Cataracts
Cataracts - Summary
A cataract is an opacity (cloudy area) within the lens of the eye; it may affect one or both. Most cataracts occur in adults and are age-related. Other causes include a family history of cataracts, diabetes mellitus, and corticosteroid use (topical, oral and inhaled).
The progression of age-related cataracts is variable and unpredictable. Untreated, most people with a cataract will become severely visually impaired. With surgery, 95% of people will have 6/12 best corrected vision (measured on a Snellen chart) if there is nothing else wrong with the eye.
Untreated cataracts in young children (younger than 10 years of age) cause deprivation amblyopia, leading to lifelong visual impairment even if the cataracts are removed later.
The symptoms of a cataract vary depending on its location, size, and whether the cataracts are unilateral or bilateral.
Symptoms include gradual and painless onset of:
Difficulty reading, recognizing faces, and watching television.
Difficulty seeing in bright light.
Reduction in colour intensity and contrast.
Difficulty driving at night or in the daytime.
Frequent changes of spectacles (refractive change).
Double vision in one eye (monocular diplopia).
Being able to read without glasses (cataract increases the converging power of the lens and makes the person short sighted — myopic).
Reduced need for distance spectacles — long-sighted eyes may become focused in the distance as a result of myopia.
On examination with an ophthalmoscope, an opacity can be seen in the lens (this can range from a small dot to complete opacification). In addition, the person may have:
A reduction in visual acuity.
Reduced red reflex on ophthalmoscopy.
A brown or white eye lens (if a bright light is shone onto the surface of the eye).
Cataracts are best diagnosed using a slit lamp with a dilated pupil.
The person should be encouraged to have an eye examination by an optometrist to:
Assess visual acuity for distance vision, near vision (with and without corrective contact lenses and glasses), and the refractive power of the eyes.
Exclude other causes of visual impairment.
Referral for cataract surgery should be considered when the person has:
Visual impairment affecting their lifestyle and they want to undergo cataract surgery. There is no set level of vision for which an operation is essential.
A comorbidity that might benefit from surgery (e.g. an elderly person at risk of a fall).
Another ocular condition, where cataract surgery would help facilitate treatment and/or monitoring.
Urgent referral to an ophthalmologist should be arranged for any child or infant with a suspected cataract for confirmation of the diagnosis and early treatment.
Have I got the right topic?
This CKS topic covers the recognition and management of cataracts in adults and children in primary care.
This CKS topic does not cover the management of cataracts in secondary care.
There are separate CKS topics in the clinical speciality on Eyes.
The target audience for this CKS topic is healthcare professionals working within the NHS in the UK, and providing first contact or primary health care.
How up-to-date is this topic?
How up-to-date is this topic?
Changes
January 2011 — Minor update. The Royal College of Ophthalmologists (RCO) 2004 guidelines on cataract surgery have been superceded by the 2010 guideline, although the recommendations that relate to this CKS topic are the same in both publications. Issued in February 2011.
May to September 2010 — this is a new CKS topic. The evidence-base has been reviewed in detail, and recommendations are clearly justified and transparently linked to the supporting evidence.
Update
New evidence
Evidence-based guidelines
No new evidence-based guidelines since 1 June 2010.
HTAs (Health Technology Assessments)
No new HTAs since 1 June 2010.
Economic appraisals
No new economic appraisals relevant to England since 1 June 2010.
Systematic reviews and meta-analyses
Systematic reviews published since the last revision of this topic:
Mathew, M.C., Ervin, A., Tao, J., and Davis, R.M. (2012) Antioxidant vitamin supplement for preventing and slowing the progression of age-related cataract (Cochrane Review). The Cochrane Library. Issue 6. John Wiley & Sons, Ltd. www.thecochranelibrary.com [Free Full-text]
Primary evidence
No new randomized controlled trials published in the major journals since 1 June 2010.
Observational studies published since the last revision of this topic:
Machan, C.M., Hrynchak, P.K., and Irving, E.L. (2012) Age-related cataract is associated with type 2 diabetes and statin use. Optometry and Vision Science 89(8), 1165-1171. [Abstract]
New policies
No new national policies or guidelines since 1 June 2010.
New safety alerts
No new safety alerts since 1 June 2010.
Changes in product availability
No changes in product availability since 1 June 2010.
