Diabetic retinopathy is one of the most serious diabetic microangiopathy and the main cause of blindness in adults. With the economic development and improvement of living standard in China, there are more and more diabetic patients. Currently, there are more than 90 million confirmed diabetic patients and nearly 100, 500 million hidden patients in China. Diabetic retinopathy is a serious eye complication that is bound to occur in diabetic patients, and studies have found that the incidence of diabetic retinopathy will be as high as 75% if the duration of diabetes exceeds 15 years. The pathogenesis of diabetic retinopathy has not yet been fully elucidated, and there is no exact and effective cure. Therefore, early detection and early treatment are essential to slow down its progression and preserve useful vision for the majority of patients.
I. Symptoms in patients with diabetic retinopathy.
Most patients with diabetic retinopathy generally have no conscious symptoms in the early stages of the disease. However, with the development of the lesion, vision loss can occur to varying degrees. If the lesion involves the macula, the most important part of the retina, the visual acuity will be severely reduced, even accompanied by visual distortion and other conditions. When the disease progresses further, the patient may feel a black shadow floating in front of his eyes when a small amount of bleeding from the neovascularization enters the vitreous cavity. When a large amount of neovascularization bleeds into the vitreous cavity, patients can lose their vision. If the disease continues to develop, neovascular glaucoma may occur, and patients may experience eye pain, eye distention, headache, nausea, vomiting and other symptoms.
Pathological changes of diabetic retinopathy
Diabetic retinopathy is a microangiopathy in which elevated blood glucose causes loss of capillary endothelial cell function, resulting in capillary occlusion and thus a non-perfused area. Capillary occlusion leads to retinal ischemia and hypoxia, and the body compensates by generating neovascularization in the retina. Unhealthy neovascularization can easily rupture and bleed, leading to vitreous blood accumulation and eventual development of retinal detachment by traction.
III. Staging of diabetic retinopathy
In 1985, the third fundus group discussed and suggested that diabetic retinopathy should be divided into 6 stages, with microangioma and hemorrhagic spots visible in the fundus of stage 1, hard exudate in addition to microangioma and hemorrhage in stage 2, absorbent cotton spots in addition to microangioma, hemorrhage and hard exudate in stage 3, and non-proliferative diabetic retinopathy in stage 1-3. In stage 4, neovascularization or vitreous blood accumulation occurs in the fundus, in stage 5, intraretinal or intravitreal fiber proliferation appears, and in stage 6, retinal detachment with traction appears, and stages 4-6 are proliferative diabetic retinopathy.
In 2003, a new international staging of diabetic retinopathy was proposed, which was divided into 5 stages
Stage 1 has no obvious retinopathy and no fundus abnormality
Stage 2 mild non-proliferative diabetic retinopathy, with only microangiomas in the fundus
Stage 3 moderate non-proliferative diabetic retinopathy, with only a few more lesions than microangiomas, but not as severe non-proliferative diabetic retinopathy
Stage 4 severe non-proliferative diabetic retinopathy with fundus manifestations of any of the following: more than 20 intraretinal hemorrhages in each of the 4 quadrants, retinal vein bead-like changes in 2 quadrants, and intraretinal microvascular abnormalities in 1 quadrant
Stage 5 is proliferative diabetic retinopathy: one or more of the following manifestations appear in the fundus, such as neovascularization, vitreous or preretinal hemorrhage
IV. Common eye examinations for diabetic patients
1. Slit lamp examination: mainly to determine the presence or absence of cataract or to detect neovascularization on the iris surface.
2. Fundus examination: the most commonly used examination means, which can check whether the retina has hemorrhage, exudation and other fundus changes.
3. Color fundus photography: It is the best means to objectively record the extent of fundus lesions, and patients themselves can compare before and after by fundus photography to understand whether the disease has progressed.
