8 Eye Conditions Associated with Systemic Diseases

7. Infectious Retinitis - Systemic Infections Affecting the Eye

Infectious retinitis encompasses a spectrum of sight-threatening conditions caused by various pathogens that reach the retina through hematogenous spread from systemic infections, making the eye a critical site for diagnosing and monitoring infectious diseases. Cytomegalovirus retinitis, once a leading cause of blindness in AIDS patients, remains a significant concern in immunocompromised individuals, presenting as characteristic "pizza pie" or "cottage cheese and ketchup" retinal lesions that progress rapidly without treatment. Toxoplasma gondii, the most common cause of posterior uveitis worldwide, typically manifests as focal necrotizing retinochoroiditis with an adjacent chorioretinal scar, often representing reactivation of congenital infection during periods of immunosuppression. Bacterial endophthalmitis, though less common, can result from bacteremic spread in patients with endocarditis or other systemic infections, presenting as severe intraocular inflammation with rapid vision loss. Fungal retinitis, particularly Candida species, occurs predominantly in immunocompromised patients or those with indwelling catheters, appearing as white, fluffy retinal lesions that may extend into the vitreous. The diagnosis of infectious retinitis often requires a combination of clinical recognition, laboratory testing including polymerase chain reaction of ocular fluids, and systemic evaluation to identify the source of infection. Treatment strategies vary by pathogen but typically involve systemic antimicrobial therapy, with intravitreal injections reserved for severe cases or when systemic therapy is contraindicated. The prognosis depends on early recognition and prompt treatment, as delayed intervention can result in permanent retinal damage, retinal detachment, and irreversible vision loss.