Cornea Flashcards

1
Q

Power of cornea

A

43-45 D

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2
Q

Refractive index of cornea

A

1.37

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3
Q

Diameter of cornea

A

11-11.75

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4
Q

Megalocornea

A

> 13 mm

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5
Q

Microcornea

A

<10 mm

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6
Q

How is cornea dehydrated

A

Barrier function of endothelial cells

Na+/K+ ATPase pump

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7
Q

Number of Endothelial cells in adults

A

2500-3000 cells/ sq.mm

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8
Q

Number of endothelial cells in children

A

3500-3000 cells/sq.mm

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9
Q

Number of cells in endothelium which causes hydration of cornea

A

<500 cells/sq.mm

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10
Q

Features of corneal decompensation (hydration of cornea)

A

Stromal oedema
Bullous keratopathy
Bullae

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11
Q

Organisms which penetrate intact epithelium

A
N – Neisseria gonorrhoea
N– Neisseria meningitis
L – listeria
D – diphtheria
H – haemophilia
S – shigella
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12
Q

Name some investigations related to cornea

A
Keratometry – curvature of cornea
Corneal topography–
Plácido’s disc– qualitative assessment
Pachymetry- thickness of cornea
Specular microscopy-To examine endothelial cells
Corneal sensation 
Microbiological investigation
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13
Q

corneal sensation tests

A

Qualitative –With a wisp of cotton
Quantitative – aesthesiometre> The length of filament when patient starts feeling sensation
Shorter the length the more pressure is needed and lesser the corneal sensation

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14
Q

Microbiological investigations of cornea

A

Staining and culture

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15
Q

The main clinical features of keratitis

A
Pain
Redness (ciliary congestion)
Photophobia
Blepharospasm
Discharge
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16
Q

What are the type of redness and what is their pathology

A

Conjunctival congestion – only conjunctival pathology

Circumciliary congestion – deeper blood vessel

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17
Q

What type of hypopyon present in bacterial keratitis

A

Sterile hypopyon

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18
Q

Three types of bacterial keratitis

A

Localised
Perforating
Sloughing

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19
Q

Ulcus Serpens

A

Hypopion corneal ulcer caused by pneumococcus

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20
Q

2 things NOT to do for infective corneal ulcer

A

No steroids

No pad/bandage

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21
Q

Management of non-healing ulcer

A

Debridement
Chemical cauterisation
Conjunctival flapping

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22
Q

What are the local antiseptics used for chemical cauterisation in the management of non-healing ulcer

A

Trichloroacetic acid

Carbolic acid

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23
Q

Management of impending perforation

A

Anti-glaucoma drugs
Cyano acrylate blue
BCL – bandage contact lens

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24
Q

Types of contact lens

A

Soft

Semi soft also known as rigid gas permeable

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25
Q

Most common cause of bacterial keratitis

A

Staphylococcus aureus

Staphylococcus epidermidis

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26
Q

If there is corneal perforation in 48 hours which organism is it

A

Pseudomonas

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27
Q

Treatment of bacterial keratitis

A

Please check your notes

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28
Q

What is the aetiology of fungal keratitis

A

Drama by vegetative/organic matter

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29
Q

Fungal keratitis also known as

A

Keratomycosis

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30
Q

Most common fungus infecting cornea

A

Aspergillus fumigatus

Fusarium

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31
Q

Most common fungus infecting lids

A

Candida

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32
Q

Most common fungus infecting endophthalmitis

A

Candida

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33
Q

Most common fungus infecting orbit

A

Mucormycosis

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34
Q

Compare to bacterial keratitis which is more prominent signs or symptoms in fungal keratitis

A

Bacterial keratitis – symptoms are more than science

Fungal keratitis – signs are more than symptoms

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35
Q

Examination findings in fungal keratitis

A

Satellite nodules
hyphae
Unsterile hypopyon
Immune ring

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36
Q

Investigations in fungal keratitis

A

Staining – KOH Smear, gomori’s methamine, silver stain

Culture – SDA, brain heart infusion broth

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37
Q

Treatment of fungal keratitis

A

DOC – Natamycin
Nystatin eye ointment
Flucanazole (Candida)