Goals and outcome measures
Goals
To support primary healthcare professionals:
To identify cataracts
To appropriately refer the person with a cataract to an ophthalmologist for surgery
Background information
Definition
What is it?
Cataracts are the most common cause of blindness in the world, accounting for 47.9% of blindness worldwide [WHO, 2007].
A cataract is an opacity (cloudy area) within the lens of the eye; it may affect one or both eyes [Khaw et al, 2004]. Most cataracts occur in adults and are age-related [Robinson et al, 1997].
The opacity changes the transparency and refractive index of the lens. This results in the person's vision becoming blurred or cloudy, or in the person experiencing problems with glare from the sun or other bright lights [University of Leeds and NHS CRD, 1996; American Academy of Ophthalmology, 2006].
Cataracts are classified according to the part of the lens that is affected [Allen and Vasavada, 2006; American Academy of Ophthalmology, 2006]:
Nuclear cataracts — cause reduced contrast and colour intensity; the person has difficulty recognizing faces or car number plates. The person often retains good reading vision for many years.
Cortical cataracts — cause problems with glare when driving and difficulty reading; the person finds that sunlight is uncomfortable in winter (due to low sun on the horizon).
Subcapsular cataracts — cause difficulty in daytime driving and difficulty reading, and are visually disabling in good lighting.
Cataracts that occur in children may be classified according to the age of the child at onset [Johnson et al, 2003]:
Congenital (present at birth or shortly afterwards).
Infantile or juvenile (diagnosed in older babies or children).
Causes/risk factors
What are the causes or risk factors?
Adults
What causes cataracts in adults?
The most common cause of cataracts in adults is a gradual accumulation of yellow–brown pigment in the lens of the eye as a result of aging [Allen and Vasavada, 2006].
In addition to ageing, several factors are associated with the development of cataracts [West and Valmadrid, 1995; Johnson et al, 2003;Royal College of Ophthalmologists, 2010; American Academy of Ophthalmology, 2006]:
Family history — may account for the development of up to 50% of cortical cataracts.
Diabetes mellitus — cataract development is related to the duration of diabetes and degree of diabetic control.
Corticosteroids (topical, oral, and inhaled) — systemic adverse effects, such as cataracts, occur more frequently in people using high-dose (more than 15 mg prednisone or equivalent per day) or long-term (for more than 1 year) corticosteroids, or following heavy and protracted use of corticosteroid eye drops.
For more information on adverse effects of corticosteroids, see the CKS topics on Corticosteroids - inhaled, Corticosteroids - oral, and Corticosteroids - topical (skin), nose, and eyes.
Tobacco smoking — there is a dose-dependent association between smoking and the incidence and progression of nuclear cataracts.
High alcohol intake.
Exposure to ultraviolet B light.
Female gender — women are at slightly higher risk than men of cataract development.
Uveitis (intraocular inflammation) — may be asymptomatic as in Fuch's heterochromic cyclitis.
Certain inherited ocular disorders such as retinitis pigmentosa.
Ocular surgery — particularly glaucoma surgery.
Ocular trauma — direct penetration and contusion.
Irradiation.
Extreme shortsightedness (for example high myopia).
Statins — a recently published observational study has suggested that there is an increased risk of cataracts in people who are taking statins [Hippisley-Cox and Coupland, 2010].
In the developing world malnutrition, acute dehydration, and exposure to excessive ultraviolet rays are important risk factors for developing cataracts [Allen and Vasavada, 2006].
Children
What causes cataracts in children?
Congenital cataracts
Unilateral cataract — the cause is often unknown.
Bilateral cataracts — a cause is identified in 50% of children. Causes include:
A family history of congenital cataracts.
Intrauterine infections, such as rubella, varicella, cytomegalovirus, herpes simplex, and toxoplasmosis.
Genetic syndromes, such as Down's syndrome (trisomy 21) or Lowe's syndrome.
Congenital ocular malformation syndromes, such as Peter's syndrome or aniridia.
Infantile or juvenile (acquired) cataract
Causes or risk factors include:
Metabolic conditions such as galactosaemia or diabetes.
Eye infection with Toxocara canis.
Trauma (for example eye surgery or contusion).
