Case 2

Question 1

How do you follow up a symptom of flashing lights?

Answer 1

-onset
-both eyes or just one
-how often
-any other changes to vision
-any floaters
-any previous retinal problems like tears or trauma

Question 2

What are causes of flashing lights?

Answer 2

-retinal detachment
-ocular tumour
-headaches

Question 3

What happens to the lens, zonules and ciliary muscles when accommodation is relaxed ( distance vision)

Answer 3

-lens is stretched
-tension in zonules
-ciliary muscles are resting

Question 4

What are the 4 components of accommodation?

Answer 4

-tonic
-reflex
-vergencs
-proximal

Question 5

What is tonic accommodation?

Answer 5

The resting state so there is no stimulus

Question 6

What is reflex accommodation? What is its stimulus?

Answer 6

The automatic response of accommodation to maintain a clear retinal image so the stimulus is small amounts of retinal blur <2.00D

Question 7

What is vergence accommodation?

Answer 7

Accommodation where the stimulus is convergence and is only present when both eyes are open

Question 8

What is proximal accommodation?

Answer 8

Where the stimulus is the perception of the proximity of the fixation target

Question 9

What is far point of accommodation (FPA) in an emmetrope?

Answer 9

Infinity, where no accommodation is required

Question 10

What is near point of accommodatio NPA in an emmetrope?

Answer 10

The closest point to the eye where the image is focussed on the retina using max accommodation

Question 11

When do you measure far point of accommodation?

Answer 11

With distance correction

Question 12

What does amplitude of accommodation =?

Answer 12

Far point of accommodation to near point of accommodation

Question 13

How does accommodation change in diopters with age?

Answer 13

As you get older your ability to accommodate drops so accommodation in diopters gets smaller

Question 14

What is hofsetters formula for working out average, max and min accommodation for an age

Answer 14

Average = 18.5 -0.3 x age
Maximum = 25 -0.4 x age
Minimum = 15 - 0.25 x age

Question 15

What gender of of presbyopes are better at accommodation?

Answer 15

Men

Question 16

What gender of of presbyopes are better at accommodation?

Answer 16

Men

Question 17

Give 6 ways accommodation is actually affected

Answer 17

-age
-race
-gender
-viewing angle (accom is max when looking down and in)
-pathology
-binocular vs monocular (binocular is about 0.5D greater than monocular)

Question 18

Give 5 ways accommodation is artefactually affected

Answer 18

-compliance of subject
-pupil size
-method of measurement
-target size
-myopia, hypermetropia or latent hypermetropia that is left uncorrected

Question 19

Give 6 symptoms of presbyopia

Answer 19

-gradual onset but may appear to patients as sudden
-near tasks are held further away
-near vision is slow to focus
-accommodative spasm after near work
-Asthenopia and headaches
-needing more light to see well at near

Question 20

What are the steps in accommodation to form a blur circle at the retina?

Answer 20

1. Refractive power is increased by increasing lens power
2. The rays of light become more convergent
3. The point of focus shifts forwards and blue circle decreases until the point is achieved
4. The distant object now forms a blur circle at retina

Question 21

What are the downsides to reading additions?

Answer 21

Additional plus means distance vision will start to blur e.g. +1.00 means anything further than 1m away will start to look blurry and +2 means anything further than 50cm away will start to look blurry