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2nd Year Medicine > Opthalmology > Flashcards

Opthalmology Flashcards

1
Q

What is cerebrospinal fluid produced by?

A

Secretory epithelium of the choroid plexus

* formed in the ventricles and then circulates in the subarachnoid space and absorbed into venous circulation

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2
Q

Function of CSF? (3)

A
  • mechanical protection: protects brain tissue
  • homeostatic function: pH of CSF affects pulmonary ventilation and cerebral blood flow
  • circulation: exchange of nutrients and removal of waste
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3
Q

Which cells secrete CSF?

A

choroidal cells

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4
Q

Describe structure of choroid plexus?

A

Lots of finger-like projections , lined by ependymal cells

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5
Q

What is the choroid plexus?

A

networks of capillaries in the walls of ventricles

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6
Q

How is CSF produced by choroidal cells?

A
  • Basolateral surface absorbs H2O, Na, HCO3 + Cl

* Secreted by apical surface

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7
Q

What is the secretion of CSF by choroid plexus dependent on?

A

Active Na+ transport, which pulls Cl-, and both ions drag water by osmosis

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8
Q

Difference in composition between CSF and blood plasma?

A
  • CSF = higher concentrations of Na and Cl

* Lower concentrations of K+, glucose and protein

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9
Q

Explain how the ventricles of the brain are connected (4)

A
  • Intraventricular Foramina (of Monroe): Lateral Ventricles to Third Ventricle
  • Cerebral Aqueduct (of Sylvius): Third Ventricle to Fourth
  • Foramen of Magendie: Median aperture – Fourth ventricle to subarachnoid space
  • Foramina of Luschka: Lateral apertures – Fourth ventricle to subarachnoid space
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10
Q

Explain CSF circulation

A
  • CSF added by choroid plexus in roof of 3rd ventricle
  • Then flows through cerebral aqueduct to 4th ventricle
  • Another choroid plexus in 4th ventricle adds more CSF
  • CSF then enters subarachnoid space through median aperture + 2 lateral apertures
  • Enters spinal cord
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11
Q

How is CSF returned to venous blood?

A

through arachnoid granulations into the superior sagittal sinus (SSS)

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12
Q

Pathologies of ventricles, choroid plexus and CSF? (4)

A
  • Tumours - colloid cyst, ependymomas
  • Ventricular haemorrhage - epidural haematoma (between skull and dura), subdural haematoma (between dura and arachnoid)
  • hydrocephalus
  • idiopathic intracranial hypertension
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13
Q

Papilloedema?

s/s? (3)

A

Optic disc swelling due to increased intracranial pressure

  • enlarged blind spot
  • blurring of vision
  • Vision loss
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14
Q

Aqueous humor?

Function? (2)

A

Specialised fluid that bathes structures within the eye

  • provides oxygen and metabolites
  • contains bicarbonate to buffer H+ produced in cornea
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15
Q

Where is aqueous humor produced?

A

Produced by epithelium of ciliary body into anterior chamber of eye

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16
Q

Describe structure of ciliary body

A

2 layers of epithelial cells

  • pigment epithelium of retina
  • nonpigmented epithelial layer (NPE) - it is NPE layer that generates aqueous humor
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17
Q

Describe production of aqueous humor (5)

Which drugs inhibit this pathway?

A
  • HCO3 and H+ are formed in epithelial cells from hydration of CO2 by carbonic anhydrase
  • Transported out of cell in exchange for influx of Cl and Na
  • Cl and Na pass from PE into NPE through gap junctions
  • Transported out of NPE into aqueous humor by Na/K/Cl co-transporter
  • Water follows through aquaporins

CA inhibitors block pathway decreasin production of aqueous humor

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18
Q

Examples of carbonic anhydrase inhibitors (2)
What are they used to treat?
Mechanism?

A

Dorzolamide + acetazolomide
* Glaucoma - raised intra-ocular pressure caused by too much aqueous humor

Mechanism: reduces production of aqueous humor

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19
Q

Innate immune system of the eye? (3)

A

Blink reflex
* Tears (physical) - flushing, mucous layer

Chemical
* Tears (chemical) - lysozyme, (gram -ve bacteria + fungi), lactoferrin and transferrin (gram ve+), lipids, secretory IgA, antimicrobials (IL-6)

Cellular
* Tears (cellular) - neutrophils, macrophages, conjunctival mast cells

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20
Q

What is the principle APC for external eye?

Where are they found?

A

Langerhans cells

* found at corneo-scleral limbus + peripheral cornea (absent from central 1/3rd cornea)

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21
Q

What is the only part of the eye with lymphatic drainage?

Features of conjunctival immunity (5)

A

Conjunctiva

  • lymphocytes
  • dendritic cells
  • MALT
  • macrophages, langerhans cells and mast cells
  • commensal bacteria
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22
Q

Features of cornea and sclera immunity? (5)

A
  • Avascularity
  • No lymphoid tissue
  • Lack of APCs
  • Langerhans cells only in peripheral cornea
  • downregulated immune environment
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23
Q

Lacrimal gland immunity (2)

A
  • More IgA and CD8 T cells compared to conjunctiva

* Lacrimal drainage system - lymphoid tissue

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24
Q

What make up the blood-ocular barrier? (2)

Immunity? (2)

A

Retina and choroid

  • lack of APCs
  • downregulated immune environment
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25
Q

In which areas of the eye is immune system downregulated?(5)

A
  • Vitreous
  • Choroid
  • Retina
  • cornea
  • sclera
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26
Q

What sites of the eye are immune privileged? (5)

What is meant by immune privilege?

