Cataract

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Cataract is an opacification of the crystalline lens, leading to progressive visual impairment. It is the leading cause of reversible blindness worldwide.

Aetiology

  • Age-related: the most common cause due to protein denaturation in the lens.
  • Congenital: associated with genetic conditions, intrauterine infections, or metabolic disorders.
  • Traumatic: blunt or penetrating ocular trauma.
  • Metabolic: diabetes mellitus, galactosaemia.
  • Drug-induced: prolonged corticosteroid use.
  • Radiation exposure: UV light or ionising radiation.

Pathophysiology

  • Oxidative stress and protein aggregation lead to lens opacification.
  • Light scattering increases, reducing visual acuity and contrast sensitivity.
  • Disruption of normal lens architecture can lead to refractive changes (myopic shift in nuclear cataracts).

Risk Factors

  • Advancing age.
  • Smoking and alcohol consumption.
  • Diabetes mellitus.
  • Prolonged corticosteroid use.
  • Ocular trauma or surgery.
  • Excessive UV light exposure.
  • Genetic predisposition.

Signs and Symptoms

  • Blurred vision: gradual, painless reduction in visual acuity.
  • Glare sensitivity: difficulty seeing in bright lights or at night.
  • Reduced contrast sensitivity: difficulty distinguishing objects from backgrounds.
  • Myopic shift: increased refractive power in nuclear cataracts.
  • Monocular diplopia: double vision in one eye.
  • Absent or diminished red reflex: seen on fundoscopy.

Investigations

  • Visual acuity testing: Snellen chart to assess visual impairment.
  • Slit-lamp examination: identifies lens opacities and cataract type.
  • Fundoscopy: assesses retinal pathology if the fundus view is clear.
  • Tonometry: rules out associated glaucoma.

Management

1. Conservative Management:

  • Optimisation of vision with spectacles.
  • Increased lighting and use of magnifiers.

2. Surgical Management:

  • Phacoemulsification: standard surgical procedure with intraocular lens implantation.
  • Extracapsular cataract extraction (ECCE): reserved for advanced cataracts.
  • Laser-assisted cataract surgery: newer technique offering enhanced precision.

3. Postoperative Care:

  • Topical antibiotics and anti-inflammatory drops.
  • Activity restrictions to prevent raised intraocular pressure.
  • Regular follow-up for refractive assessment and complications.

4. Referral:

  • Ophthalmology: all visually significant cataracts should be referred for surgical assessment.
  • Endocrinology: if diabetes related cataracts are suspected.
Eye DiseasesmypanotesCataract