Diabetes Can Affect Vision
If you have diabetes, your body is unable to use and store sugar properly. Diabetes results in increased blood sugar, excessive thirst, frequent urination as well as changes in blood vessels (arteries and veins). Diabetes can affect vision in different ways. It can lead to cataract and glaucoma, and most importantly, it can damage blood vessels in the eyes.
What is diabetic retinopathy?
Diabetic retinopathy is a complication caused by changes in blood vessels. Retina is a nerve layer at the back of the eye which perceives light and sends images in the form of nerve signals to the brain. When blood vessels of retina are damaged, they may cause leakage of fluid or blood, or may lead to the growth of new fragile vessels and destroy retina; as a result, the image sent from retina to brain is blurred or skewed.
Diabetic retinopathy is one of the main causes of vision loss and people with untreated diabetes are 25 times more at the risk of blindness compared with normal people.
The longer the duration of diabetes, the more probable the diabetic retinopathy. In approximately 80% of people with 15 years of diabetes, some damage to retinal vessels is observed. Patients with type 1 diabetes (juvenile type) are more at the risk of developing diabetic retinopathy at younger ages. If you have diabetes, you should know that today, thanks to improved diagnostic tools and treatment procedures, only a few patients with diabetes face serious problems of vision loss provided that they visit ophthalmologist at the right time.
Types of Retinopathy
- Underlying Retinopathy: It is the first phase of diabetic retinopathy in which small blood vessels of retina are damaged; hence, fluid or blood leaks from them. Fluid leakage results in swelling of retina or production of deposits called “exudates”
.Although this phase usually has no effect on eyesight, it might turn to a more severe phase later and lead to vision loss. Therefore, underlying retinopathy is considered a warning sign.
Sometimes, the leaking fluid is gathered at macula. Macula is responsible for seeing details of objects (for example, letters or numbers). This problem is known as macula edema and might cause difficulty in reading or doing short-distance work.
- Proliferative Retinopathy: In this phase, new and abnormal blood vessels grow on the surface of retina. This is called neovascularization. These new blood vessels have weaker walls; accordingly, they are more delicate and may bleed. Vitreous humor is a transparent jelly like material which fills inside of the eye. Blood leakage may blur vitreous and cloud vision; as a result, the image will be blurred and distorted. These abnormal blood vessels might harden and cause retinal detachment severe vision loss and blindness.
Abnormal blood vessels may also grow around pupil and iris and cause glaucoma by increasing internal pressure of the eye.
- Proliferative retinopathy is the most severe diabetic retina disease. Twenty percent of diabetic people will be affected by it, which may lead to their severe vision loss or blindness.
What are the symptoms of diabetic retinopathy?
Usually, underlying retinopathy does not have any symptoms. However, gradual blurring of vision may occur in the case of macula edema. People may never notice changes of their vision. Ophthalmologic examination is the only way of tracking changes inside the eye.
After bleeding, the vision is blurred and some stains are found on that. It may even result in full vision loss. Although proliferative retinopathy is painless, it is a severe type of the disease and requires immediate medical care. Pregnancy and hypertension may exacerbate diabetic retinopathy.
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How is diabetic retinopathy diagnosed?
The best diagnosis for diabetic retinopathy is made through regular eye examination by an ophthalmologist. Severe retinopathy may be absolutely symptom-free. The disease could be improved by treatment. In order to diagnose diabetic retinopathy, an ophthalmologist checks inside the eye using a device called ophthalmoscope. Before eye examination, an eye drop may be used to dilate the pupil.
In case the ophthalmologist diagnoses diabetic retinopathy, an image from the back of the eye should be taken through “fluorescein angiography” to verify if treatment is needed. At fluorescein angiography, a special dye is injected into a blood vessel and images are taken from the eye.
How is diabetic retinopathy treated?
An ophthalmologist considers the following points for the treatment:
- Medical history
- Extent of retinal damage
In many cases, no treatment is needed but the patient must undergo regular eye examinations. In other cases, treatments are aimed to stop damage of diabetic retinopathy and improve vision, if possible. Laser Surgery:
This method is mostly effective in treating diabetic retinopathy. A strong ray of laser is focused on the damaged part of the retina. Laser seals the leaking blood vessels and, accordingly, resolves macula edema. This type of treatment is called "photocoagulation".
In cases of abnormal growth of blood vessels (neovascularization), laser is used in all lateral parts of the retina. This reduces abnormal blood vessels, and attaches retina and prevents its detachment.
Laser surgery can be performed for outpatients either in an ophthalmology office or in a clinic. If diabetic retinopathy is diagnosed in its early stages, laser surgery can slow down the trend of vision loss. Even in advanced stages, namely proliferative retinopathy, laser surgery decreases the risk of severe vision loss. Cryotherapy:
If vitreous humor is blurred due to the presence of blood, laser surgery must be postponed until the blood is absorbed. In some cases of vitreous bleeding, cryotherapy may be helpful in shrinking abnormal blood vessels. Vitrectomy:
The ophthalmologist may recommend removal of vitreous in advanced proliferative retinopathy. This microscopic surgery is performed in the operating room. In Vitrectomy, vitreous humor which is filled with blood is removed and substituted by a transparent material. Approximately 70% of the patients experience improved vision after the surgery. The ophthalmologist may sometimes wait for a couple of months or a year before removing the vitreous, hoping that blood is naturally absorbed. Retinal Repair:
In case destroyed tissue results in retinal detachment, severe vision loss or blindness is expected unless the surgery for retinal attachment is successfully performed timely. What is the patient’s role in his/her treatment?
Successful care from diabetic retinopathy does not solely depend on the primary treatment by the ophthalmologist. It is necessary that the patient pay attention to medical treatment and observe diabetic diet. The patient must maintain a proper blood sugar level and avoid smoking, and pay attention to his blood pressure. Mostly, patients with diabetic retinopathy have no restriction on physical activities. However, sometimes, patients with an active type of proliferative retinopathy are recommended to limit their physical activities. Vision Loss Can Be Prevented to a Large Extent
- Diabetic retinopathy may have no symptoms.
- Early diagnosis of diabetic retinopathy is the best way to avoid vision loss.
- Diabetic patients must be examined by an ophthalmologist at least once a year. After diabetic retinopathy, more examination is necessary at shorter intervals.
- Treatment should commence prior to damage through ophthalmologist’s precise examination. Surgery and laser are quite effective treatments for diabetic retinopathy.
Diabetic Retinopathy Brochure