A
  • Cornea
  • anterior chamber
  • lens
  • vitreous
  • subretinal space

These sites can tolerate foreign pathogens without generating immune response

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27
Q

Mechanisms of ocular immune privilege? (4)

A
  • blood-ocular barrier
  • lack of lymphatic drainage/lymphoid tissue
  • immunosuppressive molecules
  • anterior chamber-associated immune deviation (ACAID)
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28
Q

What does ACAID result in?

Function?

A

Peripheral tolerance to ocular antigens

* protects eye from potentially damaging immune response

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29
Q

Immunological ignorance?

A

Corneal cells have decreased expression MHC class I molecules and do not express MHC class II

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30
Q

Sympathetic opthalmia?
What is injured eye known as?
Other eye?
Can you tell the difference between the eyes?

A

rare, BILATERAL, granulomatous uveitis due to trauma or surgery to ONE eye

  • injured eye = exciting eye
  • other = sympathising eye

Clinically both eyes appear the same and it is only by history that one can identify which eye is the exciting eye

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31
Q

Type I hypersensitivity disease of the eye?
Type 2?
3?
4?

A

Type 1 = acute allergic conjunctivitis
Type 2 = occular cicatrical pemphigoid (blistering disease)
Type 3 = autoimmune corneal melting
type 4 = corneal graft rejection

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32
Q

Side effects of steroids on the eye? (2)

A
  • Cataracts

* Steroid-induced glaucoma

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33
Q

pathway for signal transmission in the eye?

What lateral connections influence signal processing? (2)

A

Photorecpetors (innermost part) -> bipolar cells -> ganglion cells

  • Horizontal cells - receive input from photoreceptors and project to other photoreceptors and bipolar cells
  • Amacrine cells - receive input from bipolar cells and project to ganglion cells, bipolar cells and other amacrine cells
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34
Q

Function of photoreceptors?
Structure? (4)
Types of photoreceptors? (2)

A

Converts electromagnetic radiation to neural signals (transduction)

4 main regions

  • outer segment
  • inner
  • cell body
  • synaptic terminal

Types
* rods and cones

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35
Q

Explain phototransduction (2)

A
  • Photoreceptors have depolarised Vm (compared to other neurons, resting Vm is more positive ~ -20mV)
  • with light exposure, Vm HYPERPOLARISES (unlike most neurones)
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36
Q

What causes positive Vm of photoreceptors?

A
  • positive Vm is because of the “dark current”. A cGMP-gated Na+ channel that is open in the dark and closes in the light
  • change in Na+ with light is the signal that enables the brain to perceive objects in the visual field

i.e. light causes less glutamate (neurotransmitter) secretion

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37
Q

Explain the “dark current”

A

In the dark
* Pna = Pk

In response to light

  • Pna is reduced (Pk > Pna)
  • therefore hyperpolarises
  • change is LOCAL and GRADED
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38
Q

In which conditions is more glutamate released in the eye?

A

In dark, more glutamate (neurotransmitter) released than in light

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39
Q

What is the visual pigment molecule in rods?

A

Rhodopsin

* Retinal (vit A derivative) + opsin (GPCR)

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40
Q

Molecular basis of phototransduction?

A
  • Light converts 11-cis-retinal to all-trans-retinal (activated form)
  • all-trans-retinal activates transducin
  • decreases cGMP
  • leads to closure of cGMP-gated Na+ channel
  • lowered Na results in hyperpolarisation
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41
Q

What is visual acuity?

A

Ability to distinguish between 2 nearby points

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42
Q

What are rods used for?
Cones?
Are rods high convergence or low convergence?

A 
Rods = seeing in dim light
Cones = seeing in normal daylight
  • More convergence in rod system, increasing sensitivity + decreasing acuity
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43
Q

Differences between rods and cones? (5)

A

Rods

  • achromatic
  • peripheral retina
  • high convergence
  • high light sensitivity
  • low acuity

Cones

  • chromatic
  • central retina (fovea)
  • low convergence
  • low light sensitivity
  • high acuity
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44
Q

Differences between rods and cones? (5)

A

Rods

  • achromatic
  • peripheral retina
  • high convergence
  • high light sensitivity
  • low acuity

Cones

  • chromatic
  • central retina (fovea)
  • low convergence
  • low light sensitivity
  • high acuity
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45
Q

Explain the visual field of the eye

A
  • Each eye sees a part of the visual space - monocular visual field
  • but their
    visual fields overlap to create a binocular visual field
  • retina is divided in half, relative to the fovea, into a nasal and
    a temporal hemiretina
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46
Q

Explain nerve fibres from nasal and temporal sides of retina

A
  • Nasal half (60%) = cross over at optic chiasm

* Temporal (40%) do not

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47
Q

Where is information from right visual field processed?

Superior visual field?

A
  • Right = left cortext

* Superior = lower cortext

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48
Q

Amblyopia?
Ax?
Tx?

A

Cortical blindness - visual disorder when there is no problem with the eye i.e. one eye has better vision than the other

  • Ax = strabismus (wandering eye)
  • Tx = surgery
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49
Q

Hydrocephalus?

Sign?

A

Increased CSF in cranium

* white showing above and below iris

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50
Q

What are meninges?

Where is CSF found?

A 
3 layers surrounding brain
(from superficial to deep)
* Dura mater 
* arachnoid mater 
* pia mater (thinnest)

CSF found deep to arachnoid mater

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51
Q

What is found between the 2 layers of the dura mater?

A

Venous sinus

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52
Q

What happens when there is increased pressure via fluid in the brain?

