Circular RNAs (circRNAs) refer to a newly recognized family of non-coding RNA 
with single-stranded RNAs. Despite emerging evidence indicating that circRNAs 
are abundantly expressed in various tissues, especially in the brain and retina, 
the role of circRNAs in retinal function and diseases is still largely unknown. 
Circular Rims2 (circRims2) is highly expressed and conserved in both the human 
and mouse brains. However, little is known about the expression and function of 
circRims2 in the retina. In the current study, the high-throughput RNA-seq 
analysis reveals a high expression of circRims2 in the retina. In addition, it 
is found that circRims2 is mainly located in plexiform layers that contain 
synapses between retinal neurons. Knocking down circRims2 with short hairpin RNA 
through subretinal adeno-associated viral (AAV) delivery in the mice leads to 
the decrease of the thickness of the outer and inner segment (OS/IS) layers and 
outer nuclear layer (ONL), and cessation of scotopic and photopic 
electroretinogram responses. Furthermore, the current study finds that circRims2 
deficiency evokes retinal inflammation and activates the tumor necrosis factor 
(TNF) signaling pathway. Therefore, circRims2 may play an important role in the 
maintenance of retinal structure and function, and circRims2 deficiency may lead 
to pathogenic changes in the retina.