Eyedocs Flagged corrections

Question 1

Thickness of cornea

Answer 1

Central 0.5-0.6mm
Peripheral 0.6-0.8mm

Question 2

How to work out power of CL

Answer 2

f(CL) = f(glasses) - vertex distance

Question 3

Which puctum is more medial?

Answer 3

Superior punctum is more medial

Inferior pucutm is more lateral

Question 4

What tumour impairs olfaction

Answer 4

Meningioma below frontal lobe - olfactory groove meningioma

Question 5

What is the grey line

Answer 5

Mucocutaneous junction - outer keratinised skin squamous epithelium

Stratified columnar epithelium of tarsal conjunctiva

Question 6

Where is occulomotor nerve in relation to optic chiasm?

Answer 6

LAteral to chiasm

Chiasm is inferior to olfactory tract
Floor of recess of third ventricle

Question 7

Where are touton cells seen

Answer 7

Juvenile xanthogranoloma

Recurrent hyphema from iris
Yellow orange papules on skin

Touton cells are fusion of epithelioid cells (macrophages) with nuclei surrounded by foamy cytoplasm

Question 8

What does working distance of 2/3m indicate in retinoscopy

Answer 8

-1.5D power

0.5m is -2D power

Question 9

After cycloplegia do you need stronger or weaker convex lenses

Answer 9

Stronger convex lenses because of indeced hypermetropia of eye from loss of ciliary tone

Question 10

What is effect of against the rule astigmatism on convex lenses

Answer 10

Horizontal meridian of cornea is steeper
For hypermetropic eye, less plus required for horizontal meridian so horizontal meridian reflex neutralised first as plus increased

Question 11

Tumour suppressor genes

Answer 11

P53
Rb
APC
VHL
P16
BRCA

Question 12

Oncogenes

Answer 12

abl
bcl
hox11
c-myc
ras
ret

Question 13

Enzyme for O2 radical to O2 and H2O2

Answer 13

Superoxide dismutase

Question 14

Enzyme for H2O2 to H2o +O2

Answer 14

Catalase

Question 15

Enzyme for H2O2 to GSSG and H2O

Answer 15

GSH peroxidase

Question 16

What is the origin of inferior oblique

Answer 16

Maxillary bone just lateral to the nasolacrimal canal

Question 17

What is Sampaolesi’s line

Answer 17

Pigmentation anterior to Schwalbe’s line in pigment dispersion syndrome and pseudoexfoliations

Question 18

Power in relation to image length and object length

Answer 18

Power = 1/f2 = 1/i - 1/o

Note object length will be negative as you need to travel back from lens to get to it

Question 19

Which bone is catilaginous in origin?

Answer 19

Ethmoid

The rest are membranous

Question 20

AC depth

Answer 20

3.1mm

Question 21

Which cranial nerve passes through petrous temporal bone

Answer 21

Facial

Question 22

Map dot fingeprint dystophy histology

Answer 22

Duplication of BM
Fibrillary materail between basement membrane and Bowman’s layer

Question 23

What does off centre on surround ganglion cells do?

Answer 23

Stimulation of central photoreceptors is inhibitory
Stimulation of peripheral photoreceptors is excitatory

Question 24

Where are anterior and posterior ethmoidal foramina located?

Answer 24

Along frontoethmoidal suture in midorbit

Anterior 0 anterior ethmoidal artery, vein and nerve to anterior and middle ethmoidal cells, fortnal cinsu and anterosuperior lateral nasal wall

Posterior - Posteiror ethmoidal artery, vein and nerve which supply PES, sphenoid sinuses

Question 25

What is hamartoma? Vs choristoma

Answer 25

Tissue found at site growing in disorganised mass Choristoma - normal tissue in abnormal location NORMISTOMA normal tissue abnormal locations e.g. dermoid

Question 26

Treatment for CMV retinitis

Answer 26

Oral Gancyclovir

Question 27

Which part of corneal stroma is stronger

Answer 27

Anterior - has most thinner and interwoven collagen fibres

Question 28

Which area of retina is perfused last in prem infant?

Answer 28

Temporal is perfused last - ischaemic retinal growth factors are produced that drive new abnormal vessel formation

Question 29

What is against motion with strek oriented at 90 degrees

Answer 29

There is myopic astigmatism in the 180 degree meridian Streak oriented at 90 assesses horizontal meridian Streak orientated at 180 assesses vertical meridian

Question 30

What to do with working distance

Answer 30

Power is 1/working distance in m You should subtract this power from the lens infront of eye

Question 31

What is the active form of acanthomeoba

Answer 31

Trophozoite active stage Cyst is inactive

Question 32

What is normal stereoacuity

Answer 32

60 seconds of arc Better = smaller 250 seconds of arc excludes amblyopia

Question 33

What chromosome is p53 located on

Answer 33

17

Question 34

Where is scleral rupture most common?

Answer 34

At the limbus

Question 35

Ocular effects of tamoxifen

Answer 35

White retinal crystals CMO maculopathy

Question 36

Sympathetic fibres to iris dilator come from?

Answer 36

Superior cervical ganglion

Question 37

Epithelium of lacrimal canaliculi

Answer 37

Stratified squamous non keratinised

Question 38

What % of tears through lower punctum

Answer 38

70%

Question 39

An object is placed 50 cm from a -10.00D lens. Image distance form lens?

Answer 39

-10 = (1/image distance in m) – (1/-0.50) -10 = (1/image distance in m) + 2 1/image distance in m = -12 image distance in m = -1/12 = -0.0833m = 8.33cm to the left of the lens To determine magnification we use the equation: Magnification, M = image size/object size = image distance/object distance (Cartesian convention)

Question 40

A patient wears the following prescription: OD: - 1.00/ + 2.00 x 180 OS: - 2.50/ + 1.00 x 90 Add + 3.00DS OU His bifocal segment is located 10 mm inferior to the optical center of the glasses. How much relative prism is induced when he looks through the top of his bifocal?

Answer 40

Prentice's rule is used to calculate the prismatic effect of the lenses acting in the 90° meridian OD: (+ 1.00 D) x (1.0 cm) = 1.00PD Base-up OS: (- 2.50 D) x (1.0 cm) = 2.50PD Base-down Combining the prisms results in 3.50PD base-up over the right eye.

Question 41

What happens when convex spherical lens is placed in material of higher refractive index?

Answer 41

Diverges parallel light

Question 42

Indirect ophthalmoscopy through small pupil?

Answer 42

Examiner move head away from lens

Question 43

Effect of increasing base curve on power of negative lens?

Answer 43

Increases power of negative lens

Question 44

Keratin-filled cavity within the dermis lined by keratinized stratified squamous epithelium.

Answer 44

Epidermoid cyst

Question 45

Which bones catilaginous in origin?

Answer 45

Ethmoid Maxilla

Question 46

Where is vitreous most firmly attached

Answer 46

At the vitreous base