Long-term corticosteroid use (topical, inhaled or oral) — children are more prone than adults to developing corticosteroid-induced cataract. The exact time taken for a cataract to develop is not known. For more information on the adverse effects of corticosteroids, see the CKS topics on Corticosteroids - inhaled, Corticosteroids - oral, and Corticosteroids - topical (skin), nose, and eyes.
[Johnson et al, 2003; Mukherjee, 2005; Guercio and Martyn, 2007]
Prevalence
How common is it?
Adults
In England and Wales, it is estimated that 2.4 million people 65 years of age and older have a visually impairing cataract in one or both eyes [Royal College of Ophthalmologists, 2010].
Cataract surgery is the most common elective surgical procedure in the UK. In England alone, there were 329,447 cataract operations between 2008 and 2009 [Hospital Episode Statistics, 2009].
A UK study which randomly sampled 1547 people 65 years of age and older for visually impairing cataract in one or both eyes found visually impairing cataracts in 30% of people older than 65 years of age (a further 10% had cataract surgery in one or both eyes) [Reidy et al, 1998]. The prevalence of cataract increased with increasing age. Visually impairing cataracts were found in:
16% of people 65–69 years of age.
24% of people 70–74 years of age.
42% of people 75–79 years of age.
59% of people 80–84 years of age.
71% of people older than 85 years of age.
Children
Cataracts in children are much less common. An observational study in the UK found that [Rahi et al, 2001]:
About 3 out of every 10,000 children born each year were diagnosed with having a cataract by their first birthday (two-thirds had bilateral cataracts).
This increased to 4 out of every 10,000 children by 15 years of age.
Prognosis
What is the prognosis?
Adults
Age-related cataracts are progressive, and the progression is variable and unpredictable.
If cataracts are left untreated, most people with a cataract will become severely visually impaired [University of Leeds and NHS CRD, 1996; American Academy of Ophthalmology, 2006].
With surgery, 95% of people will have 6/12 best corrected vision (measured on a Snellen chart) if there is nothing else wrong with the eye [Jaycock et al, 2009]. This meets the driving requirements in the UK.
Children
Untreated cataracts in young children (younger than 10 years of age) cause deprivation amblyopia, leading to lifelong visual impairment even if the cataracts are removed later [Khaw et al, 2004; Lloyd et al, 2007].
The outcome of treatment is difficult to predict. CKS found no relevant observational studies which assessed the outcome of treatments in children with cataracts. However, it is thought that [Childhood Cataract Network, 2008]:
Most children with a unilateral cataract have normal vision in the eye without the cataract, poor vision in the affected eye, and as adults are able to hold a Group 1 driving licence in the UK.
Most children who have treatment for bilateral cataracts achieve only partial sight.
Diagnosis
Diagnosis of cataracts
Diagnosis - adult
How do I diagnose a cataract in an adult?
The symptoms of a cataract vary depending on its location, size, and whether the cataracts are unilateral or bilateral. Symptoms include gradual and painless onset of:
Difficulty reading — as the cataract becomes more dense reading becomes difficult.
Difficulty recognizing faces.
Difficulty watching television.
Difficulty seeing in bright light — problems with glare from the sun or other bright lights.
Reduction in colour intensity.
Gradual reduction in contrast.
Difficulty driving at night or in the daytime.
Frequent changes of spectacles (refractive change).
Double vision in one eye (monocular diplopia).
Being able to read without glasses (cataract increases the converging power of the lens and makes the person short sighted — myopic).
Reduced need for distance spectacles — long-sighted eyes may become focused in the distance as a result of myopia.
On examination with an ophthalmoscope, an opacity can be seen in the lens (this can range from a small dot to complete opacification). In addition, the person may have:
A reduction in visual acuity.
Reduced red reflex on ophthalmoscopy — small cataracts stand out as dark defects in the red reflex. A large cataract may obliterate the red reflex.
A brown or white eye lens (if a bright light is shone onto the surface of the eye).
Cataracts are best diagnosed using a slit lamp with a dilated pupil.
Basis for recommendation
Basis for recommendation
The information on how to diagnose a cataract is based on expert opinion from a review article [Allen and Vasavada, 2006] and textbooks [Khaw et al, 2004; Colby, 2008].
Diagnosis - child
How do I diagnose a cataract in a child?
In the UK, all babies are screened for congenital cataracts at birth (as part of the physical examination of newborn babies) and again when they are 6–8 weeks of age.
