Exam 4 -- EOG

Question 1

What are the five indications for an EOG?

Answer 1

Retinitis Pigmentosa
Siderosis Bulbi
Vitelliform Dystrophy (Best Disease)
Fundus Favimaculatis (Stargardt Disease)
Chloroquine (Plaquenil) Retinopathy

Question 2

The Arden Ratio for a patient with ocular albinism is above what value?

Answer 2

300%

Question 3

What are the light sensitive components of the EOG?

Answer 3

Photoreceptors

Question 4

Plaquenil is used for autoimmune diseases like lupus. What is the name of the sign that can be seen on OCT of a patient with Plaquenil retinopathy?

Answer 4

Flying saucer sign

Question 5

What part of the retina is often affected first in a patient with RP? Which visual field?

Answer 5

Inferior retina, superior visual field.

Question 6

The Arden Ratio is the light rise divided by the dark trough. What are normal values?

Answer 6

180% to 250%

Question 7

True or false: in the dark, the front of the eye is more negatively charged than the back of the eye?

Answer 7

False; the front of the eye is more positive than the back of the eye.

Question 8

True or false: even though the macula is normal looking (or near normal) in previtelliform stage of Best Disease, the EOG is still abnormal.

Answer 8

True.

Question 9

What would cause an erroneously high Arden Ratio?

Answer 9

If the patient can’t see the end points.

Question 10

How long does a dark trough take to reach its minimum on an EOG?

Answer 10

8 minutes

Question 11

How long does a light rise take to reach its peak on an EOG?

Answer 11

10-15 minutes.

Question 12

What is Usher syndrome?

Answer 12

RP + deafness

Question 13

Best Disease is inherited in what fashion?

Answer 13

Autosomal dominant

Question 14

What is the name of the condition that can occur with a metallic foreign body, causing the eyes to turn a rusty color and the pupil to dilate?

Answer 14

Siderosis Bulbi

Question 15

Adult vitelliform macular dystrophy resembles Best Disease, but can be distinguished by its later age of onset, smaller lesion size, and what other feature?

Answer 15

Normal EOG finding.

Question 16

In the final stage of Best Disease, atrophic, the small macular scar that remains can cause VA to drop below what level?

Answer 16

20/200

Question 17

What kind of scotoma is often found in a patient with RP?

Answer 17

Ring scotoma

Question 18

What VF testing would you order for a patient on Plaquenil?

Answer 18

A 10-2 central VF

Question 19

What are the light insensitive components of the EOG?

Answer 19

RPE, cornea, lens, etc, but not the photoreceptors. These establish the dark trough.

Question 20

What are the five stages of Best Disease?

Answer 20

1. Previtelliform
2. Vitelliform
3. Pseudohypopyon
4. Vitelliruptive
5. Atrophic

Question 21

In which stage of Best Disease does the lesion become like a scrambled egg in appearance? How bad can VA get in this stage?

Answer 21

Vitelliruptive; VA no worse than 20/100

Question 22

True or false: the voltage of the eye is greater in the light than it is in the dark.

Answer 22

True.

Question 23

What is the resting potential of the front of the eye?

Answer 23

About 6 mV

Question 24

What is the name of the syndrome if a patient has RP and deafness?

Answer 24

Usher Syndrome

Question 25

During the vitelliform stage of Best Disease, the lesions has an egg-yolk appearance and are usually centered on the macula and can be multifocal. How bad is VA in this stage?

Answer 25

VA is usually in the 20/20 to 20/40 range.

Question 26

What would cause an erroneously low Arden Ratio?

Answer 26

If the patient closes their eyes or looks away.

Question 27

In which stage of Best Disease does the yellow material break through the RPE and accumulate in the subretinal space? What condition may this appear like?

Answer 27

Pseudohypopyon; may appear like central serous choroidopathy