Eye-movement-based assessment of visual function in patients with infantile nystagmus syndrome.
OBJECTIVE
Infantile Nystagmus Syndrome (INS) is an ocular motor system dysfunction characterized by the rhythmic to-and-fro oscillations of the eyes. Traditionally, the assessment of INS visual function solely focused on null- or primary-position visual acuity. Our purpose is to use the past four decades of INS research to introduce a more complete assessment of visual function in patients with INS.


METHODS
All eye-movement data were obtained using high-speed digital video, infrared reflection, or scleral search coil systems.


RESULTS
We have introduced four important aspects of a more complete INS visual function assessment: the eXpanded Nystagmus Acuity Function and visual acuity measurements in primary position; broadness of the eXpanded Nystagmus Acuity Function peak and high-acuity field; target acquisition time; and gaze-maintenance capability.


CONCLUSIONS
Visual function in patients with INS is multifactorial and the simple assessment of primary position visual acuity is both inadequate and may not be the most important characteristic in overall visual function. A more complete visual function assessment should also include primary and lateral gaze eye-movement and visual acuity examinations, target acquisition time and gaze holding.
Wang
Zhong I
ZI
The Daroff-Dell'Osso Ocular Motility Laboratory, Louis Stokes Cleveland Department of Veterans Affairs Medical Center and CASE Medical School, Cleveland, Ohio 44106, USA.
Dell'Osso
Louis F
LF
D053483:Eye Movement Measurements; D005403:Fixation, Ocular; D006801:Humans; D009039:Motion Perception; D020417:Nystagmus, Congenital / Q000175:diagnosis* / Q000503:physiopathology; D011930:Reaction Time; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity; D014794:Visual Fields