Symptoms of cataracts in children vary depending on the location of the cataract, the degree of opacification, whether the cataracts are unilateral or bilateral, and the age of the child at onset.
Infants may present with:
A white or grey pupil (seen by the naked eye — these cataracts are usually at the front of the lens).
Involuntary eye movements (nystagmus).
Squint (strabismus).
Poor vision — parents may suspect their child does not have good vision because the child may not notice them or does not follow objects with its eyes.
Older children may also present with:
A white or grey pupil (seen by the naked eye — these cataracts are usually at the front of the lens).
Involuntary eye movements dating back to the first 3 months of life.
Squint.
Diminished vision.
Other features which may be present include:
Sensitivity to light or problems with glare (the child may close the affected eye to ward off the glare).
On examination with an ophthalmoscope, an opacity can be seen in the lens (this can range from a small dot to complete opacification). In addition, the child may have:
A reduction in visual acuity.
Reduced red reflex on ophthalmoscopy — small cataracts stand out as dark defects in the red reflex. A large cataract may obliterate the red reflex.
A brown or white eye lens (if a bright light is shone onto the surface of the eye).
Basis for recommendation
Basis for recommendation
This information is based on expert opinion in textbooks [Khaw et al, 2004; Mukherjee, 2005].
Differential diagnosis
What else might it be?
Other conditions that may cause painless visual disturbance include:
Refractive error.
Some types of corneal disease (for example Fuch's endothelial dystrophy).
Presbyopia.
Age-related macular degeneration (for more information, see the section on Diagnosis in the CKS topic on Macular degeneration - age-related).
Primary open-angle glaucoma (central visual field loss occurs late in the course of the disease).
Chemicals or medication (for example methanol, chloroquine, hydroxychloroquine, isoniazid, thioridazine, isotretinoin, tetracycline, or ethambutol).
Pituitary tumour and papilloedema (particularly if chronic, such as in idiopathic intracranial hypertension).
Diabetic lens — undiagnosed or uncontrolled diabetes can cause vision changes.
Retinoblastoma — nearly always affects children younger than 5 years of age. The pupil may look white (loss of red reflex), the eye may be red and inflamed (usually painless), and vision may be impaired.
Chronic uveitis.
Diabetic retinopathy.
Diabetic maculopathy — type 2 diabetes may present with chronic visual loss from maculopathy.
The following conditions may cause more rapid visual loss:
Cerebrovascular disease, including amaurosis fugax, transient ischaemic attack, and cerebrovascular accident.
For more information, see the CKS topic on Stroke and TIA.
Posterior vitreous detachment, vitreous haemorrhage, or retinal detachment (usually present with floaters or flashing lights).
For more information, see the CKS topic on Retinal detachment.
Central or branch retinal vein thromboses.
Retinal artery occlusions.
Basis for recommendation
Basis for recommendation
The list and descriptions of differential diagnoses which cause painless visual disturbances are based on expert opinion from a textbook [Khaw et al, 2004] and have been extrapolated from guidelines for the management of age-related macular degeneration from the Royal College of Ophthalmologists [Royal College of Ophthalmologists, 2009].
Management
Management
Scenario : Adults: covers the primary care management of adults with a cataract, in particular when to refer to an ophthalmologist for surgery.
Scenario : Children: covers the primary care management of children with cataracts.
Scenario : Adults
Scenario : Management of cataracts in adults
Management and referral
How should I manage someone with a suspected cataract?
Encourage the person to have an eye examination by an optometrist to:
Assess visual acuity for distance vision, near vision (with and without corrective contact lenses and glasses), and the refractive power of the eyes.
Exclude other causes of visual impairment.
Consider referral for cataract surgery when the person has:
Visual impairment caused by the cataract, and the cataract is affecting the person's lifestyle (for example driving, reading), and the person wants to undergo cataract surgery.
There is no set level of vision for which an operation is essential.
A comorbidity that might benefit from surgery (for example an elderly person at risk of a fall).
Another ocular condition, where cataract surgery would help facilitate treatment and/or monitoring (for example a diabetic person whose photographic screening is compromised by the presence of a cataract).
If referral for surgery is being considered:
Consider whether the patient has the capacity to co-operate with eye examinations, surgery, and postoperative eye drop treatment.
