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