ophtha - cornea, sclera Flashcards
5 layers of cornea
- Epith - 5 cells thick
- Bowman’ mem
- Stroma / substantia propria - 90% collagen; 5% cells and mucopolysaccharide
- Descemet’s mem
- Endothelium - for corneal hydration
Clear transparent ocular medium of the eye which is anterior portion of external coat of eye
Cornea
Cornea is rich in _____ this pain is the most common symptom
Sensory nerve supply
Cornea is a vascular thus dependent on ___ for nutrition
Air, tears and aqueous humor
Embryological origin of corneal epithelium
Surface ectoderm
Embryological origin of stroma and endothelium
Para-axial mesoderm
Derived from corneal subs appearing at end of 5th month
Bowman’s capsule
Derived from endothelium
Descement’s capsule
Sign of active corneal inflammation
Cellular infiltration of stroma
Edema
Neovascularization
Necrosis
Organisms that cause focal central inflammation of cornea
Herpes simplex
Hypes zoster
Bacteria
Fungi
Org that cause diffused inflammation of cornea
Adenovirus
Vaccinia
Chlamydia
Most common agent in bacterial corneal ulcer abroad
Pneumococcus (most common)
Poor axels
P. Aeruginosa
Most common agent in bacterial corneal ulcer in Philippines
P. Aeruginosa (most common)
Staph aureus
D. Pneumonia
Corneal ulcer may end up
Heal without scarring
Penetrate into stroma
Penetrate deeply to expose descemet’s mem
Perforate - Panophthalmitis
Viral keratitis is most common due to what virus
Herpes simplex
Gives rise to superficial ulcer forming branch-like extension (dendritic ulcer) when stained with Fluoroscein
Viral keratitis
With history of trauma with vegeteble matter
Fungal keratitis
Org that cause fungal keratitis
Fusarium
Aspergillus
Mycelia sterila
Appears as white or gray-white elevated hard ulcer with dot like satellite opacities
Fungal keratitis
Coin like corneal opacities common in farmers and agricultural workers
Padi keratitis
Padi keratitis is caused by
Virus
Superficial punctuate keratitis (SPK) is caused by what virus
Adenovirus Inclusion Cytomegalic virus Measles Mumps Trachoma
Multiple minute epith erosion which stains with Fluoroscein
SPK
Characterized with presence of vesicles or bless accompanied by foreign body sensation and pain
Bullous keratopathy
The scarring process on corneal opacities is due to
Collagen formation (which contracts as it matures)
Classif, of corneal scared as to density:
Faint cloud like seen with oblique illum
Nebula
Classif, of corneal scared as to density:
Large enough to be seen as gray spot
Macula
Classif, of corneal scared as to density:
Dense and white scar
Leukoma
When iris become
S attached to scar tissue resulting to visual disturbance becoz of diffusion if light and irreg refraction esp located within optical centre of cornea
Adherent leukoma
Charac by bulging cicatricix of cornea as a result of perforation and iris becomes adherent to back surface if cornea
Corneal staphyloma
Corneal staphyloma has no recoverable vision and is painful
True
Final outcome of severe inflammation in corneal opacity asso with measles
Blindness
Central corneal opacity which gradually tapers towards periphery. Opacity starts Posteriorly and drags ally involve more anterior layers. Asso with consumption of black rice.
Mindoro corneal opacity
Microcornea
<10mm
Megalocornea
> 13.5
Opaque ring within cornea scleral junction charac by lipid deposits demonstrating fat stain
Arcus senilis
Calcific degeneration of bowman’s mem. A sequela. Of uveitis, keratitis and long standing glaucoma
Band keratopathy
Treatment for band keratopathy
O.4-1.8% Ethylene diamine tetra acetic acid (EDTA) as cheating agent ff by scrapping of Ca deposits
Small excrescences in periphery of descemet’s mem.
Hassan Henle bodies
If Hassan Henle bodies changes centrally
So renal gluttata
Progressive disease of cornea starting at periphery and progresses centrally
Mooren’s ulcer
Marginal opacification of some superficial peripheral vascularization ff by loss of corneal subs
Senile marginal degeneration (terrien ulcer, gutter degeneration)
Bilateral, begins as endothelial degeneration ff by stromal and epithelial edema and appearance of bulbar.
Endothelial (fuch’s) dystrophy
Hereditary bilateral corneal lesion showing hyaline like deposits in stroma
Familia dystrophy
Non inflammatory protrusion if center of cornea due to gradual thinning of apex
Keratoclonus
Lower lid bulges when pt looks down
Munson’s sign
Thinning of apex
Corneal hydrops
Softening of cornea
Keratomalacia
Most common malnutrition blindness in India
Kereatomalacia
Replacement of partial or full thickness of diseased cornea with donor tissue
Keratoplasty
Indications for keratoplasty
Improvement if visual func of opaque or diseased cornea
Correction of severe altered struc
Replacement of active diseased cornea
Improvement if cosmetic appearance of cornea
Unfavorable factor in keratoplasty
Presence of vascularization
Tunic coat mainly for protection, covered by tenons capsule and conjunctiva
Sclera
Superficial inflammation of sclera
Lesion appears as flat or raised hard immovable nodule surrounded by far red or purple congestion
Usually at temporal side
Young adults
Episcleritis
Inflammation of deeper portion of sclera Bluish red in color Most common symptom: severe pain Recurrence ipsi common Young adults
Scleritis
Most freq predisposing cause
TB
