Vitritis is often secondary to inflammatory diseases of surrounding tissues, such as intermediate uveitis and posterior uveitis. It can also result from trauma or surgery introducing pathogenic microorganisms into the eye. Vitritis is classified into non-infectious and infectious forms.
Non-Infectious Vitritis
The inflammatory response originates from surrounding tissues such as the iris, ciliary body, and choroid.
Infectious Vitritis
Endogenous Causes
Pathogenic microorganisms may enter the eye through the bloodstream or lymphatic system, or infections may occur due to immunosuppression or immune deficiency. Conditions such as bacterial endocarditis or pyelonephritis can lead to bacterial infections of the vitreous. Fungal infections are often observed in patients who have undergone organ transplantation, chemotherapy for tumors, or prolonged use of broad-spectrum antibiotics, with Candida being the most common pathogen.
Exogenous Causes
The vitreous provides an excellent medium for microbial growth. The entrance of bacteria or other microorganisms into the vitreous cavity can result in vitreous inflammation, also referred to as endophthalmitis.
Postoperative Endophthalmitis
This can occur after any intraocular surgery, such as procedures for cataract, glaucoma, corneal transplantation, vitrectomy, or repairs for penetrating ocular injuries. Staphylococcus species are the most common pathogens. Pathogens may originate from the eyelids, eyelashes, or lacrimal drainage system, and surgical sutures or intraocular lenses can also serve as sources of infection.
Open Globe Injuries
Injuries such as globe rupture or the presence of intraocular foreign bodies are particularly prone to causing vitreous infection.
To be continued