Abstract |
PURPOSE: To study monovision performance using electrophysiological
recordings of Visual Evoked Potentials (VEPs) at an intermediate distance (1
meter), and compare the results with those of Visual Acuity, exploring any
possible differences in blurring the dominant vs. the non-dominant eye.
Additionally, to explore how pupil diameter / retinal luminance influences
monovision, under similar experimental conditions.
METHODS: The effect of defocus, induced by positive lenses, was
measured on the pattern reversal visual evoked potentials and on visual
acuity (VA). All these measurements (VEPs and VA) were recorded
binocularly, in monovision the defocus was alternating between the
dominant and the non-dominant eye. We measured 12 young (29±6.84)
volunteers under defocus up to 3.00 D in monovision conditions and up to
2.50D for binocular defocus. VEPs were elicited using reversing 10 arcmin
checks with a contrast of 100% and mean luminance of 30 cd/m2. VA was
measured under the same conditions using ETDRS charts. All these
measurements were performed at 1 meter distance with best spherocylindrical
correction. Finally, we followed exactly the same procedure, by
applying artificial pupil of 3 and 6 mm in aperture (in 3 volunteers under
cycloplegia).
RESULTS: In conditions of monovision, amplitudes and implicit times of
P100 component of VEPs were greater and shorter, respectively, in all cases
than for binocular defocus. Statistical significant differences occur, between
binocular and monocular defocus, from 1.50 D up to 3.00 D. However, no
significant differences were observed between the two conditions of
monovision (i.e. dominant eye vs. non-dominant eye selected for distance
vision). Although VEP P100 latency and amplitude correlates well with VA for
the range of defocus tested, VEPs for a more “sensitive” procedure in
Abstract
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monovision correction. Artificial pupils result to better performance (shorter
P100 latency and higher P100 amplitudes) for the 6 mm apertures than with
3 mm.
CONCLUSIONS: Monovision performance at the distance of 1 meter was
independent to the eye selected for distance (dominant vs. non-dominant).
By comparing VEPs recordings with those of VA we showed that VEPs form a
more sensitive technique to evaluate the effect of monovision on
performance than VA. Monovision performance was better with larger pupil
apertures, hinting that retinal illuminance is more important than depth-offocus
(which is achieved with smaller pupils).
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