The Lens

Lens

Anatomy of the lens

Cataract

Definition Types of cataract: 1- According to its site within the lens: 2- According to maturation: 3- According to its onset:

Lens

Held by zonules Epithelium produces lens fibres throughout life High protein content Nutrients/oxygen from aqueous Cataract can affect all conponents

Acquired cataract

Cause: 1- Age-related cataract 2- Pre-senile cataract 3- Traumatic cataract 4- Drug-induced cataract 5- Secondary cataract:

Symptoms and signs of diseases of lens

1- painless gradual impairment visual acuity 2- Presbyopia 3- Nuclear sclerosis 4- Monocular diplopia



Treatment of catract:
SURGERY●

Indications of surgery:

1- Visual improvement: 2- Medical indications: 3- Cosmetic indication:

Types of cataract surgery:

Types of cataract surgery

Types of cataract surgery

3- Phacoemulsification:

Aphakia

Treatment:
1- High powered convex lenses in spectacles: (30% magnification).
2- Contact lens (1% magnification).
3- IOL (intraocular lens):

Congenital cataract

1- Isolated hereditary cataracts:
2- Metabolic cataract: a- galactosaemia b- Lowe's (oculocerebral) syndrome:
3- Prenatal infections: a- Congenital Rubella: b- Others: Cytomegalovirus, Herpes simplex and Varicella.
4- Chromosomal abnormalities: a- Down syndrome (Triosomy 21). b- Other: Patau syndrome (Triosomy 13) Edward syndrome


Lowe's (oculocerebral) syndrome

galactosaemia

galactosaemia

Prenatal infections:

Down syndrome

Ectopia lentis

Complications of ectopia lentis:
1- Refractive errors
2- Glaucoma:
3- Endothelial touch:
4- Lens induced uveitis: