Cornea

Question 1

Layers of cornea

Answer 1

1 epithelial - 5-6 layers
2 bowman’s layer-condensed collagen fibers
- can’t regenerate if destroyed so heals by scarring
3 stroma-contains type 1 & 5 collagen fibrils intervened by type 4 fibers
-fibers are embedded in hydrated proteoglycans
-Wandering macrophages,histocytes & few leukocyte are present
4 descement membrane-contains collagen and glycoproteins
-it can regenerate
- it is very resistant to trauma chemical & pathalohical process
5 endothelium-contain hexagonal cells single layer
-cells do not proliferate and it is compansated by polymegathism

Question 2

Congenital anomalies of cornea

Answer 2

Megalocornea
Micro cornea
Cornea plana
Cloudy cornea

Question 3

Morphological classification of corneal ulcers

Answer 3

Ulcerative keratitis

Non ulcerative keratitis

Question 4

Ulcerative keratitis

Answer 4

1.depending upon location 
2 depending upon purulence
3 depending upon hypopyon
4 depending upon depth
5 depending upon slough formation

Question 5

Non ulcerative keratitis

Answer 5

1 superficial 
-diffuse 
-punctate
2 deep keratitis 
-non suppurative 
-suppurative

Question 6

Etiological classification of keratitis

Answer 6

1 infective
2 allergic
3 trophic
4 associated with disease of skin and mucous
5 associated with systemic collagen disease
6 idiopathic keratitis
6 traumatic keratitis

Question 7

Organisms which invades intact corneal epithelium

Answer 7

1 neisseria gonorrhoeae
2 corynebacterium diphtheria
3 neisseria meningitidis

Question 8

Aetiology of bacterial corneal ulcers

Answer 8

2 thing are responsible
• damage of corneal endothelium
• infection of eroded area

Question 9

Corneal epithelial damage of bacterial corneal ulcers

Answer 9

• corneal abrasion
• epithelial drying
• necrosis
• epithelial damage
• desquamation of epithelial cells

Question 10

Source of infection of bacterial corneal ulcers

Answer 10

• exogeneous
• endogenous
• secondary

Question 11

Causative organisms of bacterial corneal ulcers

Answer 11

Staphylococcus 
Streptococcus 
N.gonorrhoeae
N.meningitidis
Corynebacterium diphtheria 
E.coli 
Proteus
Klebsiella

Question 12

Stages of bacterial corneal ulcers

Answer 12

1 stage of progressive infiltration
2 stage of active ulceration
3 stage of regression
4 stage of cicatrisation

Question 13

Based on virulence, host defence and treatment corneal ulcers may be

Answer 13

Localised
Perforating
Sloughing

Question 14

Symptoms of corneal ulcers

Answer 14

Pain 
Photophobia 
Lacrimation 
Redness 
Diminution of vision 
Blepharospasm

Question 15

Sign of corneal ulcers

Answer 15

Lid- oedema 
Conjuctiva-chemosis & congestion 
Ciliary-congestion 
Corneal ulcers-yellowish-white
-irregular shape
-margins swollen 
-floor contains necrotic debris
Anterior chamber-hypopyon may be or may not be
Iris - muddy colour 
Pupil-small or constricted 
IOL-may be raised

Question 16

Treatment of uncomplicated corneal ulcers

Answer 16

1 antibiotics 
• vancomycin and ciprofloxacin 
• cefazolin and amikacin 
2 supportive 
• cycloplegic
• anti inflammatory & analgesic 
• vitamins
3 general measures 
• Hot fomentation
• dark goggles 
• rest,good diet,fresh air

Question 17

Treatment of non healing corneal ulcers

Answer 17

1 treatment of underlying cause
2 debridement
3 cauterisation 
4 bandage soft contact lens
5 peritomy

Question 18

Treatment of impending perforating corneal ulcers

Answer 18

1 no strains 
2 pressure bandage
3 lowering of IOL
4 tissue adhesive glue
5 bandage soft contact lens
6 conjunctival flaps
7 amniotic membrane transplantation 
8 penetrating therapeutic keratoplasty

Question 19

Treatment of perforated corneal ulcers

Answer 19

Best option is therapeutic keratoplasty but, 
These can be done 
•tissue adhesive glue 
•conjunctival flaps
•use of bandage soft contact lens 
•keratoplasty

Question 20

Complications of corneal ulcers

Answer 20

1 toxic iridocyclitis
2 secondary glaucoma 
3 descematocele
4 perforation of ulcer
5 scarring

Question 21

Complications of perforated corneal ulcerS

Answer 21

1 prolapse of iris
2 subluxation of lens
3 anterior capsular cataract 
4 corneal fistula 
5 uveitis 
6 endopthalmitis 
7 panopthalmitis 
8 intraocular haemorrhage in for of vitreous or choroidal haemorrhage

Question 22

Hypopyon corneal ulcers

Answer 22

Characteristic ulcer caused by pneumococcus

Also called ulcus Serpens

Question 23

Aetiology of hypopyon corneal ulcers

Answer 23

Causative organisms- pneumococcus

Source of infection- chronic dacryocystitis

Question 24

Mechanism of hypopyon corneal ulcers

Answer 24

Diffusion of toxins causes iritis in corneal ulcer caused by pneumococcus
Because of iritis leukocyte gravitate at the bottom in anterior chamber in the form of pus

Question 25

Symptoms of hypopyon corneal ulcers

Answer 25

``` Pain Photophobia Redness Lacrimation Foreign body sensation Diminution of vision Blepharospasm ```

Question 26

Signs of hypopyon corneal ulcers

Answer 26

In general signs are same as bacterial corneal ulcers Specific characteristics- • yellowish white occurring near centre • ulcer has tendency to creep over cornea in serpiginous fashen • violent iridocyclitis is present

Question 27

Mycotic corneal ulcers

Answer 27

It refers to fungal corneal ulcer It is suppurative ulcer It's incidence increased in recent years because of injudicious use of steroids and antibiotics

Question 28

Aetiology of Mycotic corneal ulcers

Answer 28

Causative organisms- aspergillus,fusarium,cephalosporiums,penicilliums,candida & cryptococcus Mode of injury- •injury by vegetative material •injury by animal tail •secondary fungal ulcers Role of antibiotics

Question 29

Symptoms of Mycotic corneal ulcers

Answer 29

Same as bacterial ulcers but are less marked and slow

Question 30

Signs of Mycotic corneal ulcers

Answer 30

-ulcer is dry looking and greyish white Feathery finger like extension are present in stroma Sterile immune ring is present Small satellite lesions may be present around lesion Big hypopyon is present Perforation is rare

Question 31

Treatment of Mycotic corneal ulcers

Answer 31

Specific treatment • topical - natamycin, amphotericin b fluconazole & nystatin •Systemic- in severe case ex: fluconazole & ketoconazole Non specific treatment Therapeutic penetrating keratoplasty

Question 32

Cornea

Answer 32

Transparent Avascular Watch glasslike structure