Normal Fundus 2 - CSB Flashcards
Is a tilted disc normal?
Yes
What’s the only problem with a tilted disc from an optometrists POV?
you cant really see the cup well so its difficult to assess for signs of glaucoma.
For most of the fundus there are two layers of capillaries- what are they?
- A superficial network in NF (nerve fibre) layer
- A deep network at junction of inner nuclear and outer plexiform layers
Where in the fundus are there no capillaries?
The macula
What is the macula dependant on for blood supply?
Underlying choroidal circulation
When looking at blood vessels what are we not seeing in direct ophthalmoscopy?
The walls of the blood vessels - these are transparent - what we are actually seeing is the blood inside the vessels.
What is a linear light reflex of arterioles?
A lovely shine reflex along the arteriole ( and venules but most notably in arterioles). It is an image of the opthalmoscope beam
What is the light reflex in blood vessels, occuring when using an ophthalmoscope formed by?
¨Reflection at convex cylindrical blood column
¨Reflection from the convex vessel wall
¨Both surfaces act as convex mirrors
[The light reflex can be seen in the image attached - it is the light white stripe across the blood vessel when you look closely]
What is the purpose of retinal vessels?
The purpose of retinal vessels is to supply oxygen and other nutrients from the blood to first six layers of the retina.
Why are optometrists so concerned with blood vessels of the retina (other than their purpose to supply the retina nutrients)?
The health of vessels reflects health of circulation throughout the body.
Examination of retinal BVs (blood vessels) assists detection and monitoring of systemic diseases – e.g hypertension, arteriosclerosis, diabetes.
How do we evaluate the health of blood vessels?
-Looking at where they cross over
What is an A/V crossing?
A crossing of blood vessels where the arteriole goes over the veinule (most common type of crossing).
So basically arteriole continues at a normal level in the nerve layer and the venule dips underneath to avoid colliding into the arteriole.
What is a V/A crossing?
Blood vessels crossing over where the veinule crosses over the arteriole.
So in this case the arteriole dips and venule remains in the layer its travelling in.
Do arterioles cross arterioles and do veinules cross veinules?
Typically no.
How do normal healthy vessels appear at crossings?
Retinal vessels normally curve very gently with no deflections (no changings of path) at the A/V and V/A crossings.
What is an indication of poor health that can be seen at blood vessel crossings?
Changes in the course of vessels - this could be nipping or deflections.
[normally (in healthy people) at a blood vessel crossing, one vessel dips under and one stays where it is - thus no vessel actually chnages direction - they just keep going on their way]
What is nipping of a blood vessel at a blood vessel crossing?
So e.g. in the case of an A/V crossing it would be where the arteriole atually squashes/presses down into the veinule below it thus the veinule is ‘nipped’.
What is a deflection at a blood vessel crossing and what is this caused by?
A deflection at a blood vessel crossing is where the blood vessels don’t continue straight after crossing.
It can be caused by influence of the arteriole squishing/pressing down on the vein.
[In the image attached focus on the S shape made]
What can changes in the course of vessels i.e. deflections or nipping, be an indication of?
Hypertension - high blood pressure (artheroscelerosis).
What course of action would you take if you saw nipping or deflections at blood vessel crossings?
Refer the patient to their GP to have their blood pressure checked.
Define Tortuosity of vessels
Wiggliness of vessels
What are causes of tortuous arterioles?
Congential - but in this case that turtuosity of blood vessels should be uniform across the fundus and always have been present.
Isolated sections in the fundus of arteriolar tortuosity suggest sclerosis. If arterioles suddenly become more tortuous its a sign the patient may be developing sclerosis.
[Always record tortuosity of vessels even in young patients]
In regards to vessels what can we see here?
AV nipping and tortuousity of vessels.
What does focal narrowing of arterioles refer to?
A small area of the fundus in which arterioles are narrowed.
[It can be seen in the image - in the black circle the arteriole gets thinner however outside of the black circle it gets fatter}
Other than hypertension what other examples of conditions may narrowing of arterioles be seen in?
Retinitis Pigmentosa
[The photo also shows a stripy fundus - tigroid]
In what conditions are dilated tortuous veins seen?
In retinal vein occlusions - where for example the vein has been blocked by an embolus, thrombus, etc.
(You tend to see lots of haemorrhages as well - in this picture its those red dots)
What are changes in the calibre of veins typically a sign of?
Diabetic retinopathy where ischaemia is kicking in - a lack of blood supply to the retina.
When seen this change in calibre of veins is called venous beading.
What venous changes are a sign of ischaemia in diabetic retinopathy?
Changes to veinous calibre.
Presence of structures such as veinous loops .
What are features of a Choroidal Naevus (6)?
- Round or oval in shape
- Uniform slate grey or brown colour
- Most are less than 3 disc diameters
- Flat or minimally elevated
- Often overlying drusen (which are like white freckle-like spots- which can be seen in the image)
- Benign
What are features of a Malignant Choroidal Melanoma (7)?
- Often mottled.
- Range in colour from white to greenish grey.
- Often become larger than naevi
- May present with serous retinal detachment
- Often significantly elevated
- May have overlying orange pigmentation (lipofuscin).
- Usually asymptomatic, but may present with metamorphopsia, photopsia, visual field defect, hypermetropic shift.
Just so your aware not all malignant choroidal melanomas are dark. This one is light but still has all the features.
- Often mottled.
- Range in colour from white to greenish grey.
- Often become larger than naevi
- May present with serous retinal detachment
- Often significantly elevated
- May have overlying orange pigmentation (lipofuscin).
- Usually asymptomatic, but may present with metamorphopsia, photopsia, visual field defect, hypermetropic shift.
What are features of a Congenital Hypertrophy of RPE (CHRPE) (3)?
- Congenital flat black lesion with sharply demarcated outline
- Ring of hypopigmentation is frequently seen
- Benign
What is an iris coloboma?
Where the iris has failed to close.
How big is the macula and where is it usually present?
- The macula is 1.5 to 2 disc diameters temporal to disc and usually just below centre of disc
Where is the fovea centralis?
