Paper 2 Flashcards

1
Q

What does a polarising light do to light rays

A

only transmit light rays which are vibrating in one plane

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2
Q

What does a polarising medium do

A

reduces radiant intensity but does not affect spectral composition

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3
Q

What do dichroic substances do

A

block transmission of light waves not aligned with its structure by absorption.

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4
Q

If a plane mirror is rotated while light is incident upon the centre of rotation, how much is the reflected ray deviated by

A

2i

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5
Q

What type of lenses are found in a Maddox rod

A

High powered convex cylindrical lenses mounted side by side in a trial lens

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6
Q

What kind of movement does a concave lens create with respect to a cross

A

with movement

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7
Q

What kind of movement does a convex lens create with respect to a cross

A

against movement

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8
Q

What did recent systematic review by Wang and
colleagues (2018) with regards to IOL power in short eyes

A

Haigis formula

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9
Q

What are features of PALs with hard designs

A

wider distance and near portions and a
narrower power progression corridor, near which aberrations can occur

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10
Q

What are features of PALs with soft designs

A

a wider power progression corridor and smaller distance and nearer portions—these tend to be better tolerated

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11
Q

Are individuals requiring a wider near portion likely to be satisfied by PAL’s

A

NO

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12
Q

What orientation of prisms is the Wollaston prism made up of

A

The two constituent prisms are positioned such that their optical axes are perpendicular.

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13
Q

What luminous intensity is produced by a laser light producing 5 lumens of light

A

a beam of luminous intensity equal to 500,000,000 candela.

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14
Q

Which muscle is the frowning muscle

A

Corrugator supercilli

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15
Q

What is the length of the lacrimal cannalicula

A

10mm long

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16
Q

What is the length of the nasolacrimal duct

A

18mm long

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17
Q

Where is the nasolacrimal duct narrower

A

narrower in the middle as compared to either end.

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18
Q

Which bone does the foramen spinosum perforate

A

Greater wing of the sphenoid posterolateral to the foramen ovale

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19
Q

At which points is the choroid thickest

A

thickest at the posterior pole and thinnest proximal to
the optic disc

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20
Q

How thick is the retina at the ora serrata

A

0.1mm

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21
Q

How thick is the retina at the optic disc

A

0.56mm

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22
Q

What layers of the optic cup is the inner and outer retina derived from

A

Inner layer is derived from the inner layer of the optic
cup.
Outer layer is derived from the outer layer of the optic cup.

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23
Q

Diameter of Gangion cells

A

10 to 30 micrometres

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24
Q

Diameter of lens at birth vs adults

A

6.5 mm at birth
10 mm in adults.

