Refractive Status Flashcards
Is used to describe the measurement of the posterior principal focus of the eye’s refractive mechanism with accommodation at rest
Static Refraction
Is used when the refractive power of the eye is determined when accommodation is not at rest or active
Dynamic Refraction
Incident parallel rays of light converge to form a circle known as
Circle of Least Confusion
Refractive status with accommodation at rest, wherein incident rays of light converge to form the circle of least confusion upon the retina
Emmetropia
Refractive status wherein the circle of least confusion is formed in front of the retina
Myopia
Refractive status wherein the circle of least confusion is formed behind the retina
Hyperopia
Refractive status where a single focus for all meridians does not exist due to a differing refractive power
Astigmatism
Premature children often exhibit what type of EOR
Hyperopia
If a child at 6 has EOR of 0-+0.50D, there is high probability he will be a?
Myopic
If the error is between +0.50D- +1.25D, the child has chance to become an?
E
Mid-Europeans show increased ___ than Scandinivians
M
Negroes & Eskimos show little M but more ____
H
Japanese & Chinese a high incidence of ____
M
Egyptians are more ___ than Sudanese
M
A customary type of myopia, mildly progressive, or if progressing occurs during the years of growth
Simple/Benign
A classification of myopia by origin due to an abnormal development of one of the components of the ocular refracting mechanism or malignant effect
Pathological component
-0.25D to -1.00D
Very Low
-1.25 to -3.00D
Low
-3.25D to -6.00D
Medium
-6.25D to -10.00D
High
Above -10.00D
Very High
A type of hyperopia where it is produced by normal biological variations
Simple hyperopia
A type of hyperopia which is caused by congenital & acquired elements outside the normal variation
Pathologic hyperopia
A type of hyperopia which is due to the accommodative influence of reflex origin, or maybe due to a paralysis of accommodation
Functional hyperopia
He suggested what is now known as Standard Notation
H. Knapp (1866)
Was credited to give accurate description of astigmatism in 1800
Thomas Young
Reported that in 1575, Pare produced stenopaic spectacles; he gave the clue that a certain defect of vision could be remedied by cylindrical lenses
Donders
Produced the 1st distance test charts for astigmatism including the now familiar Clock Dial
John Green
A refractive condition in which variation of power exists on the different meridians of the eye
Astigmatism
Each meridian of the cornea is uniform throughout, and exist at right angles to each other
Regular
Curvature of greatest power lies nearest the vertical meridian falling within the area between 60th-120th meridian
WTR
Meridian exhibiting the greatest curvature lies within the range between 30th and 150th meridian
ATR
Meridian of greatest curvature lies between 30th-60th or 120th-10th meridian
Oblique
Total of degrees representing the 2 principal meridians corrected by cylinders of the same sign equals 180 degrees
Symmetrical
When the 2 principal meridians of both eyes do not total 180 degrees
Asymmetrical
In which ASTIG is due to unequal curvature of lens surface or layers
Lenticular
With accommodation relaxed, one meridian would focus on the retina, while the other falls behind the retina
SHA
With accommodation relaxed, the posterior principal focus of both meridians fall beyond the retina
CHA
With accommodation relaxed, one meridian would focus on the retina, while the other falls infront of the retina
SMA
With accommodation relaxed, the posterior principal focus both meridians fall infront of the retina
CMA
With accommodation relaxed, one meridian would focus behind the retina, while the other falls infront of the retina
Mixed astigmatism
The distance between two focal lies, which includes the circle of least confusion
Interval of Sturm
A series of point sources of light
A line
