Fundus

Question 0

.Location of image of non-contact funds lens

Answer 0

Btwn fundus lens and slit lamp (closer to doctor)

Question 1

.Det horiz and vert C:D ratio

Answer 1

Horiz
Nasal + Temp neural rim thicknesses (% expressed as decimal, rounded to nearest 0.05= Disc)
1-Disc = Cup = C:D ratio

Vert
Sup + Inf

Question 2

.Photostress recovery test (PSRT) - Def

Answer 2

Based on recovery of vision (after bleaching) dep on intact retina/photoreceptors/RPE/choroid

Takes longer if macular disease
BUT
Normal (undetected) if optic nerve disease

BUT
Not valid w/ 20/80 VA, or worse

Question 3

.Photostress recovery test (PSRT) - Norms

Answer 3

Recover in < or = 50 sec

Avg 27 sec +/- 11 sec

Avg diff btwn 2 eyes = 6 sec (up to 20 sec)

Question 4

.Orientation of image through DO vs. BIO vs. non-contact fundus lens, rel to retina

Answer 4

DO - Upright
BIO, Non-contact - Inverted
(e.g. Sup nasal -> Inf temp)

Question 5

.Distinguish arteries vs. veins in fundus

Answer 5

Arteries

• Thinner
• Brighter/Lighter color
• Bright light reflex

Question 6

.Color defects in optic nerve vs. retinal disease

Answer 6

• Optic nerve- R/G defect

- Retinal - B/Y defect

Question 7

.Effects of using higher P lens to image retina

Answer 7

Increase P
Increase FoV

Decrease focal length (imaged closer to lens)
Decrease mag (image size)

Question 8

.Purpose of red cap test

Answer 8

Desaturated appearance indicates optic nerve defect

Question 9

.Procedure for photostress recovery test

Answer 9

1) Test normal eye first (w/ better VA)
2) Hold light 2-3 cm from eye
3) Have patient look directly into the light for 10 sec
4) Time how long it takes for patient to be able to read any 3 letters in 1 line above T

Question 10

.Amsler grid - Dimensions

Answer 10

20 squares x 20 squares
100 mm x 100 mm

At test distance = 30 cm,
Each square = 5 mm x 5 mm = Subtends 1 deg

Question 11

.Typical rel thicknesses for neural rims in optic nerve

Answer 11

ISNT rule

Thickest -> Thinnest
Inferior, Superior, Nasal, Temporal

Question 12

.Features of true nerve fiber layer defect

Answer 12

1) Dark greyish region (lack of ganglion cells)

2) Touch optic nerve - Gets larger as it goes away from optic nerve (wedge shape)

Question 13

.Illumination used to make it easier to see nerve fiber layer defect

Answer 13

Red-free filter

Question 14

.Fundus vascular findings indicative of hypertension

Answer 14

1) Arterial reflex > 1/4 - 1/3 of artery width
2) AV nicking - Arteries cross over veins - Pinch veins
3) Smaller A/V ratio < 3/4 to 4/5

Question 15

.Conditions under which spontaneous venous pulsation will disappear

Answer 15

1) Increased intra-cranial P

2) Decreased IOP

Question 16

.Optic nerve - Size, location

Answer 16

1.5 mm diameter
(Usually taller than wide)

15 deg nasal to fovea

Question 17

.Depth of lamina cribrosa

Answer 17

2/3 mm

Question 18

.Variations which might make optic nerve margins less distinct

Answer 18

Scleral crescent
Choroidal crescent 
Oblique insertion 
Small ONH 
Nerve fiber myelination

Papilledema
Optic neuritis
Buried ONH drusen