Dr Babak Babsharif, Ophthalmologist, Subspeciality in Cosmetic Eye Surgeries (Oculoplastics), & Strabismus
Member of American Academy of Ophthalmology (AAO)
Member of European Society of Cataract & Refractive Surgery (ESCRS)
Certificate of Ophthalmology from International Council of Ophthalmology (ICO) Cambridge, UK
Medical Degree 1989
Board of Ophthalmology 1997
Subspeciality Degree 2006
Complementary Education in University of Texas, USA
One study in London found that:
30% of people aged 65 years and over were found to have a visually impairing cataract in one or both eyes.
A further 10% of people in this age group had previous cataract surgery in one or both eyes.
• The prevalence of visually impairing cataracts rose steadily with age: 16% in those aged 65 to 69 years, 24% in those aged 70 to 74 years, 42% in those aged 75 to 79 years, 59% in those aged 80 to 84 years, and 71% in people of 85 years of age or more.
The prevalence of cataracts (after adjusting for age) was higher in women.
Apart from age, cataract risk factors include
Nutrition and socio-economic status
Smoking and alcohol
Metabolic disorders - eg, galactosaemia in children.Genetic studies estimate that the heritability of an age-related cataract could be between 48% and 59%
Three types of age-related cataracts occur
Nuclear sclerosis: this cataract is formed by new layers of fibre (added with ageing) compressing the nucleus of the lens
Cortical: new fibres are added to the outside of the lens, which age and produce cortical spokes. These may not produce symptoms unless on the visual axis or the 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
Paediatric cataracts may be
Congenital: hereditary/genetic, metabolic (eg, galactosaemia), in-utero infection (toxoplasmosis, other, rubella, cytomegalovirus, herpes simplex (TORCH))
Developmental: genetic, metabolic (eg, galactokinase deficiency)
Acquired: metabolic (eg, diabetes mellitus), traumatic, post-radiotherapy
The most common cause of congenital cataract is infection; rubella (the most common), measles, chickenpox, cytomegalovirus, herpes simplex, herpes zoster, poliomyelitis, influenza, Epstein-Barr virus, syphilis and toxoplasmosis. Other causes are metabolic and genetic syndromes
See also the separate article on Examination of the Eye
This depends upon the size and location of the opacity and whether one or both eyes are affected. Serious co-existing eye conditions such as glaucoma, age-related macular degeneration, diabetic retinopathy and amblyopia are often present in patients requiring cataract surgery]
Typical symptoms are
Gradual painless loss of vision
ifficulties 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 when driving at night with oncoming headlights (the scattering of light by the cataract produces haloes and distortion)
Opacities can be seen as defects in the red reflex obtained when the ophthalmoscope is held 60 cm from the eye. This is best seen with a dilated pupil. The 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
The patient can indicate where a light is placed. Pupillary reactions are normal.Differential diagnosis
There is no proven prevention or medical treatment for a cataract. Surgical removal of the cataract remains the only effective treatment available to restore or maintain vision. Cataract surgery in the UK is performed predominantly on elderly patients, with over 90% being 60 years of age or older and just under 60% being 75 years or older
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
This is the most widely used, safest and most effective technique. There is no absolute threshold of visual acuity at which surgery is indicated. It all depends upon the impact of the cataract on the patient's quality of life. There is no longer a need to wait for the cataract to 'ripen' so that contents are liquid and can be easily aspirated
An incision approximately 3 mm in diameter is made in the sclera. A round hole of approximately 5 mm diameter is made in the lens capsule
The hard lens nucleus is liquefied by an ultrasonic probe inserted through the hole, and extracted
Soft lens fibres are aspirated
The replacement lens is placed folded into the now empty capsular bag where it unfolds
The hole heals without sutures
This can be performed on a day-case basis, either with a locally injected anaesthetic or even with anaesthetic eye drops. Postoperative care includes the 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. Multifocal (non-accommodative) intraocular lenses can be implanted during surgery and provide good vision.]
Advise the person not to drive and to contact the DVLA if either of the following apply (includes severe bilateral cataracts, failed bilateral cataract extractions and post cataract surgery where these are affecting the eyesight
Group 1 entitlement (to drive a car or motorcycle): the person is unable to read a modern vehicle number plate in good light, using corrective lenses if necessary, at a distance of 20 metres (approximately equivalent to a visual acuity of 6/10 measured on a Snellen chart)
Group 2 entitlement (to drive a larger vehicle): must have a visual acuity, using corrective lenses if necessary, of at least 6/7.5 (0.8 decimal) in the better eye and at least 6/12 (0.5 decimal) in the other eye. The uncorrected acuity in each eye must be at least 3/60. Where glasses are worn to meet the minimum standards, they should have a corrective power ≤+8 dioptres. It is also necessary for all drivers of Group 2 vehicles to be able to meet the prescribed and relevant Group 1 visual acuity requirements.
In the presence of a cataract, glare may affect the ability to meet the number plate requirement, even with appropriate acuities.
If there is any uncertainty about fitness to drive, advise the person to contact the DVLA or to seek clarification from an eye specialist.
Posterior capsule rupture (the most common - approximately 3%)
Trauma to the iris
Wound gape or prolapse of iris
Anterior chamber haemorrhage
Rupture of the lens capsule with loss of vitreous
Hypopyonthe 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
Posterior capsule opacification - this is a late complication in 20% and is the most common finding. Vision can usually be restored with laser treatment.
Cystoid macular oedema (more frequently diagnosed by angiography)
Open angle glaucoma
Closed angle glaucoma
Bullous keratopathy a rare complication
Increased risk of age-related macular degeneration requiring photodynamic therapy
Thickening of the lens capsule frequently occurs over time, causing gradual deterioration of vision. This is treated by splitting the capsule with a laser
Age-related cataracts are progressive and the progression is variable and unpredictable. Without treatment, most people with a cataract will become severely visually impaired
With surgery, 95% of people will have 6/12 best corrected vision if there is nothing else wrong with the eye
Untreated cataracts in children younger than 10 years of age cause amblyopia, leading to lifelong visual impairment even if the cataracts are later removed
Most children with a unilateral cataract have normal vision in the eye without the cataract. Most children who have treatment for bilateral cataracts achieve only partial sight