Normal fundus 2

Question 1

are myelinated nerve fibres (feature of the optic disc) physiological or pathological

Answer 1

physiological, but not present on most people

it i non-progressive and benign

Question 2

when are nerve fibres usually myelinated until

Answer 2

not myelinated until the lamina cribrosa

Question 3

where can nerve fibres sometimes retina their myelin sheaths

Answer 3

on the disc or the retina

Question 4

why are retinal ganglion axons usually unmyelinated as they cross the retina

Answer 4

because even though myelin sheaths speed up nerve transmission, if the RGC axons were myelinated across the retina, we won’t be able to see anything as they’re opaque, so it will block the light hitting the retina

Question 5

what symptoms will a person have if they have myelin sheaths on their retina

Answer 5

visual field defect corresponding to there the myelin sheaths are on the retina

Question 6

what is the appearance of the nerve fibres as a result of myelin sheaths on the retina

Answer 6

normally transparent nerve fibres now appear a brilliant white against the fundus background

Question 7

describe the two layers of capillaries that are over most of the fundus

Answer 7

• a superficial network in the nerve fibre layer close to the vitreous
• a deep network at the junction on the inner nuclear & outer plexiform layers

Question 8

where in the retina are no capillaries found

Answer 8

central macula

Question 9

what are the outer layers of the retina e.g. photoreceptors supplied by

Answer 9

the underlying choroidal circulation which is not directly visible with the direct ophthalmoscope

Question 10

what circulation is seen when doing ophthalmoscopy and what does it consist of

Answer 10

the inner retinal circulation only, consisting of central retinal arteries & veins which branch out to supply the inner retinal layers & those two capillary networks are found in the retina

Question 11

what is the appearance of a normal blood vessel wall and what is visible when seen with the direct ophthalmoscope

Answer 11

normal walls of bv’s are transparent and only the blood column of the vessels is seen

Question 12

what is a notable feature of arterioles seen as a reflex in the ophthalmoscope light

Answer 12

linear light reflex which is a light following the arterioles

Question 13

what 2 things is the linear light reflex seen in the arterioles formed by

Answer 13

• reflection from convex, cylindrical blood column
• reflection from convex vessel wall
• both surfaces act as convex mirrors
  linear light reflex is more obvious in arteries than veins

Question 14

what is the purpose of the retinal vessels

Answer 14

to supply oxygen and other nutrients from the blood to the 6 inner layers of the retina & take away waste materials

Question 15

what does the health of the retinal vessels reflect upon

Answer 15

the health of the circulation throughout the body

Question 16

what does examination of the retinal blood vessels assist in

Answer 16

detection and monitoring of systemic diseases e.g. hypertension, arteriosclerosis, diabetes

Question 17

what do arterioles not cross

Answer 17

other arterioles

Question 18

what do venules not cross

Answer 18

other venules

Question 19

what is the normal positions of the arterioles and venules in the retina

Answer 19

usually
arterioles remain at normal level in the nerve fibre layer and venule dips to avoid the arteriole, called a/v crossing (artery crossing over vein)

Question 20

what is the normal appearance of the route of the arterioles and venules at the a/v and v/a crossings in the retina

Answer 20

retinal vessels normally curve very gently with no deflections at the a/v and v/a crossings = carry on in their normal directions & don’t look like they’re being squashed

Question 21

what 2 things does hypersensitive retinopathy cause to the retinal blood vessels

Answer 21

• a/v nipping

- tortuosity (BV’s become wiggly)

Question 22

how does a/v nipping occur

Answer 22

a/v crossing changes are caused, where the underlying venule is compressed by the sclerosed/hardened artery as it crosses over and causes pressure on the vein which gets pinched by the artery

Question 23

what can a further hardening of the arteriole in the retina cause to the course of the venule

Answer 23

may cause deflection of the venule which means it changes directions in right angle

Question 24

what is a normal cause of tortuous arterioles

Answer 24

congenital which should then be uniform across the fundus

Question 25

what does isolated regions of arteriolar tortuosity suggest

Answer 25

sclerosis of arteriole due to high blood pressure

Question 26

what do pathological changes to the arterioles cause to their appearance

Answer 26

causes arteriole narrowing

Question 27

what do pathological changes to the venules cause to their appearance

Answer 27

an increase in width

Question 28

what does pathological changes in vessel calibre (thickness) cause to the a/v ratio

