Abstract
Purpose: :
To analyze the ocular micro-saccades and to establish their correlation with the biometric and refractive parameters of the eye.
Methods: :
The micro-saccades of 120 healthy eyes of 60 volunteers (mean age 37 years ± 16, range 19-81) including ametropia were prospectively recorded with the Orbscan device using the software "Track Eye Movement". The properties of the saccades including mean movement and rate were analyzed and correlated to the biometric and refractive parameters including axial length, anterior chamber depth, corneal curvature, pachymetry, spherical equivalent, astigmatism and visual acuity. The axial length was measured with A-scan ultrasound and the biometry of the anterior segment with the Orbscan topography system. The difference between two successive measurements was calculated to determine the reproducibility.
Results: :
The reproducibility of the measurements of the saccades was 25% for the average movement and 21% for the average rate. The movement and rate of the saccades did not differ from the fellow eye (p ≥ 0.36) and were correlated significantly with the fellow eye (rs ≥ 0.49; p < 0.001). In addition they were correlated to the spherical equivalent (rs ≥ 0.20; p < 0.015) and the axial length of the eye (rs ≥ -0.17; p < 0.03). However the properties of the micro-saccades were not significantly influenced by astigmatism, BSCVA, sex and age (p ≥ 0.05).
Conclusions: :
Visually triggered saccades of myopic eyes and great axial length turn out to be slower and smaller than those of hyperopic eyes and short axial length. A deeper understanding of ocular saccades could be of clinical interest particularly for the improvement of eye-tracking-systems in the field of refractive surgery, but also diagnostically for topographic systems such as the Orbscan device.
Keywords: eye movements: saccades and pursuits • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • refraction