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38
Q

Causes of viral keratitis

A

HSV (More common)

HZO

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39
Q

Pathognomic feature of viral keratitis

A

Decreased corneal sensation

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40
Q

Other causes of decreased corneal sensation

A

Diabetes

Leprosy

41
Q

Examination findings in herpes simplex keratitis

A

Endothelium
Corneal oedema, disciform keratitis (endothelitis in disc shape)

Stroma
keratitis

Epithelium
Superficial punctate keratitis, dendritic ulcers with knobbed ends
Geographical ulcer

42
Q

Treatment of herpes Simplex keratitis

A

Acyclovir eye ointment (3%)

Five times a day

43
Q

What are the three main components of herpes zoster ophthalmicus

A

Skin lesion
Eye involvement
Trigeminal neuralgia

44
Q

Hutchison’s rule. And why?

A

If the tip of the nose is involved the eye will be involved

It indicates involvement of nasociliary nerve (ophthalmic division of fifth nerve)

45
Q

Examination findings in herpes zoster ophthalmicus

A

Endothelium
Disciform keratitis

Trauma
Nummula keratitis

Epithelium
SPK
Pseudo dendritis/micro dendritis

46
Q

Herpes zoster ophthalmicus is associated with

A

Uveitis
Cranial nerve palsy three, four, six
Most commonly third nerve

47
Q

Treatment of herpes zoster opthalmicus

A
3% Acyclovir  five times a day
Oral antiviral (acyclovir/vancyclovir)
48
Q

Meta herpetic keratitis

A

Keratitis due to toxicity of anti-viral drugs

Ulcer not healing

49
Q

Most common nerve involved in zoster

A

Frontal nerve

50
Q

Aetiology of acanthamoeba keratitis

A

Soft contact lens users
Washing lenses with tap water
Or
Swimming without goggles and soft contact lens

51
Q

What is the most common infection after contact lens use

A

Pseudomonas

52
Q

Metabolically most active layer of cornea

A

Endothelium

53
Q

Examination findings of acanthamoeba keratitis

A

Ring lesion

Can I present with pseudodendrites or reticular patter

54
Q

Investigations in acanthamoeba keratitis

A

Staining
Calcoflour white
Acridine Orange
Lactophenol blue

Culture
Non-nutrient agar with E. coli

55
Q

Treatment of acanthamoeba

A

PHMB (find full form)
Propamidine isothionate
Neomycin

56
Q

Interstitial keratitis

A

Stromal keratitis with no involvement of epithelium and endothelium

57
Q

Aetiology of interstitial keratitis

A
Syphilis
Leprosy
TB
Sarcoidosis
Cogan syndrome (interstitial keratitis plus deafness)
58
Q

Salmon patch seen in which condition

A

Interstitial keratitis

59
Q

Keratoconus

A

Elastic dystrophy of cornea characterised by its conical protrusion

60
Q

Dystrophy meaning

A

Idiopathic spontaneous change with no inflammatory component

61
Q

What is keratoGlobus

A

Uniform protrusion of the cornea

62
Q

What is the vision defect of keratoconus

A

Myopia plus irregular astigmatism

63
Q

What is Flescher’s ring

A

Iron in epithelium
Seen in keratoconus

Generally recall all the examination findings of keratoconus

64
Q

What is Munson’s sign

A

V shaped deformity of lower lid on down gaze

Seen in keratoconus

65
Q

What do you see in retinoscopy of keratoconus

A

Scissors reflex

66
Q

Causes of thickening of corneal nerves

A

Leprosy

NF1

67
Q

What is votes striae Vogt striae

A

Break in descemets membrane

68
Q

In which condition is oil globules reflex scene

A

In patients of anterior lenticonus (slitlamp examination)

69
Q

What is the treatment of keratoconus

A
Contact lens (RGP)
C3R treatment Corneal collagen cross-linking plus riboflavin
70
Q

Best prognosis of penetrating keratoplasty is in?

