cataract
CATARACT
Cataract is the presence of opacity in the crystalline lens of the eye. It causes painless, progressive blurring of vision.
It is the leading cause of blindness worldwide and the most prevalent ocular disease.
The initiating events that lead to loss of transparency of both the cortical and nuclear lens tissue is the oxidation of the membrane lipids, structural or enzymatic proteins or DNA by peroxidases or free radicals induced by UV light.

Introduction

  • Cataract is the presence of opacity in the crystalline lens that causes painless, progressive blurring of vision
  • Leading cause of blindness worldwide & the most prevalent ocular disease
  • Mechanism of cataract formation is multifactorial
  • Chronic & age-related

Signs and Symptoms

  • Decreased vision & increased problems w/ glare are the hallmark symptoms
  • Increased nearsightedness called “myopic shift “before opacity of the lens occur
  • Typically bilateral but often asymmetrical

Etiology

  • Initiating events that lead to loss of transparency of both the cortical & nuclear lens tissue is the oxidation of the membrane lipids, structural or enzymatic proteins or DNA by peroxidases or free radicals induced by ultraviolet (UV) light

Risk Factors

  • Increasing age
  • Ultraviolet (UV) radiation - ultraviolet B (UVB) cumulative lifetime exposure
  • Diabetes mellitus, hypertension, high body mass index
  • Drugs (eg long-term topical, systemic or inhaled corticosteroids, Phenothiazine, Chlorpromazine)
  • Smoking
  • Drinking excessive amounts of alcohol
  • Gender - females are most likely to have cataract & progress to blindness
  • Nutrition - low antioxidant levels is associated w/ increased risk of cataract formation
  • Obesity
  • Dehydration/diarrheal crises
  • Genetics in age-related cataract cases (eg cortical cataracts & nuclear cataracts)
  • Prior intraocular surgery
  • Moderate to high myopia
  • Exposure to ionizing radiation (eg chest x-ray, radiation therapy)
Editor's Recommendations
Most Read Articles
Jairia Dela Cruz, 21 Mar 2018
Duration and quality of sleep in infancy exert no effect on the risk of developing refractive error at 3 years, according to a Singapore study.
Tristan Manalac, 12 Apr 2018
The biomechanical response of the optic nerve head (ONH) appears to be related to disease severity in eyes with primary open-angle glaucoma (POAG), but not primary angle-closure glaucoma (PACG), a recent Singapore study has found.
30 Mar 2018
Infectious uveitis appears to be the most common type of uveitis in Indonesia, with toxoplasmosis and tuberculosis emerging as the leading causes, a study reports.