Monitoring Intravitreal Injection Patients for Neurotrophic Keratitis

Overview

Intravitreal injections, commonly used for age-related macular degeneration and diabetic macular edema, can lead to neurotrophic keratitis (NK), especially after multiple injections. Early detection through patient history, corneal sensitivity testing, and clinical examination is crucial to prevent progression and vision loss.

Background

Neurotrophic keratitis is a progressive corneal disease characterized by impaired corneal nerve function and healing. Anti-VEGF intravitreal injections may exacerbate corneal nerve damage due to VEGF's role in nerve regeneration. Risk factors such as diabetes, stroke, autoimmune diseases, and prior ocular surgeries increase susceptibility to NK. Early stages show subtle signs like reduced vision clarity and mild conjunctival hyperemia, while advanced stages involve corneal ulcers and stromal melting.

Data Highlights

Studies indicate corneal nerve length and density changes occur after the third intravitreal injection. Anti-VEGF injections cause more corneal damage compared to other intravitreal agents. The Ocular Surface Disease Index survey includes vision-related questions aiding early NK detection. Corneal sensitivity can be quantitatively assessed using esthesiometers or cotton wisp with a grading scale developed by Dr. Mark Milner.

Key Findings

• Corneal nerve damage increases notably after the third intravitreal injection.
• Anti-VEGF injections impair corneal healing more than other intravitreal treatments.
• Risk factors for NK include diabetes, stroke, autoimmune disease, dry eye history, and multiple ocular surgeries.
• Corneal sensitivity testing should be performed before any eye drop instillation to avoid false results.
• Early NK presents with central corneal punctate epithelial defects and mild conjunctival hyperemia; advanced NK shows central ulcers and stromal thinning.
• Regular screening of intravitreal injection patients can enable early intervention and prevent progression to severe NK and vision loss.

Clinical Implications

Clinicians should routinely inquire about the number and type of intravitreal injections and assess for NK risk factors. Employing corneal sensitivity testing and the Ocular Surface Disease Index survey can facilitate early diagnosis. Prompt identification allows for timely management to halt NK progression and preserve vision.

Conclusion

Monitoring patients receiving intravitreal injections for early signs of neurotrophic keratitis is essential. Early detection and intervention can improve patient outcomes and reduce the risk of severe corneal complications.

References

1. Theriot PE 2024 -- Monitoring Intravitreal Injection Patients