Vitritis is inflammation of the vitreous, the gel-like substance that fills the interior of the eye. It shows up as an infiltration of immune cells into the vitreous body, most often in the context of intraocular inflammation, though not always.1PubMed. Differential Diagnosis of Vitritis in Adult Patients Because the vitreous sits right in the line of sight, this cellular invasion can blur vision, produce floating spots, and, if left unchecked, threaten permanent visual damage. The condition is not a standalone disease so much as a sign that something else is going wrong, and the list of possible culprits ranges from infections and autoimmune disorders to post-surgical reactions and even cancer.
How Vitritis Differs from Uveitis
You will often see vitritis discussed alongside uveitis, and the two terms overlap but are not identical. Uveitis refers broadly to inflammation of the uveal tract, which includes the iris, the ciliary body, and the choroid. When that inflammation spills into or primarily involves the vitreous humor, the resulting cellular haze is called vitritis. In clinical classification, vitritis is most closely associated with intermediate uveitis (where the vitreous is the main site of inflammation) and posterior uveitis (where the retina and choroid are inflamed and vitreous cells accumulate secondarily). A patient can have uveitis in the front of the eye without any vitritis at all, and conversely, some conditions produce vitritis with relatively little inflammation elsewhere in the eye.
What Causes Vitritis
Pinning down the cause is the single most important step in managing vitritis, because the treatment changes dramatically depending on whether the inflammation is driven by an infection, an immune misfire, a drug reaction, or something more sinister like lymphoma. Here are the major categories.
Infections
Bacteria and fungi can invade the interior of the eye after surgery or trauma, a condition called endophthalmitis. These infections often lead to severe vision loss if not treated urgently.2PubMed Central. Proteomic profiling reveals immunomodulatory role of IL-33 in ocular bacterial and fungal infections Viral infections such as herpes simplex, herpes zoster, and cytomegalovirus (CMV) are another well-known set of triggers, particularly in people whose immune systems are compromised. Toxoplasmosis, a parasitic infection, is one of the most common infectious causes of posterior uveitis worldwide and can produce dense vitreous inflammation. In people with advanced HIV/AIDS, toxoplasmosis of the eye has been documented alongside other retinal infections including CMV and syphilis, sometimes even occurring simultaneously in the same eye.3PubMed Central. Ocular toxoplasmosis in AIDS patients Tuberculosis and syphilis round out the infectious list, and both can mimic noninfectious inflammation closely enough to fool clinicians if lab testing is skipped.
Autoimmune and Inflammatory Diseases
A large share of vitritis cases have no detectable pathogen. Instead, the immune system attacks the eye’s own tissues. Sarcoidosis, Behçet’s disease, Vogt-Koyanagi-Harada syndrome, and sympathetic ophthalmia are among the best-studied examples. In these conditions, T-helper lymphocytes and human leukocyte antigens are thought to play central roles, though the precise triggers that kick off the immune response remain unclear. The working theory is that an external agent, whether a virus, a bacterium, or an endogenous molecule, sets the process in motion, and then the immune system sustains it long after the initial trigger is gone.4Survey of Ophthalmology. Immunopathology of posterior and intermediate uveitis Multiple sclerosis, juvenile idiopathic arthritis, and inflammatory bowel disease can also be associated with intermediate uveitis and significant vitritis.
Post-Surgical and Drug-Induced Inflammation
Vitritis can appear after eye injections or surgery even when no infection is present. This sterile form of inflammation has been documented after intravitreal injections of both corticosteroids like triamcinolone acetonide and anti-VEGF agents like bevacizumab, which are widely used for conditions such as macular degeneration and diabetic eye disease. In most of these cases, vision loss comes on suddenly but is painless, and the anterior segment of the eye shows only mild to moderate inflammation while dense vitreous opacity dominates the picture.5PubMed Central. Sterile endophthalmitis after intravitreal injections The reaction is thought to be triggered by components of the drug formulation or by the preservatives used, rather than by bacteria.
