Types of Cataract

By

Prof. Naimatullah Khan KundiHead, Department of Ophthalmology

Khyber Teaching Hospital Peshawar

Metabolic Cataract Diabetes Mellitus

True diabetic cataract rare Snow storm opacities – subcapsular

opacities in young uncontrolled diabetics ↑ blood sugar – myopia ↓ blood sugar – hyperopia Lens uses glucose through four

pathways Glycolysis Pentose shunt Kreb’s cycle Sorbitol pathway

Pathways for glucose metabolism in the lens

Metabolic Cataract

Metabolic Cataract

Diabetes Mellitus

Glycolysis, Pentose shunt and Kreb’s cycle

depend on glucose – 6 – P

At high glucose level Hexokinase saturated

Sorbitol pathway becomes significant

Metabolic Cataract

Metabolic Cataract

Metabolic Cataract Diabetes Mellitus

Sorbitol sugar can not defuse through lens fibers ↑ intralenticular osmolarity Water is drawn Water vacuoles developed Hydropic lens fibers more permeable and rupture Na+ influx → further water absorption Loss of K+, AA, glutathione and proteins

Metabolic Cataract

Metabolic Cataract Galactosemia

Types Transferase deficiency type (classic) Galactokinase deficiency type (milder)

Transferase deficiency type Galactose – 1 – PO4

uridyl tranferase deficiency Cataract

75% Droplet opacities Anterior/posterior

Metabolic Cataract

Metabolic Cataract

Galactosemia

Galactokinase deficiency type

Features

Infantile cataract

Metabolic Cataract

Metabolic Cataract Pathogenesis

Dulcitol, sugar similar to sorbitol causes osmotic swelling with lens fiber membrane damage and ↑ permeability

Diagnosis Reducing sugars in urine

Treatment Elimination of lactose and glactose from the diet

and replacing with synthetic formulas for milk and milk products.

Metabolic Cataract

Metabolic Cataract

Metabolic Cataract Hypocalcaemia

Infantile tetany Hypo para thyroidism Rickets

Punctate opacities in subcapsular area With treatment these opacities sink and

form lamellar cataract Progression to maturity

Metabolic Cataract

Metabolic Cataract

Wilson’s disease

Deposition of metallic copper in the lens

capsule

Sun flower cataract

Glaucomatous flecks

Cataracta glaucomatosa Multiple white punctate opacities in

anterior subcapsular clear zone due to damage of the lens epithelium

Vaculation of subcapsular cortex with focal necrosis of affected fibers and adjacent epithelium

With time opacity sink

Dermatogenic Cataract

Skin and lens – Ectodermal Cataract BL Young age Atopic dermatitis

Allergic condition with familiar tendency PSC 10% Most common skin disease associated with

cataract Other skin diseases

Rothmund syndrome Werner’s syndrome

Infectious diseases associated with cataract Viral

Congenital rubella syndrome Congenital cytomegalovirus disease Herpes simplex Variola (small pox)

Treponemal Congenital syphilis

Protozoal Congenital toxoplasmosis

Nematode Onchocerciasis

Cataract associated with systemic disease Dystrophica myotonica

Autosomal dominant Excessive contractility and slow relaxation of

muscles PSC 90% Ptosis Retinal pigmentary degeneration Sluggish pupillary response

Down’s syndrome Other syndromes