Purchase this article with an account.
Nancy J. Coletta, Lenna E. Walker, Fuensanta A. Vera-Diaz; Fixational eye movements in a visual acuity task. Journal of Vision 2017;17(7):13. doi: 10.1167/17.7.13.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Introduction: Corrected myopes exhibit larger visual acuity loss at low luminance (1, 2) and less precise fixational eye movements (3) than emmetropes. We examined the relationship between fixation stability and acuity at two light levels.
Methods: Subjects (31 young adults; dominant eye refraction +2.25 to −10.88 D) were corrected with contact lenses if needed. Mesopic (0.276 cd/m2) and photopic (325 cd/m2) acuity was measured while eye movements were recorded (EyeLink 1000). Fixations were analyzed for letter sizes corresponding to mesopic and photopic acuity limits. Fixation stability is reported as the bivariate contour ellipse area (BCEA), defined as the area of fixation for 68% of the time (4), during acuity reading.
Results: Mesopic acuity was worse for higher myopia (p=0.03) and BCEA were larger for myopes at both light levels (mesopic, p<0.01; photopic, p<0.01). Subjects with smaller photopic BCEA had higher mesopic acuity (p=0.01) and smaller loss of acuity in dim light (p=0.02) relative to their photopic acuity.
Conclusions: Fixation instability in myopia may be associated with difficulty in visual tasks under challenging conditions, such as low luminance.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting
This PDF is available to Subscribers Only