Answer 28

it gets altered to e.g. 1/4 or 1/5

Question 29

what is a normal a/v ratio considered to be

Answer 29

2/3

Question 30

how are you supposed to check the a/v ratio in order to detect change in vessel calibre

Answer 30

- chose vessels of comparable order of branching i.e. vessels that branch by the same amount e. g. if artery we're looking at has branched twice since the optic disc, then compare that with a vein thats branched twice since the optic disc

Question 31

what naturally happens to the vessel calibre of all the vessels the further away they get from the disc

Answer 31

get narrower the further away from the optic disc

Question 32

what two things must you look for when detecting abnormal changes e.g. from hypertension in vessel calibre (thickness)

Answer 32

- focal narrowing | - generalised narrowing to arterioles (severe narrowing in the case of hypertension)

Question 33

when is mild generalised narrowing of the arteriole normal

Answer 33

found in a healthy elderly fundus

Question 34

what does focal narrowing of the vessels look like

Answer 34

a patch of narrowing of changes of vessel thickness as you go along

Question 35

what is leakage of a vessel a sign of

Answer 35

pathology

Question 36

what 3 things are shown in a fundus when a blood vessel leaks

Answer 36

- hard exudates (lipids) - haemorrhages (blood) - oedema (fluid e.g. plasma or serum)

Question 37

what is oedema fluid e.g. plasma or serum viewed in a OCT scan as

Answer 37

dark patches within the reflective layers

Question 38

which imaging technique is oedema hard to view

Answer 38

in fundus photography, may see a bit of swelling

Question 39

in a healthy eye, what is the only non visible part of the vessel

Answer 39

the part of the vessel (e.g. of a venule) that is obscured by an arteriole at an a/v crossing

Question 40

by what 2 things may a vessel be obscured in a non usual way

Answer 40

- myelinated nerve fibres or - pre retinal haemorrhages obscures the retina

Question 41

how does a inner retinal haemorrhage occur

Answer 41

when the inner circulation has bled into the vitreous cavity

Question 42

name 3 causes of hyperplasia of pigment in the retina

Answer 42

- choroidal naevus - malignant choroidal melanoma - congenital hypertrophy of the RPE - CHRPE

Question 43

what is a choroidal naevus

Answer 43

a harmless area of increased pigment of the choroid

Question 44

what colour does a choroidal naevus appear

Answer 44

uniform slate grey or brown colour

Question 45

what shape does a choroidal naevus appear

Answer 45

round or oval

Question 46

how large are most choroidal naevus

Answer 46

less than 3 disc diameters in diameter

Question 47

how deep is a choroidal naevus and how can you tell this

Answer 47

flat or minimally elevated, blood vessels passing over will stay in focus & not change course

Question 48

what can also be spotted on top of a choroidal naevus

Answer 48

overlying drusen speckled on top of it (white spots)

Question 49

what must you note down when looking at the retina as seen by the ophthalmoscope

Answer 49

any pigment deposition seen in retina

Question 50

is a choroidal naevus dangerous

Answer 50

no it is benign and won't cause any problems to the patient at all

Question 51

what causes a choroidal naevus

Answer 51

accumulation of melanocytes in the choroid

Question 52

what is the cause of a malignant choroidal melanoma

Answer 52

a cancerous tumour which can metastasise = life threatening

Question 53

what colour and appearance is a malignant choroidal melanoma

Answer 53

ranges in colour from white to greenish grey and has a mottled appearance

Question 54

how large is a malignant choroidal melanoma

Answer 54

often larger than a naevus >3 disc diameters

Question 55

if a malignant choroidal melanoma is larger than 3 disc diameters in size, what 2 things can this cause

Answer 55

- a serous retinal detachment | - disrupts transport between fluid & RPE

Question 56

how deep is a malignant choroidal melanoma and how can you tell this

Answer 56

significantly elevated ophthalmoscope will go out of focus as it passes over it and the blood vessels also goes higher as the melanoma acts as a bridge so it looks like the blood vessels are changing direction

