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Pursuit eye movement can be divided into two stages: open-loop pursuit and closed-loop pursuit. Open-loop pursuit is the visual system's first response to a moving object we want to track and typically lasts ~100 ms. Therefore, this stage is ballistic: Visual signals have not yet had time to correct the ongoing pursuit velocity or direction. [9]
The testing typically takes place in a dark or dimmed room with the patient laying or sitting, depending on the test, on a table or chair that can lean back to a flat position. [2] The patient wears goggles containing a camera that tracks the pupils using infrared imaging; the video eye-tracking system records and sends pupil movement tracings ...
Screenshot of a computerized version of the pursuit rotor task. The pursuit rotor task is a simple pure visual-motor tracking test that has consistent results within age groups. [20] This displays a measurement of procedural memory as well as demonstrates the participant's fine motor skills. The pursuit rotor task tests the fine-motor skills ...
The visual field index (VFI) reflects retinal ganglion cell loss and function, as a percentage, with central points weighted more. [ 21 ] It is expressed as a percentage of visual function; with 100% being a perfect age-adjusted visual field and 0% represents a perimetrically blind field.
ENG or VNG can be used to record nystagmus during oculomotor tests such as saccades, pursuit and gaze testing, optokinetics and also calorics (dithermal or monothermal). Abnormal oculomotor test results may indicate either systemic or central pathology as opposed to peripheral (vestibular) pathology.
The optokinetic reflex (OKR), also referred to as the optokinetic response, or optokinetic nystagmus (OKN), is a compensatory reflex that supports visual image stabilization. [1] The purpose of OKR is to prevent motion blur on the retina that would otherwise occur when an animal moves its head or navigates through its environment.
The Benton Visual Retention Test is composed of 3 sets, or forms, of 10 designs (each 8.5 × 5.5 in.) that measure the examinee's visual and memory abilities as well as a set of alternate designs for repeated tests. [4] The examinee is given a booklet containing 10 blank pages on which they reproduce the designs.
Perimetry or campimetry is one way to systematically test the visual field. [1] [failed verification] It is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. Perimetry more carefully maps and quantifies the visual field, especially at the ...