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
Elvira Manzano, 6 days ago
Bisphosphonates have proven antifracture efficacy and remain to be the cornerstone of osteoporosis treatment. However, a drug holiday is of particular importance with bisphosphonates due to some signals with long-term use of the drug, including rare incidence of atypical femoral fracture (AFF) and osteonecrosis of the jaw (ONJ), says a leading endocrinologist at AFOS 2017.
Yesterday
Drinking coffee, whether caffeinated or decaffeinated, is associated with a reduced risk of cardiovascular disease (CVD) and ischaemic heart disease (IHD) mortality in patients with a prior myocardial infarction (MI), according to a recent study.
3 days ago
Breast cancer patients have notably different microbiomes in the local breast tissue and urinary tract, a recent study reveals. Particularly, species in the Methylobacterium genus are reduced in the local breast tissue while the urinary tract is enriched in gram-positive bacteria.
Pearl Toh, 13 Oct 2017
Women with higher plasma tryptophan concentrations were less likely to have poor sleep quality during pregnancy, especially among those with anxiety symptoms, according to the GUSTO* study.