A

Brain will be pushed through tentorial notch, causing pressure on brainstem

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53
Q

What is the first sign of ICP>

A

The eyes

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54
Q

Where are the third and fourth ventricles found?

A
  • Third ventricle = between thalami

* Fourth = between pons and cerebellum

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55
Q

Eye s/s with ICP? (5)

A
  • blurred vision
  • double vision (diplopia)
  • loss of vision
  • papilloedema (swelling of optic disc due to raised ICP)
  • pupillary changes
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56
Q

Why is optic nerve considered an extension of the brain?

A

It has meninges

  • dura
  • arachnoid
  • pia
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57
Q

What is the space between arachnoid and eyeball called?

A

Subarachnoid space

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58
Q

Complications of raised ICP? (3)

A
  • Compress optic nerve
  • compress central artery and vein of retina
  • papilloedema
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59
Q

Occulomotor nerve function? (2)

S/s of CN III damage? (4)

A
  • Supplies somatic motor to extrinsic muscles of eye
  • constricts pupil via parasympathetics

S/s

  • no pupillary light reflex
  • dilated pupil
  • ptosis
  • eye looking down + out
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60
Q

Complications of damage to trochlear nerve? (3)

A
  • Paralysis to superior oblique muscle
  • inferior oblique is unopposed to eye cannot move inferomedially!!
  • Diplopia when looking down
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61
Q

Complications of damage to abducent nerve? (2)

A
  • Paralysis of lateral rectus muscle

* medial deviation of eye

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62
Q

What does cavernous sinus contain?

A
  • oculomotor nerve
  • trochlear nerve
  • trigeminal nerve
  • abducens nerve
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63
Q

Ax of neuro-opthalmic disease (movement + visual defects)? (6)

A
  • Vascular disease
  • Tumours (primary and secondary) - SOLs
  • Trauma
  • Demyelination
  • Inflammation/infection
  • Congenital abnormalities
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64
Q

Ix cause of neuro-opthalmic disease? (2)

A
  • Blood tests

* Imaging (MRI - gold standard)

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65
Q

Ocular motility defects? (5)

A
  • IIIrd Nerve
  • IVth Nerve
  • VIth Nerve
  • Inter-nuclear
  • Supra-nuclear (initiation of movement of eye is broken)
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66
Q

Ax VIth nerve palsy?

S/s?

A
  • Microvascular
  • Raised Intracranial pressure (papilloedema)
  • Tumour
  • Congenital

Lateral rectus - no abduction

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67
Q

IVth nerve?

S/s palsy? (4)

A

Superior oblique
* Intorsion (depression in adduction)

  • Patients often compensate with head tilt
  • Sclera visible below iris (eye elevated)
  • problems with eye depression
  • patients will have double vision
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68
Q

Why is 6th CN prone to be affected by raised ICP?

A
  • close to petrous tip
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69
Q

Ax IVth nerve palsy?

A

Congenital decompensated
Microvascular
Tumour
Bilateral – closed head trauma

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70
Q

CN III nerve function?

A 
Medial rectus muscle
Inferior rectus 
Superior rectusInferior oblique
Sphincter pupillae (efferent - remember afferent is optic nerve)
Levator palpebrae superioris
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71
Q

IIIrd nerve palsy s/s? (2)

Ax?

A

Eye down and out
Ptosis

  • Microvascular
  • Tumour
  • Aneurysm!!! (particularly susceptible)
  • MS
  • Congenital
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72
Q

Painful third nerve palsy?

A

ANEURYSM

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73
Q

Function of inter-nuclear pathways?

A

Helps eyes work together

LOOK LEFT!
Left eye looks left
Right eye looks left
At the same time and same speed

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74
Q

Inter-nuclear opthalmoplegia?

Ax inter-nuclear opthalmoplegia? (2)

A

If left inter-nuclear opthalmoplegia, can still move right eye left, but left eye cannot (eye can’t catch up so will see nystagmus!)

  • Multiple sclerosis
  • Vascular (stroke)
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75
Q

Visual field defects? (5)

Ax? (4)

A 
optic nerve
 chiasm
 optic tracts (1-sided field)
 optic radiations (split into quadrants)
 cortex

Ax

  • Vascular disease - CVA
  • Space occupying lesion (SOL)
  • Demyelination (MS)
  • Trauma - including surgical
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76
Q

Plaques on MRI?

A

MS - demyelinating disease (cause of inter-nuclear opthalmoplegia)

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77
Q

Optic nerve pathology? (3)

A 
Ischaemic Optic Neuropathy
Optic neuritis – commonly MS
Tumours - rare
* Meningioma
* Glioma
* Haemangioma
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78
Q

How does optic nerve pathology affect visual field?

A

Either complete or horizontal

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79
Q

Optic neuritis s/s? (4)

Tx?

A
  • Progressive visual loss (unilateral)
  • Pain behind eye, especially on movement
  • Colour desaturation
  • Central scotoma (missing central/macular vision)

Tx
Gradual recovery over weeks - months

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80
Q

Complication of optic neuritis?

A

Optic atrophy
(optic nerve appears incredibly pale)
- marked RAPD

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81
Q

Optic chiasm pathology?

Tx?

A

Pituitary tumour
Craniopharyngioma
Meningioma

  • Tx pituitary tumours = Visual loss or disturbance is commonly reversed after the tumour is decompressed or removed
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82
Q

Visual defect of optic chiasm pathology?

