The ultimate role of ocular movements is to keep the image of an object within the fovea and thereby prevent image slippage on the retina. Accurate evaluations of eye movements provide very useful information for understanding the functions of the oculomotor system and determining abnormalities therein. Such evaluations also play an important role in enabling accurate diagnoses by identifying the location of lesions and discriminating from other diseases. There are various types of ocular movements, and this article focuses on saccades, fast eye movements, smooth pursuit, and slow eye movements, which are the most important types of eye movements used in evaluations performed in clinical practice.

Citations

• COMPARISON OF RANDOM SACCADE TEST AND CLINICAL SACCADOMETRY TEST RESULTS OF HEALTHY ELDERLY AND YOUNG INDIVIDUALS
  Gülce KİRAZLI, Gökçe SAYGI UYSAL, Ece ÇINAR, Aykut ÖZDOĞAN, Şüheda BARAN, Fatih TEKİN
  Turkish Journal of Geriatrics.2025;[Epub]     CrossRef
• Analysis of Eye Movements in Adults with Spinal Muscular Atrophy
  Marek Krivošík, Zuzana Košutzká, Marián Šaling, Veronika Boleková, Rebeka Brauneckerová, Martin Gábor, Peter Valkovič
  Medicina.2025; 61(4): 571.     CrossRef

Eye movements serve vision by placing the image of an object on the fovea of each retina, and by preventing slippage of images on the retina. The brain employs two modes of ocular motor control, fast eye movements (saccades) and smooth eye movements. Saccades bring the fovea to a target, and smooth eye movements prevent retinal image slip. Smooth eye movements comprise smooth pursuit, the optokinetic reflex, the vestibulo-ocular reflex (VOR), vergence, and fixation. Saccades achieve rapid refixation of targets that fall on the extrafoveal retina by moving the eyes at peak velocities that can exceed 700?s. Various brain lesions can affect saccadic latency, velocity, or accuracy. Smooth pursuit maintains fixation of a slowly moving target. The pursuit system responds to slippage of an image near the fovea in order to accelerate the eyes to a velocity that matches that of the target. When smooth eye movements velocity fails to match target velocity, catch-up saccades are used to compensate for limited smooth pursuit velocities. The VOR subserves vision by generating conjugate eye movements that are equal and opposite to head movements. If the VOR gain (the ratio of eye velocity to head velocity) is too high or too low, the target image is off the fovea, and head motion causes oscillopsia, an illusory to-and-fro movement of the environment.