Diabetic retinopathy Hyperglycemia: a key factor in the control of diabetic retinopathy Hyperglycemia is a key reversible risk factor for the development of DR. The pathological changes caused by a persistent hyperglycemic state are not only retinopathy, but invade all parts of the eye, including conjunctival lesions, reduced corneal perception, cataracts, anterior uveitis, neovascular glaucoma, refractive and regulatory changes, and ocular muscle paralysis. The duration of diabetes is the most significant risk factor for DR, and patients with longer duration of diabetes almost always have varying degrees of retinal vascular disease. In addition, hypertension, dyslipidemia, obesity, nephritis, peripheral neuropathy, poor lifestyle (including smoking and alcohol consumption), and ocular factors such as myopia and posterior vitreous detachment (PVD) are all risk factors associated with DR. Targeted screening of these risk factors and timely treatment measures are essential to control the progression of DR from the non-proliferative to the proliferative phase. In addition, it is worth mentioning that DR may not have conscious symptoms in the early stage of the disease, and the patient’s visual acuity is not a criterion to determine the presence of DR. In order to miss the best time for treatment as much as possible, the fundus should be checked as soon as diabetes is diagnosed, and it should be reviewed regularly once or twice a year. Diagnosis: Fundus photography is necessary for patients in the early stages of diabetes. The diagnosis of DR can be made on the basis of the duration of diabetes, previous blood glucose levels and past history (onset of puberty, obesity, renal disease, systemic hypertension, lipid levels, pregnancy, etc.), combined with ophthalmologic and ancillary findings. The ophthalmologic examination includes best-corrected visual acuity, intraocular pressure, slit-lamp microscopy (anterior if needed), and atrial angioscopy to rule out atrial neoplasia. If necessary, anterior chamber angioscopy should be performed to rule out atrial corners neovascularization). Fundus examination is necessary after pupil dilatation, with special attention to the peripheral retina and vitreous. Auxiliary tests include fundus photography, fluorescein fundus angiography, ophthalmic coherence tomography, retinal thickness checker, and ocular ultrasonography. Fundus photography is necessary for patients with diabetes, especially in the early stages, as a baseline information to document the initial fundus condition. FFA is an important tool for diagnosis of fundus disease, and can be used for dynamic in vivo response to blood-retinal barrier function, capillary leakage, and circulation to compare the effect of whole retinal photocoagulation treatment before and after, to judge its effect and provide a basis for patching photocoagulation. oCT is more sensitive and intuitive, and is better for diagnosing macular edema (DME) and tracking the efficacy of laser photocoagulation. In the diagnosis of DR, microaneurysms, hard exudates, cotton wool spots, and neovascularization are the main signs (see figure). 74.2% of DR patients have macular degeneration, and the degree of macular degeneration can be unbalanced with other parts of the retina. At any stage of the DR disease, vascular lesions invading the macula can cause central vision loss. Diabetic macular lesions include DME, macular ischemia, macular traction. DME accounts for 96.4% of diabetic macular lesions. For clinically significant macular edema, the Early Diabetic Retinopathy Study Group considers one of the following to be present: retinal thickening involving or <500 μm from the central macular recess; hard exudate in the central recess or hard exudate <500) μm from the central recess with adjacent retinal thickening; one or more retinal thickening areas ≥1 optic disc area, and any part of this lesion <1 optic disc area from the central macular recess. macular sulcus <1 optic disc area. Diabetic vitreoretinopathy precisely describes the spatial relationship between the retinal surface and the vitreous humor. It is recommended that proliferative diabetic retinopathy should be changed to proliferative diabetic vitreoretinopathy when there is vitreous blood accumulation or neovascularization of the membrane into the vitreous cavity. And when incomplete posterior detachment of the vitreous body occurs in non-proliferative diabetic retinopathy, it should be changed to non-proliferative diabetic vitreoretinopathy. The American Academy of Ophthalmology and the International Academy of Ophthalmology in 2003 recommended DR staging criteria as shown in Award 1, which is simple and practical. This staging is valuable in assessing whether the nonproliferative type survives into the proliferative type. The best time to perform total retinal photocoagulation for DR is in the DR-III stage, i.e., severe NPDR. This staging criteria defines DR-0. This staging criteria defines the DR-0 stage is very meaningful and clarifies the importance of regular follow-up in diabetic patients to avoid blindness. DR-l stage is also a milestone definition, i.e. once MA is detected, it means the beginning of NVD/NVE/vitreous hemorrhage/pre-retinal hemorrhage in DR. Treatment: a long-term integrated multidisciplinary systemic project The treatment of DR is a long-term, integrated, multidisciplinary systemic project, in which the effective cooperation between internists and ophthalmologists is very important. Internal medicine treatment is its foundation, aiming to control blood sugar, blood pressure, lipid management, while treating other complications and slowing down the progression of DR; reduce the high leakage response of retinal vessels in diabetes, reduce high blood viscosity, reduce high platelet aggregation. Ophthalmologists also need to be aware of the patient's blood glucose, blood pressure and lipid status so that ophthalmology-related treatment can have the best effect; and internists need to know when to refer patients to ophthalmology to avoid delaying the disease. Pharmacological inhibition of VEGF is an effective treatment option for eye diseases caused by blood retinal barrier disruption and neovascularization. It can significantly reduce the degree of diabetic macular edema and improve the patient's visual function. As an adjunct to vitreous surgery, vitreous cavity injections of anti-VEGF drugs are effective in reducing neovascularization and complications of vitreous surgery. Total retinal photocoagulation is an effective treatment for DR today. Multicenter, randomized, controlled studies conducted by the Diabetic Retinopathy Study Group and the ETDRS, two major prospective clinical randomized controlled studies in the United States, confirmed that timely laser photocoagulation reduced the risk of severe vision loss by 50% in patients with DR. Standard total retinal photocoagulation extends from 1 PD-2PD beyond the optic papilla to the fundus beyond the equator, leaving the posterior pole between the macula and the superior and inferior temporal vascular arches of the optic disc unphotocoagulated. The number of photocoagulation points ranges from 1200-1600, depending on the severity of the retinal lesion, the size of the nonperfused area, and the extent of neovascularization. The spot size should generally be 500 μm, . Within the temporal vascular arch 200 μm, laser exposure time is mostly 0.1-0.2 s. Whole retinal photocoagulation should be completed in 3-5 times. The spot interval is 1 to 2 spot diameters. The output power should be a Class III spot response. An effective photocoagulation area is the key to successful PRP treatment, and long-term follow-up ensures that the ultimate goal is achieved. Patients are usually recommended to have their fundus reviewed by a fundus specialist at 1 month after PRP treatment and FFA at 3 months, with additional photocoagulation of neovascularization based on FFA results. Thereafter, patients should be reviewed every 3 to 6 months. Diabetic proliferative retinopathy is the result of a race in time between diabetic vasculopathy and diabetic vitreopathy. Surgical treatment is mandatory for proliferative diabetic retinopathy. Vitreous hemorrhage, retinal detachment involving the macula, retraction and hole-derived retinal detachment, preretinal hemorrhage and fibrovascular proliferation, and early iris neovascularization are all indications for surgery.