Update on cataracts

Cataracts are a clouding or opacification of the lens inside the eye.  They are generally a result of ageing and long-term exposure to ultraviolet light.  Cataracts may also be caused by trauma to the eye and in rare cases they can be present at birth.  Note that cataracts simply represent a change in or alteration to the lens material – they are not a growth.  Cataracts are very common in people over the age of 65 and a family history of cataracts can increase the likelihood of developing the condition.  Over time cataracts will generally get worse, with increased opacification of the lens causing the patient’s sight to become worse.  Thankfully, cataracts can be surgically removed when they reduce vision to the point that the patient’s quality of life is starting to be affected.  Cataract surgery is now a relatively minor and straight forward procedure – usually performed on an out-patient basis – and most patients will have an intraocular lens inserted at the time of surgery to replace their own cloudy lens.


What determines when a cataract should be removed?  In the old days, patients were made to wait until the cataracts were advanced – that is, the lens opacification was very marked – such that they then had minimal sight.  These days, cataracts can (thankfully) be removed at a much earlier stage when – as stated above – they are starting to impact on the patient’s quality of life.  There are two main factors (inter alia) I consider when deciding if a person should be referred off for cataract surgery.  First, if they are still driving, is their vision for driving affected to the point that they are now unsafe on the road.  Secondly, are they more at risk of having falls due to the reduced vision associated with their cataracts.  I think this second factor is extremely important.  Over the past few years there have been a number of excellent papers published that all showed a very high correlation between cataracts and falls.  Given that cataracts are more likely to affect the elderly population, and knowing that the consequences of falls amongst this age group can be horrible and often disabling, referral for cataract surgery should be strongly considered at the first sign that cataract is having a visual impact.


There is also another nice upside of cataract surgery.  The point was made earlier that most patients will have an intraocular lens (with a very high optical power) inserted at the time of surgery to replace their own cloudy lens (which normally contributes about one third of the refractive power of the eye).  If a patient has a significant long-standing refractive error prior to the cataract surgery – be it myopia (short-sightedness), hyperopia (long-sightedness) or astigmatism – then a calculation can be done whereby the power of the intraocular lens can be modified such that the patient’s refractive error is totally eliminated post-surgery.