Diabetic retinopathy is a common and serious complication of diabetes and one of the leading eye diseases of visual impairment and blindness worldwide. Before the advent of photocoagulation therapy, diabetic retinopathy was an incurable ophthalmic condition that could only progress in term once it occurred. Since the 1970s, retinal laser treatment has saved a large number of diabetic patients who were about to go blind. Fundus laser treatment has been able to reduce the rate of blindness by 60-80%. Nowadays, laser treatment for diabetic retinopathy is commonly performed in China, but many diabetic patients lack knowledge and understanding of laser treatment. In this article, we will introduce the basic knowledge of fundus laser treatment to diabetic patients. I. How is fundus laser treatment achieved? When it comes to laser therapy, many patients feel confused or even afraid, not knowing what laser therapy is all about. In fact, fundus laser treatment is the earliest area of medicine where laser technology has been successfully applied. Because the eye itself is an ideal optical system, the laser has a great advantage in the treatment of fundus diseases. The most important characteristic of laser is its good directionality. It can pass through the transparent refractive interstitium of the eye and reach the fundus directly, and achieve the effect of photocoagulation through the absorption of light by the retinal pigment tissue, so that the treatment of fundus disease can be completed without any incision or damage to the eye. Before laser treatment, the pupil needs to be dilated, then the patient sits in front of the slit lamp as if undergoing an eye examination, and the doctor sits across from the patient and performs photocoagulation on the diseased retina under the guidance of a laser contact lens. There may be slight swelling and pain during the treatment, and there is usually no significant discomfort at the end of the treatment and you can walk home. In the short term after laser treatment, there may be a transient loss of vision that recovers in 1-2 months. In general, all patients with vision-hazardous diabetic retinopathy need laser treatment. Vision-threatening diabetic retinopathy refers to proliferative retinopathy and diabetic macular edema. Proliferative retinopathy is marked by the appearance of neovascularization in the retina and, if left untreated, often leads to blindness due to complications of vitreous hemorrhage and detachment of the retina by traction. Macular edema is an abnormal blood vessel in the macular region of the retina, with leakage leading to localized retinal edema and thickening, and occurs in patients with type 2 diabetes. Significant macular edema is a common cause of moderate visual impairment in diabetic patients. Therefore, laser treatment should be considered when diabetic retinopathy progresses to the proliferative stage or macular edema appears. III. Timing of fundus laser treatment Diabetic retinopathy is a long developmental process. In mild cases, there are only a few microangiomas or hemorrhages in the fundus, which may not have any effect on the patient’s vision and therefore do not require laser treatment, while in severe cases, extensive proliferative vitreoretinopathy may occur and the best time for laser treatment will be lost. The best time for laser treatment of proliferative retinopathy is before advanced complications occur, when the fundus is staged as stage IV. At this time, the refractive interstitium is clear and the retina responds clearly and reliably to laser photocoagulation. Treatment is effective. Patients with severe stage III, which we call preproliferative, can also be treated with laser earlier and often have a good visual prognosis. Macular edema can occur at any stage of the fundus lesion. Those who meet the criteria for significant macular edema are indications for laser treatment. Therefore, regardless of the stage of fundus degeneration, once there is significant macular edema, laser treatment should be considered immediately. IV. Why fundus laser treatment can reduce blindness in diabetic patients Diabetic retinopathy causes blindness due to severe proliferative retinopathy resulting in vitreous hemorrhage and detachment of the retina by traction. Timely laser treatment can improve retinal ischemia and hypoxia, induce atrophy of neovascularization and cessation or regression of proliferative retinopathy, thus preventing the occurrence of vitreous hemorrhage and retinal detachment. Laser treatment of macular edema can close the leaky point and diseased blood vessels, reduce retinal exudative lesions, make macular edema subside, and prevent further vision loss. It is worth emphasizing that whether laser treatment is effective or not cannot be decided according to the visual acuity after treatment, but depends on whether the fundus lesions are stable and the factors that endanger the vision are eliminated. In a word, the purpose of laser treatment is to prevent blindness. The post-treatment visual acuity depends on the level of vision before treatment. Therefore, fundus laser treatment is more effective when it is performed before severe vision impairment. V. Number of times of fundus laser treatment The number of times of fundus laser treatment depends on the kind of laser treatment done. If the macular edema does not improve after 3-4 months, the laser treatment can be repeated. Proliferative retinopathy requires total retinal photocoagulation, which usually requires 3-4 laser treatments.
4 times to complete the laser treatment, each time at an interval of one week, with a minimum of not less than 4 days. The total number of light spots is around 1000. The purpose of split laser treatment is to reduce the damage of laser photocoagulation on eye tissue and avoid the side effects of laser treatment. Sixth, the review after fundus laser treatment The fundus laser treatment must be reviewed regularly. The purpose is to understand the efficacy of laser treatment including whether the density and scope of photocoagulation is sufficient, whether the fundus lesion is improved and whether additional laser treatment is needed. According to the author’s experience, the visual acuity and fundus should be reviewed at 2 and 6 months after whole retinal photocoagulation laser treatment, and fundus angiography should be reviewed one year after surgery. If the edema does not subside significantly, fundus angiography should be done to clarify the site of leakage and supplement laser treatment or give other treatments according to the situation. It should be noted that the treatment of diabetic macular edema also has other methods such as not vitreous cavity drug injection treatment, which will not be discussed in this paper. In summary, fundus laser treatment is currently an effective means of preventing diabetic blindness. Fundus laser treatment is not only less painful, but also convenient and economical. Every diabetic patient should understand and correctly understand the role of fundus laser treatment, have regular dilated fundus examinations, detect diabetic retinopathy that endangers vision in time, and receive laser treatment in time, so as to ensure your quality of life and save your vision from damage.