Question 57

what may be found overlying a malignant choroidal melanoma

Answer 57

orange pigment = lipofuscin

Question 58

what symptoms are presented with a malignant choroidal melanoma

Answer 58

``` often asymptomatic, but may present with: - metamorphopsia - photopsia - visual field defect - hypermetropic shift all of which disrupt vision ```

Question 59

what action must be taken when seeing a malignant choroidal melanoma

Answer 59

urgent referral

Question 60

what is congenital hypertrophy of the RPE (CHRPE) caused by

Answer 60

congenital hyper pigmentation of the RPE

Question 61

what appearance of congenital hypertrophy of the RPE (CHRPE)

Answer 61

a flat black lesion with sharply remarked outline, darker than a naevus

Question 62

what is also frequently seen around congenital hypertrophy of the RPE (CHRPE)

Answer 62

ring of hypo pigmentation

Question 63

is congenital hypertrophy of the RPE (CHRPE) dangerous

Answer 63

no it is benign

Question 64

what must you do to monitor a congenital hypertrophy of the RPE (CHRPE)

Answer 64

take a photo to monitor and make sure it doesn't change size

Question 65

what is the appearance of a coloboma of (retina) choroid

Answer 65

large, white oval lesion in fundus, benign, non-progressive appearance of retina

Question 66

what is the appearance of a coloboma of (retina) choroid

Answer 66

large, white oval lesion in fundus, benign, non-progressive appearance of retina, can see right through to sclera underneath

Question 67

where abouts is a coloboma of (retina) choroid usually found in the retina

Answer 67

usually inferior nasal region

Question 68

what is a coloboma of (retina) choroid a result of

Answer 68

failure of the embryonic fissure to close = missing part of retina

Question 69

can a coloboma of (retina) choroid affect one or both eyes

Answer 69

can be unilateral or bilateral

Question 70

what symptoms may a px with coloboma of (retina) choroid experience

Answer 70

visual field defect corresponding to the missing part of retina e.g. superior temporal VF defect if the coloboma is at the inferior nasal region of fundus

Question 71

what other visual problem may a px with coloboma of (retina) choroid have

Answer 71

px is often amblyopic

Question 72

how far away is the centre of the macula from the optic disc

Answer 72

1.5 - 2 disc diameters away

Question 73

where is the macula located in the fundus

Answer 73

temporal to and slightly lower than the disc

Question 74

what is the shape of the macula

Answer 74

oval with the long axis horizontal

Question 75

how large is the macula

Answer 75

a bit larger than the optic disc ~20 degrees diameter

Question 76

where is the macula entered on

Answer 76

the fovea

Question 77

where does the colour of the macula come from

Answer 77

accumulation of macula pigment

Question 78

what component of the fundus does not permeate around the macula

Answer 78

blood vessels

Question 79

what is the name of a macular reflex

Answer 79

foveal reflex

Question 80

what is the appearance of a normal foveal reflex

Answer 80

bright spot of light at centre of fovea

Question 81

what is the only real landmark on a healthy macula

Answer 81

bright foveal reflex

Question 82

how is a macular/foveal reflex formed

Answer 82

by an image of the ophthalmoscope beam formed by the concave surface of the fovea (foveal pit), acting as a concave mirror

Question 83

what can someone with early ARMD go on to get

Answer 83

dry or wet stages

Question 84

what stages can someone with early ARMD go on to get

Answer 84

dry or wet stages

Question 85

what dos early stages of ARMD show

Answer 85

extensive drusen

Question 86

what is drusen

Answer 86

pockets of the RPE layer

Question 87

what characteristic signs on the retina does wet AMD cause

Answer 87

exudates and haemorrhages of the blood vessels

Question 88

what does dry AMD cause

Answer 88

death/atrophy of the retina & RPE in that area of the macula, causing a complete scotoma corresponding to the atrophy, also called geographic atrophy

Question 89

what characteristic signs of the retina does dry AMD cause

Answer 89

can see through to underlying choroid where retina & RPE have died away

Question 90

what is toxoplasmosis caused by

Answer 90

a parasite

Question 91

what are the symptoms of toxoplasmosis if its in the periphery

Answer 91

none

Question 92

what is the appearance of an inactive toxoplasmosis

Answer 92

sharply defined edges & pigmented

Question 93

what are the symptoms of toxoplasmosis if its on the macula

Answer 93

complete scotoma

Question 94

what is the appearance of an active toxoplasmosis

Answer 94

it means the parasite is still there, and has more of inflammation & pigmentation comes in a later stage