Cornea Flashcards
What is keratometry?
What are keratometric mires?
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
What is pachymetry?
What is esthesiometry?
Measurement of corneal thickness…..500-600u
Eliciting corneal sensation…..by Cochet Bonnet esthesiometer
Specular microscopy?
Confocal microscopy?
To visualise count endothelial cells
To visualise any layer of cornea
Also corneal nerves,Fungal hyphae,Acanthamoeba cysts*****
Corneal topography nd instruments?
Uses of Gonioscopy?
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
Dyes used in staining corneal ulcers?
- Fluorescein dye- base or floor
- Rose Bengal dye- margins
- Alicante blue dye-Mucin nd filaments
- Lissamine green-not healthy surface
Other uses of fluorescein dye?
- Goldman’s AT in glaucoma
- Dx of Dry eye
- Jones dye test- for lacrimation assessment
- Seidel’s test- detect leakage thr perforation
Staining nd culture for diff organisms?
- Bacterial- Grams stain- Blood/chocolate agar
- Fungi- 10%KOH- SDA
- Acanthamoeba= Gomori’s methamine silver stain- Non nutrient agar with E-coli overlay
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
Staphylococcus aureus
Streptococcus pneumoniae
Pseudomonas aeruginosa(green discharge)
Atypical mycobacterium
Bacteria that penetrate intact epithelium
- N.g, N.m
- C.d
- H.aegypticus
- Listeria
- Shigella
Symptoms in bacterial CU
- Defective vision
- Photophobia
- Lacrimation
- Redness
- Pain nd FBS
Hypopyon CU
By streptococcus pneumoniae
Etio = Chronic dacrocystitis
Serpenginous ulcer nd violent iridocyclitis nd 2” glaucoma
Sterile,mobile
Complications of bacterial CU
- Toxic iridocyclitis
- 2” glaucoma
- Descematocele
- Perforation = iris prolapse,Ant capsular cataract,end/panophth,phthisis
- Scarring
Treatment of uncomplicated bacterial CU
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
Wreath pattern or Pin head ulcer is caused by?
Nocardia
Signs are out of proportion in which ulcer?
Symptoms are out of proportion in which ulcer?
Fungal keratitis(vegetable,animal trauma)
Acanthamoeba keratitis(unhygienic contact lens users)
Signs of fungal corneal ulcer
- Dry looking
- Feathery margins
- Satellite lesions
- Sterile immune ring of WESLEY
- Hypopyon= not sterile,immobile
- Endothelial plaque
DOC in fungal keratitis
For Aspergillus fumigatus= 5% NATAMYCIN
For Candida albicans= 0.15% Amphotericin B