Induced aniseikonia diminishes binocular contrast sensitivity and binocular summation.
OBJECTIVE
To study the effect on binocular contrast sensitivity and binocular summation of aniseikonia induced by size (afocal) lenses.


METHODS
In 18 young emmetropic observers, the monocular and binocular contrast sensitivity function was measured under normal conditions and after inducing different degrees of aniseikonia (2%, 3%, and 5% and for 6 observers, 8%) in the right eye. The spatial frequencies tested were 2.4, 3.7, 6.0, 9.2, 12, 15, 20, and 24 cpd.


RESULTS
The results reveal a significant decline in binocular contrast sensitivity and binocular summation for 5% aniseikonia, this decline being more pronounced for intermediate and high spatial frequencies.


CONCLUSIONS
These results, together with others on different binocular functions, show the importance of aniseikonia in binocular vision. On this basis, we recommend that aniseikonia be considered in surgical processes such as cataract and refractive surgery, whereby aniseikonia could be induced and binocular performance subsequently diminished.
Jiménez
José Ramón
JR
Departamento de Optica, Facultad de Ciencias, Universidad de Granada, Granada, Spain.
Ponce
Ana
A
Anera
Rosario González
RG
D000293:Adolescent; D000328:Adult; D000839:Aniseikonia / Q000503:physiopathology*; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D015348:Vision, Binocular / Q000502:physiology*