Which route may cause systemic poisoning via exposure to the eyes?

• A. Ocular
• B. Inhalation
• C. Injection
• D. Ingestion/Oral

Answer: (A)

Exposure of a chemical to the eye can lead to systemic poisoning because the eye’s surface is a moist mucous membrane with vascular tissue. Substances dissolved in tears can be absorbed through the conjunctiva and corneal surfaces into the local blood supply. Additionally, tears drain through the nasolacrimal duct into the nasal cavity, where the highly vascular mucosa can rapidly absorb chemicals into the bloodstream. So, while eye exposure is often discussed in terms of local eye damage, certain chemicals can reach systemic circulation after contacting the eye. Inhalation, ingestion, and injection are other routes of systemic exposure, but the ocular route specifically explains how exposure to the eyes can cause systemic toxicity.