Related to this topic: Leaflets | UK Guidelines | Online Videos | News | Weblinks | Equipment | Books | Your Experience | Other resources | Glossaries
Print options: Printer friendly version of this leaflet (html)     Other options:  AddThis Social Bookmark Button (what's this?)

PatientPlus articles are written for doctors and so the language can be technical. However, some people find that they add depth to the articles found in the other sections of this website which are written for non-medical people.

Cataracts and Cataract Surgery

Cataracts are lens opacities that can range in severity from unnoticed dots, to total fogging. Main cause is deterioration of lens with age but congenital cataracts also occur.

Epidemiology

16 million people worldwide have cataracts; it is the commonest cause of reversible loss of useful vision.

Incidence

  • 200,000 cataract removals in the UK per annum.1
  • Congenital cataract occurs 3.18/10,000 population cumulatively over 5 years.2

Prevalence

100% in those aged >80 years, 65% in patients in their 50s.

Risk factors

Aetiology

Three types of age related cataracts occur:

  • Nuclear sclerosis; this cataract is formed by new layers of fibre (added with ageing) compress the lens nucleus.
  • Cortical; new fibres are added to outside of lens, which age and produce cortical spokes. These may not produce symptoms unless on visual axis or entire cortex is affected when it is "mature".
  • Posterior subcapsular; opacities in the central posterior cortex. This may occur in younger patients and may cause glare ± deterioration in near vision.

The most common cause of congenital cataract is infection; rubella (the most common), rubeola, chicken pox, cytomegalovirus, herpes simplex, herpes zoster, poliomyelitis, influenza, Epstein-Barr virus, syphilis, and toxoplasmosis. Other causes are metabolic and genetic syndromes.

Presentation

This depends upon the size and location of the opacity and whether one or both eyes are affected.

Typical symptoms are:

  • Gradual painless loss of vision
  • Difficulties with reading
  • Failure to recognise faces
  • Problems watching TV
  • Diplopia in one eye and haloes (less commonly)


Central cataracts cause deteriorating vision in bright light, as pupil constriction confines the transmission of the image to passing through the cataract. This can be a particular problem driving at night with oncoming headlights (scattering of light by the cataract produces haloes and distortion).
Signs:

  • Opacities can be seen as defects in the red reflex obtained when the ophthalmoscope is held 60cm from the eye. This is best seen with a dilated pupil.
  • Lens may appear brown or white when a bright light is shone on the eye.

Check that:

  • Visual acuity is not improved by viewing test through pinhole.
  • Patient can indicate where a light is placed.
  • Pupillary reactions are normal.
Management

In older patients with undemanding visual needs, it may be enough to recommend the use of a strong reading light placed above and behind the patient.

Phacoemulsification

This is the most widely used, safest and most effective technique. No absolute threshold of visual acuity at which surgery is indicated.3 It all depends upon the impact of the cataract on the patient's quality of life. Now no longer need to wait for cataract to "ripen" so that contents are liquid and can be easily aspirated.

CATARACT (OM875a.jpg)

  • Incision approximately 3mm in diameter is made in the sclera.
  • Round hole of approximately 5mm diameter is made in lens capsule.
  • Hard lens nucleus is liquefied by ultrasonic probe inserted through the hole and extracted.
  • Soft lens fibres are aspirated.
  • Replacement lens is placed folded into the now empty capsular bag where it unfolds.
  • Hole heals without sutures.

This can be performed on day-case basis either with a locally injected anaesthetic or even anaesthetic eye drops. Postoperative care includes use of topical antibiotics and steroids with avoidance of strenuous activity.
A technique now reserved for specific situations is the intracapsular method where the whole lens is extracted in its capsule. In this technique which has been used widely in the past, very thick glasses are required as no intraocular lens is present. These cause significant visual problems including objects being apparently nearer than they really are, loss of visual field and a ring of blindness. Contact lenses are better but can be a problem with the elderly.
The extracapsular method is now outmoded.

