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
11 days ago
Increased serum levels of C-X-C motif chemokine (CXCL)-11, CXCL-9, CXCL-10 and interferon (IFN)-γ are associated with clinical manifestations of adult-onset Still’s disease (AOSD), reports a new study.
3 days ago
At a recent lunch symposium during the 14th Annual Scientific Meeting of the Malaysian Society of Hypertension, Dr Chow Yok Wai spoke on the importance of patient adherence in the management of hypertension, highlighting the role of combination therapy in improving treatment outcomes.
5 days ago
Myopia is associated with depressive symptoms in Chinese adults, a new population-based study shows.
5 days ago
Chronic obstructive pulmonary disease (COPD) is currently the 10th commonest cause of death in Singapore, with a disease burden of 5.9 percent according to a 2015 population-based survey (EPIC-Asia survey) in Singapore. Pearl Toh spoke with Dr Augustine Tee, chief and senior consultant of the Department of Respiratory and Critical Care Medicine at Changi General Hospital (CGH) in Singapore, on how COPD is often underdetected in the primary care population as symptoms are not specific and diagnosis requires a combination of clinical risk factors, symptoms and spirometry testing.