Published date:Dec 31 2024

Journal Title: Journal of Ophthalmic and Vision Research

Issue title: Oct–Dec 2024, Volume 19, Issue 4

Pages:449 - 458

DOI: 10.18502/jovr.v19i4.14429

Elissavet Kemanetzogloulisakemanetzoglou@gmail.comFirst Department of Neurology, National and Kapodistrian University of Athens, Eginition Hospital, School of Medicine, Athens, Greece

Klio Chatzistefanoukliochat@med.uoa.grFirst Department of Ophthalmology, National and Kapodistrian University of Athens Gennimatas General Hospital, School of Medicine, Athens, Greece

Nikolaos Smyrnissmyrnis@med.uoa.grSecond Department of Psychiatry, National and Kapodistrian University of Athens, Attikon General Hospital, School of Medicine, Athens, Greece

Evangelia Kararizouekarariz@med.uoa.grFirst Department of Neurology, National and Kapodistrian University of Athens, Eginition Hospital, School of Medicine, Athens, Greece

Evangelos Anagnostoueanagnost@eginitio.uoa.grFirst Department of Neurology, National and Kapodistrian University of Athens, Eginition Hospital, School of Medicine, Athens, Greece

Purpose: To examine the natural adaptive course of ocular motor system in unilateral abducens nerve palsy while addressing the scarce literature on saccade dynamics and natural adaptation.
Methods: Binocular horizontal eye movements were recorded from 18 healthy adults and 21 adults with unilateral abducens nerve palsy during the acute and chronic phases. Dynamics of the paretic and non-paretic eyes were compared, and the non-paretic eye dynamics were correlated with the respective prism diopters. Non-parametric tests were used for statistical comparisons.
Results: The paretic eye, compared to the non-paretic eye, presented a slightly lower saccadic gain and velocity/amplitude ratio and a higher duration/amplitude ratio. The nonparetic eye, compared to healthy controls, showed consistent amplitude gain (>1) and a tendency for a higher duration/amplitude ratio. In the acute phase, when the non-paretic eye was covered, the paretic eye’s amplitude ratio was lower and the duration/amplitude ratio decreased significantly. In the acute phase, a greater degree of esotropia in the paretic eye was associated with a lower amplitude gain and duration/amplitude ratio in the nonparetic eye.
Conclusion: During adaptation in abducens nerve palsy, the saccade duration of the paretic eye increased, and a similar tendency was observed in the non-paretic eye. This finding likely reflects a change in the “pulse-step” pattern and may be related to plastic changes in central structures, such as the cerebellum, that support learning processes.

Keywords: Saccade, Abducens nerve palsy, Eye Movements

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