4. Fluorescein fundus angiography: First of all, we would like to introduce fluorescein fundus angiography, sodium fluorescein is a contrast agent, which can emit green light under the excitation of blue light, injecting sodium fluorescein into the blood vessels, and through the vascular circulation, sodium fluorescein enters the retinal vessels. Normal blood vessels sodium fluorescein cannot leak out from normal blood vessels, while the neovascularization is unhealthy, sodium fluorescein can leak out from it and enter the retinal tissue, which is excited by blue light and emits green light, thus being captured. It is the most definitive means of clarifying the severity of diabetic retinopathy. Fundoscopy sometimes does not detect peripheral retinopathy or microvascular occlusion resulting in nonperfusion areas or neovascularization, while fluorescein fundus angiography is extremely sensitive to detect nonperfusion areas and neovascularization, so that problems can be detected and treated in time to avoid progression. Fluorescein fundus angiography is also an important tool to guide retinal photocoagulation.
5. Ocular ultrasound: It helps to understand the condition of vitreous and retina.
6. IOP: to clarify the presence of neovascular glaucoma.
V. Relevant factors affecting the development of DR
The occurrence and development of DR is related to many factors, mainly related to the duration of diabetes, blood sugar control, blood pressure, lipids, kidney disease, and other factors. Han Jindong, Department of Vitreoretinal and Ocular Trauma, Eye Hospital of Tianjin Medical University
1. Duration of disease: The duration of disease has the greatest impact on the occurrence of diabetic retinopathy and is the key factor determining the development of diabetic retinopathy. The duration of diabetes is positively correlated with the development of diabetic retinopathy. The incidence of diabetic retinopathy increases as the duration of the disease increases. 25% of diabetic retinopathy occurs within 5 years, 50% of diabetic retinopathy occurs between 5 and 15 years, and up to 75% of diabetic retinopathy occurs over 15 years.
2, blood sugar control: ideal control of blood sugar in diabetic patients, blood sugar fluctuations are small, can significantly reduce the risk of diabetic retinopathy and delay the progression of diabetic retinopathy.
3, blood pressure: high blood pressure causes endothelial hyperplasia, sclerosis, luminal narrowing and even occlusion of arteries, causing retinal ischemia, hypoxia, and neovascularization, and increased blood pressure is positively correlated with the occurrence and development of diabetic retinopathy.
4, lipid: diabetic patients often combined with high lipid, abnormal lipid metabolism can increase blood viscosity leading to abnormal microcirculation, aggravate the retinal exudation and edema, seriously affect the macular function of patients.
5, trace elements magnesium: recent years of research shows that the change in the amount of trace elements affect the development of DR, it is now widely believed that the reduction of serum magnesium is one of the factors affecting the development of DR. Diabetic patients due to dietary control and osmotic diuresis lead to varying degrees of magnesium deficiency, resulting in hypomagnesemia.
6, nephropathy: diabetic nephropathy and DR pathogenesis have many similar basis and characteristics, and the two often coexist with each other, the severity of the relationship is also parallel. Therefore, once the patient found diabetic nephropathy, should promptly perform eye examination, when almost all patients have eye damage.
7. Other: There are many other factors affecting DR, such as inflammation, obesity, smoking, alcoholism and other factors, but the role of its impact on diabetic microvascular complications is uncertain, and the mechanism needs further study.
Sixth, the ocular factors affecting diabetic retinopathy
Eye surgery: Some studies have shown that patients with existing diabetic retinopathy who have not yet undergone retinal laser treatment will have accelerated progression of diabetic retinopathy after cataract surgery. Of course, we are not saying that diabetic patients cannot have cataract surgery, but we just remind these patients that they should have their eye fundus checked and treated accordingly after surgery to prevent the progression of the disease.
DR treatment: Intensive blood sugar control is the key factor to slow down the development of DR.