Beyond intravitreal injections, uveitis and vitritis have been linked to various systemic, topical, and intraocular medications.6PubMed Central. Medication-induced Uveitis: An Update Rifabutin, an antibiotic used for tuberculosis and related infections, is one of the more commonly cited culprits. Certain immunotherapy drugs, including checkpoint inhibitors used in cancer treatment, have also been associated with ocular inflammation. When drug-induced vitritis is suspected, stopping or switching the offending medication is usually the first therapeutic step.
Masquerade Syndromes
Some of the most dangerous causes of vitritis are conditions that mimic standard inflammation but are actually something else entirely. Primary intraocular lymphoma (PIOL) is the classic masquerade syndrome. It tends to affect older adults and can look like chronic uveitis for months before the true diagnosis is made. In one study of 84 vitrectomy specimens from patients suspected of having masquerade syndrome, about three-quarters showed a reactive cellular infiltrate that looked inflammatory, while roughly 14% were confirmed as malignant lymphoma. All confirmed lymphomas were diffuse large B-cell lymphoma. In some cases, an additional biopsy from the choroid and retina was needed to reach a definitive diagnosis.7Graefe’s Archive for Clinical and Experimental Ophthalmology. Evaluation of vitrectomy specimens and chorioretinal biopsies in the diagnosis of primary intraocular lymphoma in patients with Masquerade syndrome This is a situation where missing the diagnosis can be fatal, so clinicians are trained to suspect lymphoma when vitritis does not respond to standard anti-inflammatory therapy.
Symptoms and How They Feel in Daily Life
The hallmark symptom of vitritis is floaters, those drifting spots, strands, or cobweb-like shapes in your field of vision. They result from clumps of inflammatory cells and protein casting shadows on the retina. As the inflammation worsens, floaters multiply and vision becomes increasingly hazy, as if you are looking through fog. Blurred vision is the other major complaint. In severe cases, the vitreous becomes so clouded that it is difficult to read, drive, or recognize faces.
Pain is variable. Some causes of vitritis, particularly infections, bring noticeable pain and redness. Others, especially the sterile post-injection variety, are largely painless. In a study comparing noninfectious vitritis episodes after different anti-VEGF injections, rates of pain, blurred vision, and floaters did not differ significantly across medications.8Retina. Noninfectious Vitritis after Intravitreal Injection of Anti-VEGF Agents The lack of pain does not mean the condition is benign, though. Painless vitritis can still threaten sight if the underlying cause is aggressive.
Beyond the physical symptoms, vitreous opacities carry a genuine psychological burden. A systematic review found that patients with vitreous opacities reported higher levels of depression, perceived stress, and anxiety compared with healthy controls, along with lower vision-related quality of life and diminished social functioning.9PubMed. Psychological implications of vitreous opacities – A systematic review This is worth knowing because patients sometimes feel their complaints about floaters are dismissed as trivial. The evidence suggests they are not.