Complications4,5

Early complications

  • Posterior capsule rupture ( most common - approximately 3%)
  • Trauma to iris
  • Wound gape or prolapse of iris
  • Anterior chamber haemorrhage
  • Rupture of lens capsule with loss of vitreous
  • Vitreous haemorrhage
  • Choroidal haemorrhage
  • Hypopyon (least common)
  • Postoperative infection (endophthalmitis) occurs in around 0.13% of cases, presenting with red eye and loss of vision. Occasionally, low grade infection presents late with refractory uveitis. This can be avoided by intraoperative antibiotic prophylaxis.6

Late complications

Thickening of the lens capsule frequently occurs over time causing gradual deterioration of vision. This is treated by splitting the capsule with a laser.

Prognosis

95% of patients with otherwise healthy eyes achieve postoperative corrected acuity of 6/12.1 Diabetic retinopathy and diabetes are the major risk factors that affect prognosis.8


Document references
  1. Desai P, Minassian DC, Reidy A; National cataract surgery survey 1997-8: a report of the results of the clinical outcomes. Br J Ophthalmol. 1999 Dec;83(12):1336-40. [abstract]
  2. Rahi JS, Dezateux C; Measuring and interpreting the incidence of congenital ocular anomalies: lessons from a national study of congenital cataract in the UK. Invest Ophthalmol Vis Sci. 2001 Jun;42(7):1444-8. [abstract]
  3. Desai P, Reidy A, Minassian DC; Profile of patients presenting for cataract surgery in the UK: national data collection. Br J Ophthalmol. 1999 Aug;83(8):893-6. [abstract]
  4. Kamalarajah S, Silvestri G, Sharma N, et al; Surveillance of endophthalmitis following cataract surgery in the UK. Eye. 2004 Jun;18(6):580-7. [abstract]
  5. Asbell PA, Dualan I, Mindel J, et al; Age-related cataract. Lancet. 2005 Feb 12-18;365(9459):599-609. [abstract]
  6. Barry P, Seal DV, Gettinby G, et al; ESCRS study of prophylaxis of postoperative endophthalmitis after cataract surgery: Preliminary report of principal results from a European multicenter study. J Cataract Refract Surg. 2006 Mar;32(3):407-10. [abstract]
  7. Kaiserman I, Kaiserman N, Elhayany A, et al; Cataract surgery is associated with a higher rate of photodynamic therapy for age-related macular degeneration. Ophthalmology. 2007 Feb;114(2):278-82. [abstract]
  8. Ocampo VV, Foster CS; Cataract, senile. eMedicine, September 2005.

Internet and further reading
  • Khaw PT, Shah P, Elkington AR. ABC of Eyes, 4th edition.; BMJ Books.
  • Tey A, Grant B, Harbison D, et al; Redesign and modernisation of an NHS cataract service (Fife 1997-2004): multifaceted approach. BMJ. 2007 Jan 20;334(7585):148-52. [abstract]
  • Bashour MB, Menassa J; Cataract, congenital. eMedicine, April 2006.
Acknowledgements EMIS is grateful to Dr Hayley Willacy for writing this article. The final copy has passed scrutiny by the independent Mentor GP reviewing team. ©EMIS 2008.
DocID: 1918
Document Version: 21
DocRef: bgp875
Last Updated: 10 Apr 2007
Review Date: 9 Apr 2009




















Disclaimer: Patient UK has no control of the content of the above links. Inclusion does not imply endorsement by Patient UK.

Advertise on this site














Disclaimer: Patient UK has no control of the content of the above links. Inclusion does not imply endorsement by Patient UK.

Advertise on this site


PS - Health and Poverty

Perhaps the biggest cause of ill health in the world is poverty. Help to Make Poverty History. For example, why not lend some of your money to disadvantaged communities to enable them to trade their way out of poverty through schemes such as Shared Interest.

See also MAKEPOVERTYHISTORY North East for details and links to campaigns against poverty.

^ Top of Page