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1. Types of Cataract
By
Prof. Naimatullah Khan Kundi
Head, Department of Ophthalmology
Khyber Teaching Hospital
Peshawar

2. 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

3. Pathways for glucose metabolism in the lens

4. 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

5. Metabolic Cataract

6. 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

7. 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

8. Metabolic Cataract
 Metabolic Cataract
 Galactosemia

Galactokinase deficiency type
 Features

Infantile cataract

9. 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.

10. Metabolic Cataract

11. 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

12. Metabolic Cataract
 Metabolic Cataract
 Wilson’s disease

Deposition of metallic copper in the lens
capsule

Sun flower cataract

13. 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

14. 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

15.  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

16.  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