CATARACT AND OTHER DISORDERS OF THE LENS

1. CATARACT AND OTHER DISORDERS OF THE LENS

2. Anatomy of the Lens • The crystalline lens is a transparent biconvex structure. • Has 4 parts: epithelium, capsules, cortex, and nucleus. • Lies within the anterior segment of the eye, behind the pupil and in front of the vitreous. • Attached by the suspensory ligaments called zonules to the ciliary body.

3. Contd. • The epithelium(with cuboidal cells) is limited only to the anterior surface of the lens which is less curved than the posterior surface. • The epithelium acts as progenitors for the development of lens fibre and for the transportation of nutrients into the eye using the Na/K Atpase.

4. Contd... • The Lens capsule is elastic and made up of collagen. • This is useful in accommodation. • The lens has no nerves, blood vessels and connective tissue.

5. Cataract • Cataract is opacification of the crystalline lens.

6. CLASSIFICATION OF CATARACT A. Congenital and Acquired B. Morphology C. Maturity D. Associated with systemic disorders

7. Congenital Cataract • Cataractacentralispulverulenta : within lens nucleus • Nuclear cataract: within anterior and post Y sutures • Lamellar cataract: b/w clear nucleus and cortex. • Sutural cataract • Polar cataract • Membranous cataract: lenticular material is partially or completely reabsorbed leaving a chalky white lens b/w the capsules.

8. Acquired • Age related: • Subcapsular: anterior, posterior • Nuclear • Cortical • Christmas tree

9. Traumatic • Commonest cause of unilateral • Causes: • Penetrating Injury • Blunt Injury(concussion) • Electric shock • Lightning • Ionizing radiation to ocular tumors.

10. Toxic cataract • Steroids (systemic and topical) • Chlorpromazine • Miotics • Busulphan (CMLeukaemia) • Amiodarone(cardiac arrythmia) • Gold (rheumatoid arthritis)

11. Secondary Cataracts • Due to other ocular diseases. • Causes: • Chronic anterior uveitis: most common cause of secondary cataract. • Acute Congestive angle closure glaucoma. • High myopia • Hereditary fundus dystrophies eg retinitis pigmentosa, Stickler syndrome.

12. Cataract Maturity • Immature • Mature • Hypermature • Morgagnian

13. Morphology • Nuclear • Cortical • Subcapsular

14. Associated with systemic disorders • Diabetes Mellitus • Myotonic dystrophy • Atopic dermatitis • Neurofibromatosis 2

15. Clinical Features • Painless progressive loss of vision • Glare • Diplopia • Myopic shift with better near vision • Features of other causes such as trauma etc

16. Examination/Investigation • Visual acuity • Light projection • Pupillary reflex • Colour discrimination • Slit lamp examination • Fundoscopy • Intraocular pressure • Ocular ultrasound • Biometry: A-scan, keratometry

17. Treatment • Medical: • Dilating drops for immature cataract • Refraction • Surgical • ICCE • ECCE • SICS • Phacoemulsification

18. Post-Op Treatment • Topical Antibiotics(prophylaxis) • Topical Anti inflammatory • Further Management • Refraction 6-8 weeks post op. for spectacles

19. Post op complications • Infection : endophthalmitis • Rupture of posterior capsule • IOL displacement • Posterior loss of lens fragments • Posterior capsule opacification

20. Other Lens Disorders • Ectopialentis : Displacement of the lens from its normal position. • May be luxated or subluxated. • Hereditary or acquired

21. Acquired • Trauma • Large eyes: Buphthalmos, High myopia • Anterior uvealtumors • Hypermature cataract

22. Hereditary • Marfans syndrome: • connective tissue disorder AD. Fibrillin gene. Chromosome15q. • Skeletal anomalies: long limbs, long spindly fingers,pectusexcavatum, high arched palate etc. • Muscular underdevelopment: hernia • Cardiovascular anomalies: aortic: dilatation, aneurysm, regurgitation; mitra; valve prolapse.

23. Contd.. • Bilateral symmetrical non progressive and upward dislocation of the lens in 80% of cases. • Microspherophakia. • Intact accommodation. • Others: • Angle anomaly, RD, Flat cornea, blue sclera, axial myopia, hypoplasia of dilator pupillae.

24. Contd... • Weill – Marchessani syndrome • Bilateral and downward displacement in 50% of cases • Microsperophakia • Angle anomaly • High myopia • Retinal detachment.

25. Contd. • Homocystinuria: • Downward displacement usually by age 10 years. • Glaucoma(pupil block) • Hyperlysinaemia:microspherophakia and occasionally subluxation. • Sulphite oxidase deficiency: ectopialentis,progressive muscular rigidity, death b4 5years of age.

26. Contd. • Sticklers syndrome • Ehlers Danlos syndrome • Familial Ectopialentis: May be associatd with a displaced pupil in the opposite direction. • Aniridia: occasionally associated with ectopialentis.

27. Problems • Lenticular Myopia • Astigmatism • Glaucoma • Lens induced uveitis • Cataract

28. Management • Spectacle Correction • Surgical removal • Nd: YAG laser zonulysis: to displace the lens out of the visual axis.

29. Other Lens disorders... • Lens coloboma: notching of inferior equator of the lens • Posterior lenticonus : rare and progressive. • Anterior lenticonus: axial projection of central 3-4mm of the lens. • Lentiglobus: very rare, unilateral, generalized hemispherical deformity of the lens. • Microphakia: smaller than normal diameter. • Microspherophakia: small diameter and spherical shape.