MIDTERM

Question 1

Any condition that alters the clarity of several clear structures may result in overall blurred or hazy vision, impaired detail vision or significant glare without a field deficit

Answer 1

Cloudy media

Question 2

Certain disease preferentially affect the peripheral retina or nerve pathways that carry information from the peripheral visual field.

Answer 2

Peripheral field deficit

Question 3

Functional implications of symptoms in cloudy media

Answer 3

o Generalized hazy or blurred vision
o Lost of ability to perceive sharp details
o Printed materials appeared faded, as do colors
o Focal opacities sometimes cause monocular diplopia
o Sunlight and direct lighting tend to cause glare
o Contrast is usually reduced causing poor border detection of both small and large objects

Question 4

Improving contrast almost always helps. Measures include enhancing print contrast through large print and with dark, felt-tipped markers, along with yellow filters indoors and plum (light or medium) outdoors. CCTV provides a range of magnification along with improved contrast.

Answer 4

Central field deficit

Question 5

allows you to predict the add from the best corrected distance acuity.

Answer 5

Kestenbaum’s rule

Question 6

allows you to read the predicted add directly from the near visual acuity chart.

Answer 6

Lighthouse method

Question 7

Functional test result: often 20/200 or worse

Answer 7

Visual acuity

Question 8

Functional test result: blurred

Answer 8

Amsler grid

Question 9

Functional test result: strong positive

Answer 9

Glare test

Question 10

Functional test result: loss at all frequencies

Answer 10

Contrast sensitivity

Question 11

Management of cloudy media

Answer 11

Careful refraction which may involve automated refraction and keratometry.

Moderate increase light can help patients with reduced contrast to perform better.

Sun visor
Typoscope
CCTV
Sunglasses
UV filters
Polarizing filters
Anti-reflective coating

Question 12

General measures to improve contrast:

Answer 12

Yellow filters or amber glasses
CCTV with variable contrast
Large print books
Felt-tipped markers

Question 13

Functional implications of symptoms in field deficit

Answer 13

o Performance of the peripheral retina worsens at night or under poor illumination

o Patients may be unable to perceive people or objects in the surroundings unless the object appears in their remaining visual field

o Difficulty ambulating in unfamiliar environment and anxiety about bumping into peripheral objects.

o Difficulty in locating objects.

Question 14

Functional test result: no macular disease or cataract

Answer 14

Visual acuity

Question 15

Functional test result: normal if there is no macular disease, periphery is missing if field constriction is advance

Answer 15

Amsler grid

Question 16

Functional test result: negative unless media pathology co-exists

Answer 16

Glare test

Question 17

Functional test result: usually normal (except glaucoma) but may be difficult to test if the central field is less than 5 degrees

Answer 17

Contrast sensitivity

Question 18

Functional test result: reduced

Answer 18

Visual field

Question 19

When macular function is intact and visual acuity is preserved, what to perform?

Answer 19

Refraction

Question 20

adapt by looking slightly off center so the healthy part of the retina is pointing straight ahead to receive the image.

Answer 20

Eccentric viewing

Question 21

predicts an add based on both the patient’s best-corrected distance acuity level and the actual desired near acuity level

Answer 21

Reciprocal vision

Question 22

Peripheral field defects causing functional deficits generally fall into two categories

Answer 22

the general constriction and the sector or hemianopic field defect

Question 23

Field expansion lenses uses what prism

Answer 23

Molded prism

Question 24

Hemifield loss may be aided by:

Answer 24

Visual awareness training
Improved scanning techniques
Mirrors
Full-field and partial field prisms

Question 25

environmental modifications include:

Answer 25

o Use of contrasting colors
o Enhanced or task lighting

Question 26

Orientation and mobility training is often the focus of rehabilitation for patients with advanced peripheral field loss. Such may be necessary:

Answer 26

o Mobility canes

o Guide dogs

o Learning to travel with a sighted guide

Question 27

Consider the primary goal of the patient particularly the tasks and history.

Answer 27

Deciding on style

Question 28

defined as the optical power needed to focus parallel rays of light at 1 meter.

Answer 28

Diopter

Question 29

the distance at which a lens focuses parallel rays of light.

Answer 29

Focal length

Question 30

Types of magnification

Answer 30

Relative size
Relative distance
Angular magnification

Question 31

Also known as linear maginification

Answer 31

Relative size magnification

Question 32

Also known as approach magnification

Answer 32

Relative distance magnification

Question 33

Also known as optical magnification

Answer 33

Angular magnification

Question 34

An optical instrument designed to make objects appear nearer, containing an arrangement of lenses by which rays of light are collected and focused and the resulting image magnified

Answer 34

Telescope

Question 35

Two specifications that differentiate telescopes from one another

Answer 35

Magnification power
Field of view

Question 36

consists of a convex objective lens separated from a concave ocular lens by the sum of their focal lengths.

Answer 36

Galilean telescope (terrestrial)

Question 37

consists of convex objective lens separated from a convex ocular lens by the sum of their focal lengths.

Answer 37

Keplerian telescope system (astronomical)

Question 38

Galilean Design:

Answer 38

• Smaller field of view at a given magnification level
• Usual magnification available: 4X
• Light Weight
• Image formed is erect
• Less expensive

Question 39

Keplerian Design:

Answer 39

• Larger field of view at a given magnification level
• Usual magnification available: 10x
• Heavier Weight
• Inverted image, needs an internal re-inverting prism
• More expensive