Polyvinyl alcohol
Polyvinyl alcohol is a synthetic water-based tear substitute used for the lubrication of dry eyes. In cases of **keratoconjunctivitis sicca (KCS)**, it improves ocular surface lubrication, tear retention, and patient comfort while lacrostimulation therapy (e.g., topical ciclosporin) is initiated. > **Clinical Pearl:** It is more adherent and less viscous than hypromellose. However, because it requires very frequent application (often every hour), patient compliance can be poor. Consider longer-acting tear replacements (like cross-linked hyaluronic acid or carbomer gels) if frequent dosing is impractical.
Mechanism: Acts as a **lacromimetic** (tear substitute). It mimics the **aqueous layer** of the trilaminar tear film, providing physical lubrication and moisture to the corneal and conjunctival surfaces.
Dosing by species
- Keratoconjunctivitis sicca (KCS) / Dry eye lubrication · 1 drop per eye · topical · q1h · As needed · Patient compliance is poor if administered >q4h; consider using a longer acting tear replacement.
- Dry eye lubrication · 1 drop per eye · topical · q1h · As needed · Patient compliance is poor if administered >q4h; consider using a longer acting tear replacement.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Monitoring
- Clinical signs of dry eye (corneal health, conjunctival hyperemia, comfort)
- Schirmer tear test (STT) to monitor underlying KCS progression
Overdose
No specific information available. Overdose via topical ophthalmic administration is highly unlikely to cause systemic toxicity. Excess fluid will simply drain from the eye.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.