How Vitritis Is Diagnosed
A slit-lamp examination is the starting point. The ophthalmologist looks through the slit lamp at the vitreous and grades the amount of haze, which reflects how many inflammatory cells are present. The standard clinical grading scale runs from 0 (clear) to 4+ (very dense haze that obscures the retinal view). Because this grading is somewhat subjective, researchers have developed photographic techniques to make assessments more reproducible. One approach uses calibrated diffusion filters placed over a camera lens to simulate vitreous haze at different levels, producing an ordinal scale from 0 to 8, with each step corresponding to a measurable loss of contrast.10American Journal of Ophthalmology. Scale for Photographic Grading of Vitreous Haze in Uveitis This photographic method has been validated against clinical scores with moderate correlation.11PubMed Central. Validation of a photographic vitreous haze grading technique for clinical trials in uveitis
Imaging tools add further detail. Optical coherence tomography (OCT) can quantify vitreous inflammation and detect related complications like macular swelling. Ultrasound is useful when the vitreous is too opaque to see through, allowing the clinician to check for retinal detachment or masses behind the haze. A systematic review of noninvasive instruments for detecting vitreous inflammation found that OCT and retinal photography both showed good reliability between observers, with OCT correlation to clinical grading in the range of 0.53 to 0.60 across studies.12PubMed Central. Noninvasive Instrument-based Tests for Detecting and Measuring Vitreous Inflammation in Uveitis: A Systematic Review
Laboratory Work
When the cause is not obvious from the clinical picture, lab tests become essential. Blood work can screen for sarcoidosis, syphilis, tuberculosis, and autoimmune markers. For infections suspected to be inside the eye, sampling the aqueous humor (fluid from the front of the eye) or the vitreous itself allows for polymerase chain reaction (PCR) testing, which hunts for DNA from specific pathogens. One study found that PCR testing of aqueous and vitreous specimens identified the infectious agent in about four out of five patients who were clinically diagnosed with infectious uveitis.13PubMed Central. Polymerase chain reaction analysis of aqueous and vitreous specimens in the diagnosis of posterior segment infectious uveitis In cases where lymphoma is suspected, vitreous biopsy with cytology and flow cytometry is the gold standard.14PubMed Central. Vitreous analysis in the management of uveitis
Treatment Strategies
Treating vitritis means treating whatever is causing it. The approach divides broadly into anti-inflammatory therapy for noninfectious causes, antimicrobial therapy for infections, and surgery for cases that do not respond to medication or that require tissue sampling.
Corticosteroids for Noninfectious Vitritis
Corticosteroids remain the mainstay of treatment when infection has been ruled out.15PubMed Central. Dexamethasone intravitreal implant for the treatment of noninfectious uveitis The route of delivery depends on severity. Mild cases may be managed with steroid eye drops alone. More significant vitritis typically calls for periocular injections (around the eye) or intravitreal injections (directly into the vitreous gel). Intravitreal steroids deliver high drug concentrations right where they are needed while limiting the side effects that come with taking steroids by mouth.16PubMed Central. Intravitreal steroids for the treatment of retinal diseases
For patients who need longer-term control, sustained-release implants have changed the landscape. A dexamethasone intravitreal implant, for example, slowly releases the steroid over months. In patients with recalcitrant noninfectious uveitis, such implants have been shown to decrease uveitis activity, improve average visual acuity from around 20/80 to 20/40, and reduce retinal thickness substantially over a follow-up period averaging nine months.17Karger. Dexamethasone Intravitreal Implant: An Effective Adjunctive Treatment for Recalcitrant Noninfectious Uveitis Steroid implants are not without trade-offs: elevated eye pressure and cataract formation are well-documented risks that require monitoring.
When corticosteroids alone are not enough or when side effects become limiting, immunosuppressive drugs such as methotrexate, mycophenolate, azathioprine, or biologic agents like adalimumab may be added. These are typically managed by both an ophthalmologist and a rheumatologist or immunologist.
Antimicrobial Therapy for Infectious Vitritis
Treating infectious vitritis with anti-inflammatory drugs alone can be disastrous because suppressing the immune response lets the pathogen proliferate. The correct approach is targeted antimicrobial therapy, chosen based on the organism identified. Intravitreal injection of antibiotics or antifungals can bypass the blood-ocular barrier and deliver high drug concentrations directly to the infected tissue, and in many cases this is combined with systemic (oral or intravenous) therapy.18PubMed Central. A Review of Antimicrobial Therapy for Infectious Uveitis of the Posterior Segment Toxoplasmosis, for example, is treated with a combination of anti-parasitic drugs, sometimes with a short course of corticosteroids added once the antimicrobial is on board. Viral causes like herpes and CMV require antiviral medications, often for extended courses.
