Chapter 13

Question 1

What Bifocal add pier is virtually the maximum effective power for near vision for a person who is older than 60 or has hyperopia?

Answer 1

+3.00 D.
Single vision spectacles greater than plus 3 are prescribed for people with low vision. Reading material must be held increasingly close to the face the higher the power

Question 2

When should a patient be referred to a low vision specialist?

Answer 2

When low vision doesn’t improve from refraction or medical/surgical improvement. Pt may have a degenerative disease and it be evaluated properly

Question 3

Legal blindness can be defined as best-corrected visual acuity of 20/200 or less in the better setting Eye or as what degree of visual field loss?

Answer 3

Visual field reduced to 20 degrees or less in the better seeing eye.
No peripheral vision, no central vision, less than 20/200, limited portions of the visual fields, light perception only, no light perception, or fluctuations in vision can impair visual function

Question 4

What can reduce glare and improve reading ability for this with low vision?

Answer 4

Wearing a hat with a brim.
This can be helpful c glare from an overhead source, sunglasses can be helpful but dark tints can reduce light transmission to the eye

Question 5

For a patient requiring high magnification and contrast, what nonoptical visual aid would be most helpful?

Answer 5

Closed-circuit television.
CCTV use a video camera to protect a magnified image of printed material onto a television screen allowing for higher magnification and brightness adjustment

Question 6

What is the most common cause of blindness in developing countries?

Answer 6

Cataract.
Ocular traumas, High refractive error, Corneal scaring, macular degeneration, glaucoma, onchocerciasis, diabetic retinopathy, congential causes, and retinopathy of prematurity also are common causes

Question 7

At a 10in distance how much magnification will a + 10.00 Lens provide.

Answer 7

2.5x
In Kestenbaum’s rule, you divide the Snellen denominator by the Snellen Numerator to get the magnification in diopters. You then multiply by the distance in meters to get the magnification power

Question 8

What items are considered low bison devices?

Answer 8

Glasses, magnifying glasses, and telescopes.
Magnifying glasses help with near Vision, but the hard part is increased surface area decreases the magnification power. Telescopes help with distance, but handheld telescopes have a small field of view and ones that fit on lenses are expensive