A

Bi-temporal field defect

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83
Q

Optic tracts and radiations pathology? (3)

S/s? (4)

A

Tumours (primary or secondary)
Demyelination
Vascular anomalies

S/s

  • Homonomous defects
  • Macula not spared
  • Quadrantanopia
  • Incongruous (not symmetrical)

(remember, once past, defects are only on one side. If only in quadrants, have not reached lateral geniculate)

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84
Q

Occipital cortext pathology Ax? (2)

S/s? (3)

A 
Vascular disease (CVA)
Demyelination

S/s

  • Homonomous defect
  • Macular sparing
  • Congruous
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85
Q

Hyphaema?

A

Blood in anterior chamber of eye (intra-oculr injury i.e. rupture of iris)

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86
Q

What are the signs of corneal laceration?

A

if break in cornea, iris will plug wound meaning pupil will be mishapen

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87
Q

Sidel test?

A

Flouroscien in full penetrating injury

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88
Q

When is penetrating foreign body suspected? (4)

A
  • pupil irregular
  • anterior chamber shallow
  • localised cataract
  • gross inflammation
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89
Q

what should you do if you suspect intra-ocular foreign body?

A

ALWAYS X-RAY!!!!

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90
Q

Difference between acid and alkali burns eye?

A
  • Akali - easy, rapid penetration

* Acid - little penetration

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91
Q

What is it important to look for in alkali burns?

A

Ischaemia (especially limbal ischaemia where stem cells are i.e. cornea may never heal)

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92
Q

Tx of chemical injury? (2)

A
  • IRRIGATE!! (2l saline)

* Asses at slit lamp

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93
Q

What is the lens lined with?

What is the main pathology of the lens?

A

Epithelium

* main pathology = cataracts

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94
Q

What are cataracts?

Ax? (6)

A

Opacifications within lens

Ax

  • age-related (degenerative)
  • UVB damage
  • hypertension
  • smoking
  • post-op
  • DIABETES!!!!!
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95
Q

Glaucoma?

Ax?

A

Increase in pressure in the eye

  • aqueous humor normally drains through trabecular meshwork + canal of schlemm
  • glaucoma occurs when there is a blockage in drainage thru canal
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96
Q

Types of glaucoma?

A
  • Open angle = most common (poor drainage thru trabecular network)
  • closed angle = drainage thru network is patent but iris is opposed to anterior eye and fluid can’t get past
97
Q

Open vs closed glaucoma?

A

Open

  • slow onset, often asymptomatic
  • tx = pharmacological

Closed

  • emergency! can lose sight quickly
  • laser surgery
98
Q

Opthalmoscopy sign of glaucoma?

A

Cupping = raised intra-ocular pressure damaged optic disc and nerve (increased size of cup)

99
Q

What is papilloedema?

A

swelling of optic nerve/disc due to raised ICP

100
Q

Difference between scleritis and episcleritis?

A

Scleritis

  • more severe
  • associated with pain on movement
  • underlying autoimmune disease e.g. SLE

Episcleritis
* superficial and self-limiting

101
Q

ARMD?

Types? (2)

A

Age-related macular degeneration

  • Dry = no significant vascular proliferation
  • wet = vascular proliferation (wet due to haemorrhage) - associated with far more visual loss!!
102
Q

What accumulates in ARMD?

A

Drusen - proteins, lipids and inflammatory mediators

* look like yello wplques, similiar to atheroma

103
Q

What leads to wet ARMD?

Tx?

A

VEGF - new vessels are leaky

Tx = monoclonal antibodies ot VEGF

104
Q

Diabetic eye conditions? (6)

A
  • blurred vision
  • Argyll Robertson pupil -often called prostitute’s pupil because it accomodates (near and far) but doesn’t react (pupil dilation)
  • Cataracts
  • Glaucoma - in diabetes, called rubeotic glaucoma
  • Diabetic retinopathy - leaky vessels and small aneurysms form
105
Q

Vascular diseases of the eye? (4)

A

Arterial occlusion and venous occlusion

  • Central retinal artery occlusion (CRAO)
  • Central retinal vein occlusion (CRVO)
  • Arterial thromboembolism in eye - curtain
  • Vasculitis can affect vessels of the eye – Giant cell!!
106
Q

Malignancy of the eye? (3)

A

Same as skin

  • BCC
  • SCC
  • Melanoma (retinal melanoma = melanocytes at back of eye)
107
Q

Which drugs are good for penetrating cornea?

A

LMW drugs - cornea is a lipid-water-lipid sandwich (epithelium is lipophillic, stroma is hydrophillic)

Therefore, lipid soluble drugs penetrate epithelium and water soluble drugs penetrate stroma

108
Q

Example of a drug that has both lipophillic and hydrophillic properties? Advantage?

A

Chloramphenicol - can penetrate cornea easily

109
Q

What are hydrophillic drugs limited by?

Hydrophobic drugs?

A
  • Hydrophillic drugs limited by epithelium

* Hydrophobic drugs limited by stroma

110
Q

what is added to topical steroids to make them more hydrophobic?
Hydrophillic?

Examples? (2)

A
  • Hydrophobic = alcohol or acetate
  • Hydrphillic = phosphate

Prednisolone acetate
Prednisolone phosphate

111
Q

Properties of prednisolone acetate? (3)

Prednisolone phosphate? (3)

A

Prednisolone acetate

  • hydrophobic
  • good penetration in uninflamed cornea
  • used post-operatively

Prednisolone phosphate

  • hydrophilic
  • Poor penetration in uninflamed cornea (inflammation can reduce hydrophobic nature of cornea)
  • Used for cornea disease or when want low dose steroids
112
Q

What is benzylkonium? Used for?

A

A preservative that disrupts lipid layer of tear film

* aids penetration of some drugs

113
Q

what is bimatoprost?

