Cataract: a complete guide

A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil, the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.

What Causes Cataracts

As we get older the the protein in our lens, which is normally perfectly arranged to let light pass through and keep the lens clear, may start to clump together and start to cloud in a small area of the lens. This clouded area may grow over time making vision more blurred.

Risk Factors

Age, diabetes mellitus, corticosteroid use, female gender, socio-economic status, ethnicity, smoking and alcohol are all cataract risk factors.


Cataract Types

There are several types of cataracts including nuclear, cortical, posterior subcapsular and mixed. Nuclear cataracts result in progressive opacification of the central lens, typically causing impaired distance vision. Cortical and posterior subcapsular cataracts typically cause disabling glare, even before visual acuity is markedly impaired and can progress rapidly.


Cataract Treatments

Surgery is currently the only effective treatment for cataracts. This surgery involves the replacement of the natural lens being replaced by a clear intraocular lens implant. The benefits of the surgery are lifelong unless negated by other eye disease.

Phacoemulsification (removal of the cataractous lens using ultrasound) is the standard surgical technique and is used in over 99.7% cataract operations in the NHS. Those who do not qualify for NHS treatment can get the treatment done privately in many clinics across the UK.


Cataract Surgery Cost Effectiveness

The evidence suggests cataract surgery is generally highly cost effective, even for those who have mild visual impairments due to cataracts. It is estimated have an incremental cost per quality adjusted life year (QALY) of £13,172 over an individual’s lifetime (assuming an anticipated lifespan of 10 years following surgery). Overall cataract surgery is reported to be comparable to hip replacement in cost effectiveness.


Access To Cataract Surgery

There is currently a wide variation in access to cataract surgery across England due to differences in health commissioning policies. A recent study found 9 in every 10 cataract surgery commissioning policies contained criteria that followed “neither national guidance nor scientific evidence.”

Half of commissioners were found to have restricted access to cataract surgery by using clinical thresholds and 1 in 3 made no allowance for second eye surgery. Accessing quality cataract surgery on the NHS really a postcode lottery at the moment.

Additionally, there is almost a threefold variation in the number of people having cataract surgery across England, with rates ranging from 285 to 804 per 100,000 population which cannot be fully explained by variations in known risk factors for the development of cataract.


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