Cataract

A Brief Description about Cataract

1. CATARACT

2. Def : Opacification of lens is known as Cataract. LENS TRANSPARENCY Factors that play significant role in lens transparency are : Avascularity Tightly packed nature of Lens Cells Arrangement of lens proteins Semipermeable character of lens capsule Pump mechanism of lens fibre membranes Auto oxidation & high concentration of Glutathione in lens

3. SENILE CATARACT : Senile cataract is normal ageing process hence it is also called as age related cataract. Affecting equally persons of either sex above 50 yrs of age This is usually bilateral, but almost always one eye is affected earlier than other Morphologically this cataract occurs in 2 forms Cortical (soft) cataract Nuclear (hard) cataract

4. Etiology The precise etiopathogenesis is not clear , following factors are implicated in etiology are as follows A. Factors affecting age of onset , type and maturation of cataract Heredity Ultraviolet radiations Dietary factors Dehydrational crisis smoking

5. B. Causes of presenile cataract Heredity Diabetes mellitus Myotonic dystrophy Atopic dermatitis Term presenile is used when the cataractarous changes similar to senile cataract occur before 50 yrs of age . The common causes are :

6. It is basically different for Nuclear & Cortical Senile Cataracts. 1. Cortical Senile Cataract PATHOGENESIS

7. 2. Nuclear Senile Cataract In it the usual degenerative changes are Intensification of age related Nuclear Sclerosis associated with dehydration & compaction of Nucleus resulting in hard cataract. However, the total protein content distribution of Cations remain normal

8. Maturation of Cortical Senile Cataract Stage of Lamellar Separation There is demarcation of cortical fibres owing to their separation by fluid. This phenomenon can be demonstrated by slit lamp examination only. These changes are reversible. Stage of Incipient Cataract Early detectable Opacities with clear areas between them are seen. Two types of senile cortical cataracts can be recognised at this stage. Stages of Maturation

9. i) Cuneiform Senile Cortical Cataract There wedge shaped opacities with clear areas between them. These extent from equator towards centre & can only be demonstrated after dilatation of pupil. Opacities are present both in Anterior & Posterior Cortex. On oblique illumination these present as typical radial spoke- like pattern of Greyish white opacities. On distant direct Opthalmoscopy, these Opacities appear as Dark lines against the Red Fundal Glow

10. ii) Cupuliform Senile Cortical Cataract : Saucer-shaped opacity develops just below the capsule usually in the central part of posterior cortex, which gradually extend outwards. There is usually a definite demarcation between cataract & the surrounding clear cortex.

11. Immature Senile Cataract ( ISC ) Opacification progresses further. Cuneiform & Cupuliform patterns can be recognised till the advanced stage when opacification becomes more diffused & irregular. Lens appear greyish whit but clear cortex is still present & also Iris shadow is visible. In some patients, at this stage lens may become swollen due to continued hydration. This condition is called “ Intumescent Cataract ”. Due to swollen lens anterior chamber becomes shallow.

12. Mature Senile Cataract ( MSC ) In this stage opacification becomes complete ( Whole of the cortex is involved ) Lens becomes pearly white in colour . Such a cataract is also labelled as “ Ripe Cataract ”.

13. Hypermature Senile Cataract ( HMSC ) When the mature cataract is left insitu the stage of hypermaturation occurs. The hypermature cataract may occur in two forms. i ) Morgagnian Hypermature cataract : In this after maturity the whole cortex liquefies & the lens is converted into a bag of milky fluid. A small brown nucleus settles at the bottom. Sometimes in this stage calcium deposits may also be seen on the lens capsule .

14. ii) Sclerotic Type Hypermature Cataract : After the stage of maturity, the cortex becomes disintegrated & lens becomes shrunken due to leakage of water. The anterior capsule is wrinkled & thickened due to proliferation of anterior cells & dense white capsullary cataract is formed in the pupillary area. Due to shrinkage of lens, anterior chamber becomes deep.

15. Maturation of Nuclear Senile Cataract In it, the sclerotic process renders the lens inelastic & hard, decreases the ability to accommodate & obstructs the light rays. The changes begins centrally & slowly spread peripherally almost upto the capsule. The nucleus may become diffusely cloudy ( Greyish ) or tinted ( yellow or black ) due to deposition of pigments. Commonly observed pigmented nuclear cataracts are : Brown ( Cataracta Brunesens ) Black ( Cataracta Nigra ) Reddish ( Cataracta Rubra )

16. Symptoms Glare Uniocular Polyopia ( Doubling or Trebling of objects ) Coloured Halos Black Spots in front of eyes Image blur or distortion of images & Misty vision Loss of vision Clinical features

17. Signs : Following examination should be carried to look for different signs Visual Acuity Testing Oblique illumination Examination Test for Iris shadow Distant direct opthalmoscopic examination Slit lamp examination

18. Features Immature Senile Cataract Nuclear Sclerosis 1. Iris shadow Present Absent 2. Distant Direct Opthalmoscopy Reveals Black Spots against red glow No black spots are seen against red glow 3. Slit lamp examination Reveals area of Cataractous cortex Reveals clear lens 4. Visual acuity Does not improve on pin hole testing Improves on pin hole testing Differential Diagnosis

19. Features Mature Senile Cataract Leukocoria 1. Size of the pupil Usually Normal Usually Semidilated 2. Fourth Purkinje image Absent Present 3. Slit lamp examination Cataractous Lens Transparent lens with white reflux behind the lens. 4. Ultrasonography Normal Reveals opacity in the vitreous cavity

20. THANK YOU Dr. V.Mukesh Krishna