A

Drug used to lower IOP in glaucoma (benzylkonium aids penetration)

114
Q

How can you prevent systemic absorption of topic eye drugs?

A

tears pumped out of lacrimal sac rapidly = limited by punctal occlusion

115
Q

Types of ocular injection? (2)

A
  • Intravitreal

* Intracameral

116
Q

What are examples of eye drops used to treat infections? (2)

A
  • Chloramphenicol

* Zovirax

117
Q

Anti-inflammatory agents for the eye? (4)

A

Steroids
Topical NSAIDs
Anti-histamines
Mast cell stabilisers

118
Q

When are steroids used topically on the eyes?

A
  • post op cataracts
  • uveitis
  • to prevent corneal graft rejection
119
Q

Local side effects of steroid drops? (3)

Systemic? (6)

A

Local

  • cataract
  • glaucoma
  • exacerbation of viral infection

Systemic

  • Gastric ulceration
  • Immunosuppression
  • Osteoporosis
  • Weight gain
  • Diabetes
  • Neuropsychiatric effects
120
Q

Examples of topical steroids? (3)

A
  • Predsol (prednisolone phosphate)
  • Betamathasone
  • Dexamethasone/ prednisolone acetate
121
Q

What are antihistamines and mast cell stabilisers used in?

NSAIDs?

A
  • Antihist and MCS = hayfever or allergic conjunctivitis

* NSAIDs use din pain relief

122
Q

Glaucoma medication? (5)

A
  • Prostanoids e.g. latanoprast (Xalatan)
  • B-blockers
  • CA inhibitors e.g. dorzolamide
  • Alpha agonists e.g. brimonidine
  • Parasympathomometic - pilocarpine
123
Q

What drugs are administered through intravitreal methods? (3)

A
  • Antibiotics in endophthalmitis
  • intra-ocular steroids
  • anti-vegf
124
Q

Endophthalmitis?

A

Inflammation of interior eye (normally post-surgery)

SIGHT-THREATENING!!

125
Q

How do local anaesthetics of the eye work?

Used for? (5)

A

Block sodium channels and impede nerve conduction

  • foreign body removal
  • tonometry (IOP measurement)
  • corneal scraping
  • comfort
  • cataract surgery
126
Q

Most common diagnostic dye for eyes?

Uses? (6)

A

Fluorescein

  • shows corneal abrasion
  • dendritic ulcer
  • leaks
  • tonometry
  • nasolacrimal duct obstruction
  • angiography
127
Q

Mydriatics?
Examples?
Side effects? (2)

A

Drugs that cause pupil dilation by blocking parasympathetic supply to iris
* e.g. tropicamide, cyclopentolate

Side effects

  • blurring
  • angle-closure glaucoma
128
Q

Signs of acute angle closure glaucoma? (2)

A
  • Headache

* Vomiting

129
Q

Sympathomimetics?
Cycloplegia?
Do all sympathomimetics cause cycloplegia?

A

Act of sympathetic system and cause pupil to dilate

Cycloplegia = paralysis of ciliary muscle

  • some cause = atropine
  • some don’t = phenylephrine
130
Q

why do antibiotics given systemically not enter the eye?

A

Inner and oter retinal blood barrier

131
Q

Goldren rule with herpetic keratitis?

A

NEVER give steroids

132
Q

ethambutol associated with?
chloroquine?
Amiodarone?

A
  • optic neuropathy
  • maculopathy
  • vortex kerotopathy
133
Q

Types of eye infection? (4)

A
  • Conjunctivitis
  • cornea = keratitis
  • entire globe = endophthalmitis
  • cellulitis
134
Q

Bacterial conjunctivits in neonates caused by?

What about all other ages? (3)

A
  • staph aureus
  • neisseria gonorrhoeae
  • chlamydia trachomatis

Other ages

  • staph aureus
  • strep pneumoniae
  • haemophilus influenzae
135
Q

Tx bacterial conjunctivitis?

A

Chloramphenical

* DO NOT use if history of aplastic anaemia or allergy!!

136
Q

Ax viral conjunctivitis? (3)

A
  • Adenovirus
  • Herpes simplex
  • herpes zoster
137
Q

Chlamydial conjunctivitis?

A

Chronic history - unresponsive to tx (may or may not have symptoms of urethritis, vaginitis)

138
Q

Ax microbial keratitis? (3)

A
  • Bacteria
  • Viruses - herpes, adenovirus
  • Fungi
139
Q

Tx bacterial keratitis? (2)

A
  • Admission for hourly drops

* daily review

140
Q

Pathogenesis of diabetic retinopathy?

A
  • Chronic hyperglycaemia leads to glycosylation of protein/basement membrane
  • loss of pericytes leading to microaneurysms
  • Microaneurysms can either cause leakages or ischaemia
141
Q

Signs of non-proliferative retinopathy?

A 
microaneurysms / dot + blot haemorrhages
hard exudate
cotton wool patches 
abnormalities of venous calibre
Intra-retinal microvascular abnormailities (IRMA)
142
Q

Where do new vessels grow?

A

grow on disc (NVD)
grow in the periphery (NVE)
grow on iris if ischaemia is severe

143
Q

Difference between NVE and NVD?

A

NVE

  • Periphery
  • ischaemia is local
  • better prognosis

NVD

  • optic disc
  • ischaemia is widespread
  • worse prognosis
144
Q

What is rubeosis iridis?

A

Progressive ischaemia = iris affected (sight restoration is impossible)

145
Q

what do diabetic patients lose vision due to? (3)

A
  • retinal oedema affecting fovea
  • vitreous haemorrhage
  • scarring
146
Q

Classification of retinopathy?