A

Keratoconus

Chances of graft rejection is minimum

71
Q

Main principle of keratoplasty

A

Replacement of diseased cornea by donor cornea

72
Q

Within how many hours of death should the cornea be taken from the cadaver

A

Within Six hours of death

It may be extended to 12 hours

73
Q

Types of storage media of cornea and number of hours can be stored

A

Short-term storage – 48 hours: moist chamber
Intermediate term – four days: MK medium, McCary kaufman
Long-term –
30 days: organ culture
In definite: cryopreservation

74
Q

Types of keratoplasty

A

Penetrating full thickness replacement

Lamellar partial thickness replacement-Anterior lamellar, posterior lamellar

75
Q

DALK
DLEK
DSEK/DSAEK
DMEK

Full forms of all lol
Also know what is being removed in the Donor and what is being put in the host

A

Deep anterior lamellar keratoplasty
Deep lamellar endothelia keratoplasty
Descemet’s stripping endothelial (automated) keratoplasty
Descemet’s membrane endothelial keratoplasty

76
Q

Clinical signs of graft rejection

A
Corneal oedema (most) 
Keratic precipitates
Corneal vascularisation 
Stromal infiltrates
Khodadoust line
Krachmer spots(Least)
77
Q

What is khodadoust line

A

Corneal graft endothelial rejection line composed of inflammatory cells

78
Q

What is krachmer spots

A

Sub-epithelial infiltrates

79
Q

Most common infection after keratoplasty

A

Staphylococcus epidermidis

80
Q

Indications of keratoplasty

A

keratoconus
Corneal dystrophy
Bullous keratopathy (Aphakia,pseudophakia)
Central corneal opacity

81
Q

What is keratoprosthesis

A

Surgical procedure where diseased cornea is replaced by artificial cornea

82
Q

Names of keratoprosthesis

A

Boston KP

OOKP (osteo – odonto – KP)

83
Q

What is Arcus senilis

A

Lipid deposition in stroma

84
Q

Band shaped keratopathy

Aetiology

A

Calcium deposition in the form of a band
Mostly idiopathic, or chronic uveitis in children of JRA
Pthysis bulbi
Hypercalcaemia (sarcoidosis)

85
Q

Treatment of band shaped keratopathy

A

Debride epithelium
Chelation with EDTA
Bandage

86
Q

Climatic droplet keratopathy

Aetiology

A

Also known as actinic keratopathy

Exposure to UV rays

87
Q

Pathogenesis of Actinic keratopathy

A

UV rays act on serum protein causing golden proteinaceous deposit on cornea

88
Q

Degrees of corneal opacity is

A

Nebular
Macular
Lucomatous
Adherent leucoma

89
Q

Which type of corneal opacity has maximum diminishing of vision

A

Nebula

Because it diffract light and interferes with the function of normal/clear cornea as well

90
Q

Types of corneal dystrophy

A

Epithelial
Stromal
Endothelial

91
Q

Types of epithelial dystrophy cornea

A

Micro cystic or map – dot or fingerprint
Meesmans
Reis buckler

92
Q

Types of stromal corneal dystrophy

A

Granular
Macular
Lattice

93
Q

Types of endothelial corneal dystrophy

A

Fuch’s endothelial dystrophy

Posterior polymorphous dystrophy

94
Q

Most common corneal dystrophy

A

Micro cystic

95
Q

Most common stromal Corneal dystrophy

A

Lattice

96
Q

Least common corneal dystrophy

A

Macular

97
Q

Which corneal dystrophy is autosomal recessive

A

Macular

98
Q

Which corneal dystrophy is associated with mucopolysaccharide

A

Macular

99
Q

Which part of the cornea does Reis Buckler affect

A

Bowmans membrane