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Contrast sensitivity, optotype acuity and fixation eye movement abnormalities in amblyopia under binocular viewing
Cody S Dulaney1, Jordan Murray1, Fatema Ghasia1
1Cleveland Clinic Cole Eye Institute, Visual Neurosciences and Ocular Motility Laboratory, Cleveland, OH, USA.
Journal of the Neurological Sciences
|July 11, 2023
Summary
Fixation eye movement abnormalities in amblyopia correlate with reduced binocular contrast sensitivity and optotype acuity. These deficits are most severe in patients with Fusion Maldevelopment Nystagmus (FMN).
Area of Science:
- Ophthalmology
- Neuroscience
- Vision Science
Background:
- Amblyopia, or
Purpose of the Study:
- To investigate the relationship between Fixation Eye Movement (FEM) abnormalities and binocular vision deficits in amblyopia.
- To assess how FEM abnormalities correlate with contrast sensitivity and optotype acuity in amblyopic individuals.
Main Methods:
- Recruited 25 amblyopic subjects and 10 controls.
- Measured binocular contrast sensitivity and optotype acuity using a staircase procedure.
- Recorded Fixation Eye Movements (FEMs) via video-oculography, classifying subjects by nystagmus presence and type (None, without FMN, with FMN).
Main Results:
- Amblyopic subjects, particularly those with Fusion Maldevelopment Nystagmus (FMN), exhibited significantly worse binocular contrast sensitivity and optotype acuity compared to controls.
- Increased fixation instability and altered FEM parameters (amplitude, velocity) were directly correlated with reduced contrast sensitivity and optotype acuity in amblyopic eyes.
Conclusions:
- Fixation instability and FEM abnormalities are linked to visual function deficits in amblyopia, even during binocular viewing.
- The severity of these visual impairments and FEM abnormalities is most pronounced in amblyopic individuals with FMN.