A
  • No retinopathy
  • mild
  • moderate
  • severe
  • proliferative retinopathy
147
Q

Management of diabetic retinopathy/maculopathy? (2)

A

Laser
* PRP (essentially cooking and killing bits of retina)
Surgery - virectomy (only way to get rid of scarring)

148
Q

disadvantage of laser therapy for diabetic retinopathy?

A

sacrifice peripheral sight for central

149
Q

Tx disc neurovascularisation? (2)

A
  • Laser

* Intra-ocular anti-VEGF

150
Q

Features of hypertensive retinopathy? (4)

A
  • cotton wool spots (associated with hypertension more than diabetic retinopathy)
  • hard exudates
  • retinal haemorrhage
  • optic disc oedema
151
Q

S/s central retinal artery occlusion? (3)

A
  • Sudden painless loss of vision
  • very profound loss of vision
  • retinal nerve fibre layer becomes swollen except at fovea (cherry red spot)
152
Q

CRVO s/s? (2)

A
  • sudden painless visual loss

* range of visual loss

153
Q

branch vein occlusion? (2)

A
  • painless disturbance in vision

* may be asymptomatic

154
Q

Features of thyroid eye disease?

A

Extraocular

  • proptosis
  • lid retratcion, oedema, lag
  • restricitve myopathy = diplopia

Intra-ocular

Anterior segment

  • chemosis
  • glaucoma

Posterior segment

  • choroidal folds
  • optic nerve swelling
155
Q

what is thyroid eye disease characterised by?

Tx? (3)

A

swelling of the extraocular muscles and orbital fat

Tx

  • control thyroid levels
  • lubricants
  • surgical decompression (for glaucoma and that)
156
Q

How does RA affect eyes? (3)

A
  • Dry eyes (keratoconjunctivitis sicca)
  • scleritis
  • corneal melt
157
Q

Sjogren’s syndrome triad?

A
  • keratoconjunctivitis sicca
  • xerostomia (dry mouth)
  • rheumatoid arthritis
158
Q

Stevens-Johnson syndrome affects eye? (3)

A
  • symblepharon (adhesions of palpebral conjunctiva of eyelid to bulbar conjunctiva of eyeball)
  • occlusion of lacrimal glands
  • corneal ulcers
159
Q

Herpetic keratitis?

A
  • very painful

* recurrent

160
Q

why should you NEVER treat kerpetic keratitis with steroids??

A

can cause corneal melt and perforation of cornea!!

161
Q

Adenoviral keratitis features? (4)

A
  • bilateral
  • follows URTI
  • contagious
  • may affect vision
162
Q

Tx adenoviral keratitis?

A
  • topical AB

* steroids to speed up recovery if becomes chronic

163
Q

What fungi are associated with keratitis caused by contact lenses?

A

Acanthamoeba

pseudomonas aeruginosa

164
Q

Fungal keratitis features? (2)

A
  • Takes long time to heal

* contact lesnes

165
Q

Features of orbital cellulitis? (5)

A
  • painful - especially on eye movement
  • proptosis
  • associated with sinusitis
  • pyrexial
  • sight-threatening
166
Q

Organisms involved in orbital cellulitis? (4)

A
  • staphylococci
  • streptococci
  • coliforms
  • haemophilus influenzae!
167
Q

Tx orbital cellulitis? (2)

A
  • broad spectrum AB

* drain abscesses

168
Q

Endophthalmitis?

S/s? (3)

A

Devastating infection inside of the eye

  • extremely painful!!
  • very red eye
  • sight threatening
169
Q

Organisms involved in endophthalmitis?

A
  • often conjunctival commensals

* most common is staph epidermidis

170
Q

Tx endophthalmitis?

A

Intravitreal

  • amikacin
  • ceftazidime
  • vancomycin
171
Q

Ax chorioretinitis? (3)

A
  • CMV in AIDS
  • toxoplasma gondii
  • toxocara canis (worm)
172
Q

toxoplasmosis?
Ax?
S/s?

A 
protozoan infection (toxoplasmosis gondii)
* Ax = cats + raw meat
  • Mild flu like symptoms
  • in immunocompetent patient = cyst formation (pathogen is latent, can reactivate)
173
Q

Tx toxoplasmosis?

A

If reactivates, can be sight-threatening

So reqs systemic tx

174
Q

Toxocara?

S/s? (2)

A

Parasitic nemotode (roundworm)

  • often self-limiting cause they can’t replicate in humans
  • however, can form granulomas which can result in irreversible visual loss
175
Q

Dx eye infections? (5)

A
  • swabs for culture = bacterial, chlamydial, viral
  • corneal scrapes = bacterial keratitis
  • aqueous/vitreous culture in endophthalmitis
  • microscopy/culture for acanthamoeba
  • serology for toxoplasma or toxocara
176
Q

chloramphenicol mechanism?

Used for? (2)

A

Inhibits peptidyl transferase enzyme (stops protein synthesis)

  • bacteriocidal = strep and haemophillus
  • bacteriostatic = staph
177
Q

chloramphenicol side effects? (3)

A
  • allergy
  • irreversible apastic anaemia
  • grey baby syndrome
178
Q

Antibiotics that inhibit cell wall synthesis?

A

B lactams = penicillins and cephalosporins

179
Q

Antibiotics that inhibit nucleic acid synthesis?

A

Quinolones e.g. ofloxacin (inhibit DNA gyrase)

180
Q

What is a common contaminant in eye drop bottles?

