Anisometropia and Aniseikonia Flashcards
Defined as 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 other is 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 amount of the sane error of refraction.
Anisometropia
Different type of errors such as hyperopia vs. myopia or spherical vs. astigmatic.
Antimetropia
Differences in error totaling no more than 2.00.
Low/ Low by Degree
This occurs because of differential growth of the eyeball of both eyes. It is hereditary in origin.
Congenital Anisometropia
Created by trauma, pathology of the results of systematic changes.
Acquired Anisometropia
Uniocular aphakia, wrong IOL power trauma, keratoplasty.
Acquired Anisometropia
It is a condition in which the refractive power of the two eyes is unequal.
Absolute Anisometropia
It is the 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
The total refraction of the two eyes can be equal, but the axial length may be different.
Relative Anisometropia
One eye is normal and the other is either hypermetropic or myopic.
Simple/ Simple Absolute Anisometropia
Both eyes are ametropic either hyperopic or myopic, but one eye has a higher refractive error.
Compond/ Compound Absolute Anisometropia
Both eyes are ametropic. One eye is hyperopic and the other is myopic.
MIxed/ Mixed Absolute Anisometropia
Mixed Absolute Anisometropia is also called.
Antimetropia
When one eye is normal and the other has either myopic or hyperopic astigmatism.
Simple Astigmatic Anisometropia
When both eyes are astigmatic but of unequal degree.
Compound Astigmatic Anisometropia
Small degrees of 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, the patient gets into a habit of using the hypermetropic eye for distance and the myopic eye for near vision.
Alternating Vision
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
A concomitant convergent squint occurs in children with eye having the defect becoming convergent.
Strabismus
Commonly referred as lazy eye. This is when a child has reduced vision in one of their eyes because during childhood they have not used that eye adequately.
Amblyopia
This is when a person is not able to align both of their eyes under normal conditions simultaneously and is referred as being cross eyed.
Strabismus
This is when a person has double vision.
Diplopia
Clinical test mainly used for assessing a patient’s degree of “binocular vision” and “binocular single vision”.
Worth Four Light Test/ Worth’s Four Dot Test/ W4LT
Occurs during binocular vision when the brain does not process the information received from either of the eyes.
Suppression
The corrective spectacles can be tolerated up to maximum difference of 4D. HIgher than that, diplopia may occur.
Spectacles
Advised for higher degrees of anisometropia.
Contact Lens
For uniocular aphakia.
IOL implantation
For unilateral high myopia, astigmatism, and hypermetropia.
Refractive Corneal Surgery
Unequal images.
Aniseikonia
A binocular condition, so the image in one eye is perceived as different in size compared to the image in the other eye.
Aniseikonia
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
Lenses which correct aniseikonia and include also the correction of refractive error.
Iseikonic Lenses
Eyes are gazing in a certain direction.
Images are different in size.
Static Aniseikonia
Optic induced anisophoria.
Eyes have to rotate a different amount to gaze at the same point in space.
Dynamic Aniseikonia
The size of one ocular image is symmetrically larger than the other.
Overall
The size of one ocular image is symmetrically larger than the other in one meridian only.
Meridional
Combination of overall and meridional is manifested.
Compound
Variation in size 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
