Final Exam Peavc Flashcards
Is defined as a condition in which the refractive status of one eye different 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
Anisometropia is has 3 generally classified
BY TYPE
By DEGREE
BY ETIOLOGY
By type
Different amount of the same error of refraction
ANISOMETROPIA
By type
Different types of errors such as hyperopia vs myopia or spherical vs astigmatic.
ANTIMETROPIA
By degree
Difference in error totaling no more than 2.00D
LOW
ANISOMETROPIA IS DERIVED FROM THE GREEK AND MADE UP OF FOUR PARTS
AN-NOT
ISO-EQUAL
METR-MEASURE
OPIA-VISION
THE CONDITION IN WHICH THE TWO EYES UNEQUAL REFRACTIVE POWER.ONE EYE MAY BE MARKEDLY STRONGER THAN THE OTHER
ANISOMETROPIA OR ASYMMETROPIA
By etiology
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 systematic changes.
-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 a type of REFRACTIVE anomaly in which although the total refraction of the two eyes is equal the components elements in each show relatively large differences. In other words the total refraction of the two eyes can be equal but the axial lenght may be different
Relative anisometropia
Type of absolute anisometropia
-simple
-compound
-mixed
-simple astigmatic anisometropia
-compound astigmatic anisometropia
One eye is normal and the other is either hypermetropic or myopic
Simple anisometropia
Both eyes are ametropic either hyperopic or myopic ;but one eye has a higher refractive error
Compound
Both eyes are ametropic, one eye is hyperopic and the other is myopic.
Mixed 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
CLINICAL FEATURES:
Small degree 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 PATIENTS GETS INTO THE HABIT OF USING THE HYPERMETROPIC EYE FOR DISTANCE AND THE MYOPIC EYE FOR NEAR VISION
ALTERNATING VISION
If the defect is 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 the eye having the defect becoming convergent
Strabismus
Is a serious concern in newborns and young children because it can lead to amblyopia (impaired vision in one eye) with a major degree of anisometropia the brain cannot reconcile the difference in images coming from two eyes it develops a preference for the image coming from one eye suppresses the image from the other eye and in time the brain loses the ability to see the image from the suppressed eyes
ANISOMETROPIA