Diabetes mellitus a growing problem

Diabetes
mellitus is a growing problem here in the Cayman Islands but accurate
statistics on incidence and prevalence of this disease are not available at
present.

The
Public Health department recently estimated that there are more 2,000 diabetics
in the Islands, with an increasing number of young children affected. 

Diabetes
mellitus is a chronic metabolic disease characterised by lack of control of
blood glucose (sugar) levels, usually because the beta cells of the pancreas
can no longer produce enough insulin for the amount of sugar that is eaten.

Glucose
in the blood spontaneously combines with many of the large blood proteins,
including antibodies and clotting factors, changing their structure and
reducing their effectiveness. So patients with diabetes tend to have blood that
clots more easily, leading to more heart attacks and strokes, and they are
unable to fight infections as readily as someone who is not diabetic.

In
addition, small blood vessels in all parts of the body become damaged over
time. This is particularly evident in the eye, the kidney and in the blood vessels
supplying the nerves. 

Several
randomised controlled trials have shown evidence that good control of blood
sugar over time reduces the rate of complications of diabetes such visual loss
and blindness from diabetes, kidney failure and amputation. 

Control
of blood sugar is normally monitored by measuring the amount of haemoglobin,
the protein that carries oxygen in the red blood cells, which has been
“glycosylated” (glycHb or HbA1C).  This
is usually expressed as a percentage of the total haemoglobin level.

At
a level of 7 per cent and above, the risk of developing complications increases
sharply, so it is best to try to stay below 7 per cent.  Generally this test should be performed at
least twice a year, more often if the glycHb level is greater than 7 per cent.
This will help your physician to determine the next step in treatment.

Diabetes
can affect the eye in many different ways. For example, newly diagnosed
diabetics can often recall how their vision seemed to fluctuate throughout the
day for months before and after they were diagnosed, as the natural lens swells
and shrinks depending upon the rapidly rising or falling blood glucose
level. 

Diabetes
can increase the risk of developing cataracts faster – diabetics develop
cataracts in their natural lens about 10 years younger than people without
diabetes. They tend to have a greater risk of infection after eye surgery and
of developing cystoid macular oedema that can persist, together with a risk of
epi-retinal membrane formation that can distort and reduce central vision in
the eye. 

Diabetes
increases the risk of developing glaucoma and of sudden blood vessel occlusion
such as retinal vein occlusion and retinal artery occlusion, both of which can
cause sudden total loss of vision.

As
time goes on, more and more areas of the retina – the inner lining of the eye –
lose their blood supply, because small blood vessels in the eye accumulate
damage from high blood glucose levels over time. 

These
damaged blood vessels leak, releasing fluid, protein and fat from the blood
stream into the retinal tissue, causing it to swell. This swollen retina cannot
function well. If the central and most sensitive part of the retina, the fovea,
becomes swollen then vision usually drops dramatically and often permanently. 

Diabetic
retinopathy is the most common cause of blindness in young people of working
age. That is why it is imperative that all diabetics attend an annual screening
examination with an ophthalmologist – medical doctors who are trained to detect
leaking blood vessels at an early stage and to treat them with Argon laser if
necessary. 

At
a very advanced stage, it may be necessary to inject directly into the eyeball
drugs, such as triamcinolone or bevacizumab (Avastin), a monoclonal antibody to
vascular endothelial growth factor that has been shown to be highly effective
in some forms of macular oedema.

If
a large enough area of the retina loses its blood supply, then new vessels will
grow into the vitreous gel that fills the eyeball. Occasionally, they can cause
a slowly progressive loss of vision by causing a retinal detachment. 

Eventually
they will bleed into the vitreous, causing immediate loss of vision. Sometimes
the blood will clear slowly on its own or sometimes a retinal surgeon will have
to remove the vitreous gel with the blood. That entails a trip off-island, as
there is no retinal surgeon here in Cayman.

The
bottom line is that diabetes is a disease that will wreak havoc in your life if
it is not controlled, treated and monitored properly. That means it is up you
to take the medication prescribed and to visit your physician regularly for
glycHb (HbA1C) testing and urine testing at least twice a year. 

Be
sure also to visit an ophthalmologist at least once a year for screening,
because early diagnosis and treatment may prevent you losing your sight. 

The
Lions Eye Clinic has recently acquired a state-of-the-art optical coherence
tomography machine from Topcon that makes early detection of diabetic
retinopathy and macular oedema easier and faster. The Lions Eye Clinic can be
contacted on 244-2818.

Dr.Pandit is a Consultant ophthalmologist at Cayman
Islands hospital

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