Types of Cataract (Part-II)19-05-2008.ppt

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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 – PO
4

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