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Opt 210
Test 1 Direct Opthalmoscopy
47
Other
Not Applicable
10/13/2007

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Cards

Term
What is the pale color of the optic cup due to?
Definition
Exposure from the lamina cribrosa and loss of glial tissue
Term
What supports the superficial layer of the optic nerve?
Definition
astrocytes
Term
Which layer of the optic nerve is only visible in the central cup?
Definition
Prelaminar layer
Term
What layer of the optic nerve consists of the lamina cribrosa and nerve fiber bundles?
Definition
laminar layer
Term
What is the tissue between the outer edge of the optic cup and the edge of the optic disc called?
Definition
neuroretinal rim
Term
What color is the neuroretinal rim?
Definition
orange/pink and of uniform width
Term
What is the prelaminar optic nerve?
Definition
The part of the nerve in front of the lamina cribrosa
Term
When is the prelaminar layer visible in Direct Opthalmoscopy?
Definition
only visible in the central cup
Term
Which optic nerve layer consists of lamina cribrosa and nerve fiber bundles?
Definition
laminar layer
Term
What is the maximal area of optic contrast or the area of the optic cup lacking blood vessels?
Definition
pallor
Term
What is the term for the bending in the vaculature of the optic nerve?  It is best observed by evaluating the blood vessels as they cross the disc.
Definition
cupping
Term
What is the relationship between pallor and cupping in the normal eye?
Definition
They are the same
Term
What happens to pallor and cupping with age?
Definition
With aging, cupping increases and pallor remains the same.
Term

How much do the horizontal and vertical cups have to differ to suspect problems?

Definition
0.2 or more difference between horizontal and vertical cup
Term
How big must a cup to disc ratio be to be considered suspect?
Definition
0.7
Term
What is a normal cup to disc ratio?
Definition
0.3
Term
What are cotton wool spots?  What causes them?  What diseases are they often associated with?
Definition
White puffy patches on the retina caused by swelling of the surface layer of the retina which damages the nerve fibers.  They are often found in diabetic or hypertensive patients.
Term
How are pallor and cupping related in glaucoma?
Definition
In glaucoma, pallor=cupping, but with time both pallor and cupping increase.
Term

What would you suspect if pallor is greater than cupping?

Definition

a neurological lesion

Term
How big is the macula?
Definition
5mm
Term
What is the shape of the macula and where is it located?
Definition
oval area in the posterior pole
Term
What type of pigment does the macula contain?
Definition
xanthophyll
Term
How many ganglion cell layers are at the macula?
Definition
The macula has less than one layer of ganglion cells.
Term
What shape of light reflex is the fovea?
Definition

oval light reflex

Term
How big is the fovea?
Definition
1.5 mm diameter same as the average optic disc
Term
What does the foveola consist of?
Definition

only cones and their nuclei, devoid of ganglion cells

Term
How big is the foveola?
Definition
0.35 mm
Term
What is the thinnest part of the retina?
Definition
foveola
Term
What is the tiny depression in the center of the foveola?
Definition
umbo
Term
What are the limits of the foveal avascular zone?
Definition
Inside the fovea but outside the foveola
Term
What separates the RPE from the choriocapillaris?
Definition
Bruch's membrane
Term
What do changes in Bruch's membrane often lead to?
Definition
macular disorders
Term
What do you call a distortion in image shape?
Definition
metamorphopsia
Term
What do you call a decrease in image size caused by an increased distance in foveal cones?
Definition
micropsia
Term
What do you call an increase in image size caused by a compression of foveal cones?
Definition
macropsia
Term
What magnification does Direct Opthalmoscopy give?
Definition
15X, a good magnification
Term
What type of image does Direct Opthalmoscopy give?
Definition
upright, magnified, and real image
Term
Does Direct Opthalmoscopy offer a good assessment of lens clarity?
Definition
Yes
Term
Why would you use a slit in Direct Opthalmoscopy?
Definition
The slit aperture is useful for contours.
Term
What is the field of view for Direct Opthalmoscopy?  What is the field of view with a panoptic?
Definition
6.5-10 degrees, 25 degrees with the panoptic
Term
Why do you dim the room lights in direct opthalmoscopy?
Definition
to maximize pupil dilation and reduce glare
Term
What type of disc crescents are brown or black?
Definition
pigmented
Term
What type of disc crescents are gray or green?
Definition
choroidal
Term
What type of crescents are white?
Definition
scleral
Term
How do you document the macula?
Definition
(-)FLR  Flat and avascular macula
Term
Which way do you tilt the lens when the patient looks superiorly in non contact fundus examination, 90D or 78D?
Definition
The inferior lens is tilted toward the patient and the superior of the lens is tilted to the examiner.
Term

Which way do you tilt the 90 or 78D lens when the patient is gazing inferiorly?

Definition
Top of the lens is tilted to the patient and the bottom to the examiner
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