Aniseikonia Flashcards
In Greek, aniseikonia is
unequal images
• It is a binocular condition, so the image in one eye is perceived as different in size compared to the image in the other eye.
Aniseikonia
He discussed the possibility (1903)
• C.Hess
He commented upon the probability of unequal image sizes. (1864)
• Donders
He designed iseikonic lenses for aniseikonia
• Von Rohr
– Condition in which ocular images are unequal in size and shape
• Aniseikonia
– Condition in which the size and shape of the ocular images are equal
• Iseikonia
– Lenses which correct aniseikonia and include also the correction of refractive error.
• Iseikonic Lenses
eyes are gazing in a certain direction
• Static Aniseikonia
– eyes have to rotate a different amount to gaze at the same point in space
• Dynamic Aniseikonia
combination of overall and meridional is manifested.
Compound
the size of one ocular image is symmetrically larger that the other in one meridian only
Meridional
the size of one ocular image is symmetrically larger that the other.
Overall
Classifications of Aniseikonia
Symmetrical and Asymmetrical
― Variation in size differ from different positions of the visual field
Asymmetrical
image distortion increases progressively in both directions
Pincushion
image distortion decreases progressively in both directions
Barrel
image difference increases progressively in one direction
Prismatic
image size remains the same but there occurs an oblique distortion of shape.
Oblique
asymmetric convergence and stereoscopic disparities exists as when viewing the object located to one side.
Normal
Symmetrical and Asymmetrical
Abnormal
based on binocular space perception
SPACE EIKONOMETRIC METHOD
based on directly comparing perceived image sizes between the two eyes
DIRECT COMPARISON METHOD
instrument for measuring aniseikonia.
Space Eikonometer
is indicated by the power of the size lens that swings the target back into a frontoparallel plane.
amount of aniseikonia
test for Aniseikonia provides a manual method to detect and calibrate the Aniseikonic condition.
Awaya
is an easy-to-use Windows software program to test the aniseikonia of a patient.
Basic Aniseikonia Test
is a Windows software program for the clinical management of aniseikonia
Aniseikonia Inspector
