Perimetría automática y neuro-oftalmología. Correlación topográfica

Resumo

Visual fields continue to be a key exploration for the diagnosis and follow-up of patients in neuro-ophthalmology. The pattern of visual field defects helps, and in many cases allows, the identification of brain damage location. Manual kinetic perimetry has been replaced by automated methods. 24-2 SITA (Humphrey Visual Field Analyser) and TOP (Octopus) are regarded as the standard perimetric explorations in neuro-ophthalmology. Goldmann perimetry remains as an useful exploration for temporal crescent detection in occipital lobe diseases, and it could be more accurate and consistent for studying lesions in the post-geniculate pathway. Frequency doubling perimetry could be useful for detecting neuro-ophthalmic visual field defects, but does not provide an accurate characterisation of the lesions. From the neuro-ophthalmic point of view, visual field defects could be divided in pre-chiasmatics, chiasmatics and post-chiasmatics. Pre-chiasmatic defects are strictly unilateral, do not respect the vertical meridian, often have a nasal step associated and are usually accompanied by ocular pathology detectable in an ophthalmic examination. The characteristic perimetric pattern of chiasmal disease is bi-temporal hemianopsia. Homonymous contralateral defects are the characteristic perimetric pattern of post-chiasmal disease, and their congruency increases when the lesions are closer to the occipital lobe. Neuroimage studies are mandatory in all patients with a perimetric defect pattern compatible with chiasmal or post-chiasmal lesions. Magnetic Resonance Imaging may be normal in a patient with homonymous defects in Alzheimer's disease, the Heidenhain variant of Creutzfeldt-Jakobs disease, carbon monoxide poisoning and mild occipital ischemia demonstrated by SPECT or PET imaging (Arch Soc Esp Oftalmol 2002; 77: 413-428).