This document discusses the anatomy and physiology of the lens and various types and causes of cataract formation. It describes the normal lens size, shape, position and refractive properties. It then covers abnormalities in lens shape, size and position. Various classifications of cataract are presented, including congenital/developmental cataracts, cataracts associated with ocular diseases, cataracts associated with systemic diseases, and cataracts due to other causes such as trauma or radiation. The objectives and suggestions for further reading are also listed.

1. Dr.Swathi.N
MGMC & RI

2. • Anatomy
• Position abnormalities of lens
• Etiopathogenesis
• Classification
• Special types of cataract
Objectives :
Of cataract

4.  Transparent
 Biconvex
 Elliptical
 Avascular
 Crystalline appearance
 Located between the iris and the vitreous
 In patellar fossa
 Suspended by zonules

5. equatorial diameter (adult) : 9-10mm
axial width : 3.5 - 4.0mm at birth,
about 4mm at 40 years
4.75 to 5.0 mm in extreme old age.
Physiological change observed daily?

6. varies markedly with accommodation
radius of curvature –
anterior surface : 10 mm (changes to 6 mm on accomodation)
posterior surface : 6mm

7. Refractive index : 1.39
Dioptric contribution :15 D
Accommodative power : 15-16 D : At birth
7-8 D : 25 years
2 D : 50 years.
Why decrease with age?

8. Abnormalities in the lens:
Shape / size
Position
Transparency

9. Abnormal shape / size :
• Coloboma
• Spherophakia
• Microphakia
• Microspherophakia
– ass. with Weil-Marchesani syndrome
Persistent hyperplastic primary vitreous
Posterior / anterior lenticonus

10. Microspherophakia
Coloboma

11. Persistent hyperplastic primary vitreous

12. Anterior /
Posterior
lenticonus

13. Abnormal position

16. Etiopathogenesis :
• Degeneration & opacification of formed lens
fibres
• Formation of aberrant lens fibres
• Deposition of other materials
• Abnormality of lens proteins – disturbance of
intra- & extra- cellular equilibrium of water &
electrolytes

17. • Hydration
• Denaturation
• Slow sclerosis

18. Morphological classification of cataract

20. Congenital / Developmental cataract :
• Blue dot cataract
• Sutural cataract – anterior / posterior
• Cataracta centralis pulverulenta
• Zonular cataract

22. • Fusiform / coralliform
• Nuclear cataract
• Coronary cataract
• Anterior/ postrior polar cataract

24. Associated with ocular diseases :
Complicated cataract
• posterior cortical /
posterior subcapsular
• polychromatic lustre
• Breadcrumb appearance
• Iridocyclitis , ciliary body tumour, choroiditis, degenerative
myopia, retinitis pigmentosa, retinal detachment

25. Associated with systemic diseases :
• Diabetic – snowflake cataract
• Parathyroid tetany – anterior / posterior
punctate subcapsular opacity

26. • Myotonic dystrophy – christmas tree cataract
• Galactosemia – oil droplet cataract
• Down syndrome – punctate subcapsular
opacities
• Atopic cataract

27. Due to other causes :
• Heat / infrared cataract
• Irradiation cataract
• Electric cataract
• Traumatic cataract – rosette cataract

28. • Enumerate the cause of cataract in a given age
group (child, middle aged, elderly)
• Zonular cataract
• Traumatic cataract
• Complicated cataract
• Subluxated lens
• Diagnosis of cataract
• Congenital cataract
• Diabetic cataract

29. Suggested reading
• Etiopathogenesis of cataract
• Symptoms of cataract
• Complications of cataract