Refractive Status Flashcards
Distance at infinity
At 20ft or 6m
Distance beyond infinity
beyond 20ft or 6m
Distance within infinity
Within 20ft or 6m
PPF means?
Posterior principal focus
used to describe the measurement of the posterior principal focus of the eye’s refractive mechanism and the retina of the same eye, with accommodation at rest
Static refraction
In static refraction, the eye is looking (at, beyond, within) infinity
at infinity
It is used when the refractive power of the eye is determined when accommodation is not at rest or accommodation is active
Dynamic refraction
In dynamic refraction, the eye is looking (at, beyond, within) infinity
within infinity
Variations from perfect coincidence of posterior principal focus of the eye with the retina
Refractive Anomalies or Errors of Refraction
A perfect optical system converges incident parallel rays of light to a _____ point.
Single point
The human eyes are a/an (perfect/ imperfect) optical system
imperfect
The incident parallel rays of light converge to form a circle called?
The circle of least confusion
Refractive status with accommodation at rest, wherein incident parallel rays of light converge to form the circle of least confusion UPON THE RETINA
Emmetropia
Refractive status with accommodation at rest, wherein incident parallel rays of light converge to form the circle of least confusion INFRONT OF THE RETINA
Myopia
Refractive status with accommodation at rest, wherein incident parallel rays of light converge to form the circle of least confusion BEHIND THE RETINA
Hyperopia
Refractive status with accommodation at rest, wherein incident parallel rays of light do not focus anywhere in the optical system
Astigmatism
In an astigmatic eye, no single focus exists in the retina due to differing power of the various _____ of the eye.
meridians
Premature children usually exhibit what EOR?
Hyperopia
The hyperopia in premature children may disappear within?
The first year of life
Weigh of premature children at birth
less than 1,200 grams
There is a high incidence of hyperopia during birth because?
Because at birth, the size of the eyeballs is small
True or false
Emmetropia is common in newborn
FALSE. Emmetropic newborn babies are rare
As age increases to school years, there will be an increase in (myopia, hyperopia)
Myopia
If a 6-year-old child has an EOR of 0 to +0.50D, the child will likely become (myopic, hyperopic, emmetropic)
Myopic
If a 6-year-old child has an EOR of +0.50 to +1.25D, the child will likely become (myopic, hyperopic, emmetropic)
Emmetropic
If a 6-year-old child is myopic, the child will likely become (myopic, hyperopic, emmetropic)
Myopic
In a mature individual, the trend towards _____ exceeds that towards _____.
hyperopia, myopia
In matured individuals, low myopia will:
a. increase
b. decrease
c. remain constant
Low myopia will remain relatively constant
High myopia increases slightly from what ages?
ages 60-75
High myopia increases slightly from ages 60-75, probably due to?
cataract formation
Mid-Europeans show increased (myopia, hyperopia) than Scandinavians
myopia
Negroes and Eskimos show little _____ but more_____.
myopia, hyperopia
Japanese and Chinese show a high incidence of (myopia, hyperopia)
myopia
Egyptians are more (myopic, hyperopic) than Sudanese
myopic
Jews are more (myopic, hyperopic) than non-Jews
myopic
There is (little, high) difference observed in refractive status for sexes
little difference
Girls appear to become (myopic, hyperopic) at an earlier age
Myopic
True or False:
The association of nutrition and diet to refractive status is indecisive
TRUE. Different reports contradict each other.
True or False:
Ametropia has a genetic basis
True
The association of refractive status with intelligence was made by?
Tscherning (1883) and Seggel (1884)
(Myopia, Hyperopia) is predominant among desk and professional workers
Myopia
True or False:
Desk and professional workers were assumed to be non-intellectuals back then.
FALSE. They were assumed as intellectuals.
An association of (myopia, hyperopia) with mental deficiency has been reported.
hyperopia
