July 16, 2012 Diabetes mellitus (DM), i.e. diabetes, in the world today has a 2 – 3% of the population. Today we are talking about two forms of DM:
Insulin-dependent (type I) usually aged 10-20 years.
Insulin independent (type II) usually aged 50-70 years.
Diabetic retinopathy is a retinal vascular complication of diabetes and it is the leading cause of blindness (vision <0.1 in the better eye) in people below the age of 60. Diabetics are 25 x more likely than non diabetic of the same sex and age to develop blindness.
The earliest stage of the disease is known as non-proliferative diabetic retinopathy. At this stage, the retinal arteries become weakened and begin to leak plasma and blood cells, which is why the small, dotted hemorrhage occurs. Also, micro-aneurysms occur (veins bulge) and exudates (retinal deposits as a result of increased vascular permeability). In the macula (yellow spot) may appear thickening (edema), which leads to a reduction of visual acuity and distortion that can be register and tracked with Amsler’s test.
More severe degree of disease is called proliferative diabetic retinopathy. Due to the reduced supply of oxygen to the retina and the resulting ischemia, new blood vessels are created (the body in this way wants to increase the supply of blood and oxygen to the affected area). The formation of new blood vessels is called neovascularization. However, new blood vessels are of poorer quality and break easily and can lead to bleeding in the vitreous (the interior of the eye) due to which a person can see “floating blurs” and stains In front of the affected eye. Also, vision can be significantly reduced.
In the final stage, further growth of abnormal blood vessels and creation of connective scarring inside the eye causes serious complications such as detachment of the retina and glaucoma (damage to the optic nerve due to elevated intraocular pressure), resulting in a complete loss of vision.
Causes:
Onset and progression of diabetic retinopathy depends on the duration of diabetes mellitus (diabetes), metabolic control of sugar (cannot prevent but may delay the onset of DR) and other factors: hypertension, renal disease, obesity, hyperlipidemia, smoking, anemia, pregnancy…
Symptoms:
Blurred and distorted vision (often associated with the level of sugar in the blood), “floating blurs” and flashes before the eyes, sudden loss of vision.
Types:
There are two types of DR: non-proliferative and proliferative form.
Non-proliferative DR
Clinical manifestations are micro-aneurysms (small capillary dilation, which look like small red spots with sharp edges); bleeding: dot & blot and flame – retinal hemorrhage, preretinal and vitreous hemorrhage, exudates: hard (lipoprotein deposits in the outer plexiform layer of white or yellowish color with unclear irregular borders), soft (those are deposits of white to pale gray color, unclear boundaries, resulting from a focal ischemic infarct in the layer of nerve – ax plasmatic debris), arterial occlusion, venous dilatation, discalibration, tortuosity; retinal edema (as a result of leakage from microaneurysms , intraretinal microvascular abnormalities (IRMA), dilated capillaries that surround the area of non-perfusion).
Proliferative DR
Clinical manifestations have already been mentioned: IRMA, microvascular formations, neovascularization (NVD-in optical drive, NVE-in other locations of the retina), fibrous proliferations and traction retinal ablation = as the main features of proliferative form of diabetic retinopathy.
Developmental stages:
Treatment:
In people with diabetes it is important to have regular sight examinations in order to detect the disease early and treat it for possible complications. Most people with diabetes are under the constant supervision of an internist or endocrinologist who works closely with ophthalmologist. The diagnosis of diabetic retinopathy is set based on a thorough examination of the retina.
There are several ways of treating diabetic retinopathy, depending on the stage of the disease and specific problems that the patient has. Examinations, which accompanies the progression of the disease and is the basis for making decisions about treatment include: fluorescein angiography (FAG) (recording retinal blood vessels), optical coherence tomography (OCT), retinal photography and ultrasound eye examination.
One of the most common problems treated by vitreoretinal surgeons is the growth of abnormal blood vessels and bleeding from them. This issue is treated by panretinal photocoagulation (PRP), which is performed by a laser. The surgeon is using the laser to “destroy” ischemic (oxygen-free) retinal tissue, which is outside the boundaries of the central and clearest vision in patients. In this way they create blind spots in the field of peripheral vision, but PRP prevents the growth of new abnormal blood vessels and stops the bleeding from a pre-existing ones. The goal of treatment is to stop disease progression.