Transactions from the Xth International Orthoptics Congress 2004

Near
Far
70
60
50
40
30
20
10
0
Right Left Alternating
70
60
50
40
30
20
10
0
Right Left Alternating
Sighting
Sensory
Sighting
Sensory
Figure 2: Responses (in %) of right eye, left eye or alternating dominance as assessed
by the Sighting Test (light grey) and the Sensory Test (dark grey) for far and near. Alternating
sensory dominance is particularly evident for near on the sensory test and there are a similar
number of right and left dominant responses for far on the sensory test.
Discussion
These findings confirm those of Coren and Kaplan (2) in that there was no relationship found
in laterality between the two forms of ocular dominance and thus each test can be categorised
relative to the visual task required. That is, sighting dominance is indicated by a number of
tasks which all require input from one eye either be excluded or ignored. Sensory dominance
appears in situations where the system is trying to suppress visual confusion based upon
conflicting inputs to the two eyes (2).
Further investigations are necessary to compare success of monovision correction
based on whether when the sensory or the sighting dominant eye is corrected for distance
fixation. However it is important to note that a high percentage of subjects had no eye
preference, particularly at near, according to the sensory test. These results were similar to the
results found by Robboy and Erickson (3) who used the anisometropic blur suppression test to
determine sensory ocular dominance. The smaller standard deviation of right eye response in
the sensory dominance test at near also demonstrates a weaker sensory dominance than at
distance where a larger standard deviation is present.
The responses of a sighting dominance test therefore cannot predict the responses of s
sensory dominance test and the two forms of ocular dominance can be considered to be two
separate entities. Sighting dominance is indicated by a number of tasks which all require
input from one eye either be excluded or ignored and sensory dominance occurs in situations
where the system is trying to suppress visual confusion based upon conflicting inputs to the
two eyes.
References
1. Pearlman, A. (1897) The central visual pathways. in Moses RA, & Hart WM (Ed), Adler s Physiology of the
Eye: Clinical Application. (pp583-618). St Louis: Mosby,
2. Coren, S., Kaplan, C. (1973) Patterns of ocular dominance. J Optom Arch Am Acad Optom 50, 283-292
3. Robboy, M., Cox, I., Erickson, P. (1990) Effects of sighting and sensory dominance on monovision high and
low contrast visual acuity. CLAO J 16(4), 299-301
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