can be prevented by treatment with panretinal laser photocoagulation. the goal is to create 1,600–2,000 burns in the retina with the hope of reducing the retina's oxygen demand, and hence the possibility of ischemia. it is done in multiple sittings. in treating advanced diabetic retinopathy, the burns are used to destroy the abnormal new blood vessels that form in the retina. this has been shown to reduce the risk of severe vision loss for eyes at risk by 50%. before using the laser, the ophthalmologist dilates the pupil and applies anaesthetic drops to numb the eye. in some cases, the doctor also may numb the area behind the eye to reduce discomfort. the patient sits facing the laser machine while the doctor holds a special lens on the eye. the physician can use a single spot laser, a pattern scan laser for two dimensional patterns such as squares, rings and arcs, or a navigated laser which works by tracking retinal eye movements in real time. during the procedure, the patient will see flashes of light. these flashes often create an uncomfortable stinging sensation for the patient. after the laser treatment, patients should be advised not to drive for a few hours while the pupils are still dilated. vision will most likely remain blurry for the rest of the day. though there should not be much pain in the eye itself, an ice-cream headache like pain may last for hours afterwards. patients will lose some of their peripheral vision after this surgery although it may be barely noticeable by the patient. the procedure does however save the center of the patient's sight. laser surgery may also slightly reduce colour and night vision. a person with proliferative retinopathy will always be at risk for new bleeding, as well as glaucoma, a complication from the new blood vessels. this means that multiple treatments may be required to protect vision. intravitreal triamcinolone acetonide triamcinolone is a long acting steroid preparation. treating people with dme with intravitreal injections of triamcinolone may lead to a some degree of improvement in visual acuity when compared to eyes treated with placebo injections. when injected in the vitreous cavity, the steroid decreases the macular edema (thickening of the retina at the macula) caused due to diabetic maculopathy, and that may result in an increase in visual acuity. the effect of triamcinolone is not permnanent and may last up to three months, which necessitates repeated injections for maintaining the beneficial effect. best results of intravitreal triamcinolone have been found in eyes that have already undergone cataract surgery. complications of intravitreal injection of triamcinolone may include cataract, steroid-induced glaucoma, and endophthalmitis. intravitreal anti-vegf a 2017 systematic review update found moderate evidence that aflibercept may have advantages in improving visual outcomes over bevacizumab and ranibizumab, after one year. in cases with vitreous hemorrhage, however, anti-vegf injections proved to be less effective in restoring visual acuity than vitrectomy combined with panretinal laser-photocoagulation. surgery instead of laser surgery, some people require a vitrectomy to restore vision. a vitrectomy is performed when there is a lot of blood in the vitreous. it involves removing the cloudy vitreous and replacing it with a saline solution. studies show that people who have a vitrectomy soon after a large hemorrhage are more likely to protect their vision than someone who waits to have the operation. early vitrectomy is especially effective in people with insulin-dependent diabetes, who may be at greater risk of blindness from a hemorrhage into the eye. vitrectomy may be done under general or local anesthesia. the doctor makes a tiny incision in the sclera, or white of the eye. next, a small instrument is placed into the eye to remove the vitreous and insert the saline solution into the eye. patients may be able to return home soon after the vitrectomy, or may be asked to stay in the hospital overnight. after the operation, the eye will be red and sensitive, and patients usually need to wear an eyepatch for a few days or weeks to protect the eye. medicated eye drops are also prescribed to protect against infection. there is evidence which suggests anti-vegf drugs given either prior to or during vitrectomy may reduce the risk of posterior vitreous cavity haemorrhage. vitrectomy is frequently combined with other modalities of treatment. epidemiology around 35% of people with diabetes have some kind of diabetic retinopathy; around 10% experience some degree of vision loss. diabetic retinopathy is particularly common in those with type 1 diabetes – affecting 25% of people five years from diagnosis, 60% 10 years from diagnosis, and 80% 15 years from diagnosis. chances of disease progression are heavily influenced by blood sugar control, but on average 7% of those with diabetes experiencing proliferative diabetic retinopathy and 7% diabetic macular edema. diabetic retinopathy is the leading cause of vision loss in those 20–74 years old. the global burden of diabetic retinopathy increased dramatically from 1990 to 2015—from 1.4 million to 2.6 million people with visual impairment; from 0.2 million to 0.4 million blinded—due in large part to the increasing burden of type 2 diabetes in low- and middle-income countries. research several large multicenter randomized clinical trials have been done to evaluate treatment protocols for those with diabetic retinopathy, namely the early treatment for diabetic retinopathy study, diabetic retinopathy vitrectomy study, diabetic retinopathy study, diabetes control and complications trial, uk prospective diabetes study, and the diabetic retinopathy clinical research network protocols i, s, and t. light treatment a medical device comprising a mask that delivers green light through the eyelids while a person sleeps was under development in 2016. the light from the mask stops rod cells in the retina from dark adapting, which is thought to reduce their oxygen requirement, which in turn diminishes new blood vessel formation and thus prevents diabetic retinopathy. as of 2016 a large clinical trial was underway. as of 2018, the results from the clinical trial showed no long-term therapeutic benefit from using the mask in diabetic retinopathy patients. c-peptide c-peptide had shown promising results in treatment of diabetic complications incidental to vascular degeneration. creative peptides, eli lilly, and cebix all had drug development programs for a c-peptide product. cebix had the only ongoing program until it completed a phase iib trial in december 2014 that showed no difference between c-peptide and placebo, and it terminated its program and went out of business. stem cell therapy clinical trials are under way or are being populated in preparation for study at medical centers in brazil, iran and the united states. current trials involve using the patients' own stem cells derived from bone marrow and injected into the degenerated areas in an effort to regenerate the vascular system. blood pressure control a cochrane review examined 15 randomized controlled trials to determine whether interventions that sought to control or reduce blood pressure in diabetics had any effects of diabetic retinopathy. while the results showed that interventions to control or reduce blood pressure prevented diabetic retinopathy for up to 4–5 years in diabetics, there was no evidence of any effect of these interventions on progression of diabetic retinopathy, preservation of visual acuity, adverse events, quality of life, and costs. fundoscopic image analyses distribution in percentage of pre-processing techniques from 2011 to 2014 diabetic retinopathy is diagnosed entirely by recognizing abnormalities on retinal images taken by fundoscopy. color fundus photography is mainly used for staging the disease. fluorescein angiography is used to assess the extent of retinopathy that aids in treatment plan development. optical coherence tomography (oct) is used to determine the severity of edema and treatment response. because fundoscopic images are the main sources for diagnosis of diabetic retinopathy, manually analyzing those images can be time-consuming and unreliable, as the ability of detecting abnormalities varies by years of experience. therefore, scientists have explored developing computer-aided diagnosis approaches to automate the process, which involves extracting information about the blood vessels and any abnormal patterns from the rest of the fundoscopic image and analyzing them.