Eye-health conditions

The 3 most common eye conditions are cataracts, macular degeneration and glaucoma.

Cataracts

Everybody gets cataracts.  The lens inside our eye adds a new layer of tissue to itself year after year in much the same way as a tree adds a new outer layer each season.  When we are born, the lens is crystal clear and really flexible.  With each new layer the lens becomes less flexible and less clear.  By the time you are 60 the lens has lost its flexibility and by the time you hit 120, the lens is opaque.  So if you live to 120 you will definitely be blind due to cataract.  Of course, your vision will be affected by cataract earlier than that and most folk benefit from having cataracts removed somewhere between 75 and 85 years of age.  The purpose of the cataract operation is to replace the cloudy lens with a clear one.

Private cataract surgery costs $3500-$4000 per eye and can be done in Christchurch, Timaru or Dunedin.  In the public system the treatment is free, but your vision has to be poor in both eyes before you qualify for publicly funded surgery.

Glaucoma

The optic nerve is the cable connecting the eyeball to the visual cortex in the brain.  It is approximately the thickness of a 2-minute noodle and yet contains over 1million nerve fibres.  The number of functioning fibres decreases as we get older, and that’s OK because we don’t need all 1 million of them.  However the rate of fibre function loss accelerates in an eye with glaucoma.  The problem is that for most folk who have glaucoma there are no symptoms until more than half of the optic nerve is dead.  By then the damage is done.  The best outcomes are achieved for those who are detected early.  That is why having an eyetest every 2 years is vital.

Normally the treatment for glaucoma is just eyedrops.  The treatment is for life, but putting in eyedrops once a day is a very small price to pay for retaining vision.

Macula degeneration

Unfortunately everything wears out sooner or later, and the retina is no exception.

The retina is the light-sensitive membrane at the back of the eye responsible for delivering vision to the brain.  The macula is the centre, or sweet spot, of the retina.  Folk with macular degeneration (AMD) lose their central vision but retain their peripheral vision.  This means that reading, writing, recognising faces, driving and watching TV can become difficult or impossible.

AMD starts as an accumulation of cell waste deep in the retinal tissue.  Essentially it’s like the rubbish truck has stopped coming to remove the waste to make way for new cells.  This accumulation of cell waste is called drusen.  AMD can progress to a “wet” form where fluid leaks from surrounding blood vessels and causes the macula to become swollen or boggy.

As yet there is no treatment available for getting rid of the drusen.  There is treatment available for the wet type of AMD in the form of eye injections, requiring a trip to an eye specialist.

The best way to postpone the development of AMD is to have a diet high in anti-oxidants (dark green leafy vegetables are especially good) and to exercise regularly.  Oh, and to not smoke.

Anyone with a strong family history of AMD and anyone with AMD should consider taking a dietary supplement aimed at providing the macula with all the nutrients it needs.