Accommodation

Question 1

What system is stimulated in positive accommodation?

Answer 1

Parasympathetic nervous system

Question 2

What occurs in positive accommodation?

Answer 2

Ciliary contraction
Ciliary body moves forward
Ligament tension is released
Lens becomes more convex
Increase in dioptric power

Question 3

What occurs in negative accommodation?

Answer 3

Tension on ciliary muscle is released
Capsule flattens
Decrease in dioptric power

Question 4

What are the 4 types of normal accommodation?

Answer 4

Reflex accommodation
Tonic accommodation
Convergence-accommodation
Psychic or near accommodation

Question 5

What stimulates reflex accommodation?

Answer 5

The quality of retinal images

Question 6

What system operates reflex accommodation?

Answer 6

Parasympathetic nervous system

Question 7

What is the pathway in the PSNS to increase the power of the lens?

Answer 7

CN III
Short posterior ciliary nerves
Ciliary body

Question 8

On what is tonic accommodation dependent?

Answer 8

The tone of the ciliary body

Question 9

What removes the appreciation of blur?

Answer 9

Darkness

Question 10

With which type of accommodation is night myopia or empty field myopia associated?

Answer 10

Tonic accommodation

Question 11

Convergence-accommodation is also known as ___?

Answer 11

Relative accommodation

Question 12

When trying to measure accommodation, we can use minus lenses to do what? Plus lenses?

Answer 12

Induce accommodation

Relax accommodation

Question 13

What is psychic accommodation?

Answer 13

Accommodation induced by the awareness of nearness of a targe

Question 14

What are some examples of psychic accommodation?

Answer 14

Using:
Microscopes
Auto-refractor
Eyestrain
Charts less than 20ft

Question 15

Accommodating slightly less than the needed amount is called what?

Answer 15

Accommodative lag

Question 16

Accommodating slightly more than is needed is called ___?

Answer 16

Accommodative lead

Question 17

Most people show an accommodative lag of how much?

Answer 17

+0.50D

Question 18

We expect intermittent accommodation at 5-8” for how long?

Answer 18

Short periods of time

Question 19

We expect sustained reading at 40 cm for how long?

Answer 19

At least 2 hours

Question 20

What are the two suggestions about the normal amplitude of accommodation made my Donders?

Answer 20

It decreases with age

There is biological variation

Question 21

What is the Hofstetter formula for minimum expected accommodative amplitude?

Answer 21

15-(0.25)(age)

Question 22

What is the Hofstetter formula for average expected accommodative amplitude?

Answer 22

18.5-(0.40)(age)

Question 23

What is accommodative facility?

Answer 23

Ability to repeatedly stimulate and relax accommodation with ease

Question 24

What is the expected normal finding when testing accommodative facility?

Answer 24

Adults - 10 cycles per minute binocularly

Children - 5 cpm binocularly

Question 25

If a patient is having trouble clearing additional minus power at near, what do they have?

Answer 25

Accommodative insufficiency

Question 26

What are 3 signs of accommodative insufficiency?

Answer 26

Abnormally high lag
Response is reduced for their age
Trouble clearing additional minus power at near

Question 27

What is accommodative excess?

Answer 27

Having abnormally high lead

Question 28

Trouble clearing additional plus lens power is a sign of what?

Answer 28

Accommodative excess

Question 29

Accommodative excess is usually seen in whom?

Answer 29

Younger patients

Question 30

The inability to relax from accommodative lead is called what?

Answer 30

Accommodative spasm