Cornea Flashcards

1
Q

What is keratometry?

What are keratometric mires?

A

Measurement of corneal curvature.
Normal=42-46
Image is seen in the form of keratometric mires.
-minus sign btw vertical mires overlap
-plus sign btw horizontal mires overlap

Mires-horizontally oval=with the rule astigmatism
-vertically oval=against the rule “
PULSATING=Keratoconus

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2
Q

What is pachymetry?

What is esthesiometry?

A

Measurement of corneal thickness…..500-600u

Eliciting corneal sensation…..by Cochet Bonnet esthesiometer

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3
Q

Specular microscopy?

Confocal microscopy?

A

To visualise count endothelial cells

To visualise any layer of cornea
Also corneal nerves,Fungal hyphae,Acanthamoeba cysts*****

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4
Q

Corneal topography nd instruments?

Uses of Gonioscopy?

A

To assess surf elevation
Measured by 1.Placebo disc
2.Orb scan(th+curv)
3.Pentacam(5)

Visualise angle structures-schwalbe’s line nd very early KF ring

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5
Q

Dyes used in staining corneal ulcers?

A
  1. Fluorescein dye- base or floor
  2. Rose Bengal dye- margins
  3. Alicante blue dye-Mucin nd filaments
  4. Lissamine green-not healthy surface
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6
Q

Other uses of fluorescein dye?

A
  1. Goldman’s AT in glaucoma
  2. Dx of Dry eye
  3. Jones dye test- for lacrimation assessment
  4. Seidel’s test- detect leakage thr perforation
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7
Q

Staining nd culture for diff organisms?

A
  1. Bacterial- Grams stain- Blood/chocolate agar
  2. Fungi- 10%KOH- SDA
  3. Acanthamoeba= Gomori’s methamine silver stain- Non nutrient agar with E-coli overlay
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8
Q

Mcc in the world?

Mcc in India/Mcc of hypopyon CU

Mcc in contact lens user/fast spreading/Mcc of perforation

Mcc in post keratoplasty pts

A

Staphylococcus aureus

Streptococcus pneumoniae

Pseudomonas aeruginosa(green discharge)

Atypical mycobacterium

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9
Q

Bacteria that penetrate intact epithelium

A
  1. N.g, N.m
  2. C.d
  3. H.aegypticus
  4. Listeria
  5. Shigella
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10
Q

Symptoms in bacterial CU

A
  1. Defective vision
  2. Photophobia
  3. Lacrimation
  4. Redness
  5. Pain nd FBS
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11
Q

Hypopyon CU

A

By streptococcus pneumoniae

Etio = Chronic dacrocystitis

Serpenginous ulcer nd violent iridocyclitis nd 2” glaucoma

Sterile,mobile

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12
Q

Complications of bacterial CU

A
  1. Toxic iridocyclitis
  2. 2” glaucoma
  3. Descematocele
  4. Perforation = iris prolapse,Ant capsular cataract,end/panophth,phthisis
  5. Scarring
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13
Q

Treatment of uncomplicated bacterial CU

A

Topical fortified antibiotics
1.Cefazolin5% + Tobramycin1%
Or
2.Vancomycin 5% + FQs(cipro 0.3% or moxi 0.5%)

Every 5min for 30min…..every 15min for 2hrs…..1hrly for 2 days….4-6hrly till healed

Cycloplegics(A=dec pain nd prevent synechae nd inc BF)
Analgesics(paracetamol,ibuprofen)
Vitamins

Dark goggles,hot fomentation

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14
Q

Wreath pattern or Pin head ulcer is caused by?

A

Nocardia

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15
Q

Signs are out of proportion in which ulcer?

Symptoms are out of proportion in which ulcer?

A

Fungal keratitis(vegetable,animal trauma)

Acanthamoeba keratitis(unhygienic contact lens users)

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16
Q

Signs of fungal corneal ulcer

A
  1. Dry looking
  2. Feathery margins
  3. Satellite lesions
  4. Sterile immune ring of WESLEY
  5. Hypopyon= not sterile,immobile
  6. Endothelial plaque
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17
Q

DOC in fungal keratitis

A

For Aspergillus fumigatus= 5% NATAMYCIN

For Candida albicans= 0.15% Amphotericin B

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18
Q

Symptoms of Acanthamoeba keratitis

Signs seen in “

A
  1. Pain d/t Radial Perineuritis nd Radial keratoneuritis
  2. Blepharospasm
  3. FBS,watering
  4. Epith=Radial keratoneuritis nd Psuedodendrites
  5. Limbal=limbitis
  6. Stromal=RING infiltrate nd Ring abscess
19
Q

Fungal hyphae nd Acanthamoeba cysts can be seen with?

