Pathology of Cataracts

Cataracts occur due to structural and chemical changes in the proteins and fibers of
the lens.

• Age-related (Senile): As the lens ages, it increases in mass and thickness but
  decreases in accommodative power. New layers of cortical fibers form
  concentrically, compressing and hardening the central nucleus (a process called nuclear sclerosis).
• Secondary pathology: Metabolic disorders like Diabetes or drugs like Steroids can cause aberrant enlargement of lens cells, leading to opacities in specific areas like the sub-capsular region.

 Causes of Cataracts

Causes are categorized into acquired and congenital factors:

•  Age: The most common cause (Senile cataract).
• Systemic Disease: Primarily Diabetes Mellitus
• Drug-induced: Most notably long-term use of Corticosteroids(systemic,     inhaled, or topical), but also Phenothiazines and Amiodarone.                  Trauma; Physical injury to the eye.
• Inflammation: Secondary to conditions like uveitis.
• Congenital: Maternal infections (TORCH) or metabolic errors like Galactosaemia