Surgery
Pars plana vitrectomy, a surgical procedure that removes the vitreous gel, serves two purposes in vitritis. First, it can be diagnostic: extracting vitreous gives pathologists material to examine for lymphoma cells, infection, or other clues. Second, it is therapeutic. Removing the inflamed, opaque vitreous physically clears the visual axis and reduces the load of inflammatory cells. In an early evaluation of this approach, visual acuity improved in the majority of eyes that underwent vitrectomy for chronic uveitis with dense vitreous opacification, vitreous hemorrhages from retinal vessel inflammation, and endophthalmitis.19PubMed. Pars plana vitrectomy in the management of intraocular inflammation Modern vitrectomy instruments are smaller and more refined, and the procedure is now considered a reasonable option when medical therapy has plateaued or when a tissue diagnosis is needed.
Complications of Uncontrolled Vitritis
Persistent or recurrent vitreous inflammation can damage surrounding structures. Macular edema, swelling of the central retina, is one of the most common and vision-threatening complications. Other documented complications include cataract formation, retinal detachment, vitreous hemorrhage, glaucoma, and even optic nerve inflammation.20PubMed. Ocular Complications of Intermediate Uveitis Some of these problems, particularly cataract and elevated eye pressure, can also be caused or worsened by the very steroids used to treat the inflammation, creating a balancing act between controlling the disease and avoiding treatment-related harm.
Band keratopathy, a calcium deposit on the cornea, and posterior synechiae, where the iris sticks to the lens, are additional complications seen in chronic cases. Retinoschisis, a splitting of the retinal layers, and vasoproliferative tumors at the retinal periphery round out the list of less common but recognized sequelae. The sheer breadth of potential complications underscores why early and sustained treatment matters.
Vitritis in Children
Pediatric uveitis, including intermediate uveitis with vitritis, deserves special mention because it presents distinct challenges. Children may not complain about visual symptoms until significant damage has occurred. Examination itself is more difficult with young children, and the prolonged burden of inflammation over a developing visual system raises the risk of amblyopia, where the brain essentially stops using a poorly functioning eye. Severe vision loss has been reported in roughly a quarter to a third of pediatric uveitis cases.21PubMed Central. Pediatric uveitis: An update Juvenile idiopathic arthritis is one of the most common systemic associations in children, and screening guidelines exist specifically to catch uveitis early in these patients. Treatment options are somewhat more limited in children because of concerns about long-term steroid side effects on growth and bone density, which pushes clinicians toward earlier use of steroid-sparing immunosuppressives.
When to Seek Urgent Care
Not every floater is vitritis, and not every episode of blurred vision is an emergency. But certain symptom patterns should prompt you to see an ophthalmologist quickly rather than waiting for a routine appointment:
- Sudden floaters: A burst of new floaters, especially accompanied by flashing lights, can signal either acute vitritis or retinal detachment.
- Rapid vision drop: Any noticeable decline in vision over hours to days warrants same-day evaluation, particularly after recent eye surgery or an injection.
- Pain with redness: This combination suggests an infectious or severely inflammatory process that may require urgent intervention.
- Known immune compromise: If you are immunosuppressed (from HIV, chemotherapy, or transplant medications), new visual symptoms carry a higher probability of serious infection.
Early evaluation matters because the difference between infectious and noninfectious vitritis can be impossible to tell from symptoms alone, and giving the wrong treatment, particularly giving steroids when an infection is present, can accelerate damage.
Living with Recurrent Vitritis
Many of the conditions that cause vitritis are chronic and relapsing. Sarcoidosis, Behçet’s disease, and idiopathic intermediate uveitis can flare repeatedly over years. For people living with these patterns, management becomes less about curing a single episode and more about long-term suppression of inflammation. This usually means regular monitoring visits, sometimes as often as every few weeks during flares, and ongoing medication adjustments.
The psychological weight of this cycle is real. Persistent vitreous opacities interfere with work, reading, and driving, and the unpredictability of flares adds chronic stress. As noted earlier, research has documented measurably higher rates of depression and anxiety in people living with vitreous opacities compared with the general population.9PubMed. Psychological implications of vitreous opacities – A systematic review Acknowledging that burden, and seeking support when needed, is as much a part of managing vitritis as the eye drops and injections.