Diabetic Retinopathy - The Silent Killer of Eye Sight of a Diabetic Patient
What is retina?
The retina is the light-sensitive structure at the back of the eye just like a film in a camera. It captures and processes visual information before sending it via the optic nerve to the brain to form visual images. The center of the retina is known as macula.
What is Diabetes?
Diabetes Mellitus is a condition which impairs the body's ability to use and store sugar. It may be Type 1 or Insulin Dependent (IDDM) and Type 2 or Non-Insulin Dependent (NIDDM).
How does Diabetes affect your eyes?
Diabetes affects many parts of the body and the eyes are not spared. Diabetes may affect vision by causing cataract, glaucoma, cranial nerve palsy, optic neuropathy and most importantly diabetic retinopathy.
What is diabetic retinopathy?
Diabetic retinopathy is a disorder of the retinal blood vessels resulting from diabetes mellitus essentially causing microangiopathy of the pre-capillary arterioles, capillaries and post-capillary venules. It is the most common and serious eye complications to result from diabetes leading to poor vision and in extreme cases, even blindness.
Prevalence of diabetic retinopathy:
Diabetic blindness is emerging strongly on our horizon. It is the second most common cause of legal blindness in the world under the age of 65 years. It is commoner in type 1 (40 per cent) than in type 2 diabetes mellitus 20 per cent), though the incidence of diabetic maculopathy is higher with type 2 diabetes mellitus. Recent studies at BIRDEM shows that the prevalence of diabetic retinopathy among type 2 diabetic patients in Bangladesh is 27.7 per cent.
Inevitably, the longer someone has diabetes, the more likely he or she will get diabetic retinopathy. In patients diagnosed with diabetes before the age of 30 years, the incidence of diabetic retinopathy after 10 years is 50 per cent and after 30 years 90 per cent. Nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime.
Types of Diabetic Retinopathy:
Non-proliferative diabetic retinopathy:
It is an early stage of diabetic retinopathy and progress slowly over the years. The retina usually shows evidence of tiny blood spots such as microaneurysm, retinal hemorrhage and fatty deposits such as exudates. The majority of the patients has normal vision and they do not experience any vision loss aside from a gradual blurring of vision which can often go unnoticed.
In some patients, blood vessels leak at macula, causing accumulation of fluid and exudates in the macula. The condition is known as diabetic maculopathy, which is the most common cause of visual loss in diabetes and may be mild to severe, but even in the worst cases, peripheral vision continues to function.
Proliferative diabetic retinopathy:
This is an advanced stage of diabetic retinopathy. The retina is severely lacking in oxygen and there is a growth of abnormal new blood vessels (neovascularisation). However, these immature blood vessels are brittle and have a tendency to rupture easily and can bleed either between the vitreous and the retina, known as preretinal hemorrhage or into the vitreous cavity in the middle of the eye termed as vitreous hemorrhage. Unless the blood is cleared by the eye spontaneously or surgically removed, it can result in severe vision loss and blindness. This collected blood in the vitreous cavity can also cause inflammation and fibrous scar tissue to grow, which may contract and pull on the retina to cause a tractional retinal detachment. Occasionally abnormal new blood vessels grow on the surface of the iris (colored part of the eye) and into the angle of the eye blocking the normal flow of fluid out of the eye. This results in intense pressure build up in side the eye causing neovascular glaucoma, a severe painful blinding eye disease.
Who are at risk of diabetic retinopathy?
The high-risk groups are:
- Those with type 1 and type 2 diabetes
- Those with high blood pressure and high cholesterol
- Pregnant women
- Those with poorly controlled blood sugar levels
- Obese individuals
- Kidney disease patients
What are the symptoms of diabetic retinopathy?
Initially, most people with diabetic retinopathy experience mild to no vision problems or pain. In fact, the disease can progress to an advanced stage without any noticeable change in vision. Some of the symptoms may include:
- The presence of 'spiders', 'cobwebs' or tiny specks floating in your vision
- Dark streaks or a red film that blocks vision
- Blurred vision or poor night vision
- A dark or empty spot in the middle of your vision
- Difficulty in adjusting from bright light to dim light
- Severe impairment of vision or complete loss of vision
- How is diabetic retinopathy diagnosed?
Diabetic retinopathy is usually spotted either during the course of a routine eye check up of a diabetic patient or it is discovered by the patient himself or herself after a certain amount of eye damage has already occurred.
The following examinations and tests aid diagnosis of diabetic retinopathy and help determining which treatment will be most appropriate.
- Detailed Eye and Retinal Examination: The eyes are dilated using special eye dilating drops and details eye & retina examinations include slit-lamp bio-microscopy using 78 D or 90 D lens, direct and indirect ophthalmoscopy.
