Diabetes can affect your eyesight
If you have diabetes, your body is no longer able to use and store sugar properly. High blood sugar can damage the blood vessels of the retina, the vital tissue in the eye that senses light and transmits images to the brain. Damage is called diabetic retinopathy and can lead to vision loss.
Types of diabetic retinopathy
There are two types of diabetic retinopathy: non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).
NPDR, also known as background stage diabetic retinopathy, is an early stage of diabetic retinopathy. In this stage, small blood vessels in the retina leak blood or exudate. The exudate thickens the retina with edema, and the lipids in the exudate are deposited in the retina to form a yellowish-white hard exudate.
Many diabetic patients have mild NPDR, but their vision is not affected. Vision loss occurs when macular edema or macular ischemia occurs.
Macular edema is a swelling or thickening of the retina in the macula. The swelling is caused by leakage of fluid from the retinal vessels. The macula is a small area in the center of the retina, the most acute part of vision, and once damaged, there is a significant loss of central vision. This is the most common cause of vision loss in diabetic patients. The degree of vision loss can be mild or severe, but peripheral vision can continue to function even in the worst cases.
Macular ischemia is caused by the closure of small blood vessels (capillaries). As the macula lacks an adequate blood supply, function is impaired and vision is lost.
PDR occurs when abnormal neovascularization begins to grow on the surface of the retina or optic disc. the primary cause of PDR is a large blockage of retinal blood vessels that does not provide adequate blood flow. As a result, the retina grows neovascularization to supply blood to the area where the original blood vessels are closed.
Unfortunately, the neovascularization does not restore the normal blood supply to the retina. Moreover, neovascularization is often accompanied by proliferation, which can lead to retinal wrinkling and even retinal detachment.
Because PDR can affect both central and peripheral vision, vision loss is more pronounced in PDR than in NPDR.
Proliferative diabetic retinopathy often results in vision loss through
Vitreous hemorrhage Neovascular hemorrhage into the vitreous, a clear gelatinous substance that fills the center of the eye. If the vitreous hemorrhage is mild, the patient may see only a few new, darker floaters. A large amount of hemorrhage results in a significant loss of vision. Depending on the amount of hemorrhage, it may take days, months or even years for the vitreous hemorrhage to gradually resolve. If the vitreous hemorrhage is not absorbed for a long time, vitrectomy may be performed. Vitreous hemorrhage does not cause permanent loss of vision, and if the macula is not damaged, vision may be restored to previous levels after removal of the blood collection.
In the PDR stage of retinal detachment, the proliferating membrane that accompanies neovascularization crinkles and pulls on the retina. Macular wrinkling can cause distortion of vision. If the macula or extensive retinal detachment occurs, severe vision loss can occur.
Extensive retinal vascular occlusion in neovascular glaucoma can sometimes cause new abnormal blood vessels to grow on the iris (the colored part of the eye, the tissue around the pupil) and in the anterior chamber angle (the channel that drains the atrial fluid in a circle around the iris). This prevents the normal flow of aqueous from the atrial angle in the eye and increases intraocular pressure, leading to neovascular glaucoma, a serious eye disease that can damage the optic nerve.
How is diabetic retinopathy diagnosed?
Regular eye exams can detect and treat diabetic-related eye disease in a timely manner, when you may not have any visual problems. Your ophthalmologist will dilate your pupils with dilating eye drops and use special equipment and lenses to look at the fundus of your eyes.
Once diabetic retinopathy is present, color photography of the retina or a special test (sodium fluorescein angiography) may be required to determine if you need treatment. During this test, dye will be injected into your arm and the fundus will be photographed to find out where the fluid is leaking.
How is diabetic retinopathy treated?
The best approach is to prevent the development of retinopathy as much as possible. Tight control of blood sugar will significantly reduce the risk of vision loss due to diabetic retinopathy. If hypertension and kidney disease are also present, prompt treatment is required.
Intraocular injections of anti-vascular endothelial growth factor (VEGF) drugs, which are essential for the production of neovascularization, can stop the growth of new blood vessels and secondary hemorrhage. Sometimes intraocular hormone injections are also used.
Laser treatment Laser treatment is usually used for patients with macular edema, PDR and neovascular glaucoma.
To treat macular edema, laser photocoagulation of the damaged retina near the macula may be used to reduce fluid leakage. The main goal of treatment is to prevent further vision loss. Patients with vision loss due to macular edema are less likely to regain normal vision, but some patients may improve.
Treatment of PDR involves laser photocoagulation of the entire retina except for the macula. This total retinal laser photocoagulation shrinks the new blood vessels and stops their continued growth. It also reduces the likelihood of vitreous hemorrhage or retinal detachment.
Depending on the condition, some patients will require multiple laser treatments. Laser treatment will not completely cure diabetic retinopathy and, in some patients, will not necessarily prevent further vision loss.
Vitrectomy For advanced PDR, your ophthalmologist may recommend vitrectomy. This is now primarily a minimally invasive procedure that removes the blood-accumulated vitreous and replaces it with a clear solution, which may require an injection of inert gas or silicone oil, depending on the severity of the condition. Usually, the ophthalmologist will observe the patient for several months, waiting for the vitreous blood to clear on its own, before performing the vitrectomy described above if necessary.
The vitrectomy usually removes or closes the abnormal blood vessels causing the hemorrhage to stop further bleeding. If there is a retinal detachment, it may be reset intraoperatively. Because macular distortion or retinal detachment by traction can cause permanent vision loss, early surgery is required. The longer the macula is distorted or displaced, the more severe the vision loss will be.
Vision loss is largely preventable
If you have diabetes, it is important to understand that with the current advanced diagnostic and treatment methods, fewer people will lose their vision due to diabetic retinopathy. Early detection of diabetic retinopathy and prompt treatment are the best measures to prevent vision loss.
Tight control of your blood sugar and regular visits to the eye can significantly reduce the risk of vision loss.
When to schedule an exam
Patients with type 1 diabetes should schedule exams within 5 years of diagnosis and annually thereafter. patients with type 2 diabetes should schedule exams at the time of diabetes diagnosis and annually thereafter.
Because retinopathy can progress rapidly during pregnancy, women with diabetes who are pregnant should schedule a fundus exam early in their pregnancy.
If you want to have an optometry appointment, be sure to control your blood sugar and keep it stable for a few days before your appointment, as the prescription for glasses from an optometry appointment is not accurate when your blood sugar is unstable. Even without retinopathy, rapid changes in blood sugar can cause fluctuations in vision in both eyes.
You should receive an eye examination as soon as possible if you experience changes in vision in the following situations.
1. Changes in vision in one or both eyes.
2. persist for more than a few days.
3. is not accompanied by changes in blood sugar.
When you are first diagnosed with diabetes, you should have an eye exam at the following times.
Within 5 years of diagnosis if you are ≤ 29 years of age
If you are ≥ 30 years of age, the examination should be performed within a few months of diagnosis.