A

Pseudomonas

181
Q

Bacterial conjunctivitis tx? (3)

A
  • chloramphenicol = treats most bactria EXCEPT pseudomonas
  • fusidic acid = treats staph aureus
  • gentamicin = treats gram -ve bacteria including coliforms + pseudomonas
182
Q

Example of antiviral drops?

A

Aciclovir
* used for dendritic ulcers of cornea

REMEMBER NEVER USE STEROIDS

183
Q

Tx chlamydial conjunctivitis?

A

Topical oxytetracycline

adults may also need oral azithromycin for genital chlamydia infection

184
Q

Tx bacterial keratitis? (2)

A
  • A 4-quinolone (ofloxacin) = treats coliforms and pseudomonas - however, not effective against strep pneumoniae
  • gentamicin and cefuroxime = combo will treat most gram +ve and gram -ve
185
Q

Ax acute red eye? (7)

A
  • conjunctivitis
  • keratitis
  • anterior uveitis
  • scleritis/episcleritis
  • acute angle closure glaucoma
  • subconjunctival haemorrhage
  • cellulitis
186
Q

types of blepharitis?

A

Anterior (lid margin redder than deeper part of lid)

  • seborrhoeic = scales on lashes
  • staphylococcal = infection of lash follicle

Posterior (redness is in deeper part of lid, lid margin normal-looking)
* meibomian gland dysfunction (MGD)

187
Q

Blepharitis s/s? (3)

A
  • gritty eyes
  • foreign body sensation
  • mild discharge

(similar to conjunctivitis)

188
Q

S/s anterior blepharitis? (2)

A

Seborrhoeic

  • lid margin red
  • scales
  • dandruff
  • no ulceration, lashes unaffected

Staphylococcal

  • lid margin red
  • lashes distorted, ingrowing lashes (trichiasis)
  • styes/ulcers of margin
  • corneal staining due to exotoxin
189
Q

S/s posterior blephritis (MGD)? (5)

A 
Lid margin skin and lashes unaffected
M.G. openings pouting & swollen
Inspissated (dried) secretion at gland openings
Meibomian Cysts (chalazia)
Associated with Acne Rosacea (50%)
190
Q

Blepharitis tx? (3)

A
  • Lid hygiene (daily bathing)
  • Supplementary tear drops
  • oral doxycycline for 2-3 months

Very difficult to eradicate!!

191
Q

Signs of conjunctivitis? (6)

A
  • red eye is diffuse towards fornices
  • discharge
  • papillae or follicles
  • sub conj. haemorrhage
  • chemosis = oedema
  • pre-auricular glands (if viral)

VISION UNAFFECTED

192
Q

Tx acute bacterial conjunctivits?

Ax organisms? (3)

A

Self-limiting (will clear in 14 days) however topical antibiotics will clear faster

  • staph aureus
  • strep.pneumoniae
  • H.influenzae
193
Q

Ax follicular conjunctivitis?

Tx?

A

Viral or chlamydial

* Tx = propine, trusopt

194
Q

what is keratitis?

Layers of the cornea?

A

Inflammation of cornea

  • epithelium
  • stroma
  • endothelium
195
Q

Ax corneal ulcers?

A

Infective (central)

  • viral
  • fungal
  • bacterial
  • acanthamoeba

Autoimmune (peripheral)

  • rheumatoid arthritis
  • hypersensitivity e.g. marginal ulcers
196
Q

s/s corneal ulcers? (8)

A
  • severe pain (except in herpes virus?)
  • photophobia
  • profuse lacrimation
  • vision may be reduced
  • circumcorneal red eye
  • corneal reflex (reflection abnormal)
  • hypopyon
  • staining with fluorescein
197
Q

Corneal ulcer tx? (4)

A
  • Identify cause (corneal scrape)
  • antimicrobial if bacterial infection e.g. ofloxacin
  • antiviral if herpetic e.g. aciclovir
  • anti-inflammatory if autoimmune e.g. steroids
198
Q

Causes of anterior uveitis? (4)

A

Autoimmune
* reiter’s, UC, Ank Spondyl, sarcoid

Infective
* TB, herpes simplex, herpes zoster

Malignancy
* leukemia

Other
* idiopathic, traumatic

199
Q

Anterior uveitis s/s? (8)

A
  • Pain (+ referred pain)
  • Vision may be reduced
  • Photophobia
  • Red eye (circumcorneal)
  • Cells & flare in anterior chamber
  • Keratic precipitates
  • Hypopyon
  • Synechiae – inflammation in fibrin (small or irregular pupil)

OFTEN MISSED AND TREATED AS CONJUNCTIVITS

200
Q

Anterior uveitis tx? (3)

A
  • topical steroids
  • mydriatics e.g. cyclopentolate
  • investigate for systemic associations if recurrent or chronic
201
Q

Features episcleritis? (4)

A
  • association with gout
  • recurrent
  • nodules may occur
  • self-limiting
202
Q

Scleritis? (4)

A
  • association with serious systemic vasculitides e.g. rh arthritis + wegener’s
  • EXTREMELY painful
  • violaceous hue
  • associted with uveitis
203
Q

How to differentiate between scleritis and episcleritis?

A

phenylephrine test (epi will blanche with topical phenyl, scleritis will not)

ALSO PAIN = scleritis way more painful

204
Q

Tx scleritis and episcleritis?

A

Episcleritis

  • self-limiting
  • lubricants
  • topical nsaids
  • mild steroids

Scleritis

  • oral nsaids
  • oral steroids
205
Q

Acute closed angle glaucoma s/s? (5)

A
  • Severe pain!!
  • Nausea, headache
  • Cornea cloudy
  • Pupil mid-dilated
  • eye stony hard
206
Q

What group of people are acute closed angle glaucomas common in?

