Background Uveal effusion syndrome is a rare disease characterized by exudative detachments of the choroid, ciliary body, and retina. Various surgical procedures and nonsurgical strategies have been described to treat uveal effusion syndrome with limited success. The treatment for uveal effusion syndrome remains a serious challenge for clinicians. To the best of our knowledge, no previous report has described a severe uveal effusion syndrome patient with nanophthalmos treated by using an anti-vascular endothelial growth factor agent alone. We report here one such case with unexpected positive results. Case presentation A 30-year-old Chinese male patient presented with painless vision loss in both eyes that had persisted for 2 months. Examination of the right eye revealed a best corrected visual acuity of 0.03; the best corrected visual acuity of the left eye was finger count/20 cm. The intraocular pressure was normal on both eyes. A-scan revealed an right eye axial length of 15.88 mm and a left eye axial length of 16.21 mm. In the right eye, half of the peripheral choroid and nearly three-fourths of the retina were detached. The left fundus was not visible because of the total retinal detachment located just behind the lens, which could be clearly observed directly with a slit lamp. Considering all the possibilities and available treatments as well as the patient's intentions after discussion, we first administered an intravitreal injection of ranibizumab 0.5 ml into both eyes. The patient's visual perception improved 3 days after the injection. One month later, most of the effusion under the choroid and retina was absorbed. Visual acuity improved from finger count to 0.05 in both eyes, and vision quality was remarkably improved. Encouraged by this good result, the patient opted to undergo a second injection 1 month later. Choroidal and retinal detachment completely vanished 30 days after the second injection. Conclusions Using an anti-vascular endothelial growth factor agent alone may be a potentially effective and safe method for managing some types of uveal effusion syndrome, such as in nanophthalmos. The injection may be administered before considering more aggressive procedures in some uveal effusion syndrome patients.