Diabetic Retinopathy
Diabetic retinopathy is the leading cause of bad vision in the working population. Several states cause the loss of vision for diabetics, including diabetic and hypertensive retinopathy, a bigger risk of retinal vascular occlusion, cataract, and glaucoma.
Although a rising number of people are suffering from diabetes, there is a certain optimism for patients suffering from serious retinopathy. Several meta-analyses with patients with type 1 diabetes have shown that the number of patients whose disorder has evolved to proliferative retinopathy and maculopathy decreased by 2/3 from 1986 to 2008 compared to the period from 1975 to 1985, thanks to the timely diagnosis and treatment of the disorder. New therapeutic approaches and intravitreal treatments may also change the outcome.
Risk Factors
Risk factors for diabetic retinopathy are the following:
- Those which can’t be influenced: genetic factor, sex, and how long diabetes lasts
- Those which can be influenced: glycemia, blood pressure, obesity, lack of physical activity, and the amount of cholesterol and triglycerides in the blood
- Additional factors: carotid artery diseases, pregnancy, kidney dysfunction, and smoking
Apart from the clinical examination, numerous tests can help to plan the correct treatment. Most often doctors use fundus photography (in color and red-free), optical coherence tomography (OCT), fluorescein angiography (FA), and ultrasonography.
The treatment of diabetic retinopathy includes the use of laser (for focal photocoagulation and pan-retinal photocoagulation), intravitreal injection, and vitrectomy.
The classification of diabetic retinopathy is dichotomous: the presence or absence of new blood vessels, the presence or absence of a subfoveolar edema in the macula.
The Treatment
Photocoagulation
Retinal photocoagulation aims to reach the pigmented layer of the retina or retinal pigment epithelium (RPE) with minimal damage on photoreceptors and loss of RPE cells, by creating a minimal scar in the outer retina.
The laser treatment usually requires a few sessions. Both eyes can be treated in the same session, whether the macula or peripheral retina is treated. The macula must be treated carefully, especially when there are exudates directly next to the foveola because it can increase, spread over the foveola, and decrease its function for good.
The goal of pan-retinal photocoagulation is to destroy the areas with no capillary perfusion and with retinal ischemia. For some eyes, that means as many as 2000 micro-burns up to 500μ in size. If there isn’t a complete regression of neovascularization, the doctor can continue the treatment one to three months since the first treatment, depending on the clinical response.
Intravitreal VEGF Inhibitors
It is well-known that levels VEGF are increased in the vitreous and the retina in patients with diabetic retinopathy. VEGF increases vascular permeability, influencing tight-junction proteins, an important factor in the occurrence of macular edema.
There are a few medications from this group in the clinical practice. Many professional papers published in recent years describe the frequency of application and efficiency to decrease macular edema.
The Treatment of Maculopathy in the Presence of Proliferative Retinopathy
Maculopathy can occur together with neovascularization. If the macula or neovascularization should be treated first depends on different factors, including the patient’s age and how serious retinopathy is.
Generally speaking, with younger patients with active neovascularization, it is better to do pan-retinal photocoagulation first because in these patients the progression of neovascularization can be aggressive. The treatment of peripheral retina can also lead to a decrease in the macular edema by decreasing VEGF production. The traditional procedure is to do pan-retinal photocoagulation in a few sessions to decrease the chance for macular edema to grow.
With patients with less aggressive neovascularization it is advisable to do the macular treatment first, and then pan-retinal photocoagulation.
Diabetic Maculopathy and Cataract Surgery
It is ideal to treat macula before the cataract surgery, i.e. to let the edema gradually decrease. However, it doesn’t always happen that macula dries up successfully. In such situations, it is advisable to use intravitreal triamcinolone during the procedure or anti-VEGF before and after the surgery. If these two options are not available, the doctor should plan focal photocoagulation before and soon after the cataract surgery.