One of the more curious conditions
in ophthalmic dispensing is diabetes. How can one's sugar
level affect one's eyes? If you have been in this field for
any good length of time, you would have very likely run into
a patient who picked up their glasses without a hitch, only
to come back some time later complaining of blurry vision.
It's normal to see a child's prescription fluctuate or
increase because they're still growing. An adult is a
different story. As an adult, one's eye prescription doesn't
fluctuate greatly without some underlying reason.
Diabetes mellitus is a disorder
that affects one's metabolism. According to WebMD, diabetes
is estimated to affect 18.2 million people, 5.2 million of
which go undiagnosed. There are three main types of
diabetes: type 1, type 2, and gestational. There are other
forms of diabetes that remain difficult to classify because
their underlying cause is unclear. It is important to
understand the role of insulin in the body. Insulin is a
hormone produced by the pancreas. The bloodstream in the
presence of glucose, a simple sugar utilized by our cells
and the main source of fuel in the body, utilizes insulin to
let the cells know to take in the glucose.
Most people are familiar with type
1 diabetes. This form of diabetes is classified as an
auto-immune disease and requires regular insulin shots in
order to survive. In type 1 diabetes, the body's immune
system attacks the insulin producing cells in the pancreas.
There is no known reason as to why this response happens.
Some symptoms include increased thirst, increased hunger,
frequent urination, blurred vision and fatigue.
Type 2 diabetes has been gaining a
lot of coverage in the news because of the "obesity
epidemic" in this country. This type is known as
insulin resistant diabetes. The pancreas in type 2 diabetes
seems to produce insulin, but is resistant to the insulin
produced. Today, more children are now being diagnosed with
this form of diabetes in greater numbers. The majority of
those who have diabetes are also obese, so a strong
correlation exists between inactivity, obesity and diabetes.
Gestational diabetes is usually a
transient form of diabetes that occurs during pregnancy.
Even though this form of diabetes may resolve on its own, it
still has potential to damage both mother and child. This
type of diabetes accounts for 2%-5% of all pregnancies.
Diabetics are prone to high blood
pressure and heart disease. Nerve damage may also result in
the extremities. The incidence of kidney disease and stroke
are higher in those who suffer from diabetes than normal.
Diabetes has some serious ocular
manifestations. There are four stages of diabetic
retinopathy: mild non-proliferative diabetic retinopathy
(mild NPDR), moderate NPDR, severe NPDR, and proliferative
diabetic retinopathy (PDR). PDR is considered to be the most
advanced stage of diabetic retinopathy. It is characterized
by neo-vascularization of the retina. Some of the new
vessels that have grown into the retina may bleed and cause
blurry vision and even cause vision loss.
Macular edema, which is a swelling
of the portion of the retina responsible for our central
vision, can, if left untreated, result in vision loss.
Macular edema can occur at any stage of diabetic
retinopathy. Age-related cataracts may form earlier in those
with type 1 and type 2 diabetes. According to the National
Eye Institute, a diabetic is twice as likely to develop
It has always struck me as odd
when a patient doesn't remember what their medical history
is. I find that most of my time is spent trying to gather
their medical history and reinforce whatever information was
said to them. When dealing with diabetic retinopathy and
other issues related to diabetes, there will be two primary
issues: blurred vision and permanently decreased visual
acuity. As in the introduction, it is important to remind
the patient that elevated blood sugar may be the cause of
their blurry vision. Once the levels normalize, their
glasses should correct their vision provided that there
isn't a significant lapse between updates in their
prescription. When dealing with permanently decreased visual
acuity, I use the camera analogy. If the camera film is
damaged, changing the lens on the camera will not improve
the image. At this point it is imperative to reinforce the
need to see an eye doctor regularly and control sugar
Blindness resulting from
uncontrolled diabetes is a strong possibility even if there
are not a lot of symptoms in its early stages. The onset of
Type 1 diabetes seems to occur quicker and is detected
sooner, but type 2 can go undiagnosed for a long time.
Regular eye exams and yearly checkups can detect this with a
great degree of accuracy in its early stages and therefore
prevent a lot of damage to one's health. As with any
patient, patience goes a long way in understanding their
frustration. Vision loss and blurry vision is difficult to
accept after one purchases a visual aid with the expectation
of seeing well, not considering what effect their systemic
health has on their vision.