Intravitreal Injection Expert Witness
An intravitreal injection expert witness evaluates claims that arise when medication is injected into the vitreous cavity of the eye, now one of the most frequently performed procedures in ophthalmology. Marc H. Shomer, MD, PhD, QME performs intravitreal injections in his own medical retina practice and reviews injection-related matters for plaintiff and defense counsel nationwide.
These cases are deceptively simple on their face. The procedure takes minutes and is repeated every few weeks, often for years, so even a very small risk per injection becomes a meaningful risk over a course of treatment. When an eye is lost, the question is rarely whether the complication is a recognized one. It is whether the preparation, the drug, the technique and above all the response met the standard of care.
What the procedure involves
The drugs fall into three groups: anti-VEGF agents (anti-vascular endothelial growth factor medications such as bevacizumab, ranibizumab, aflibercept and faricimab) for wet macular degeneration, diabetic macular edema and retinal vein occlusion; corticosteroids, including the dexamethasone implant; and the complement inhibitors approved for geographic atrophy. The injection is given in the office through the pars plana, a few millimeters behind the edge of the cornea, after the surface of the eye is treated with povidone-iodine antiseptic. The patient usually goes home within minutes.
Recurring claims
- Endophthalmitis. Infection inside the eye is the most feared complication. A meta-analysis of 350,535 anti-VEGF injections found endophthalmitis after 0.056 percent, roughly one in 1,800, with Streptococcus species over-represented and associated with poorer visual outcomes. Because infection can follow a properly performed injection, the analysis centers on antisepsis, technique and how quickly the practice acted when the patient reported pain or falling vision.
- Contaminated or compounded drug. Bevacizumab is repackaged into syringes by compounding pharmacies. In a 2011 Florida outbreak, twelve patients injected at four locations with syringes from one pharmacy developed Streptococcus endophthalmitis, and unused syringes from the same batch grew the same organism. A cluster points away from the injecting physician and toward the supply chain, which changes who the proper defendants are.
- Drug-related inflammation and occlusive vasculitis. Some agents carry risks that surfaced only after approval. The American Society of Retina Specialists reported retinal vasculitis in 26 eyes after brolucizumab and in 14 eyes after pegcetacoplan, with severe vision loss in a substantial share. Claims ask whether the patient was told once the risk was known, whether the eye was examined for inflammation before the next dose, and whether the drug was continued after warning signs.
- Wrong eye, wrong drug or wrong patient. High-volume injection clinics depend on a time-out and site verification for every patient. These events are usually process failures, and the records of the verification step decide them.
- Pressure rise and optic nerve damage. Every injection briefly raises eye pressure, and repeated steroid treatment can raise it for months. The question is whether pressure and optic nerve perfusion were checked afterward and whether a patient with glaucoma was monitored accordingly. See Glaucoma Expert Witness.
- Mechanical injury. Needle contact with the lens causing cataract, retinal tear or detachment, and vitreous hemorrhage. See Retinal Detachment.
- Treatment gaps. Wet macular degeneration and diabetic macular edema lose ground when injections are delayed. Scheduling systems, recall of patients who miss visits and decisions to extend the interval are addressed on the Macular Disease page.
The records that decide these cases
The injection note should identify the eye, the drug, the dose, the lot number, the antiseptic used and the check of vision or pressure afterward. Counsel should also obtain the consent form, the pharmacy and lot records for a compounded drug, the telephone and triage logs for the days after the injection, the culture results, and the optical coherence tomography (OCT) scans in native digital format across the whole course of treatment. The telephone log is often the most important document in an endophthalmitis case: it shows when the patient first reported symptoms and what the practice told the patient to do. General guidance is at What Records to Provide.
The infection is rarely the breach. The delay can be. A patient who calls with pain and falling vision in the days after an injection needs to be examined urgently, and suspected endophthalmitis needs prompt sampling and antibiotic injection. Hours matter with virulent organisms. An opinion that stops at "infection is a known risk" has not addressed the part of the case that is usually in dispute.
Causation: separating the complication from the disease
Every eye receiving injections already has a disease that threatens vision. Wet macular degeneration can scar the macula despite ideal treatment, and diabetic eye disease progresses with poor glucose control. The causation analysis therefore starts from the last acuity and OCT before the event and asks what that eye would likely have seen without the complication. Serial OCT makes this unusually objective, as explained in OCT Evidence. The same analysis protects defendants from being charged with loss the disease had already caused, and it protects plaintiffs from an argument that a blind eye was doomed regardless when the prior scans show otherwise.
Off-label use and consent
Bevacizumab is approved for cancer treatment and is used in the eye off-label. That use is long established and widely accepted, and off-label use alone is not a departure from the standard of care. It does bear on consent: the patient should understand that the drug is being used off-label, that it is repackaged by a pharmacy, and what the alternatives are. Consent in ophthalmic procedures is discussed at Informed Consent in Eye Surgery.
How Dr. Shomer approaches injection cases
Dr. Shomer reviews the procedure notes against what a careful injecting ophthalmologist documents, reads the OCT scans himself, reconstructs the timeline between first symptom and treatment from the call logs and chart, and states separately what the complication cost and what the underlying disease would have cost in any event. Where the dispute turns on vitreoretinal surgery performed after the complication, he says so and identifies the questions that belong to a vitreoretinal surgeon.
Frequently Asked Questions
How often does infection follow an intravitreal injection?
In a meta-analysis of 350,535 anti-VEGF injections, endophthalmitis followed 0.056 percent, or roughly one injection in 1,800. The risk per injection is low, but patients often receive many injections over several years, so the cumulative risk over a course of treatment is higher.
Is endophthalmitis after an injection evidence of malpractice?
Not by itself. Infection can follow an injection performed with proper antisepsis and technique. The questions that usually decide the case are whether accepted antiseptic steps were taken, whether the drug itself was contaminated, and how quickly the practice examined and treated the patient after symptoms were reported.
Does it matter that bevacizumab is used off-label in the eye?
Off-label use of bevacizumab in the eye is long established and widely accepted, so the choice of drug is not by itself a departure from the standard of care. It matters for consent, because the patient should be told the use is off-label and that the drug is repackaged by a pharmacy, and it matters for causation when a contaminated batch is suspected.
What records should counsel request first?
The injection procedure notes with drug lot numbers, the consent forms, the telephone and triage logs for the days after the injection, culture results, pharmacy records for any compounded drug, and the OCT scans in native digital format for the entire course of treatment.
Authorities Cited
Primary sources referenced on this page. Links open the source on the publisher’s or agency’s site.
Educational information only. This page provides general information for attorneys and other medical-legal professionals. It is not medical or legal advice, does not address any particular case, and does not create a physician-patient, attorney-client, or expert-client relationship. Opinions in any matter are formed only after review of the specific records, examination findings, and applicable literature. Past engagements do not guarantee any result.
Board-certified ophthalmologist; Adjunct Associate Professor of Ophthalmology, Keck School of Medicine of USC; active California Qualified Medical Evaluator. Full biography · Curriculum vitae
Published October 5, 2026 · Last substantive review October 5, 2026 · Medical reviewer: Marc H. Shomer, MD, PhD, QME
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