COS Ophthalmoscopy

• Ophthalmoscopy


  Fundamental part of an eye examination that allows examination of the posterior eye
• Posterior Eye


  Posterior Pole - 5-6mm diameter between inferior and superior temporal arteries
• Describing Posterior Eye Images

  • Describe if RE / LE
  • Posterior pole / periphery (which area of the retina can you see?)
  • Which anatomical structure / landmarks can you see?
• Forms of Ophthalmoscopy


  • Direct
  • Indirect
  • Monocular
  • Binocular
• Direct Ophthalmoscopy


  • More difficult with ocular media opacities
  • View affected by ametropia
  • Hand-held - good for when a slit lamp cannot be used
  • Portable
  • Good for viewing cortical and posterior subcapsular cataract
  • Can be used to observe floaters un-dilated
  • Direct view of the fundus, image erect
• Binocular Indirect Ophthalmoscopy


  • Various lens diameters and power options can provide different magnifications and, in certain cases, the ability to view the fundus without the need for dilation
  • Able to use the slit beam height to measure abnormalities / the disc
  • Ability to use slit lamp magnification
  • Better for examining the anterior eye
  • Better field of view
  • Doesn't require getting close to the patient - more comfortable
• Monocular Indirect Ophthalmoscopy


  • Better than direct ophthalmoscopy for amblyopic practitioners
  • Good where dilation not possible
  • Has more space from the patient than in direct ophthalmoscopy
  • Larger field of view than direct ophthalmoscopy
• Ophthalmoscope


  • Handle with a light source
  • Mirror
  • Aperture
  • Bank of 'compensating' lenses
• If patient / practitioner emmetropic

  Light rays will emerge from the patient's eye as parallel beam - focussed onto the practitioner's retina
• If patient / practitioner ametropic

  Light rays converge/diverge = compensating lenses required
• Magnification


  • Patient / examiner ametropia affects magnification of the image
  • If patient & practitioner is emmetropic the angular magnification is ~15x
  • Myopic eyes will magnify the image more, hyperopic less - Galilean / reversed Galilean telescope effect
• Field of View


  • Amount of retina you will be able to see at any given time
  • Impacted by: Distance from the patient's eye, Patient's pupil size, Ophthalmoscope aperture size
  • With 'proper' illumination maximum field of view is determined by the most oblique pencil of light that can still pass from the patient's pupil to the observer's pupil
• Pupil Size, Aperture Size and the Field of View

  • Field of view linked directly to the amount of light the pupil allows in
  • You cannot see what isn't illuminated!
  • Best to use a: Large aperture for dilated / large pupils, Medium aperture for un-dilated pupils in a dark room, Small aperture with small pupils in a bright room
• Working Distance and Effect on Field of View

  Closer the light source to the eye = more of the retina illuminated = wider field of view
• By law, in a 'routine sight test' you must 'perform an internal examination and carry out such additional examinations as appear to be necessary to detect signs of injury, disease of abnormality in the eye or elsewhere.'
• Before your Refraction


  Understand why a patient's VA may be affected - easier end point?
• After your Refraction


  • Changes in prescription can be used as a diagnostic tool
  • Looking for a reason for reduced VA?
  • Poor recovery from bright lights?
• Onsite Optometry Suite Ophthalmoscopes - Heine Beta 200S

  • Spectacle Rest
  • Viewing Aperture
  • Dioptre Read-out (Minus=Red)
  • Lens Wheel
  • Handle
  • Thumb Rest
  • Viewing Window
  • Aperture Selector
  • Filter Selector
  • On/off or Rheostat
• Onsite Optometry Suite Ophthalmoscopes - Keeler Specialist


  • Viewing Window
  • Graticule and Filter Control
  • Lens Wheel
  • Viewing Aperture
  • Dioptre Read-out (Minus=Red)
  • On/off or Rheostat
  • Handle
  • Pupil Gauge
  • Auxiliary Lens Dioptre Power
• Ophthalmoscope Filters & their Uses

  • Green ('red-free') - increases the contrast of blood vessels & vascular lesions
  • Blue - can be used with fluorescein to show corneal abrasions / ulcers
  • Grey - filter for photophobic patients
  • Slit - can be used to look at contour abnormalities of the cornea, lens or retina
  • Fixation target / star for eccentric fixation
  • Half circle - can be used to decrease reflections
• Method Overview


  1. Raise the chair height to a comfortable position

  2. Explain the examination to the patient and give patient instructions

  3. Consider the aperture size you would like to use for the patient

  4. Set the initial power of the lens wheel

  5. Ask the patient to remove their glasses and, if relevant, remove your own

  6. Dim the room lights

  7. Hold the ophthalmoscope in your right hand to examine the patient's RE, and vice versa

  8. Place the ophthalmoscope against your brow, looking through the aperture

  9. Position the ophthalmoscope about 15⁰ temporal to the patient's line of sight

  10. Place the hand not holding the ophthalmoscope on the back of the chair, or the wall, for stability

  11. Begin to move towards the patient until the anterior eye is in focus (~10cm)

  12. Move in closer to the patient on a line 15⁰ temporal to the patient's visual axis and decrease the dioptric power of the focusing lens as you move closer

  13. Move as close as possible without touching the patient's eye
• If you are 15⁰ temporal to the patient, the disc should now be in view. If you can see vessels, follow them to the disc - the bifurcation of vessels will point towards the direction of the disc
• Direct ophthalmoscopy


  Move in closer to the patient on a line 15⁰ temporal to the patient's visual axis and decrease the dioptric power of the focusing lens as you move closer
• Decreasing the dioptric power


  Allows you to view opacities in the vitreous
• Adding minus lenses


  Moves further back
• Adding positive lenses


  Moves further forwards
• Move as close as possible without touching the patient's eye


  The closer you are, the better the field of view and the less likely corneal reflexes will obstruct your view
• If both you and the patient are emmetropic and your accommodation is relaxed, the power of the lens wheel will be close to zero
• If you / the patient are ametropic and uncorrected the lens power needed to focus on the fundus will be different
• If you are 15⁰ temporal to the patient, the disc should now be in view
• If you can see vessels, follow them to the disc - the bifurcation of vessels will point towards the direction of the disc
• Examining the optic disc

  1. Find the disc

  2. Focus on it using the lens wheel

  3. Record the following information: distinctness of optic disc margins, optic nerve head size and shape, health of the NRR, cup size, disc depth, size/type/location of any peripapillary chorioretinal atrophy, presence of the lamina cribrosa or spontaneous venous pulsation, any additional information
• Indistinct disc margins nasally, temporal margins distinct


  Example of optic nerve appearance
• Optic disc size


  Small, medium, or large
• NRR colour


  Yellow/orange/pink = normal, light/white (pallor) = ocular pathology
• ISNT rule


  Width of NRR inferior > superior > nasal > temporal, followed in most normal eyes but inaccurate as many normal eyes don't follow it and some glaucomatous eyes do
• Notching of the NRR

  Indicates potential thinning of the NRR
• Healthy NRR


  • No notching, ISNT rule followed, no pallor - yellow colour
• Cup to disc ratio


  Comparison of cup diameter to disc diameter, average ~0.3
• Don't measure cup to disc ratio by colour change, use depth or vessel changes