VISUAL OPTICS Flashcards
1
Q
Define Astigmstism
A
Astigmstism is the difference of power between the two principal perpendicular meridians
2
Q
What effect on vertical and horizontal lines does blurring along 90 involve
A
Vertical lines appear distinct
Horizontal lines appear blurry
3
Q
Define disc of least confusion (DLC)
A
- the circular blur dioptrically midway between the astigmatic foci
4
Q
Define the far point
A
Object conjugate to the retina in unaccommodated eye
5
Q
Ocular refraction K
A
Incident vergence at the surface of the eye, required for a sharp image to fall on the retina
6
Q
Myopia
A
Ammetropia whereby the second focal point lies in front of the retina for an unaccommodated eye
7
Q
Standard observer definition
A
Person with VA that allows him to identify a letter with gap limb subtending 1’ arc