- Color Fundus Photography: This is a color photography of the retina for a base line documentation of diabetic retinopathy and for future comparison to detect progression of the disease.
- Fundus Fluorescein Angiography (FFA): This photographic process involves injection of a special dye through the arm into the blood stream. Photographs of the retina are taken as the dye passes through the blood vessels in the eye, showing areas of leakage or poor blood flow.
How is diabetic retinopathy treated?
Successful management of diabetic retinopathy depends on its early detection and treatment.
If you are a diabetic patient, you are advised to control your diabetes with proper dietary planning, meticulous exercise schedule and timely medication to delay or prevent the development of diabetic retinopathy and related complications.
Besides going for an annual eye examination, your physician or endocrinologist will help you taking steps to keep your blood pressure, lipid profile and blood sugar levels to controllable levels. High blood pressure and associated kidney problems if any need to be treated also.
Prevention of smoking, proper weight control, education about diabetes & its complications, psychological counseling of the patient & family are also very important aspect of medical management of diabetic retinopathy.
Various scientific studies have proven beyond doubt that proper eye care by ophthalmologists, laser photocoagulation and vitrectomy surgery in complicated cases are crucial in the preservation of sight in diabetic patients. Control of blood sugar and blood pressure are important but progression of retinopathy may occur despite all medical efforts.
Laser Photocoagulation: Laser treatment is used to seal or obliterate the abnormal leaking blood vessels. This procedure focuses a high-energy beam of laser light onto the damaged retina. Small bursts of the laser energy seal leaking abnormal blood vessels and form tiny scars inside the eye. The scars help regression of new blood vessels growth and cause existing ones to shrink and close, thus preventing further bleeding and complications.
Laser is often recommended for people with diabetic maculopathy, proliferative diabetic retinopathy and neovascular glaucoma.
Various types of laser treatment may be used depending on the involvement. It may be focal, grid or pan-retinal.
Laser treatments are usually carried in an outpatient setting. They do not require special preparation or admission to hospital.
Multiple laser treatments over time are sometimes necessary. Laser surgery does not cure diabetic retinopathy .The main goal of treatment is to prevent further loss of vision.
Vitrectomy : Laser photocoagulation cannot be used successfully in all patients.
Advanced cases with vitreous bleeding into the eye and scar tissue formation require a procedure called vitrectomy together with other sophisticated surgical procedures.
During this microsurgical procedure, which is performed in the operation theatre, the blood-filled vitreous is removed from the eye and replaced with a clear solution to reestablish clear vision.
The ophthalmologist may wait for several months to see if the blood clears on its own before performing a vitrectomy. If the retina is detached, it is being repaired during the vitrectomy surgery.
In this situation surgery should not be delayed because macular distortion or tractional retinal detachment will cause permanent loss of vision. The longer the macula is distorted or out of place, the more serious the vision loss will be.
Can vision loss be prevented?
If you have diabetes, it is important to know that today, with improved methods of diagnosis and treatment, only a small percentage of people who develop retinopathy have serious vision problems.
Strict control of your diabetes will prevent the development of retinopathy as much as possible and significantly reduce the long-term risk of vision loss from diabetic retinopathy.
The threat of blindness is a real one but with early detection and treatment, the risk of severe vision loss from diabetic retinopathy is small.
A timely intervention can go a long way in preventing significant visual disabilities and therefore qualitative and quantitative salvation of lifestyle of a diabetic patient.
Remember, visiting your eye specialist on a regular basis along with early detection of diabetic retinopathy is the best protection against loss of vision.
When to schedule an examination
People with diabetes should schedule eye examinations at least once a year. More frequent medical eye examinations may be necessary after the diagnosis of diabetic retinopathy.
Pregnant women with diabetes should schedule an appointment in the first trimester because retinopathy can progress quickly during pregnancy.
If you need to be examined for glasses, it is important that your blood sugar be in consistent control for several days when you see your eye doctor. Glasses that work well when the blood sugar is out of control will not work well when sugar is stable. Rapid changes in blood sugar can cause fluctuating vision in both eyes even if retinopathy is not present.
You should have your eyes checked promptly if you have visual changes that affect only one eye, if last more than a few days, if not associated with a change in blood sugar.
When you are diagnosed as a patient of diabetes for the first time, you should have your eyes checked at least within five years of the diagnosis if you are 30 years old or younger and at the time of diagnosis of diabetes if your are older than 30 years. If you already have developed diabetic retinopathy, the follow up depends on the severity of involvement. Usually non-proliferative retinopathy requires follow up every 6-12 months and proliferative retinopathy requires follow up every 3-6 months.
Similar of Diabetic Retinopathy - The Silent Killer of Eye Sight of a Diabetic Patient