ObjectiveTo observe the proteomic changes in vitreous fluid samples from patients with rhegmatogenous retinal detachment combined with choroidal detachment (RRDCD). MethodsA prospective cross-sectional clinical study. Vitreous fluid samples were collected from 35 patients with RRDCD (RRDCD group) and 40 patients with rhegmatogenous retinal detachment (RRD group) who were diagnosed at Wuhan Aier Eye Hospital between November 2021 and December 2023. Prior to vitrectomy, 0.3-0.5 μl of vitreous fluid was collected from the affected eyes. Differentially expressed proteins were analyzed using Data-Independent Acquisition (DIA). Three of these proteins were randomly selected for validation using enzyme-linked immunosorbent assay (ELISA). Bioinformatics analyses, including gene ontology functional enrichment and kyoto encyclopedia of genes and genomes pathway enrichment, were performed to explore the functions of the differentially expressed proteins. ResultsSignificant differences were observed between the RRDCD and RRD groups in intraocular pressure (t=－12.795), the number of retinal tears (t=4.601), the extent of retinal detachment (χ2=39.642), axial length (t=0.840), postoperative proliferative vitreoretinopathy incidence (χ2=4.730), single-surgery reattachment rate (χ2=7.717), and best-corrected visual acuity (t=7.033) at 6 months postoperatively (P＜0.05). A total of 237 differentially expressed proteins were identified between the RRDCD and RRD groups, with 63 upregulated and 174 downregulated. These proteins were involved in pathways such as extracellular matrix-receptor interaction, complement activation, coagulation, and lysosomal pathways. ELISA validation results showed that the expression trends of the three selected proteins in the RRDCD and RRD groups were consistent with the DIA proteomic analysis. Compared to the RRD group, proteins such as fibrin, coagulation factors, cathepsins, and trypsin inhibitors were significantly upregulated in the RRDCD group. ConclusionsThe protein expression profile in vitreous fluid samples from RRDCD patients show significant alterations compared to the RRD group. These differential changes suggest that RRDCD is closely associated with complement and coagulation cascade activation, lysosomal pathways, and extracellular matrix remodeling.