Frail patients with mental health problems such as dementia may be unfit for general anaesthesia and unable to lie still for surgery under local anaesthetic.
Discuss the risks and benefits of surgery.
Give advice on what to expect before, during, and after surgery.
This is discussed in a patient information leaflet Understanding cataracts (pdf) produced by the Royal College of Ophthalmologists.
If the person does not understand the issues relating to their specific case, offer referral to an ophthalmologist to discuss the risks and benefits of surgery as well as the risks relating to their particular cataract and any comorbidity they may have.
Referral for cataract surgery is not always necessary.
It is not usually necessary to refer people who do not want to undergo surgery, or who do not fit the referral criteria (when it is certain that any visual loss is secondary to cataract alone).
If referral is appropriate, include the person's most recent visual acuity (measured on a Snellen chart) or a copy of the most recent optometrist's eyesight test with the referral.
If referral is not appropriate, advise the person to attend for an annual eye examination to assess for decreasing visual acuity and worsening symptoms.
Provide advice on fitness to drive to all people with a cataract (when appropriate).
Basis for recommendation
Basis for recommendation
These recommendations are based on expert opinion from the Royal College of Ophthalmologists [Royal College of Ophthalmologists, 2010] and a textbook [Khaw et al, 2004].
Fitness to drive
What advice can I provide regarding fitness to drive for someone with cataracts?
Detailed guidance on fitness to drive can be found in the 'At a glance' guide on the Driver and Vehicle Licensing Agency (DVLA) website at www.dvla.gov.uk. In brief:
Advise the person not to drive and to contact the DVLA if either of the following apply:
In relation to Group 1 entitlement (to drive a car or motorcycle), the person cannot read a modern vehicle number plate in good light, using corrective lenses if necessary, at a distance of 20 metres. This is approximately equivalent to a visual acuity of 6/10 measured on a Snellen chart, but may be affected by the presence of nystagmus or problems coping with glare.
In relation to Group 2 entitlement (to drive a larger vehicle), the person's visual acuity using corrective lenses (if necessary) is worse than 6/9 (measured on a Snellen chart) in the better eye or worse than 6/12 in the other eye, or their uncorrected acuity in either eye is worse than 3/60. This applies to new applicants; there are slightly different rules for longstanding licence holders — see the DVLA website for further clarification.
If there is any uncertainty about fitness to drive, advise the person to contact the DVLA or seek clarification from their eye specialist.
Document any advice that has been given.
Basis for recommendation
Basis for recommendation
These recommendations are mainly derived from the Driver and Vehicle Licensing Agency (DVLA) publication For medical practitioners: at a glance guide to the current medical standards of fitness to drive [DVLA, 2010].
The information that being able to read a vehicle number plate at a distance of 20 metres (for Group 1 entitlement) corresponds approximately to a visual acuity of 6/10 on a Snellen chart (but may be affected by the presence of nystagmus or problems coping with glare) is based on personal communication from a medical adviser at the DVLA [Rees, Personal Communication, 2009].
The recommendation to advise the person, if there is any uncertainty about their fitness to drive, to contact the DVLA or seek clarification from their eye specialist is not based on any published guidance, but is considered by CKS to be good clinical practice.
Cataract surgery (adults)
What are the risks and benefits of cataract surgery in adults?
Benefits
Improved visual acuity.
85–90% of people will have 6/12 best corrected vision (measured on a Snellen chart). This meets the driving requirements in the UK.
However, reading glasses are usually needed after cataract surgery, and some people may require glasses for distance vision who did not previously require them.
Improved clarity of vision.
Improved colour vision.
Risks
Serious complications of cataract surgery are rare.
The most common complication is:
Posterior capsular opacification — the back part of the lens capsule becomes cloudy causing blurred vision (may come on gradually after months or years). Posterior capsular opacification is a healing response and is considered to be a possible consequence of cataract surgery rather than a complication of the surgery itself. It can be corrected by laser treatment (an outpatient clinic procedure which normally takes only a few minutes to complete).
Other complications include:
Bruising of the eye or eyelids after surgery (quite common and usually resolves without problems).
Post-operative raised intraocular pressure for the first day or so (common) which may require temporary treatment (rare with modern surgical techniques).
