ophthalmoscopy

Ophthalmoscopy

David Kinshuck

This session 1

• Over the next hour

• Ophthalmoscopy in a younger person

• Need to practice for older patients

• 15 minute introduction

• Practice on each other for 40 minutes

• 3 minute summary

• If time we may cover refraction

This session 2

• Very briefly– External examination– Test pupils– Test visual fields

• In more detail, ophthalmoscopy itself– Red reflex– Examine disc– Rest of retina

Visual fieldspaper

paper

Ophthalmoscope controls 1

• Play with ophthalmoscope

• Work out what the controls are for

Ophthalmoscope controls 2

Ophthalmoscope controls 3

Pupils

• Pupils (needs Flash player installed)

Red reflex

Ref reflex technique

• Check red reflex from 10 cm, focusing on iris

• +3.00 lens?

• Actually focus on the pupil margin

• Brightest light in ophthalmoscope

• Stay on same side of patient for both eyes

• Room lights dim

‘white’ reflex

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http://oftalmologo.bravepages.com/Leucocoria%201.jpg

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Ophthalmoscopy 2

• What is your refraction

• What is the patient’s refraction

• ……what lens do you use in the ophth.?

• Light travels from patient retina to your retina

Ophthalmoscopy 3

• Distance: closer you are, the greater the visual field..1” away is best

• Pupil size for ophthalmoscope beam must match patient’s pupil size (otherwise get too much reflection)

• Too bright…pupil goes small

• Too dim..not see

• Need room lights off/dim

Ophthalmoscopy 4

the closer you get, the larger area of retina seen at one time;

Look in from 2 cm away

Ophthalmoscopy 5Match beam diameter with pupil size.. not too wide

Just right, no reflection

Too wide a beam leads to increased reflection

Ophthalmoscopy 6Match beam diameter with pupil size..not too

narrow

Too narrow a beam…too little retina is seen

Ophthalmoscopy 7

If beam is too bright, pupil goes small (then get a reflection).

Too dim, won’t see anything!

Ophthalmoscopy 8Patient looks up, doctor down

(more comfortable/quicker)

Ophthalmoscopy 9

Index finger on focus dial,

Thumb on brightness control (rheostat)

Ophthalmoscopy 10

Consider using middle finger to gently touch cheek …steadies ophthalmoscope and prevents banging into eye

Ophthalmoscopy 11

Consider resting ophthalmoscope on thumb (which rests over eyebrow) to steady ophthalmoscope and prevent banging into the eye

Ophthalmoscopy 12

Hold ophthalmoscope immediately adjacent to your own (observer’s) eye to get the best view.

Ophthalmoscopy 13

Examine optic first (looking medially 15o. Otherwise, as soon as light hits the fovea, pupil will go smaller, making examination more difficult.

Ophthalmoscopy 14

Use the grid to locate the fovea (the centre of the macula).

What is the most important part of the retina for the none-

ophthalmologist?

• The optic nerve ….

• Papilloedema, raised intracrainial pressure & many other conditions

How to find the optic nerve

Look medially 15o …optic nerve, pituitary, optic tract/cortex lie on the same 15o axis

How to find the optic disc

Vessels point to the optic nerve, so find a vessel fork and move towards optic disc

summary

• What did you find easy• Hard• Red reflex +3.0 d

1. Retina focus..your prescription + patient’s2. Dim room light3. Match beam diameter with pupil size at 2 cm4. Get close…2 cm….larger area of retina visible5. Beam not too bright otherwise pupil goes small6. Patient looks up 15o

7. Rest finger on cheek?8. Follow vessel branching towards the optic disc9. Disc is 15o medial10. Use grid in ophthalmoscope to locate fovea

Refraction 1

Refraction 1

Which lens is needed for which eye?

Refraction 2Use the

appropriate lens for the eye

Add to your own spectacle prescription for ophthalmoscopy

Refraction 3: how to find the plus lens

Focus on something very close

Refraction 4: how to find patient’s spectacle prescription

Hypermetropic

lens magnifies

Myopic lens makes everything appear smaller

Emmetropic

Refraction 5: examining high myopes

For myopes there is only one focal plane…any further back and you will be out of focus. This is unlike emmetropes: you will be in focus even if you examine from a distance (although only a tiny amount of retina will be visible).

Also, unless you have an excellent ophthalmoscope, you may be best examining by looking through the patient’s own spectacles.