1.Medication: For diabetic retinopathy, there are no effective preventive and therapeutic drugs, but only symptomatic treatment according to the degree of the lesion. Early patients can be given drugs to improve microcirculation (such as calcium hydroxybenzene sulfonate), nutritional drugs (such as vitamin B1, methylcobalamin, etc.) and other drugs taken orally. With the development of lesions, patients with vitreous hemorrhage may be given drugs to stop bleeding, activate blood circulation and promote blood absorption (e.g. Yunnan Baiyao, Panax notoginseng powder, etc.). At the same time, blood pressure, blood lipids and other risk factors that accelerate the development of the disease should be controlled.
2.Laser treatment ：
Since the laser treatment of diabetic retinopathy was introduced in 1959, laser photocoagulation has become an important tool for the treatment of DR and is the most effective treatment method known to date. Although it is a destructive treatment, domestic and international related studies have confirmed that effective laser treatment can reduce vision loss in 50% of severe patients, especially for type II diabetic patients, early diffuse photocoagulation is currently a very effective method for reducing vision loss.
1) Mechanism of action
(1) The laser destroys the photoreceptor cells with high metabolism and oxygen consumption, reduces the oxygen demand in the outer layer of the retina, promotes oxygen diffusion to the inner layer of the retina, improves the hypoxic state of the inner layer of the retina, and prevents the expression of angiogenic factors. (2) To occlude the abnormal capillaries and neovascularization and reduce the chance of vitreous blood accumulation.
(2) Indications
Stage 3 and some stage 4 patients need to undergo total retinal photocoagulation. If the patient is found to have neovascularization in the iris, photocoagulation should be performed immediately to prevent neovascular glaucoma, even if no retinal neovascularization is found.
3) Follow-up treatment and supplemental photocoagulation after total retinal photocoagulation
Long-term follow-up after total retinal photocoagulation is necessary and is the best way to ensure stable postoperative outcomes and timely treatment of complications. Indications for supplemental photocoagulation: recurrence or the appearance of new retinal neovascularization; macular edema and treatable leakage. Follow-up should be done at least 3 times in the first year after total retinal photocoagulation at 3 months, 6 months and a year, and semi-annually in the second to third year, and annually or every 1 to 2 years thereafter, and preferably annually with FFA.
3.Surgical treatment
For proliferative diabetic retinopathy, vitrectomy should be considered for timely treatment. In fact, vitrectomy is also mainly for intraoperative and postoperative laser treatment to provide opportunities. The indications for vitreous surgery include: severe refractive interstitial clouding caused by vitreous blood accumulation, which cannot be absorbed by drug conservative treatment for 1 month; dense pre-macular hemorrhage; retinal detachment by traction; neovascular glaucoma, etc.
VIII. Follow-up
The American Diabetes Association (ADA) and the American Academy of Ophthalmology (AAO) recommend the following follow-up times for diabetic patients.
(1) no retinopathy or only microangioma, every 12 months dilated pupil examination fundus.
(2) Mild/moderate NPDR, if no DME, dilate the fundus every 6 to 12 months; if DME but no CSME, dilate the fundus every 4 to 6 months; if CSME is present, dilate the fundus every 3 to 4 months.
(3) In severe NPDR, the fundus should be examined every 3 to 4 months.
(4) PDR usually requires PRP, then follow the principle of post-laser follow-up. Do FFA examination if necessary.
The current situation in China is not suitable for the above review time, the main reasons are as follows: 1, most patients do not pay enough attention, blood sugar control is also not ideal, and will not take the initiative to carry out routine eye examinations. 2, most patients do not have relevant medical common sense, even if there is a decline in vision, but also thought it would be aging factors. 3, limited financial ability, many patients will not go to the hospital examination until completely, at this time often miss the best treatment time . We therefore suggest that according to the pathogenesis of the onset of diabetes, diabetic patients can be divided into two types, type 1 diabetes and type 2 diabetes. For type 1 diabetic patients, it is recommended that patients need to have an eye examination 1 year after the diagnosis of diabetes. For type 2 diabetes, eye exams are recommended at the time of diagnosis. For patients who are found to have early lesions in the eye (stage 1 and 2 diabetic retinopathy in China), patients are advised to have a repeat visit every 3 months. For stage 3 and some patients who can still be considered for laser treatment, it is recommended that retinal photocoagulation be completed as soon as possible, and that retinal photocoagulation be reviewed every 3 months after photocoagulation, with repeat FFA examinations and supplemental photocoagulation if necessary.