Posterior capsule rupture and/or vitreous loss — a split in the thin back wall of the cataract which may allow communication between the anterior and posterior chambers of the eye.
Cystoid macular oedema — inflammatory fluid in the centre of the retina. This is usually mild and requires no treatment, but may be severe and require prolonged treatment.
Refractive surprise — unexpectedly large (or different from expected) need for glasses.
Dropped nucleus — part or all of the cataract falls through a posterior capsule rupture into the posterior segment of the eye. An operation is usually required to remove it.
Suprachoroidal haemorrhage (very rare) — bleeding inside the eye which may require the operation to be completed on another day (may lead to loss of the eye).
Corneal decompensation — due to corneal oedema (now rare with modern techniques).
Detached retina — may occur weeks or months after surgery. More likely to occur if vitreous loss has occurred, or in eyes with severe shortsightedness (may lead to loss of the eye). There is an increased risk with posterior capsule rupture.
Infective endophthalmitis — severe and usually painful infection inside the eye (occurs in about 1 in 1000 operations). This may lead to loss of sight or loss of the eye.
Dislocation of the implant lens.
Basis for recommendation
Basis for recommendation
This information is based on published expert opinion from the Royal College of Ophthalmologists [Royal College of Ophthalmologists, 2010] and a textbook [Khaw et al, 2004].
Scenario : Children
Scenario : Management of cataracts in children
Management (referral)
How should I manage an infant or child that has a suspected cataract?
Urgently refer any child or infant with a suspected cataract to an ophthalmologist for confirmation of the diagnosis and early treatment.
Basis for recommendation
Basis for recommendation
This recommendation is from textbooks [Khaw et al, 2004; Mukherjee, 2005].
Cataracts in children are much more serious than in adults. Early diagnosis and treatment are essential because vision development may be irreversibly impaired even if the cataracts are removed later [Khaw et al, 2004].
Evidence
Evidence
Supporting evidence
The diagnosis and management (including referral) of people with cataract in primary care is based on expert opinion.
The evidence on surgical interventions for cataract has not been reviewed, as these procedures are not undertaken in primary care.
Search strategy
Scope of search
A literature search was conducted for guidelines, systematic reviews and randomized controlled trials on primary care management of cataracts.
Search dates
Dates not restricted – June 2010
Key search terms
Various combinations of searches were carried out. The terms listed below are the core search terms that were used for Medline and these were adapted for other databases. Further details are available on request.
cataract/, cataract.tw, exp cataract extraction
Table 1. Key to search terms.| Search commands | Explanation |
|---|---|
| / | indicates a MeSh subject heading with all subheadings selected |
| .tw | indicates a search for a term in the title or abstract |
| exp | indicates that the MeSH subject heading was exploded to include the narrower, more specific terms beneath it in the MeSH tree |
| $ | indicates that the search term was truncated (e.g. wart$ searches for wart and warts) |
Sources of guidelines
National Institute for Health and Clinical Excellence (NICE)
Scottish Intercollegiate Guidelines Network (SIGN)
National Guidelines Clearinghouse
British Columbia Medical Association
Institute for Clinical Systems Improvement
Guidelines International Network
National Library of Guidelines
National Health and Medical Research Council (Australia)
University of Michigan Medical School
Michigan Quality Improvement Consortium
Royal Australian College of General Practitioners
National Resource for Infection Control
NHS Scotland National Patient Pathways
Agency for Healthcare Research and Quality
UK Ambulance Service Clinical Practice Guidelines
RefHELP NHS Lothian Referral Guidelines
Medline (with guideline filter)
Driver and Vehicle Licensing Agency
NHS Plus (occupational health practice)
Sources of systematic reviews and meta-analyses
Systematic reviews
Protocols
Database of Abstracts of Reviews of Effects
Medline (with systematic review filter)
EMBASE (with systematic review filter)
Sources of health technology assessments and economic appraisals
NIHR Health Technology Assessment programme
NHS Economic Evaluations
Health Technology Assessments
Canadian Agency for Drugs and Technologies in Health
International Network of Agencies for Health Technology Assessment
Sources of randomized controlled trials
Central Register of Controlled Trials
Medline (with randomized controlled trial filter)
EMBASE (with randomized controlled trial filter)
Sources of evidence based reviews and evidence summaries
DynaMed
Central Services Agency COMPASS Therapeutic Notes
Sources of national policy
Health Management Information Consortium (HMIC)
Sources of medicines information
The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.
