This document discusses ophthalmoscopy techniques for examining the fundus of animal eyes. It describes direct ophthalmoscopy, where a handheld device is placed against the examiner's eye, and indirect ophthalmoscopy, which uses a light source and lenses. Both techniques allow viewing of the retina and optic disc but have different advantages - direct provides higher magnification while indirect allows a wider field of view. Proper animal restraint, pupil dilation, and examination procedure are emphasized. Examples of normal and abnormal fundus findings are also presented.

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OPHTHALMOSCOPY
Dr Frank FAMOSE
DVM, CES Ophtalmologie
Ekaterinburg May 2010
What is ophthalmoscopy ?
►Fundus examination ►Direct
 Tapetum ophthalmoscopy
 Non-tapetal zone
 Vascularisation ►Indirect
 Optic nerve papilla ophthalmoscopy
►Skiascopy
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Indications
► Diagnosis ► Inherited ocular disease survey
DIRECT
OPHTHALMOSCOPY
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Principles of ophthalmoscopy
History
►1704 : First description of feline ocular fundus
►1846-1854 : Babbage-Wharton-Jones
►1858 : First use of direct ophthalmology in animals
►1892 : First atlas of veterinary ophthalmoscopy
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Material
►Handheld devices
►Low price
Animal’s side Operator’s side
Direct ophthalmoscopy : technical
aspects
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What do you see ?
►Image size
 Magnification from x17 to x19
 Comparison to optic disc
(vision field about 2-3 Odisc)
► Image position
 Real image
 Erect image
Practical realization
►Animal restraint
►Sedation
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Practical realization
►Dilatation
 Tropicamide 0,5%
 1 drop ev. 5 min for
20 min
►Dark room
Practical realization : step by step
►What to do ? ►How to do ?
 Place the ophthalmoscope on  Place it against your right brow
your eye (for exam of right eye)
 Look for the Fundus reflexion  Look for it from a 0,5 to 0,75 m
(green reflex) distance
 Get closer  Till the Fundus is full field
 Follow eye movements
►Difficulties ?
 Keep both eyes opened
 Right for right, left for left
 Don’t lose fundus reflexion
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Systematic examination of fundus
Tapetum
Retinal
Vessels
Non tapetal Optic
Zone Disc
Systematic examination of fundus
First Second
quadrant quadrant
Fourth Third
quadrant quadrant
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Adjustements
►Rekoss disc
 Description
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 Uses
►Light source size
►Light colour
►Grille
►Slit source
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Pros and cons of direct
ophthalmoscopy
►Pros ►Cons
 Greater magnification  Small field of view
 Grid and slit  Short working distance
 Alteration of dioptric  Monocular vision
power  Bad vision of peripheral
 Lower cost retina
 Greater distorsion if
opacities
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INDIRECT
OPHTHALMOSCOPY
Principles of ophthalmoscopy
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History
►1853 : Ruete
►1947 : Development in human medicine
►1960 : Veterinary use
Indirect ophthalmoscopy :
technical aspects
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Equipment
►Light source
 Electric lamp
 Headband fit
►Optic system
 Converging lens
 Prisms
Equipment : digital fundus camera
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Practical realization
►Animal restraint
►Sedation
Practical realization
►Dilatation
 Tropicamide 0,5%
 1 drop ev. 5 min for
20 min
►Dark room
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Practical realization : step by step
►What to do ? ►How to do ?
 Place the ophthalmoscope on  Adjust pupillary space and
your head direction of light source
 Look for the Fundus reflexion  Look for it from a 0,5 to 0,75 cm
(green reflex) distance
 Place the lens 2-3 cm from the  Move it till the Fundus is full field
eye
 Follow eye movements
►Difficulties ?
 Placement of lens
 Inversion of movements
 Don’t lose fundus reflexion
Systematic examination of fundus
Tapetum
Retinal
Vessels
Non tapetal Optic
Zone Disc
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Systematic examination of fundus
First Second
quadrant quadrant
Fourth Third
quadrant quadrant
Normal fundus - Dog
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Normal fundus - Dog
Normal fundus - Dog
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Normal fundus - Dog
Normal fundus - Dog
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Retinal degeneration - Cat
Central retinal atrophy - Dog
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Retinal detachement - Dog
Adjustements : lenses
►Plan-convex lens :
converging effect
►Effect of power of
lens
 On magnification
 On visual field
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Pros and cons of indirect
ophthalmoscopy
►Pros ►Cons
 Larger field of view  Inversion of image
 Safer distance from the  Less magnification
patient  Technically more
 Binocular evaluation difficult
 More expensive
Conclusion
►Ophthalmoscopy : essential part of eye examination
►Direct and indirect complements each other
►Practice, practice, practice…
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