Anisometropia and Aniseikonia Flashcards
It is a binocular condition, that the image in one
eye is perceived as different in size compared to
the image in the other eye.
Aniseikonia
Discussed the possibility (1903)
C. Hess
Designed iseikonic lenses for aniseikonia
Von Rohr
Commented upon the probability of unequal
image sizes. (1864)
Donders
Lenses which correct aniseikonia and include also
the correction of refractive error.
Iseikonic Lenses
Condition in which the size and shape of the
ocular images are equal
Iseikonia
Condition in which ocular images are unequal in
size and shape
Aniseikonia
Type of Aniseikonia that the eyes are gazing in a certain direction
Static Aniseikonia
Type of Aniseikonia that the eyes have to rotate a different amount to gaze at the same point in space
or it is anisophoria (optically induced)
Dynamic Aniseikonia
the size of one ocular image is
symmetrically larger that the other.
Symmetrical Overall
the size of one ocular image is symmetrically larger that the other in one meridian only Axis 90 Axis 180 Axis oblique
Symmetrical Meridional
combination of overall and
meridional is manifested.
Symmetrical Compound
image distortion increases
progressively in both directions
Asymmetrical Pincushion
image distortion decreases progressively
in both directions
Asymmetrical Barrel
image difference increases
progressively in one direction
Asymmetrical Prismatic
image size remains the same but there
occurs an oblique distortion of shape.
Asymmetrical Oblique
Variation in size differ from different positions of
the visual field
Asymmetrical
asymmetric convergence and stereoscopic disparities exists as when viewing the object located to one side.
Normal
i. Pincushion or Barrel
ii. Ever increasing magnification towards the apex of a prism.
Abnormal Asymmetric
i. Overall
ii. Meridional
iii. Compound
Abnormal Symmetric
Testing of Aniseikonia based on binocular space perception
Space Eiknometric Method
Testing of Aniseikonia based on directly comparing perceived image sizes between the two eyes
Direct Comparison Method
instrument for measuring aniseikonia.
Space Eikonometer
3 commercially available direct comparison
tests
- New Aniseikonia Test (Awaya Test)
- Basic Aniseikonia Test (version 1)
- Aniseikonia Inspector (version 3)
provides a manual method to detect and calibrate the Aniseikonic condition.
New Aniseikonia Test (Awaya Test)
is an easy-to-use Windows software program to
test the aniseikonia of a patient.
Basic Aniseikonia Test (Version 1)
is a Windows software program for the clinical
management of aniseikonia.
Aniseikonia Inspector (Version 3)
Give atleast 3 symptoms of Aniseikonia
Headache asthenopia Photophobia Reading Difficulty Nausea Nervousness
Give atleast 4 optical correction/solution
Contact lens
Glasses Good VA
Glasses Compromised
Contact Glasses-Combination
a condition in which the refractive status of one eye differs from that the other.
Anisometropia
The condition in which the
refractive status is equal in the two eyes.
Isometropia
A form of anisometropia in which one eye is myopic and the otherhyperopic.
Antimetropia
Anisometropia or
Asymmetropia
Anisometropia is generally classified into three, what are those
By Type
By Degree
By Etiology
A type of Anisometropia that has different amount of the same error of refraction.
Anisometropia
A type of Anisometropia that has different type of errors
such as hyperopia vs. myopia or spherical vs. astigmatic.
Antimetropia
A degree of Anisometropia that its differences in error totalling no more than 2.00 D.
Low
An etiology of anisometropia that occurs
because of differential growth of the eyeball
of both eyes. It is hereditary in origin.
Congenital Anisometropia
An etiology of anisometropia that is created by
trauma, pathology or the results of systemic
changes.
Acquired Anisometropia
A classification of anisometropia that is a condition in
which the refractive power of the two eyes is
unequal.
Absolute Anisometropia
A classification of anisometropia that is that type of
refractive anomaly in which although the total
refraction of the two eyes is equal, the component
elements in each show relatively large
differences.
Relative Anisometropia
Type of absolute anisometropia that is one eye is normal and the other is either hypermetropic or myopic.
Simple
Type of absolute anisometropia that is both eyes are ametropic either hyperopic or myopic, but one eye has a higher refractive error.
Compound
Type of absolute anisometropia that both eyes are ametropic. One eye is hyperopic and the other is myopic. This is called antimetropia.
Mixed
Type of absolute anisometropia when one
eye is normal and the other has either myopic
or hyperopic astigmatism.
Simple Astigmatic Anisometropia
Type of absolute anisometropia when both eyes are astigmatic but of unequal degree.
Compound Astigmatic Anisometropia
If there is a difference of more than 5D between the two eyes, the patient loses binocularity.
Binocular Vision
If the anisometropia is high and the eyes have a
good visual acuity,
Alternating Vision
If the defect in one eye is high and if its visual
acuity is not good,
Amblyopia
A concomitant convergent squint occurs in
children with the eye having the defect
becoming convergent.
Strabismus
Tue or False Anisometropia is not a serious concern
in newborns and young children
False
Give atlest 3 symptoms of anisometropia
Amblyopia Strabismus Diplopia Eye Strain Headaches Sheer Tiredness
Tests for Anisometropia
Worth 4 light/dot Test
LEA Vision Test System (amblyopia)
Screening Test
Optical Management for Anisometropia
Spectacles
Contact Lenses
