Posterior Segment Flashcards
What is the typical shape of the disc?
Slightly oval/round
Slightly more tall than wide.
What is the typical shape of the cup?
Slight oval/round
More tall than wide
What is the average horizontal size of the disc?
1.77 mm
What is the average vertical size of the disc?
1.88 mm
What is considered a small vertical disc size?
<1.5 mm
What is considered a large vertical disc size?
> 2.2 mm
How do you measure the disk using your slip lamp?
Adjust beam to match the length inside eye. Look at size of the beam and multiply it by the image magnification (dependent on what lens you are using)
Image mag for 60D lens
1.15x
Image mag for 78D lens
0.93x
Image mag for 90D lens
0.76x
What are the two types of crescents? How do they appear?
Scleral crescent- lighter ring around disk
Choroidal crescent- more dark ring around disk
How big is the macula?
3-4 DD (5500 micrometers)
How big is the fovea?
1DD (1500micrometers)
What do you look for when looking at the macula?
Discolorations, lesions, flatness
When looking in the eye of a diabetic, you see arteries that are more straightened out and narrowed, what is this called?
Artery attenuation
When looking in the eye of a patient, you only see artery vessels (could be just veins vessels), what is this called?
Venous and arterial tortuosity
When looking in the eye of a patient, you see arteries that are hardened and putting pressure on other veins, what are you accessing
crossing changes
What do you assess when observing the arcades? (3)
1) AV ration
2) ALR
3) Curvature of vessels
Is it common for the peripheral retina to be darker?
Yes
Where would you find short posterior ciliary nerves?
6 and 12 oclock. Never 3 and 9.
Where would you find long ciliary nerves?
located temporarily and nasally
What is syneresis?
Aging of vitreous. Creates floaters in vitreous.
What is white without pressure(WwoP)?
In about 30% of people. Hyperreflective photoreceptor integrity line that reflects more light.
If you see pigmentation on the retina or discoloration, use the red-free filter to see if it disappears. If it does disappear, what layer is that hyperpigmentation in?
Choroid. Could be choroidal nevus
If you see pigmentation on the retina or discoloration, use the red-free filter to see if it disappears. If it does NOT disappear, what layer is that hyperpigmentation in?
In the RPE or retina. Could be retinal hyperplasia.
What is choroidal nevus? Does it disappear with red-free filter? What do you examine with a nevus?
Hyperpigmented (dark grey/green) lesion in choroid.
Disappears with red-free.
Examine for melanoma characteristics
List the directions from thickest to thinnest when referring to optic disc thickness.
Superior (thickest)
Inferior
Nasal
Temporal (thinnest)
What does an increased AV ratio indicate?
vascular disease
What does an increased ALR indicate?
cholesterol or vascular disease
