This study is a systematic review of the literature on etiological structure, pathogenetic mechanisms, clinical manifestations, diagnostic approaches, and therapeutic strategies for endophthalmitis. The review discusses in detail the principal clinical forms of the disease (postoperative, post-traumatic and endogenous), their microbiological characteristics, and epidemiological features. Gram-positive cocci were shown to be the leading pathogens (85.1%), predominantly Staphylococcus epidermidis (30.3%), Streptococcus viridans (12.1%), and Staphylococcus aureus (11.1%). The article presents contemporary data on the incidence of endophthalmitis after various ophthalmic procedures, ranging from 0.046% after vitrectomy to 0.366% after secondary intraocular lens implantation. The review highlights key aspects of pathogenesis, including the role of microbial virulence, biofilm formation, and the host inflammatory response, and describes in detail the clinical manifestations of different forms of endophthalmitis, with emphasis on differential diagnostic criteria. The article also presents current algorithms for laboratory and instrumental confirmation of the diagnosis, including visual acuity testing, slit-lamp biomicroscopy, B-scan ultrasonography, microbiological, and molecular genetic methods, analyzes principles of antibacterial therapy (systemic, topical, and intravitreal), and substantiates the role of early vitrectomy in severe forms of the disease. This work emphasizes the importance of interdisciplinary collaboration, preventive measures, and timely recognition of endogenous forms, and notes prospects for further research, including the implementation of nanopore sequencing and optimization of antibacterial protocols based on local antimicrobial resistance data.