Diabetes Eye Care
Diabetes Eye Care Overview
Diabetes may cause complications in our eyes; this is true for many Americans today. Armed with the proper knowledge we can help each other and our loved one's maintain their vision for a lifetime. Keep reading to find out how diabetes affects the human eye and how those complications may be treated or avoided altogether.
Dr. Hall has a special interest in diabetes. It is his goal to help ensure a lifetime of good vision through regular dilated eye exams and communication with your diabetes doctor.
Managing your diabetes is a task that you share with your physician. Documented information about the potential complications of poorly controlled blood sugars was scant until the results of the now landmark study known as The Diabetes Control and Complications Trial (DCCT) became published. The DCCT was an intensive study by scientists and physicians in the U.S. and Canada from 1983 to 1993 to study diabetes and the complications poorly controlled blood sugars may bring.
One of the well known eye complications is Diabetic Retinopathy. Diabetic retinopathy will develop with poorly controlled diabetes. These changes to the eye are a result of the blood vessels leaking on the back of our eyes in the special sensory tissue called the retina. Untreated swelling of the retinal tissue may lead to permanent decreased vision or blindness. Through regular dilated eye examinations and reports to your physician you can expect a lifetime of good vision and healthy eyes.
what is diabetic retinopathy?
The retina is the sensory tissue on the back of the eye which absorbs light energy as Einstein describes as photons and transforms light energy into electrical impulses which are sent to our brain by way of the optic nerve. This is essentially the process of vision. The retina is a very complex tissue being only as thick as a credit card yet having ten distinct layers, each having a special job to perform. The retina miraculously performs this transition of one form of energy to another. Because of this, many regard the retina as an extension of brain tissue.
The blood vessels which serve the retina lie in the middle of the retina. There are special protector cells on the surface of the blood vessels called pericytes. When blood sugar levels in our bloodstream remain elevated for prolonged periods of time or fluxuate greatly theses special protector cells die. This causes the walls of the blood vessels to weaken creating a microaneurysm. If the microaneurysm bursts blood leaks out into the retina. This extra fluid causes swelling within the retina, damaging the photoreceptor cells (rods and cones) consequently interrupting the process of vision. This interruption of vision is confined to the area of bleeding and swelling. Another problem that may occur with damaged blood vessels is that the vessels may collapse.
This collapse of blood vessels ceases blood flow to that area of retina. This area of retina has no oxygen, or becomes hypoxic and now atrophies due to lack of blood flow. These areas of atrophy are classified as hard exudates and cotton wool spots and are characterized by yellow areas against the normal red background of the retina. The doctor can easily recognize these areas of degenerated retina. These particular abnormalities in the retina are permanent in nature and vision is lost forever. The response of the retina to this hypoxic area is to grow new blood vessels to serve this oxygen-starved tissue. This process is called neovascularization. One may think this process is a noble effort by the retina but the problem with these new blood vessels created is they are only a single cell in thickness and may rupture very easily now causing a general hemorrhage in the middle of the eye known as the vitreous.
Damage to the blood vessels causing either leakage of blood into the retina or closure of blood vessels is the reason diabetic retinopathy develops. This all relates back to high, sustained levels of sugar in the bloodstream.
Retinal eye disease is silent. Changes in the retina may be taking place without the knowledge of anyone, and then all of a sudden one discovers through experience that there is a small problem or a large problem. We never desire to awaken one morning and reach this discovery point as it may be too late to save precious vision. Rather, the safe bet is to have regular eye exams to be alerted to potential problems and avoid any vision loss. Patients with diabetes are encouraged to have an eye exam annually, unless advised by your eye doctor otherwise.
CAN DIABETES CAUSE CATARACTS?
The lens inside our eyes provides the ability for us to focus throughout our youth and into our adulthood. As our eyes begin to mature in our early forties, we begin to lose our ability to focus up close. This is a natural change for our eyes. The crystalline lens is clear in our youth and begins to discolor in the fifth decade of life and can continue to discolor over time clouding our vision. This discoloration of the lens is known as a cataract. If our vision becomes diminished to an unacceptable level and interferes with our daily activities, then there is a need to remove the cataract. Cataract surgery is typically performed when the vision is reduced to about the 20/40 level or worse. Cataract surgery is a routine outpatient procedure these days with the advent of microsurgery techniques introduced in the mid 1980’s.
Diabetes can play a role to speed up the formation of cataracts. If blood sugars are higher than normal (not extreme) excess sugar accumulates in the lens which starts a cascade of biologic events that increases the water content of the lens. With increased water inside the lens, the clear fibers that comprise the lens are stretched and change shape. When blood sugars go down, this hydration process reverses and as the water content of the lens returns to normal and the fibers are relaxed. It is this constant 'push-and-pull' on the internal lens fibers that causes the fibers to prematurely discolor. With larger and more frequent swings in blood sugars this stretching activity continues, thus discoloring the otherwise clear crystalline lens.
These small changes in tissue structure over time discolor the tissue of the lens, hastening the formation of cataracts. This process is accelerated with continuous, large swings in blood sugars.
How can I prevent these changes?
Complications that diabetes may bring, such as eye disease, nerve disease and kidney disease may be avoided with good, steady blood sugar control. Plain and simple. Good glycemic control is a result of many factors which includes regular contact with your diabetes team. This means regular check ups with your doctor, having an annual dilated eye exam and consulting with your certified diabetes educator and nutritionist on a regular basis. Making good, healthy food choices throughout the day and self monitoring of blood glucose. We hear that over and over like the broken record it is. It is the time honored principle of good diabetes management.
Focusing upon self monitoring of blood glucose daily remains the key to good health and lowering ones risk of developing complications. The yardstick by which your physician measures your average blood sugars over a three to four month period is the glycosylated hemoglobin value abbreviated as the HbA1c or simply A1c. The American Diabetes Association recommends that all patients with diabetes have this test done four times a year and that patients understand what the results of this blood test means. Understanding this test and what the results mean will aid in you managing your diabetes hand-in-hand with your physician.
The Diabetes Control and Complications Trial (DCCT) is a now famous landmark study which clearly indicated that normal blood sugar levels in patients with diabetes decreases complications from diabetes. There have been other subsequent studies on this population of subjects which continues to yield more valuable information.