Basic opthalmoscopy findings - presentation at www.eyenirvaan.com

BASIC
OPHTHALMOSCOPY
FINDINGS
Isha Dave B.Sc (Hons), M.C Optom (UK)
Practicing Optometrist and Educator
To view more presentations and articles, visit www.eyenirvaan.com

The Normal Fundus
• Definition of Fundus:
– The interior of the globe as seen with an
opthalmoscope
– Limit is the orra serrata
– Direct ophthalmoscopy allows
visualisation of approx 60-70% of fundus

Fundus Background
• What colour is the
retina????

Fundus Background
• Orange/red background comes from:
– Light directly reflected from choroidal blood
vessels
– Light reflected from sclera and transmitted through
choroidal blood vessels
• Amount of light reflected depends on:
– Degree of pigmentation of retina
– Degree of pigmentation of choroid
• Most fundus layers are transparent and do
not contribute to appearance of fundus

Types of fundus
1. Dark/Negroid
2. Medium/Caucasian
3. Light/Blonde
4. Tesselated
5. Albinotic

1. Dark/Negroid
• Heavily pigmented
RPE
• Heavily pigmented
choroid

2. Medium/Caucasian
• Normally
pigmented RPE
• Normally
pigmented choroid

3. Light/Blonde
• Lightly pigmented RPE
• Lightly pigmented choroid

4. Tessilated
• Lightly pigmented
RPE
• Normal/heavily
pigmented choroid

5. Albinotic
• Virtually no pigment
in RPE or choroid

Why are some fundi more
pigmented than others?
• Age
• Race
• Hereditary
• Metabolism

Optic Disc
• Definition:
– The ophthalmoscopic view of the optic nerve head
• Features:
– Size
– Shape
– Colour (NRR)
– Margins
– Cupping
– Vessels

Optic Disc Cupping
• No detectable cup in 15% of eyes
• Can be measured by recording vertical
C/D ratio
• >0.2 difference between the eyes is
suspicious of glaucoma

Optic Disc Vessels
• Central Retinal Artery
– Becomes and arteriole
after branching
• Central Retinal Vein
– Becomes a venule after
branching
• Cilio-retinal arteries
– Not branches of CRA,
derived from blood
vessels supplying the
choroid

Optic Disc surroundings
• Elschnig’s scleral
ring
– RPE and choroid
stop short of the
disc
• Choroidal crescent
– RPE stops short of
the disc
• Peri-peripheral
pigment

Retinal Blood Vessels
• Two layers of capillaries:
– Superficial network in nerve fibre layer
– Deep network at junction of inner nuclear and
outer plexiform layer
– No capillaries at the fovea
• Walls of BVs are transparent
• Linear light reflex notable feature of arterioles
• Purpose of vessels
• Ocular vessel health reflects health of
circulation throughout body

A/V and V/A crossing
phenomena
• Generally arterioles
cross venules
• Venule dips to avoid
arteriole
• Disease induced
changes are most
noticeable at the
crossings

Vessel Calibre
• Pathological changes cause arteriole
narrowing or venule thickening
• A/V ratio good indication of patholgy
– Normal = 2/3

Macula
• Macula is 1.5 to 2 disc
diameters temporal to
optic disc
• Horizontally oval
• Roughly same size as
the optic disc
• Foveal reflex
– Bright spot of light at
centre of macula
– Only real landmark on
healthy macula

Peripheral Retina
• Peripheral retinal lesions:
– Size (in mm or DD)
– Location
– Shape
– Colour
– Flat/raised??

Direct Vs. Indirect
Opthalmoscopy
• Direct
– Good magnification
– Good for macular
assessment
– V. useful is
assessment of media
opacities
– Real image – right
way up!
– Light and portable
• Indirect
– Stereopsis!!
– Good FOV
– Good for optic disc
and peripheral retina
assessment

THANK YOU

Basic opthalmoscopy findings - presentation at www.eyenirvaan.com

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