British National Formulary (BNF)
electronic Medicines Compendium (eMC)
European Medicines Agency (EMEA)
References
Allen, D. and Vasavada, A. (2006) Cataract and surgery for cataract. BMJ 333(7559), 128-132. [Free Full-text]
American Academy of Ophthalmology (2006) Preferred practice pattern: cataract in the adult eye. ..American Academy of Ophthalmology.http://one.aao.org [Free Full-text]
Childhood Cataract Network (2008) Beginners guide. Childhood Cataract Network...www.childhoodcataracts.org.uk [Free Full-text]
Colby, K. (2008) Cataract. Merck Manual Online...www.merck.com [Free Full-text]
DVLA (2010) At a glance guide to the current medical standards of fitness to drive (August update). ..Driver and Vehicle Licensing Agency.www.dvla.gov.uk [Free Full-text]
Guercio, J.R. and Martyn, L.J. (2007) Congenital malformations of the eye and orbit. Otolaryngologic Clinics of North America 40(1), 113-140. [Abstract]
Hippisley-Cox, J. and Coupland, C. (2010) Unintended effects of statins in men and women in England and Wales: population based cohort study using the QResearch database. BMJ 340, c2197. [Abstract] [Free Full-text]
Hospital Episode Statistics (2009) Hospital Episode Statistics: main procedures and interventions: 3 character 2008-09. ..Department of Health.www.hesonline.nhs.uk
Jaycock, P., Johnston, R.L., Taylor, H. et al. (2009) The Cataract National Dataset electronic multi-centre audit of 55, 567 operations: updating benchmark standards of care in the United Kingdom and internationally. Eye 23(1), 38-49. [Abstract]
Johnson, G, J., Minassian, D.C., Weale, R.A. and West, S.K. (Eds.) (2003) The epidemiology of eye disease. 2nd edn. London: Hodder Arnold.
Khaw, P.T., Shah, P. and Elkington, A.R. (Eds.) (2004) ABC of eyes. 4th edn. London: BMJ Books.
Lloyd, I.C., Ashworth, J., Biswas, S. and Abadi, R.V. (2007) Advances in the management of congenital and infantile cataract. Eye 21(10), 1301-1309. [Abstract]
Mukherjee, P.K. (2005) Pediatric ophthalmology. India: New Age Publications.
Rahi, J.S., Dezateux, C. and British Congenital Cataract Interest Group (2001) Measuring and interpreting the incidence of congenital ocular anomalies: lessons from a national study of congenital cataract in the UK. Investigative Ophthalmology & Visual Science 42(7), 1444-1448. [Abstract] [Free Full-text]
Rees, G.B. (2009) Personal communication. Medical Adviser, Drivers Medical Group, DVLA: Swansea.
Reidy, A., Minassian, D.C., Vafidis, G. et al. (1998) Prevalence of serious eye disease and visual impairment in a north London population: population based, cross sectional study. BMJ 316(7145), 1643-1646. [Abstract] [Free Full-text]
Robinson, B., Acorn, C.J., Millar, C.C. and Lyle, W.M. (1997) The prevalence of selected ocular diseases and conditions. Optometry and Vision Science 74(2), 79-91. [Abstract]
Royal College of Ophthalmologists (2004) Cataract surgery guidelines. ..Royal College of Ophthalmologists.www.rcophth.ac.uk [Free Full-text]
Royal College of Ophthalmologists (2009) Age-related macular degeneration. Guidelines for management. ..Royal College of Ophthalmologists.www.rcophth.ac.uk [Free Full-text]
Royal College of Ophthalmologists (2010) Cataract surgery guidelines 2010. ..Royal College of Ophthalmologists.www.rcophth.ac.uk [Free Full-text]
University of Leeds and NHS CRD (1996) Management of cataract. Effective Health Care Bulletin 2(3), . [Free Full-text]
West, S.K. and Valmadrid, C.T. (1995) Epidemiology of risk factors for age-related cataract. Survey of Ophthalmology 39(4), 323-334. [Abstract]
WHO (2007) Causes of blindness and visual impairment. ..World Health Organization.www.who.int [Free Full-text]