A

Confocal microscopy

20
Q

Treatment of Acanthamoeba keratitis

A

DOC= PHMB(poly hexamethyl Biguanide) topical

  1. PHMB+ propamidine/Hexamidine
  2. Chlorhexidine+ neo/paromycin

3-4 months for early epith nd 6-12 months for stromal lesions

Unresponsive cases=Penetrating keratoplasty

21
Q

Mcc of viral keratitis

A

HSV type 1

22
Q

Epithelial keratitis signs nd treatment

A
  1. Punctate epith k
  2. Dendritic ulcer…..decreased sensations
  3. Geographic ulcer/Amoeboid ulcer

Acyclovir 3% 5times/day for 14-21 days
Other-Ganciclovir,Vidarabine

Mech debridement for resistant cases

Oral acyclovir 400mg bid for 14-21 days in recurrent cases

23
Q

Treatment for stromal keratitis

A

Topical steroid drops
+
Acyclovir

24
Q

Disciform keratitis

A

Disc shaped stromal edema d/t Endothelitis(TYPE IV Hsn)

2”OAG occurs

25
Q

Herpes zoster ophthalmicus is caused by?

A

Reactivation of VZV in the gasserian ganglion

26
Q

Mc involved nerve in HZO?

MC nerve palsy nd least common nerve palsy?

A

FRONTAL nerve

3rd nerve nd 7th nerve

27
Q

Lesion @ nose tip is accompanied by corneal involvement in HZO by which rule?

A

Hutchinson’s rule

28
Q

Signs of HZO

A
  1. Pseudo dendritic ulcer
  2. Nummular keratitis- coin shaped subepith lesions
  3. Mucosal plaque keratitis
  4. Sclerokeratitis(least common)
  5. 3 rd nerve palsy
  6. Episcleritis
29
Q

Treatment of HZO

A

Acyclovir 800mg 5/day for 10days

30
Q

What is arcus senilis?

Space btw limbus nd AS?

Cause of arcus juvenilis?

A

Paralimbal Lipid deposition @ stroma in old age(physiological)

Lucid interval of VOGT

Hyperlipidemia

31
Q

What is band shaped keratopathy?

A

It is calcific deposition in the interpalpebral zone@ bowman membrane.

Chronic Iridocyclitis in adults nd STILLs disease in children

  1. Chelation with EDTA
  2. PTK with excimer laser
32
Q

What is HUTCHINSONs TRIAD?

A
Interstitial keratitis
                \+
Hutchinson’s teeth
                \+
Vestibular deafness
33
Q

Etiology nd clinical features of Syphilitic interstitial keratitis?

A

*90% cong cases=B/L involv
3 stages
1.Initial progressive=edema nd symptoms….diffuse corneal haze=Ground glass app

  1. Florid stage=deep vascularisation-SALMON PATCH app
  2. Stage of regression= leaves opacities nd vessels
34
Q

Hallmark of keratoconus

A
Central/paracentral stromal thinning  
                         \+
Inferior Apical protrusion of Anterior cornea
                         \+
Irregular astigmatism 

***B/L,progressive,non inflam

35
Q

Signs of keratoconus

A

1.Window reflex distorted
2.Placido disc - irregularity of circles
3.Slit lamp - Fleischer ring @ base
VOGTs striae(tears of Desc memb)
4.Retinoscopy - Scissoring or Yawning reflex
5.DDO - Oil droplet reflex
6.Munson’s sign

36
Q

What is Munson’s sign?

What is Rizzuti’s sign?

A

Bulging of Lower eyelid on down gaze

Light on temporal side prod ARROWHEAD pattern on nasal limbus

37
Q

Investigation nd app seen for keratoconus

A

Corneal topography

Symmetric BOWTIE app

38
Q

Management of keratoconus

A
  1. Glasses - cylinders
  2. Contact lens - RGP
  3. Keratoplasty if apical scarring +nt
  4. ICRS-Intracorneal ring segments(PMMA)=intrastromally in mid peripheral stroma
  5. C3R-Corneal Collagen Cross linking with Riboflavin
39
Q

Complication of keratoconus

A

ACUTE HYDROPS

40
Q

Corneal opacity causes

A

STUMPED

41
Q

Cornea verticellata

A

Whorl like opacity d/t long term treatment with

  1. Amiodarone
  2. Chloroquine
  3. Phenothiazines
  4. Indonethacin

Or in Fabry disease

42
Q

Superficial corneal vascularisation is seen in?

A
  1. Superficial corneal ulcers
  2. Contact lens users
  3. Trachoma
  4. phlyctenular keratoconjunctivitis
  5. Rosacea keratitis
43
Q

Deep corneal vascularisation is seen in?

A
  1. Deep corneal ulcer
  2. Chemical burns
  3. Corneal graft rejection
  4. Interstitial keratitis
  5. Disciform keratitis