ABSTRACT
The optic radiations form the start of the second nerve fibre part of the visual pathway – the first part being the retinal nerve fibres that pass from the retinae to the lateral geniculate body where they synapse. The blood supply to the optic radiations is predominantly from the posterior and middle cerebral arteries. The optic radiations pass through a large area of the posterior cranial cavity including the temporal and parietal lobes before reaching their termination in the occipital lobe. Optic radiation lesions are mostly vascular related to either the posterior cerebral artery or middle cerebral artery territories. Temporal and parietal lobe lesions can cause higher cortical deficits including complex partial seizures, auditory or complex visual hallucinations, memory problems or a Wernicke’s aphasia. Defective associate visual processing includes visual agnosia, simultanagnosia, prosopagnosia, complex formed visual hallucinations, alexia, right/left confusion and inability to recognize colours and colour matching.
