Binocular Indirect Ophthalmoscopy- lecture 1

Question 1

Indirect ophthalmoscopy involves making the eye highly _____ by placing a ____ power ____ lens where in accordance to the eye?

Answer 1

-myopic
-high
-convex (+13D to +30D)
In front of the eye

Question 2

Indirect ophthalmoscopy creates what kind of image in front of the lens?

Answer 2

Real, inverted, and laterally reversed

Question 3

Why is the technique called indirect?

Answer 3

B/c the fundus is seen through a condensing lens

Question 4

Where is the image formed when performing indirect ophthalmoscopy?

Answer 4

Close to the principle focus of the lens, between the lens and the observer

Question 5

Preliminary step when you perform BIO

Answer 5

Explain procedure to patient

Wash your hands

Question 6

How should the headband fit for BIO?

Answer 6

Comfortably without undue tightness

Question 7

Where should oculars be with the BIO on?

Answer 7

Straight and level

Question 8

How do you want the eyepieces adjusted on BIO for maximum field of view?

Answer 8

As close to the eyes as possible, with a slight pantascopic tilt; avoid resting on bridge of nose

Question 9

When you turn your BIO on, what do you want your rheostat at?

Answer 9

To about 50%

Question 10

When you turn your BIO on, what size do you want your aperture set to?

Answer 10

Largest size

Question 11

When you turn your BIO on, what filters do you want in place?

Answer 11

None

Question 12

When you turn your BIO on, what do you want to set the mydriatic pupil setting to?

Answer 12

Maximum dilated

Question 13

What adjustment knobs are on the right of your BIO?

Answer 13

Clear, red-free, yellow and blue filters

Question 14

What adjustment knobs are on the left of your BIO?

Answer 14

3 aperture sizes plus diffuser

Question 15

What do you view when adjusting your interpupillary distance on BIO?

Answer 15

View wall or other object (your thumb) at roughly 40 cm

Question 16

How do you adjust interpupillary distance for BIO?

Answer 16

• view obj at 40 cm
• monocularly for each eye until the object is centered in the field of view
• with both eyes open, a single clear binocular image of the object should be obtained

Question 17

If diplopia is encountered, what do you do to adjust the BIO?

Answer 17

Make further adjustments to the PD until a fused img is achieved

Question 18

How do you adjust the mirror height?

Answer 18

Adjust light vertically using the mirror until it occupies the upper half of the field of view

Question 19

Available powers of condensing lenses

Answer 19

14D to 40D

Question 20

Power of lens that is a good balance b/w magnification and field of view

Answer 20

20D

Question 21

What general power of lenses offer a greater FOV and can aid with examination through small pupils?

Answer 21

Higher power lenses

Question 22

The power of the condensing lens determines these 3 things:

Answer 22

Working distance
Magnification
Field of view

Question 23

As the power of the condensing lens decreases, what happens to the field of view, working distance, and magnification?

Answer 23

FOV dec
WD inc
Mag inc

Question 24

A +30 lens power has what magnification?

Answer 24

2x

Question 25

A +30 lens power has what FOV?

Answer 25

60 degree

Question 26

A +30 lens power has what stereopsis?

Answer 26

1/2

Question 27

A +30 lens power has what working distance from cornea

Answer 27

26 mm

Question 28

A +20 lens power has what magnification?

Answer 28

3.25x

Question 29

A +20 lens power has what FOV?

Answer 29

40 degrees

Question 30

A +20 lens power has what stereopsis?

Answer 30

3/4

Question 31

A +20 lens power has what working distance from cornea?

Answer 31

47 mm

Question 32

A +14/+15 lens power has what magnification?

Answer 32

4.17x

Question 33

A +14/+15 lens power has what FOV?

Answer 33

30 degree

Question 34

A +14/+15 lens power has what stereopsis?

Answer 34

1

Question 35

A +14/+15 lens power has what working distance from cornea?

Answer 35

72 mm

Question 36

What power of lens is used to obtain a panoramic view when detail and stereopsis are not as important, and used with a small pupil?

Answer 36

30D

Question 37

Is your working distance less or more with a 30D condensing lens?

Answer 37

Less

Question 38

What power of lens is most widely used, since it provides an adequate field of view, stereopsis and magnification?

Answer 38

20D

Question 39

What power of condensing lens is most useful for detailed view of the macula or optic disc or for determining elevation of the retina in shallow retinal detachment?

Answer 39

15D

Question 40

3 important patient preparations for performing BIO, after washing your hands and explaining the test to the pt?

Answer 40

- dilation of eyes - dark room when possible - have pt chair fully reclined, enabling practitioner to move around the pt and hence gaining a full 360 degree traverse of the fundus

Question 41

If you are looking at the super quadrant, where should you be looking from?

Answer 41

180 degrees in the opposite direction (inferiorly to the pt)

Question 42

What position do you recline you patient to?

Answer 42

Supine position (or in upright seated position) with the height to about waist high or slightly lower

Question 43

How do you hold the condensing lens?

Answer 43

- grasped b/w tip of flexed index finger and ball of thumb - extended 3rd finger holds pt's lid (thumb of opposite hand is used to retract the lid not held by the 3rd finger) - -3rd finger acts as a pivot that enables the observer to tilt the lens in all planes merely by rocking the forearm on the tip of the finger

Question 44

How do you obtain a view of the fundus with the lens?

Answer 44

- Place lens close to eye to that lids, conj, and iris may be seen - Center pupil in lens - Gradually move lens away from pt, making pupil magnified until it fills the entire area of the lens

Question 45

If the img of the fundus does not fully fill the lens, what should you do?

Answer 45

- move the condensing lens closer to the eye, recenter the pupil, then lift it again - adjust your head tilt to better distribute the light entering the patient's eye - adjust the ophthalmoscope mirror up/down - adjust condensing lens laterally - adjust tilt of condensing lens - check for bino vision; readjust if necessary

Question 46

In which directions do you adjust the ophthalmoscope mirror and condensing lens if the img of the fundus does not fully fill the lens?

Answer 46

Mirror: up/down Lens: laterally

Question 47

Where must the pupil be located in order to maintain a clear view of the fundus?

Answer 47

Pupil must be kept centered in lens at all times or fundus view is lost

Question 48

What do slight movements of the eye or hand off the pupil cause when observing the fundus?

Answer 48

Distortion, shadows, or complete loss of view

Question 49

How do you want your arm and head when observing the fundus?

Answer 49

Keep arm extended and head at arms length from the lens

Question 50

What can slight adjustments in working distance effect?

Answer 50

Changes in magnification, but larger changes will produce difficulties with accommodation, convergence, and possibly diplopia

Question 51

Slight tilting of the lens will displace reflections. What will excessive tilting of the lens induce?

Answer 51

Astigmatism that will distort the fundus img

Question 52

Light intensity that's adequate for most needs?

Answer 52

Moderate light intensity

Question 53

Limit exposure to BIO light to how many seconds at a given time?

Answer 53

30 seconds or less

Question 54

2 options you can give the pt to refresh their tear film

Answer 54

- give pt a chance to blink to refresh tear film | - use artificial tears to aid in comfort (mostly for elderly patients)

Question 55

Proper room lighting for BIO?

Answer 55

Dark enough for you to achieve sufficient contrast | -avoid too much ambient light

Question 56

What light intensity do you start with when using BIO?

Answer 56

Don't begin with the brightest light; once the pt is accustomed to the light, you can gradually turn it up to double-check a selected area