Diabetes is a disease that occurs as a result of impaired glucose metabolism in the body. The hormone insulin, which makes glucose available to the body, begins to be secreted less as a result of the destruction of beta cells in the pancreas. As the use of insulin in cells is impaired, glucose circulating in the blood becomes unusable in cells. Cells cannot absorb glucose and glucose levels rise in the blood.
As a result; disorders in body vessels begin. Damage develops in many organs, especially the eyes, kidneys, heart and vascular system.
There are two types of diabetes: Insulin-dependent (Type 1 DM) and non-insulin-dependent (Type 2 DM). In both types of Diabetes, damage depends on the control of blood glucose levels and the duration of Diabetes.
Eyes in Diabetes
Diabetes can cause cataracts, glaucoma and, most importantly, diabetic retinal disease, leading to reduced vision. Diabetes patients are 25 times more likely to develop vision loss than normal individuals. It is one of the most common causes of vision loss between the ages of 20-65. The chance of developing eye damage in diabetic patients is around 20% in 10-year diabetics and 80% in 30-year diabetics. However, thanks to advances in the diagnosis and treatment of the disease, timely interventions are now less likely to cause serious damage to vision.
Diabetic Retinopathy
It is a disorder involving the vessels of the nerve layer inside the eye called the retina. Blockages and leaks occur in the vessels and the nutrition and structure of the retinal layer begins to deteriorate.
It is classified in three main stages:
1-Initial period
2-Proliferation (new vessel formations) period
3-Advanced Diabetic eye disease
Initial Period
Some of the retinal vessels that start to deteriorate show narrowing in places, while others expand and form bubbles (micro aneurysms). Blood and fluid begin to leak from these damaged vessels. This leads to retinal edema and deposits called exudates. Vision is usually unaffected during this period, but it is considered a precursor to events that can impair vision. In some cases, the leakage can collect in the macula (the detailed visual center of the eye) and impair vision, especially near vision. This is called macular edema. In 80% of people with diabetes over 15 years, there is some initial damage.
Proliferation Period
The areas that cannot be nourished by the narrowed and blocked vessels begin to deteriorate as they are deprived of oxygen and blood. In these areas, fan-shaped new vascular formations (neovascularization) and fibrotic membrane formations (fibrous proliferation) appear. The edges of the new vessels are very thin and bleed easily. The fibrotic membrane can cover the macula or cause shrinkage and impair vision. Vision is reduced to the extent that bleeding and shrinkage affect the macula. Symptoms of the proliferation period are observed in 20% of diabetics.
Advanced Diabetic Eye Diseases
The movement or contraction of the vitreous, which fills the eye, begins to attract new vessels and fibrotic membrane formations. The already thin vessels bleed and fill the eye (vitreous hemorrhage). The pulled fibrotic membranes also cause tearing and damage to the retinal tissue (fractionated retinal detachment). New vessels can also affect the outflow of eye fluid and increase eye pressure (neovascular glaucoma).
Symptoms and Diagnosis
In diabetic retinal disease, symptoms begin with the macula being affected, i.e. reduced vision. Sometimes very advanced diabetic eye disease can be asymptomatic for years. Pregnancy, high blood pressure, kidney disease and severe infections are considered to increase the risk of diabetic retinal disease. The best prevention of diabetic retinal disease is regular eye examinations. Diabetic retinal disease can be detected by an ophthalmologist with simple methods. It is recommended that every diabetic patient undergo an eye examination at least once a year. In patients with signs of diabetic retinal disease, a fundus angiography is performed to visualize damage to the retina at the vascular level.
Fundus Fluorescein Angiography (FFA)
Fundus fluorescein angiography (FFA), or fundus angiography, is a very simple examination method. The pupils are dilated with drops. A fluorescent dye is injected through the arm veins and the intraocular circulation of the dye is observed and photographed. In this way, leaks, hemorrhages, deposits, non-nourished areas, new vessels, membrane formations and other damages are detected from the vessels and the areas to be treated are determined. It is recommended to perform fundus angiography once a year for control purposes for those who have not developed diabetic retinal disease, and once every 6 months for those who have developed symptoms of retinal disease.
Laser Photocoagulation
In lasers used inside the eye, a strong electric current passes through argon or krypton gases and energy is generated. The laser device directs this energy into a narrow and uniform beam of light. This beam is focused in the eye with microscopes and lenses and this energy is used to correct retinal abnormalities or diseases in diabetic eye disease. Laser treatment is a painless procedure. The pupils are dilated with drops. An examination lens is inserted into the eye. During the laser, the patient only feels blue-green flashes (flashes of light). Laser is applied to the retina in diabetes in 2 ways. If there is only local damage or edema, laser is applied only to that area. If the diabetic damage is not limited to only one area, laser is applied to the entire retina except the macular area for several sessions. This procedure is called panretinal laser photocoagulation and is used for diabetic retinal diseases in the proliferation stage.
If there is no edema affecting vision in the initial stage, no treatment can be performed. The patient is examined at 6-month intervals.
Laser is applied to the retinal tissue if the macular period affecting vision has developed or if there are leaking drops, non-nourished areas and new vessel formations in the proliferation stage.
In advanced stages of diabetic eye disease, such as hemorrhages in the eye, shrinkage and deflation caused by fibrotic membranes, a very delicate intraocular surgery called vitrectomy is required.