Article Sections

Introduction

Cataract refers to the progressive opacification of the crystalline lens of the eye, resulting in impaired vision.  The condition primarily affects older patients and is a leading cause of reversible blindness worldwide.

Pathophysiology

The lens is composed of tightly packed, elongated epithelial cells (lens fibers) containing a high concentration of crystallin proteins, which help maintain its transparency.  It is surrounded by a thin capsule that gives it its shape.  Aging and environmental stressors can disrupt transparency and contribute to cataract formation through the following mechanisms:

  • Because older epithelial cells of the lens do not shed, new layers of epithelia form on top of older layers, compacting them underneath and causing the lens to lose transparency.
  • Photooxidative damage and cross-linking of crystallins cause brown/yellow pigmentary changes in the lens.

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