Aniseikonia and Anisometropia Flashcards
Greek word “unequal images”
aniseikonia
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 designed the iseikonic lenses for aniseikonia
Von Rohr
Commented upon the probability of unequal
image sizes. (1864)
Donders
Discussed the possibility (1903)
C.Hess
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
2 types of aniseikonia
- Static Aniseikonia
2. Dynamic Aniseikonia
- eyes are gazing in a certain direction
- images are different in size
Static Aniseikonia
- (optically induced) anisophoria
- eyes have to rotate a different amount to gaze at
the same point in space
Dynamic Aniseikonia
2 classifications of aniseikonia
- Symmetrical Aniseikonia
2. Asymmetrical Aniseikonia
3 types of Symmetrical Aniseikonia
- Overall
- Meridional
- Compound
4 types of Asymmetrical Aniseikonia
- Pincushion
- Barrel
- Prismatic
- Oblique
Variation in size differ from different positions of
the visual field
Asymmetrical Aniseikonia
image difference increases progressively in one direction
Prismatic
image distortion increases progressively in both directions
Pincushion
image distortion decreases progressively in both directions
Barrel
image size remains the same but there occurs an oblique distortion of shape
Oblique
the size of one ocular image is symmetrically larger than the other
Overall
combination of overall and meridional is manifested
Compound
the size of one ocular image is symmetrically larger than the other in one meridian only
Meridional
He utilized the classification as normal and abnormal
Davis
asymmetric convergence and stereoscopic disparities exists as when viewing the object located to one side
normal
based on binocular space perception
SPACE EIKONOMETRIC METHOD
based on directly comparing perceived image sizes between the two eyes
DIRECT COMPARISON METHOD
an instrument for measuring aniseikonia
Space Eikonometer
TRUE OR FALSE.
Aniseikonia either in one or more meridians can be measured by means of an adjustable magnifying device before one eye.
TRUE
3 commercially available direct comparison
tests are _________
- 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
use of red-green glasses
Basic Aniseikonia Test
is a Windows software program for the clinical
management of aniseikonia
Aniseikonia Inspector (version 3)
A type of test which contains
- an advanced aniseikonic test
- a design tool to calculate correcting prescriptions (aniseikonia and anisophoria corrections)
Aniseikonia Inspector (version 3)
ANISOMETROPIA
ANISOMETROPIA
The condition in which the refractive status is equal in the two eyes.
isometropia
is defined as a condition in which the refractive status of one eye differs from that the other
anisometropia
A form of anisometropia in which one eye is myopic and the other hyperopic
antimetropia
The condition in which the two eyes have unequal refractive power. One eye may be myopic (nearsighted) and the other hyperopic (farsighted) or one eye may be
markedly stronger than the other.
ANISOMETROPIA or ASYMMETROPIA
different type of errors such as hyperopia vs. myopia or spherical vs. astigmatic
Antimetropia
different amount of the same error of refraction
Anisometropia
this occurs because of differential growth of the eyeball of both eyes. It is hereditary in origin.
Congenital Anisometropia
created by trauma, pathology or the results of systemic
changes
Acquired Anisometropia
CLASSIFICATION OF ANISOMETROPIA
- Absolute Anisometropia
2. Relative Anisometropia
It 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. In other words, the total refraction of the two eyes can be equal, but the axial length may be different.
Relative
It is a condition in which the refractive power of the two eyes is unequal.
Absolute
Types of Absolute Anisometropia
- Simple
- Compound
- Mixed
- Simple Astigmatic Anisometropia
- Compound Astigmatic Anisometropia
- Mixed Astigmatic Anisometropia
when one eye is normal and the other has either myopic or hyperopic astigmatism.
Simple Astigmatic Anisometropia
In this, one eye is normal and the other is either hypermetropic or myopic
Simple
In this both eyes are ametropic. One eye is
hyperopic and the other is myopic. This is called
antimetropia.
Mixed
when both eyes are astigmatic but of unequal
degree.
Compound Astigmatic Anisometropia
In this, both eyes are ametropic either hyperopic or myopic, but one eye has a higher refractive error
Compound
A concomitant convergent squint occurs in children with the eye having the defect becoming convergent.
Strabismus
If the defect in one eye is high and if its visual acuity is not good, the eye can be excluded altogether from vision and the eye becomes amblyopic.
Amblyopia
TRUE OR FALSE.
In small degrees of anisometropia, ALTERNATING
vision occurs.
FALSE.
Binocular
Anisometropia is a serious concern in newborns and young children because it can lead to ___________
amblyopia
is a clinical test mainly used for assessing a patient’s degree of “binocular vision” and “binocular single vision”.
Worth Four Light Test
for unilateral high myopia, astigmatism, and hypermetropia.
Refractive corneal surgery
advised for higher degrees of anisometropia
contact lens
for uniocular aphakia
IOL implantation
