Any opacity in the lens or its capsule whether developmental or acquired is called cataract. Developmental cataract may be present at birth or early childhood. It has a tendency to affect a particular zone. Usually stationary but may be progressive.

Introduction to cataract

Congenital cataract

Incidence

Etiology

Symptoms

Signs

Clinical types

Investigation

Treatment

Mcqs

MCQs on Cataract

Any opacity in the lens or its capsule whether developmental or acquired is called cataract.

CONGENITAL (DEVELOPMENTAL) CATARACT: Developmental cataract may be present at birth or early childhood. It has a tendency to affect a particular zone. Usually stationary but may be progressive.

Cataract Definition

Incidence: Occurs in about 3:10,000 live births. Two-thirds are bilateral.

Etiology:
1. Heredity – ~25%, usually autosomal dominant. The most common cause is genetic mutation.
2. Maternal causes:
- Maternal Malnutrition (e.g. zonular cataract)
- Maternal infection by virus (e.g. rubella in first trimester)

Incidence & Etiology

3. Foetal causes:
- Deficient oxygenation due to severe placental hemorrhage
- Metabolic disorders of the foetus or infant like galactosaemia deficiency
- Chromosomal abnormalities e.g. in Down syndrome
4. Idiopathic – usually unilateral cataracts are usually sporadic and unknown etiology.

Etiology (cont.)

- Depends on size and position
- Central opacity → visual impairment
- White reflex (leucocoria)
- Squint or nystagmus

- White pupillary reflex
- Black opacity on red reflex (ophthalmoscopy)
- Associated anomalies: Congenital heart disease, Microphthalmos, Microencephaly, Mental retardation, Deafness, Dental anomalies

- Punctate (blue-dot) cataract – most common
- Zonular cataract – bilateral, hereditary
- Coronary cataract – appears at puberty
- Anterior capsular cataract
- Posterior capsular cataract
- Nuclear cataract
- Lamellar cataract
- Cortical cataract
- Membranous cataract
- Complete cataract

Clinical Types

- Most common congenital type
- It is bilateral with dominant inheritance hereditary tendency
- Due to malnutrition and lack of Vitamin D deficiency may cause zonular cataract along with erosion of permanent incisors and canines.
- An area around embryonic nucleus becomes opacified and two rings of opacity are seen. Linear opacities or riders may run towards equator.

Zonular Cataract

Coronary cataract:
- Commonly occurs at puberty. Situated in deep layer of cortex and superficial layer of nucleus. Club-shaped opacities near periphery.

Blue dot cataract:
- Most common variety. Multiple small, opaque, scattered dots. Usually does not interfere with vision.

Coronary & Blue Dot Cataract

1. Ocular:
- Density and morphology of cataract noted.
- Refraction by retinoscopy under atropine.
- Intraocular pressure.
- B-scan ultrasonography (posterior segment assessment).
- A-scan ultrasonography (axial length comparison).

Investigations (Ocular)

2. Systemic:
- Blood glucose, calcium, phosphorus
- Urine analysis (galactosemia)
- TORCH infections testing

Investigations (Systemic)

1. No treatment if vision is good.
2. Mydriasis with atropine (until puberty if small central).
3. Visually significant cataract should be operated early.
4. Aspiration of lens matter (material is soft in children), followed by IOL implantation.
5. Lensectomy (removal of lens and anterior vitreous).

Diagnosis investigation and treatment of congenital cataract

Course Outline