[Neuro-ophthalmological problems: the diagnostic value of contrast sensitivity].

The evaluation of the individual contrast sensitivity function may prove useful in cases affected by lesions of the optic pathways, even when the usual neuro-ophthalmological tests (i.e. visual acuity, visual field examination) are normal. The contrast sensitivity function represents an alternative method to assess the power of spatial resolution of the visual system: in particular, it enables to measure the sensitivity at high, medium and low ranges of spatial frequencies, this being unique to such a procedure. The possible physiological mechanisms underlying the contrast sensitivity function as well as its pathological changes are reviewed.