cornea Flashcards
what is average horizontal diameter of cornea
11.7mm
what is average vertical diameter of cornea
10.6mm
what is refraction of cornea
40-44D
another name for stroma layer
substantia propria
what is the epithelium of cornea
non-keratinised stratified squamous epithelium
what is the source of new epithelial cells in the cornea
limbal stem cells
shape of the cells in endothelial layer
hexagonal
minimum density of endothelium
600 cells/mm2
what are the layers of the tear film
lipid
aqueous
mucin
what makes the lipid layer
meibomian glands
what makes aqueous layer
lacrimal gland
what makes mucin layer
goblet cells
what is the role of lipid layer
prevents evaporation of tears
what is role of mucin layer
lubricates
what are accessary aqueous glands
wolfing
krause
what is an abnormal schirmer test
<10mm
<5mm
can you give steroids for bacterial keratitis
NO
what culture medium for neisseria gonorrhoea
chocolate agar
is corneal sensation diminish in herpes simplex
yes
in what form of HSV keratitis is dendritic ulcer seen
epithelial
do you give corticosteroid for epithelial keratitis
no
treatment of epithelial keratitis
topical acyclovir
what is a feature of endothelial keratitis
wessely ring
what is a common nerve palsy seen in ophthalmic herpes zoster
CN IV palsy
culture medium for fungal keratitis
sabourauds agar
what is a salmon patch a late sign of
syphilitis interstitial keratitis
what is Hutchinson triad
deafness
interstitial keratitis
notched teeth
what epithelial defect is seen in peripheral ulcerative keratitis
crescent shaped epithelial defect
what is exposure keratopathy due to
lagophthalmos
is there an increased or reduced endothelial density in Fuchs endothelial dystrophy
decreased
what is seen on descemets membrane in Fuchs dystrophy
guttata
what changes in vision are seen in Fuchs
vision gets better as day goes on
what is a fleischer ring found in
keratoconus
what causes a bad keratopathy
calcium
what causes Hudson stahli line
iron deposition
Is keratoconus bilateral or unilateral
Bilateral
Risk factors for keratoconus
Ocular rubbing
FH
Down syndrome
Sleep apnoea
What can be seen on ophthalmoscopy of keratonocouus
Oil droplet reflex
Retinoscopy of keratoconus
Scissoring reflex
Most common pathogens of bacterial keratitis
Pseudomonas aureginosa
What bacteria can penetrate an intact corneal epithelium
CNHL
- cornyebacterium
- haemophillus
- neisseria
- listeria
What has the features: pain, conjunctival injection, photophobia, blurry vision, discharge, hypopyon
Bacterial keratitis
Management of bacterial keratitis
Fluoroquinolone
What keratitis is associated with trauma
Fungal keratitis
What has stromal infiltrates with fluffy margins
Fungal keratitis
What has feathery branch lesion s
Fungal keratitis
Treatment of Candida fungal keratitis
Amphotericin B
First line for filamentous fungal keratitis
Natamycin
What is seen in epithelial keratitis
Tree like ucler
What does the ulcer in epithelial keratitis stain well with
Rose bengal
What is seen in disciform endothelial keratitis
Wesley’s rings
Central circular stromal oedema
Keratic precipitate =s
Diagnosis of endothelial keratitis
Giemsa stain
Can you give steroids to someone with epithelial keratitis
No
Can you give steroids to someone with endothelial keratitis
Yes
Management of acanthomoboea keratitis
Polyhexamethylene biguanide
What shape of infiltrate is seen on acanthomoboea keratitis
Ring shape
What culture medium for acanthomoboea
Non-nutrient agar with ecoli
What culture medium for mycobacterium
Lowenstein jensen
What culture medium for bacterial keratitis
Chocolate/blood agar
What is marginal keratitis
Inflammation of peripheral cornea, represents a type III hypersensitivity reaction to staph aureus
What is marginal keratitis associated with
Blepharitis and acne rosacea
