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Cataract

Last updated: March 12, 2020

Summary

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.

Epidemiology

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

References:[1][2][3][4]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Clouding of the lens may be congenital or acquired.

In industrialized countries, cataract is typically age-related! Other causes are rare!

References:[5][6][7]

Clinical features

General clinical features

Clinical features usually develop gradually and depend on the localization and cause(s) of corneal 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
    • A temporary improvement in near vision
    • Myopia (in nuclear cataract) improves presbyopia
  • 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

Special features in congenital cataract

Congenital cataracts usually present with different symptoms than acquired cataracts.

References:[1][5][6][7]

Diagnostics

  • Primarily a clinical diagnosis

References:[1]

Treatment

  • 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 techniques
    • Extracapsular cataract extraction (ECCE)
      • Method of choice globally
      • Removal of the lens nucleus by anterior capsulotomy (a surgical opening in the anterior capsule) with retention of posterior capsular integrity, and placement of the intra-ocular lens (IOL) in the posterior chamber.
      • Removal of the lens nucleus in ECCE can be performed manually in standard surgical ECCE or by phacoemulsification:

Cataract surgery does not require any anticoagulative measures!

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

References:[1][7][8]

Complications

  • Blindness
  • Complications after cataract surgery are rare

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

References

  1. Ocampo VVD Jr. Senile Cataract. Senile Cataract. New York, NY: WebMD. http://emedicine.medscape.com/article/1210914. Updated: March 1, 2016. Accessed: February 24, 2017.
  2. Eye Health Statistics at a Glance.
  3. Vision Problems in the U.S.: Prevalence of Adult Vision Impairment and Age-Related Eye Disease in America.
  4. Cataracts Defined Tables. https://nei.nih.gov/eyedata/cataract/tables. . Accessed: March 15, 2018.
  5. Agabegi SS, Agabegi ED. Step-Up To Medicine. Wolters Kluwer Health ; 2015
  6. Bashour M. Congenital Cataract. In: Roy H Sr, Congenital Cataract. New York, NY: WebMD. https://emedicine.medscape.com/article/1210837. Updated: March 22, 2016. Accessed: March 15, 2018.
  7. 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
  8. McCreery KM. Cataract in Children. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/cataract-in-children.Last updated: November 13, 2017. Accessed: March 15, 2018.