ObjectiveTo observe the efficacy of intravitreal injection of ranibizumab (IVR) and combined treatment for severe Coats disease. MethodsNineteen Coats disease patients (24 eyes) were enrolled in this retrospective non-comparative interventional clinical study. The patients included 17 males and 2 females. The age was ranged from 1 to 42 years old, with an average of (13.05±6.78) years. The patients included 15 children (age ≤14 years old) and 4 adults (age ≥18 years old). There were 13 patients with 3a stage and 6 patients with 3b stage. The treatment methods including IVR only, IVR combined with cryotherapy, IVR combined with cryotherapy and sclerotomy to drain subretinal fluid, IVR combined with vitrectomy. Treatments were repeated if it was necessary at the first day, the first week and the first month after injection. The interval between treatments was ≥1 month. Eleven patients (57.9%) underwent one treatment, 3 patients (15.8%) underwent 2 treatments, 3 patients (15.8%) underwent 3 treatments, 2 patients (10.5%) underwent 4 treatments. The treatment frequency including 22 times of IVR only, 6 times of IVR combined with cryotherapy, 5 times of IVR combined with cryotherapy and sclerotomy to drain subretinal fluid, 1 time of IVR combined with vitrectomy. The follow-up period was ranged from 6 to 36 months, with an average of (19.11±7.05) months. Visual acuity, retinal reattachment and ocular adverse events were observed. ResultsThree children (15.8%) were failing to test the visual acuity. Visual acuity was improved in 2 patients (10.5%), stable in 13 patients (68.4%) and decreased in 1 patient (5.3%). Three patients (15.8%) achieved totally retinal reattachment after treatment, while 16 patients (84.2%) achieved partially retinal reattachment. One patient had vitreous hemorrhage. One patient had neovascular glaucoma. ConclusionIVR and combined treatment were effective for severe Coats disease.