Does ganciclovir exert retinal toxicity after multiple continuous intravitreal injections?

Area of Science:

• Ophthalmology
• Retinal Diseases
• Pharmacology

Background:

• Acute retinal necrosis (ARN) is a severe viral retinitis.
• Standard treatment involves antiviral therapy, often with intravitreal injections.
• Visual function abnormalities can occur in ARN, but anatomical correlation is expected.

Observation:

• A 39-year-old female with ARN received nine intravitreal ganciclovir injections (3 mg/0.1 ml) over 14 weeks.
• The patient experienced progressive visual acuity decline and visual field loss.
• Ocular coherence tomography (OCT) showed minimal retinal anatomical changes, with normal capillary density on Angio-OCT.

Findings:

• Despite normal retinal anatomy, electroretinography revealed significant macular dysfunction.
• Photopic single-flash response showed decreased a-wave and b-wave amplitudes.
• Photopic 30 Hz flicker response amplitudes were also reduced, indicating photoreceptor dysfunction.

Implications:

• Multiple intravitreal ganciclovir injections at this dosage may cause ganciclovir-associated photoreceptor damage.
• This damage can lead to visual function abnormalities disproportionate to anatomical findings in ARN.
• Clinicians should consider potential drug toxicity when assessing visual deficits in ARN patients undergoing prolonged antiviral therapy.