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25
Which nerves does the Jugular foramen transmit
glossopharyngeal vagus accessory
26
Which visceral motor nuclei provides the cranial outflow of the parasympathetic nervous system: Edinger Westphal nucleus
Occulomotor nerve
27
Which visceral motor nuclei provides the cranial outflow of the parasympathetic nervous system: Superior salivatory and lacrimal nuclei
Facial nerve
28
Which visceral motor nuclei provides the cranial outflow of the parasympathetic nervous system: inferior salivatory nucleus
Glossopharyngeal nerve
29
Which visceral motor nuclei provides the cranial outflow of the parasympathetic nervous system: dorsal motor nucleus
Vagus nerve
30
When does the lens vesicle separate from the surface ectoderm
Day 36
31
Order of tear film layers, from innermost to outermost,
glycocalyx mucous aqueous lipid
32
What happens to strength, stiffness, and toughness of the corneal stroma with age
Increases due to enzymatic maturation and glycation-induced crosslinking of collagen fibrils
33
Primary structural protein in the lens zonules
Fibrillin
34
Which muscles elevate the ribcage
External intercostals Anterior serrati Scaleni
35
What do Merkel discs do
detect continuous contact of objects against the skin
36
What do Meissner's corpuscles do
present in non-hairy areas of the skin.
37
What do Ruffini nerve endings do
detect heavy prolonged touch and stretch.
38
What do Pacinian corpuscles do
detect tissue vibration
39
Examples of sites of Zonulae Occludens
blood–retinal barrier at the apex of the retinal pigment epithelium cell and at the blood–aqueous barrier of the ciliary body
40
What are the 2 types of desmosomes
Spot desmosomes (single site), also known as macula adherens. Belt desmosomes (ring round the apex of the cell), also known as zonulae adherens.
41
What are the major proteoglycans of the sclera
Proteodermatan sulphate and proteochondroitin sulphate. Others include aggrecan, decorin, biglycan, and proline–arginine–rich and leucinerich repeat (PRELP).
42
In diabetic retinopathy which growth factor synthesis is increased
VEGF and PIGF (angiogenic)
43
In diabetic retinopathy which growth factor synthesis is decreased
Pigment epithelium-derived growth factor (PEDF) is decreased (anti-angiogenic)
44
How long does panophthalmitis take to complete
48 hours
45
What type of infiltrate appears around the long and short ciliary nerves in herpes zoster ophthalmicus.
lymphocytic infiltrate
46
Which genes are implicated in the pathogenesis of POAG
Myocillin- role in the contractility of trabecular meshwork cells. Optineurin
47
Which gene mutation is implicated in Stargadt's disease
ABCA4
48
What happens to the retina in end Stage Stargadt's disease
the gliotic retina fuses with Bruch’s membrane, as the outer retinal layer is lost
49
Most common yeast responsible for corneal infections
Candida Albicans
50
Moulds responsible for corneal infections
Aspergillus, Fusarium, and Penicillium
51
What condition is also known as river blindness
Onchocheriasis Live microfilariae cause minimal tissue damage to the eyes and skin
52
What is the size of monocytes
12-20 micrometres in size. Can feature round, oval, notched, or horseshoe-shaped nuclei.
53
What percentage of people with acute anterior uveitis are HLA-B27 positive
50%
54
What is an accurate way to assess drug efficiency
Estimation of drug clearance from the circulation rather than drug half life
55
What does an ectropion do to the residence time of drug in the fornix
Reduce it
56
What do photosensitizing agents do
absorb visible and ultraviolet radiation, thereby generating free radicals.
57
Examples of photosensitizing agents
Amiodarone
58
Which drugs work on H1 receptors
Cetirizine, loratadine, and diphenhydramine
59
Which drugs work on H2 receptors
Ranitidine and cimetidine
60
Which drug works on H3 receptors
Ciproxifan
61
What are the 5 subdivisions of prophase 1
Leptotene—chromosomes begin to condense. Zygotene—chromosomes pair and form bivalents. Pachytene—main stage of chromosomal thickening. Diplotene—bivalents begin to separate. Diakinesis—bivalents separate and coil tightly.
62
What is aneuploidy
when paired chromosomes fail to disjoin, or is due to delayed movement during anaphase.
63
What can aneuploidy result in
trisomy (extra chromosome) or monosomy (missing chromosome).
64
What is HLADR4 associated with
SO and VKH
65
What is the function of Ubiquitin
role in destroying phosphorylated cyclins and cyclin inhibitors.
66
What is the Maddox wing used for
Near Phorias
67
What is the double Maddox rod used for
Torsional phorias
68
What is the Hirschberg test used for
detect manifest deviation and simply involves asking the patient to fix on a pen-torch at 33 cm, then assessing the corneal reflection.
69
What is the equivalence of 1mm deviation in prism dioptres
15PD
70
What are the stages of ICG angiography
Early phase: 2–60 seconds; prominent filling of choroidal arteries. Early mid-phase: 1–3 minutes; increased prominence of choroidal veins. Late mid-phase: 3–15 minutes; diffuse hypofluorescence (due to diffusion of dye from choriocapillaris). Late phase: 15–30 minutes; dye leaves choroidal and retinal circulations but may remain in neovascular tissue.
71
What conditions cause a normal a wave and reduced scotopic b wave on full field ERG
termed an ‘electronegative’ response X-linked retinoschisis, central retinal artery/vein occlusion (CRAO/CRVO), congenital stationary night blindness (CSNB) (Xlinked and autosomal recessive, complete and incomplete forms), quinine toxicity, melanoma-associated retinopathy, and CLN3 (juvenile Batten) disease.
72
What conditions cause a reduced a and b wave
Total retinal detachment and rod-cone dystrophy compromise the photoreceptors and so can cause reduced a-waves and consequently b-waves.
73
What is an acceptable power of a study
>80%
74
How many people in the world have a near or distance vision impairment
at least 2.2 billion people
75
What is lead time bias
occurs when earlier diagnosis of a disease falsely makes it seem like affected patients are surviving longer.
76
What is recency bias
occurs due to the tendency to favour recent events over older events.
77
What is detection bias
occurs due to systematic differences between groups in how outcomes are determined