Cataracts are the most common cause of curable blindness in the world.
Diagnosis is made by the detection of a decrease in visual acuity that cannot be corrected by refractive correction, and an eye examination that is otherwise normal apart from opacity in the crystalline lens.
Treatment is with surgery involving an incision into the eye and removal of the opacified crystalline lens. In most cases the cataract is replaced by an artificial lens made of polymethyl methacrylate, acrylic, or silicone.
If an implant lens is not used, or there is remaining refractive error (e.g., astigmatism that is uncorrected by the implant lens), the patient may need to wear either a contact lens or spectacles to achieve good post-operative vision. Adjunctive procedures may be done at the time of surgery or afterwards to correct residual refractive error.
Over time, some patients develop an opacification of the posterior capsule behind the implant lens. This condition is treated with the neodymium-doped yttrium aluminium garnet (Nd:YAG) laser, which creates an opening in the opacified membrane to restore vision.
Cataract is the opacification of the crystalline lens that results from the normal ageing process, trauma, metabolic disorders, medications, or congenital problems. This topic mainly addresses acquired cataract.
History and exam
Key diagnostic factors
- presence of risk factors
- subjective decrease in vision
- blurred or cloudy vision
- washed-out colour vision
- reduced visual acuity
- defects in the red reflex
Other diagnostic factors
- inadequate glasses prescription
- disruption in activities of daily living
- age >65 years
- female sex
- long-term UV exposure
- diabetes mellitus
- other metabolic or hereditary conditions
- exposure to ionising radiation
- eye trauma
- long-term corticosteroid use
- family history of congenital cataract or congenital influences (e.g., toxins)
1st investigations to order
- dilated fundus examination
- measurement of intra-ocular pressure
- glare vision test
- slit lamp examination of the anterior chamber
Investigations to consider
- assessment of best visual potential
cataract without concomitant eye pathology
cataract with concomitant eye pathology
post-surgical opacification of the posterior capsule + significant visual impairment
Robert T. Chang, MD
Associate Professor of Ophthalmology
Byers Eye Institute
Stanford University School of Medicine
RTC declares that he has no competing interests.
Dr Robert T. Chang would like to gratefully acknowledge Dr Creig Hoyt, Dr Leela V. Raju, and Dr M. Bowes Hamill, previous contributors to this topic.
CH, LVR, and MBH declare that they have no competing interests.
Michael P. Ehrenhaus, MD
Assistant Professor of Ophthalmology
Cornea External Disease and Refractive Surgery Local Director
Long Island College Hospital Eye Center
MPE declares that he has no competing interests.
Parwez Hossain, PhD, FRC Ophth, FRCS(Ed)
Associate Professor/Consultant in Ophthalmology
University of Southampton
PH declares that he has no competing interests.
Bob Avery, MD, PhD
University of New Mexico Medical School
BA declares that he has no competing interests.
- Refractive error
- Dry eye
- Cataract/anterior segment summary benchmark
- Comprehensive adult medical eye evaluation
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