ophthalmoscopy
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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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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.