A

Elderly* hypermetropic – thick glasses

207
Q

Causes of sudden visual loss? (7)

A
  • Vascular aetiology (retinal artery/vein occlusion)
  • Vitreous haemorrhage
  • Retinal detachment
  • Age related macular degeneration (ARMD) -wet type
  • Closed angle glaucoma
  • Optic neuritis
  • Stroke
208
Q

What is the major blood supply to eye?

A

Branches of opthalmic artery

209
Q

Vascular aetiology sudden visual loss?

A

OCCLUSION

  • retinal artery/vein
  • optic nerve circulation

HAEMORRHAGE
* abnormal blood vessels (DM, wet AMD)

210
Q

CRAO s/s? (4)

A
  • Sudden visual loss
  • painless
  • RAPD (relative afferent pupil defect)
  • pale oedematous retina, thread-like retinal vessels
211
Q

Ax CRAO? (2)

A

It’s a type of stroke!

  • carotid artery disease
  • emboli from heart (rare)
212
Q

Variants retinal artery occlusion? (2)

A
  • Branch retinal artery occlusion

* Amaurosis fugax

213
Q

What is amaurosis fugax?
S/s? (3)
Tx?

A

Transient CRAO!

  • transient painless visual loss (curtain)
  • lasts ~5 mins with full recovery
  • usually nothing abnormal on examination

Tx = urgent referral to stroke clinic

214
Q

Ax central retinal vein occlusion? (3)

A

Virchow’s triad

  • endothelial damage e.g. diabetes
  • abnormal blood flow e.g. hypertension
  • hypercoagulable state e.g. cancer
215
Q

What is occlusion of optic nerve circulation called?

Mechanism?

A

Ischaemic optic neuropathy (ION)

* Posterior ciliary arteries become occluded, resulting in infarction of the optic nerve head

216
Q

Ax ION? (2)

A
  • GCA

* medium to large sized arteries

217
Q

Visual symptoms of ION?

Why is immediate tx important?

A
  • sudden severe visual loss
  • irreversibl blindness
  • signs = swollen optic nerve!!

Immediate treatment may prevent bilateral visual loss!!

218
Q

What does sudden visual loss caused by haemorrhage involve?

A

haemorrhage often occurs into the vitreous cavity – known as a ‘vitreous haemorrhage’

219
Q

Vitreous haemorrhage s/s? (3)

A
  • loss of vision
  • floaters
  • loss of red reflex
220
Q

Retinal detachment s/s? (4)

A
  • painless loss of vision
  • flashes + floaters
  • RAPD
  • tear on opthalmoscopy
221
Q

Which type of ARMD is associated with sudden visual loss?

A
  • WET

Dry is associated with gradual visual loss

222
Q

S/s wet ARMD? (3)

A
  • rapid central visual loss
  • distortion
  • haemorrhage/exudate
223
Q

Glaucoma?

How does it result in visual loss?

A

Progressive optic neuropathy

* optic nerve damage

224
Q

Closed angle glaucoma s/s? (7)

A
  • Painful
  • red eye
  • sudden visual loss
  • headache
  • vomiting
  • cloudy cornea
  • dilated pupil
225
Q

Causes of gradual visual loss?

A
  • cataract
  • ARMD - dry
  • refractive error
  • glaucoma
  • diabetic retinopathy
226
Q

what is the number 1 cause of preventable blindness worldwide?

A

Cataract

227
Q

Catarct s/s? (2)

Tx?

A

Gradual decline in vision that cannot be corrected with glasses
Glare (can be very disabling at night when driving)

  • Tx = surgical removal with intra-ocular lens implant
228
Q

S/s dry ARMD?

A
  • gradual decline in vision
  • central vision “missing”
  • Drusen - build up of waste
  • atrophic patches of retina
229
Q

Dry ARMD tx?

A

no cure - tx is supportive with low vision aids e.g. magnifiers

230
Q

What is a refractive error?

Types? (4)

A

Eyes cannot clearly focus image

  • Myopia (short-sighted)
  • hypermetropia (long)
  • astigmatism (irregular corneal curvature)
  • presbyopia (loss of accommodation with aging)
231
Q

Glaucoma open-angle s/s? (4)

A
  • often asymptomatic
  • cupped disc
  • visual field defect
  • high IOP
232
Q

Papilloedema?

A

specific term meaning swollen optic discs secondary to raised intracranial pressure (ICP)

233
Q

What should all patients with bilateral optic disc swelling be suspected of having?

A

raised ICP due to a space occupying lesion (SOL) until proven otherwise

234
Q

Pathophysiology papilloedem?

A

Subarachnoid space around optic nerve continuous with SAS surrounding brain - raised ICP interrupts axons + venous drainage = swollen discs

235
Q

Why is raised ICP a medical emergency?

A

Further increases in volume causes blood vessels to be compressed, ultimately causing brain ischaemia with herniation through foramen magnum, brainstem compression and death

236
Q

What is a common cause of raised ICP other than SOL?

A

Hypertnesion - always check blood pressure!!

237
Q

When will CSF result in raised ICP? (3)

A
  • obstruction of CSF circulation
  • overproduction of CSF
  • inadequate absorption
238
Q

What happens if disc swelling (of any cause) becomes chronic?

A

Disc swelling subsides, discs become atrophic and pale

* can result in blindness

239
Q

What is the neurotransmitter of photoreceptors?

A

glutamate

2nd Year Medicine (24 decks)

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