Vision
Loss in Diabetes
Richard
L. Windsor, O.D., F.A.A.O.
Laura K. Windsor, O.D., F.A.A.O.
Vision Enhancement Magazine
Diabetes is the leading cause
of blindness in the United States for patients age 20 to 74. Diabetes can affect
vision in a variety of ways. Vision loss occurs commonly from two major problems
proliferative diabetic retinopathy and macular edema.
Both are treatable with laser if detected early, but laser treatments may
also create additional vision problems for the diabetic.
Low Vision Diabetic Protocols
Visually impaired diabetics
have specific needs to be addresses in the low vision examination. Diabetics
must see to fill insulin syringes or take oral medications. Diabetics need to
see to test their blood sugar. Diabetics need to read labels on food containers
to control their intake of carbohydrates. Diabetics may have neuropathies
affecting their feet. If the patient is unable to see his or her feet, other
care by their physician, podiatrist or family may be needed to monitor the
health of their feet. Glare and
loss of contrast sensitivity need to be addressed.
Fluctuating Vision
Diabetics often experience
fluctuations in their vision related to changes in nearsightedness or
farsightedness caused by ups and downs in their blood sugar. As blood sugar
changes, the shape of the human crystalline lens changes. Before prescribing
eyeglasses for a diabetic patient, doctors frequently retest the patient on
another day to test for these fluctuations.
Loss of Central Sharp Vision
Macular edema is a swelling of
the delicate macular tissue in the center of the retina. It does not cause total
vision loss but causes a loss of visual acuity. Macular edema can be treated
with laser if identified in the early stages. Your optometrist or
ophthalmologist can detect this swelling through a dilated retinal examination
using a microscope and special lenses. Laser can reduce vision loss if caught in
time.
Profound Loss of Vision
Proliferative Diabetic
retinopathy is the more dangerous condition. It has the potential to cause
profound vision loss by damaging the small blood vessels of the retina. Then
chemicals are released from the retina that cause abnormal blood vessels to
grow. These blood vessels break and bleed creating scar tissue within the eye.
As the scar tissue contracts, it may pull on the retina leading to a retinal
detachment. Laser treatment can reduce the risk of severe vision loss by 50%.
Color Vision Impairment
Color vision may be mildly
affected along the yellow-blue axis. This
allows them to accept the yellow and amber lenses often required to improve
contrast after laser, without being bothered by the degree of the yellow
color.
Reduced Side Vision After Laser
Laser treatment is crucial in
saving the sight of many diabetics. Laser, however, causes other visual problems
that should be addressed by the low vision specialist.
Pan-retinal laser treatments require hundreds of laser burns across the
peripheral retina. By lasering these peripheral areas, more oxygen is available
to the supply the crucial center of the retina, where our sharpest vision
exists. Unfortunately, some side
vision must be sacrificed to save the center vision.
Loss of Contrast Sensitivity and Glare Problems
Patients often
describe a “hazy-glare” after laser surgery. Contrast sensitivity, the
ability to judge subtle differences in images like seeing a gray object on a
dark gray background decreases. Our world is one of subtle contrasts. We use
contrast sensitivity to see faces or find a dark object on a darker background.
Amber filters like the Corning CPF series reduce the glare and may aid contrast.
Night Blindness After Laser
The peripheral retina contains
more of or rod cells that we use to see at night. Thus in lasering the
peripheral retina we lose more rod cells that we need to see with at night.
Night driving may become more difficult do to loss of the rod cells. At night
clear eyeglass lenses may be required. If extensive laser has been performed,
night driving may become dangerous. Milder forms of laser called focal laser,
may increase glare but have less effect on side and night vision.
Glaucoma
Abnormal blood vessels may also
grow into the front portion of the eye causing a severe painful glaucoma. This
form of glaucoma can be prevented by timely laser treatment of the retina but
once established is very difficult to control. It may lead to profound vision
loss.
Cataracts
Diabetics develop cataracts at
an earlier age in adults and cataract may even occur in children. The juvenile
form of cataract may be reversible with better control of
blood sugar. Cataracts may cause a foggy clouding of vision.
Diplopia
An occasional complication is
double vision caused by ocular motor paralysis. It often resolves over several
months. At the first sign of double vision, see your eye practitioner
immediately.
Conclusion
The key to diabetic vision loss
is to prevent it through early detection and treatment.
Diabetes can cause a vast range of vision problems. Once vision loss
occurs, the low vision specialist can aid the diabetic deal with many of these
problems.
You
may reach Drs. Rich and Laura Windsor at the Low Vision Centers of Indiana at
(765) 348-2020 or email richw@eyeassociates.com
or drlaura@eyeassociates.com.
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