The occipital The occipital lobes Occipital lobe - Mahidol University

23/06/54Occipital Lobes• A. Area 17• B. Areas 18 and 19A. Area 17NEUROPSYCHIATRY 115NEUROPSYCHIATRY 1161. Deficits associated with lesions-Homonymous hemaniopsia of contralateralvisual field follows unilateral lesion;scotoma, or "blind spot" follows subtotallesion.-Amblyopias, A i areas of intermediate t degree ofchange in visual function, are often foundnear scotomas.-A field defect may be reported as blindnessin the eye on that side.1. Deficits associated with lesions (cont)- Some loss of visual function may occur inintact half fields in homonymoushemianopsia.- Central scotomas may lead to subjectivelynormal visual fields with reduced acuity.- Macular sparing may occur if the lesion isclose to the occipital pole.NEUROPSYCHIATRY 117NEUROPSYCHIATRY 1181. Deficits associated with lesions (cont)Bilateral ablation may result in "corticalblindness" (inability to see, with denial andconfabulation, sometimes called Anton'ssyndrome) or to subtotal blindness withresidual ability to discri- minate luminousflux and a speckled from a grey field.1. Deficits associated with lesions (cont)- Interruption of optic pathways mayproduce similar, but not always identicalsymptoms to lesions of area 17.-Acute trauma may cause warping ofvisual coordinates, distortions, andpolyopias. These symptoms maydisappear within days or last for months.They may reap-pear ictally.NEUROPSYCHIATRY 119NEUROPSYCHIATRY 12020