We often encounter patients with diabetic fundus hemorrhage, proliferation, and basic loss of vision in our outpatient clinics. When asked about their medical history, several of these patients were not unaware of their fundus lesions, but were the result of untimely treatment. Some patients gave up laser when they heard that laser has the risk of causing vision loss; some gave up laser after 1-2 shots of vision loss; and some even complained that the doctor broke their eyes because of vision loss after laser. It must be clear that laser is currently the best treatment for proliferative diabetic retinopathy and the definitive and effective one. Even if some patients can first be treated with other methods such as intraocular injections of anti neovascular drugs, eventually laser treatment will be needed to stabilize the fundus. It usually takes 4-5 sessions to complete total retinal photocoagulation, and can be completed in 2-3 sessions for individual patients using multi-point laser. There are two main reasons for vision loss due to laser treatment: first, the laser may cause or aggravate macular edema after the laser; second, the laser may cause temporary darkening of peripheral vision. Macular edema after laser is not uncommon. Extending the laser interval can reduce the degree of edema or targeting macular edema after completing the laser. Post-laser peripheral vision darkening is related to laser spot burning and usually recovers after 3 months to 6 months. There are pros and cons to any treatment, and in the case of patients with proliferative diabetic retinopathy, the pros definitely outweigh the cons by insisting on completing total retinal photocoagulation. Otherwise, if the fundus really progresses to a point where surgery is required or inoperable, it will be too late to regret.