The appellant ophthalmologist performed cataract surgery on the respondent.
During the administration of local anaesthetic, a retrobulbar hemorrhage occurred.
The appellant noticed a small bleed but proceeded with the operation.
The respondent subsequently lost sight in her right eye due to optic nerve atrophy.
The trial judge found the appellant negligent for continuing the operation and, relying on McGhee, shifted the burden of proof of causation to the appellant.
The Supreme Court of Canada dismissed the appeal, holding that while the legal burden of proof remains with the plaintiff, causation need not be determined with scientific precision.
A robust and pragmatic approach allows the trier of fact to draw an inference of causation where the defendant's negligence makes it impossible to prove causation positively, absent evidence to the contrary.
