Direct Ophthalmoscopy

Question 1

Can you see past a media obstruction with direct or BIO?

Answer 1

BIO

Question 2

Disk size is usually

Answer 2

2.2 to 2.8mm

Question 3

Crescents are caused by what

Answer 3

RPE melanocytes. Hyper or hypo pigmentation is common near disk margin.

Question 4

Difference between choroidal and scleral crescents

Answer 4

Choroidal- dark grey, dark green. Occurs when RPE doesn’t extend to disk margin. Dark pigment of choroid shows through.

Scleral- White. Retina and choroid doesn’t extend to disk margin. White pigment of sclera shows through.

Question 5

Pallor of ONH

Answer 5

White or yellow. May be sign of optic atrophy. Pallor affects temporal rim first.
Not a sign of glaucoma usually.

Lack of color or area of optic disk lacking blood vessels/blood supply.

Question 6

Disk color that is very red is considered

Answer 6

Hyperemic. Sign of optic nerve head congestion. Lots of blood flow.

Question 7

Cupping

Answer 7

Best observed by evaluating the blood vessels as they cross the disk surface. Look for bending in the vasculature to determine where cup is. Pallor doesn’t always indicate cupping!

Question 8

Glaucoma. With progression, __ and __ increase simultaneously

Answer 8

Cupping and pallor

Question 9

When to suspect neurological lesion

Answer 9

If pallor is greater than cupping. = Anterior ischemic optic neuropathy

Question 10

ONH anatomy
Prelaminar layer
Laminar layer

Answer 10

Prelaminary/in eye: Glial tissue network provides support for nerve fibers. Sheaths of astrocytes bundle nerve fibers into fascicles.

Laminar: Lamina cribrosa (scleral perforations) and nerve fiber bundles.

Post laminar/retrolaminar: Nerve fibers become myelinated by oligodendrocytes. Nerve doubles in diameter.

Question 11

Optic nerve drusen

• Occurs in how much of the pop?
• What causes it?
• What test can you do

Answer 11

1-2% of pop
Caused by degenerative axonal byproducts
Do B scan to dx drusen. Must rule out other diagnosis. Bc can make it
May have associated vision loss.

Question 12

Malinserted/oblique disk

Answer 12

Common.
Elevation of nasal aspect of disk with temporal depression.
Usually associated with scleral or choroidal crescent.

Question 13

Myopic disk

Answer 13

Similar to malinserted disk in eye with myopic refractive error.
Prob due to axial elongation of eyeball causing portion of eye near optic nerve to tilt temporally.
Causes elevation of nasal rim tissue. Raised portion creates blurred disk margin.

Question 14

Tilted disk syndrome

Answer 14

Congenital.
Variant of incomplete closure of fetal fissure or coloboma.
Tilting of vertical axis.
Usually area of nasal choroidal ectasia/conus.
VF defect may occur.

Question 15

Bergmeister Papilla

Answer 15

Remnant of hyaloid artery.
Result due to incomplete regression of glial tissue on or above disk in form of epipapillary membranes.
Almost always on nasal side of disk. Present in 95% of premature infants.

Question 16

Optic disk hypoplasia

Answer 16

Nerve head usually 1/2 to 1/3 the size of fellow eye and pale. Surrounded by discolored zone the size of normal nerve.

Reduced vision

Present in 50% of fetal alcohol syndrome.

Question 17

Prepapillary vascular loop

Answer 17

Usually unilateral, arterial, and of embryonic origin. Benign.

Cilioretinal arteries present in 75% of arterial cases.

Exposed to IOP and may cause monocular blindness.

Can acquire them due to venous obstruction or compression from optic nerve tumors.

Question 18

Myelinated nerve fiber is also called

Answer 18

Medullated nerve fibers.

Question 19

Appearance of myelinated nerve fiber

Answer 19

Could show up below or above the blood vessels.
Retinal opacification with fuzzy edges.
May surround ON or be separate.
May create VF defect.

Rule out CWS or retinal ischemia.

Question 20

Trigroid fundus/blonde fundus

Answer 20

Loss of RPE pigment that makes choroidal vessels more visible.