Diabetes can lead to a wide variety health complications, including heart disease, nerve damage, stroke, kidney disease, and vision loss. In fact, diabetes is the leading cause of blindness among working-age Americans. Diabetes is a risk factor for developing glaucoma, as well as for developing cataracts, but the most common and debilitating vision problem experienced by diabetics is diabetic retinopathy.
Today 3.6 million Americans ages 40 and older suffer from the diabetic retinopathy. During Diabetic Eye Disease Month Friends for Sight encourages individuals with diabetes to take preventative measures and protect their eyes from the devastating effects of diabetes.
As described by the National Eye Institute, "[diabetic retinopathy] in its early stages, has no symptoms. The disease begins to damage the small blood vessels in the retina, the light-sensing layer of tissue in the back of the eye, causing them to leak fluid and blood. As the disease progresses, blood vessels become blocked and rupture or new vessels grow on the retina, leading to permanent and sometimes profound vision loss." While the effects of diabetic retinopathy are profound, there are effective treatments available. Vision loss can be prevented if early diagnosis and timely treatment are sought.
How Your Doctor Can Diagnose Diabetic Eye Disease
Diabetic retinopathy usually has no early warning signs. It can be detected only through a comprehensive eye examination that looks for early signs of the disease, including:
Leaking blood vessels
Macular edema (swelling)
Pale, fatty deposits on the retina
Damaged nerve tissue
Any changes to the retinal blood vessels
To diagnose diabetic eye disease effectively, eye care specialists recommend a comprehensive diabetic eye examination that includes the following procedures:
Distance and near vision acuity tests
A comprehensive dilated eye examination, which includes the use of an ophthalmoscope. In a dilated eye examination, it is the pupil that is dilated—not the entire eye. This allows the examiner to see through the pupil to the retina. Visual acuity tests alone are not sufficient to detect diabetic retinopathy in its early stages.
A tonometry test to measure fluid pressure inside the eye.
A fluorescein angiography test, if more serious retinal changes, such as macular edema, are suspected. Fluorescein angiography is an eye test that uses a special dye and camera to look at blood flow in the retina.
Your doctor may also use optical coherence tomography (OCT) testing to get a clearer picture of the retina and its supporting layers. OCT is a type of medical imaging technology that produces high-resolution cross-sectional and three-dimensional images of the eye.
Can a Vision Screening Diagnose Diabetic Eye Disease?
A vision screening is a relatively short examination that can indicate the presence of a vision problem, such as diabetic retinopathy, or a potential vision problem. A vision screening cannot diagnose diabetic eye disease; instead, it can indicate that you should make an appointment with an ophthalmologist or optometrist for a more comprehensive dilated eye examination.
What Is a Comprehensive Dilated Eye Examination?
A comprehensive dilated eye examination generally lasts between 30 and 60 minutes, and is performed by an ophthalmologist or optometrist. It should always include the following components:
A Health and Medication History
Your overall health and that of your immediate family
The medications you are taking (both prescription and over-the-counter)
Questions about high blood pressure (hypertension), diabetes, smoking, and sun exposure.
A Vision History
How well you can see at present, including any recent changes in your vision
Eye diseases that you or your family members have had, including macular degeneration, glaucoma, and diabetic retinopathy.
Previous eye treatments, surgeries, or injuries
The date of your last eye examination
An Eye Health Evaluation
An examination of the external parts of your eyes: the whites of the eyes, the iris, pupil, eyelids, and eyelashes.
A dilated internal eye examination: Special eye drops will dilate, or open, your pupil, which allows the doctor to observe the inner parts of your eye, such as the retina and optic nerve. This can help to detect subtle changes of the optic nerve in persons without any visual symptoms and potentially lead to early detection of disease, including diabetic retinopathy.
A test of the fluid pressure within your eyes to check for the possibility of glaucoma.
A Refraction, or Visual Acuity Testing
A refraction helps determine the sharpness or clarity of both your near (reading) and distance vision.
This includes testing your vision with different lenses (sometimes contained in a machine called a phoropter, pictured at right) to determine if your vision can be improved or corrected with regular glasses or contact lenses.
Visual Field Testing
Visual field testing helps determine how much side (or peripheral) vision you have and how much surrounding area you can see.
The most common type of visual field test in a comprehensive eye exam is called a confrontation field test, in which the doctor briefly flashes several fingers in each of the four quadrants (above, below, right, and left) of your visual field while seated opposite you.
In some cases, your doctor may also want to perform a more precise visual field measurement, using a computerized visual field analyzer, such as the Humphrey Field Analyzer (pictured at left).
Your Examination Results
The doctor will be able to determine if the visual problems you are experiencing are normal age-related changes or are disease-related, and if additional testing, referral to another doctor or specialist, or treatments are needed.