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Cataract

Last updated: June 18, 2021

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Cataract is a condition characterized by clouding of the lens of the eye. This condition most frequently occurs due to age-related degenerative processes in the lens, but can also be associated with ocular trauma, metabolic disorders, side-effects of drugs, or congenital infections. The clouding causes distortion of light, as it passes through the lens, resulting in visual impairment and glare. Initially, a cataract presents discretely and may even go unnoticed, but the visual impairment worsens as the cataract grows larger. Diagnosis is typically established on the basis of a thorough history and direct visualization of the cataract (by means of slit-lamp microscopy). Surgery is indicated with significant visual impairment and involves lens extraction and implantation of an artificial lens. Untreated cataracts eventually lead to complete blindness.

  • Leading cause of visual impairment and blindness in the world
  • Prevalence of acquired cataracts: increases with age
    • > 80 years: ∼70 %
    • 40–80 years: ∼ 17.5 %
  • Sex: >

References:[1][2][3]

Epidemiological data refers to the US, unless otherwise specified.

Clouding of the lens may be congenital or acquired.

References:[4]

  • Cataracts may be classified according to etiology (as above) or morphology
  • Morphological classification .

General clinical features

Clinical features usually develop gradually and depend on the localization and cause(s) of lens clouding.

  • Reduced visual acuity: blurred, clouded, or dim vision, especially at night
  • The impairment of vision is usually painless and often bilateral.
  • Glare: in daylight, in low sunlight, and from car headlights; associated with halos around lights .
  • Second sight
  • Opacities within the red reflex, darkening of the red reflex, or obscuration of ocular fundus detail during opthalmoscopy
  • Grey, white, yellow, or brownish clouding of the lens
  • Monocular diplopia: double vision that disappears when the eye with the pathology is covered or shut
  • Hyperopia (in cortical cataract)
  • Change in color perception
  • Special features in traumatic cataract

Special features in congenital cataract

Congenital cataracts usually present with different symptoms than acquired cataracts.

References:[4]

In most cases conservative treatment and drug therapy for cataract does not exist

  • Indications for surgical treatment
    • To improve vision in cases with significant cataract-related visual disturbances (by far the most frequent indication)
    • Medical indication (e.g., imminent phacolytic glaucoma, or in ocular fundus diseases in order to gain clear insight of the ocular fundus)

Surgical treatment

Overview of surgical techniques
Description Advantages/disadvantages
Phacoemulsification
  • Small incision, sutureless surgery, lower complication rates than ECCE
  • May not be feasible for advanced cataracts, costly surgery

Extracapsular cataract extraction (ECCE)

Intracapsular cataract extraction (ICCE)
  • Involves removal of the entire lens, including the posterior capsule.
  • The IOL can be implanted in the anterior chamber, sutured to the iris, or surgically fixated in the posterior chamber.
Manual small incision cataract surgery (MSICS)
  • Involves the manual removal of the entire lens, followed by division into small pieces, removal from the eye, and placement of a foldable lens through the same small incision.
  • Fewer sutures are used than for ECCE, cost-efficient

Cataract surgery does not require any anticoagulative measures.

Congenital cataracts should be treated surgically as soon as possible to prevent amblyopia (deprivation amblyopia)!

References:[4]

We list the most important complications. The selection is not exhaustive.

  1. Eye Health Statistics at a Glance.
  2. Vision Problems in the U.S.: Prevalence of Adult Vision Impairment and Age-Related Eye Disease in America.
  3. Cataracts Defined Tables. https://nei.nih.gov/eyedata/cataract/tables. . Accessed: March 15, 2018.
  4. Liu Y-C, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017; 390 (10094): p.600-612. doi: 10.1016/s0140-6736(17)30544-5 . | Open in Read by QxMD