5 · Factors delaying or impairing healing
Topical anesthetic abuse — toxic keratopathy
Review — modulators of corneal healing › 5 · Factors delaying or impairing healing › Topical anesthetic abuse — toxic keratopathy
Topical anesthetic abuse — toxic keratopathy
Proparacaine 0,5 %, tetracaine, oxybuprocaine, lidocaine — chronic self-administration
Oxford IV
Negative · Strong (consensus)
Present · avoidable
Mechanism (toxic)Sodium channel blockade plus direct epithelial cytotoxicity: inhibition of migration, mitosis, and adhesion, damage to microvilli/junctions, corneal neurotoxicity. Result: non-healing persistent epithelial defect, immune ring infiltrate, melting/perforation, endophthalmitis/evisceration in severe forms. Loss of sensation worsens the injury.
ContextLegitimate use = single diagnostic/procedural dose. Abuse occurs in patients who obtained drops for pain relief (post-PRK, foreign body, abrasion) — occupational risk (welders, healthcare workers). Treatment = discontinuation of the drops.
Route & dosageThe problem is repeated self-dosing. Never prescribe for home analgesia.
Level of evidenceOxford IV (case series; no RCTs for ethical reasons) but mechanistically robust and consistent · Scale: strong consensus of harm.
| Status | Approved (FDA/EU/ANSM) for in-office professional use only; labeling warns against prolonged use/dispensing. Generics available worldwide. Dispensing for home use remains restricted precisely because of abuse keratopathy. |
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Key studies: amniotic membrane for proparacaine toxic keratopathy (Cornea); proparacaine abuse → evisceration — PMID 23608875; EyeWiki "Topical Anesthetic Abuse Keratopathy."