular sheath of the lens (posterior hyaloid artery)
- Usually visually insignificant
Total cataract Congenital membranous cataract :
due to total or partial absorption of a congenital cataract. Very rare