An opacification in the crystalline lens 

 

• Symptoms:

  • Visual acuity loss

  • Reduced contrast sensitivity 

  • Glare

  • Night driving problems

    • Due to absorption and scatter of light 

 

 

​Age-related cataracts: 

• NUCLEAR

• CORTICAL 

• POSTERIOR SUBCAPSULAR 

  • Can occur individually or in combination

  • When the cataract disturbs the vision i.e. lens opacifies, then removal is considered. 

 

 

 

 

 

 

 

 

 

 

 

 

 

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• As the α-crystallin chaperone function decreases, there is an increase in aggregates

  • These aggregates are of a:

    • High molecular weight 

    • High concentration of water-insoluble proteins 

• Light scattering and loss of transparency also increases

 

• With time, the lens hardens as new layers of fibres are added

  • This causes lens yellowing, which is characteristic of a nuclear sclerosis cataract

 

 

 

 

 

 

 

• New fibres to the cortex can cause lower layers to develop spoke-like opacities

  • Common in patients with cortical cataracts

 

 

 

 

 

 

 

• Posterior subcapsular with a disc-like appearance, occur less commonly 

 

 

 

 

 

 

 

 

• UV exposure can increase the likelihood of cataract

  • In particular, UVB which causes cortical cataract

 

• Congenital cataracts: where there is a genetic linkage due to an autosomal mutation 

 

 

 

• Other risk factors of cataract formation:

  • Trauma

  • Diabetes mellitus

  • Smoking 

  • Drugs - systemic and ocular