foveation period

In congenital nystagmus it is the amount of time when the image of an object of regard is on or near the fovea and moving so slowly as to enable the patient to acquire useful visual information. The longer the foveation period and the lower the retinal image velocity, the higher the visual acuity.

Mentioned in

References in periodicals archive

Notice also the acceleration of the slow phase following the foveation period; this acceleration is usually present in IN waveforms, and is useful in arriving at a diagnosis.

Clinical assessment of nystagmus

Because of the waveform, there has been much enthusiasm for measuring the so-called 'foveation period'.

When there is no stress attached to a task (for example no time constraint on performance), increasing visual demand does not increase nystagmus, (7) but may actually increase foveation periods. (8) The effect of stress per se (for example electric shock, reward manipulation) is to increase the nystagmus intensity (reduce foveation periods), but has surprisingly little effect on VA.

(28) developed an objective performance measure based on an individual's foveation periods called a nystagmus acuity function (NAF).

Infantile (congenital) nystagmus

Insertion of acupuncture needles into the sternocleidomastoid muscles of the neck may reduce nystagmus intensity in some individuals; (61) this can also improve the duration of foveation periods, with the effects sometimes being sustained after treatment.

Management of nystagmus

All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.