Session 1 Flashcards
(22 cards)
What is m = cm = mm ?
1m = 100cm = 1000mm
What are the 1/8th increments from 0.00 to 1.00?
0.00, 0.125, 0.25, 0.375, 0.50, 0.625, 0.75, 0.875, 1.00
What causes hyperopia? and what are they known as? 2
Flat Cornea - Refractive/Curvature Hyperopia
Short Eye - Axial Hyperopia
What are 3 types of Hyperopia?
Latent Hyperopia
Manifest Hyperopia
Absolute Hyperopia
What is Latent Hyperopia?
Completely corrected by a px’s accommodation
What is Manifest Hyperopia?
Corrected by either px’s accommodation or convex lenses
What is absolute Hyperopia?
The part of the hyperopic error that the eye cannot accommodate for
What can cause Myopia? and what are they known as? 2
Steep Cornea - Refractive/ Curvature Myopia
Long Eye - Axial Myopia
What is Axial Myopia?
The eyeball is too long or larger than normal
What is curvature myopia?
The eye is normal size but the curvature of the cornea and lens are increased.
What is index myopia?
Change of refractive index in the lens (cataracts or diabetes)
What is progressive myopia?
Myopia that progressives quickly to high levels and starts at a young age. Can cause further health issues
What is common reading add for ages
42-45
45-50
50-65
+1.00 - +1.25
+1.50 - +1.75
+2.00 - +2.50 (+3.00)
What is Astigmatism?
Curvature in the cornea is inconsistent in between the perpendicular axis
Characteristic of Regular Astigmatism? 2
Can be corrected by cylindrical lens
Axes of the vertical curvature and horizontal curvature are perpendicular to one another (90 degrees apart)
Characteristics of Irregular Astigmatism ? 3
Can not be corrected by cylindrical lens
Normally due to trauma
Abnormalities in the curves, not perpendicular to one another
What is Simple Myopic Astigmatism?
(look at example of prescription)
Vertical rays = focused on retina
Horizontal rays = focused in front of retina
What is Simple Hyperopic Astigmatism?
(look at example of prescription)
Vertical rays= focused on retina
Horizontal rays= focused behind the retina
What is Compound Myopic Astigmatism?
(look at example of prescription)
Both focal points in front of the retina
What is Compound Hyperopic Astigmatism?
(look at example of prescription)
Both focal points fall behind the retina
What is Mixed Astigmatism?
(look at example of prescription)
Vertical rays = behind the retina
Horizontal rays = in front of the retina
What is Amblyopia?
Refractive error when one eye cannot focus as clearly as the other caused by abnormal development in early life.