IX. Disease prognosis and prevention
The occurrence and progression of DR is very complex and is associated with a variety of factors. Although the pathogenesis of DR has not yet been fully elucidated and there is no effective cure, strict control of blood sugar, active treatment of hypertension and hyperlipidemia, regular review of fundus, and timely laser photocoagulation and vitreous surgery are effective means to prevent or delay its progression and can preserve useful vision for the majority of patients. With early and appropriate treatment, the incidence of blindness decreases by 90% within five years. Nevertheless, only 35% to 50% of patients have regular checkups, and many patients miss the best time for laser treatment, so it is essential to improve education and screening programs for diabetic patients. Han Jindong, Department of Vitreoretinal and Ocular Trauma, Eye Hospital of Tianjin Medical University
Daily life can pay attention to.
1, diet moderation: the key to chronic diabetes moderation is diet, the dietary requirements for different types of patients are different, such as obese people to reduce caloric intake, reduce body weight, increase the sensitivity of the organism to insulin, so that blood glucose falls; lean people and young children, appropriate to increase caloric intake. The total amount of daily meals and the distribution of three meals are relatively fixed, and the diet should be low in sugar, low in fat, high in egg white and high in fiber, with more coarse grains and less refined rice, refined white flour and fruits with high sugar content, and forbidden to eat a diet rich in monosaccharides or disaccharides, such as skin sugar, pastries, ice cream and sweet drinks.
2. Self-monitoring of blood glucose: Mediate the dosage of oral hypoglycemic drugs or insulin through the measurement of urine sugar before meals. Follow the doctor’s advice on medication, not less than self-medication.
3, combined with hypertension to actively lower blood pressure: blood pressure is generally restrained below 140/ 90mmHg.
4.Prevent hypoglycemic reaction: explain to the patient the symptoms of hypoglycemic reaction and the measures to be taken, especially before meals and bedtime and after medication.
5. Pay attention to eye hygiene: avoid staying up late and using eyes at close intervals for a long time.
6, actively quit smoking; smoking will lead to increased CO in the body caused by relative hypoxia and platelet clotting, speeding up the occurrence of chronic diabetic retinopathy.
Ten, treatment myths
1, laser treatment will lead to blindness: currently it is believed that retinal photocoagulation is the most effective laser treatment for diabetic retinopathy is indeed a destructive treatment method, it is through the destruction of the outer layer of the retina tissue, reduce retinal hypoxia, so as to ensure the key inner retinal tissue, thus preserving part of the important visual function, so the treatment method will not lead to blindness of patients. There are many reasons for some patients’ vision loss or even blindness after laser treatment, such as macular edema, laser is not comprehensive enough for patients to review the supplemental laser in time leading to continued progress and eventual blindness, while there is no relationship with laser treatment.
2, laser treatment once and for all: poor control of diabetes, diabetic retinopathy will still progress, retinal ischemia and hypoxia will still aggravate, but also need close follow-up, review FFA and supplemental laser treatment when necessary.
3, laser and surgical treatment can restore vision: laser and surgical treatment for most patients can only maintain the existing vision, so that it no longer progresses, of course, for the timely treatment of retinal function is not heavily damaged many patients can improve vision, while for some advanced patients with serious damage to retinal function, any treatment may not help, so it is still recommended that patients timely consultation, early detection, early treatment, in order to Therefore, it is still recommended that patients should be seen in time for early detection and treatment in order to have more desirable results.