VASCULARIZATION OF CORNEA

Normal cornea is avascular except for small capillary loops which are present in the periphery for about 1 mm. In pathological states, it can be invaded by
vessels as a defence mechanism against the disease or injury. However, vascularization interferes with corneal

CORNEAL OEDEMA

 Corneal oedema

The water content of normal cornea is 78 percent. It is kept constant by a balance of factors which draw water in the cornea (e.g., intraocular pressure and swelling pressure of the stromal matrix = 60 mm of Hg) and the factors which draw water out of

POSTERIOR CORNEAL DYSTROPHIES

Cornea Guttata of vogt
This condition is characterised by drop-like excrescences involving the entire posterior surface of Descemet's membrane. These are similar to Hassal- Henle bodies which represent the age change and are mainly found in the

STROMAL CORNEAL DYSTROPHIES

Granular dystrophy
Also known as 'Groenouw type I, is an autosomal
dominant dystrophy characterised by milky-granular
hyaline deposits in anterior stroma. Intervening
stroma is

Anterior corneal dystrophies

ANTERIOR DYSTROPHIES

Epithelial basement membrane dystrophy
Also known as Cogan's microcystic dystrophy and
map-dot finger print dystrophy, is the most common
of all corneal dystrophies seen in working age adults.
The typical lesions, involving corneal

corneal AGE-RELATED DEGENERATIONS

Arcus senilis
Arcus senilis refers to an annular lipid infiltration of corneal periphery. This is an age-related change occurring bilaterally in 60 percent of patients between
40 and 60 years of age and in nearly all patients over the age of 80. Sometimes, similar changes occur in young persons (arcus juvenilis) which may or may
not be associated with hyperlipidemia. The arcus starts in the superior

Syphilitic (luetic) interstitial keratitis

INTERSTITIAL KERATITIS
Interstitial keratitis denotes an inflammation of the corneal stroma without primary involvement of the epithelium or endothelium.

Causes. Its common causes are:
Congenital syphilis
Tuberculosis
Cogan's syndrome
Acquired syphilis
Trypanosomiasis
Malaria
Leprosy
Sarcoidosis

Syphilitic (luetic) interstitial keratitis
Syphilitic interstitial keratitis is associated more frequently (90 percent) with congenital

ROSACEA KERATITIS

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ROSACEA KERATITIS is defined as : Corneal ulceration is seen in about 10 percent cases of acne rosacea, which is primarily a disease of the sebaceous glands of the skin.

Clinical features
1. The condition typically occurs in elderly women in the form of facial eruptions presenting as butterfly configuration, predominantly involving
the malar and nasal

Treatment of corneal ulcer

 corneal ulcer treatment

[A] Clinical evaluation
Each case with corneal ulcer should be subjected to:
1. Thorough history taking to elicit mode of onset, duration of disease and severity of symptoms.

2. General physical examination, especially for built, nourishment, anaemia and any immunocompromising disease.

3. Ocular examination should include:
i. Diffuse light examination for gross lesions of the lids, conjunctiva and cornea including testing for sensations.
ii. Regurgitation test and syringing to rule out lacrimal sac infection.
iii. Biomicroscopic examination after staining of corneal ulcer with

corneal ulcer Complications

 Complications of corneal ulcer

1. Toxic iridocyclitis. It is usually associated with cases of purulent corneal ulcer due to absorption of toxins in the anterior chamber.

2. Secondary glaucoma. It occurs due to fibrinous exudates blocking the angle of anterior chamber (inflammatory glaucoma).

3. Descemetocele. Some ulcers caused by virulent organisms extend rapidly up to Descemet's membrane, which gives a

Hypopyon corneal ulcer "cornea"

Etiopathogenesis of Hypopyon corneal ulcer " cornea"

Causative organisms. Many pyogenic organisms (staphylococci, streptococci, gonococci, Moraxella) may produce hypopyon, but by far the most dangerous are pseudomonas pyocyanea and pneumococcus. Thus, any corneal ulcer may be associated with hypopyon, however, it is customary to reserve the

corneal ulcer Pathogenesis and pathology

Pathology of corneal ulcer Once the damaged corneal epithelium is invaded by the offending agents the sequence of pathological changes which occur during development of corneal ulcer can be described under four stages, viz., infiltration, active ulceration, regression and cicatrization. The terminal course of corneal ulcer depends upon the virulence of infecting

Pathology of sloughing corneal ulcer and formation of anterior staphyloma

When the infecting agent is highly virulent and/or body resistance is very low, the whole cornea sloughs with the exception of a narrow rim at the margin and
total prolapse of iris occurs. The iris becomes inflamed and exudates block the pupil and cover the iris surface; thus a false cornea is formed. Ultimately these exudates organize and form a thin fibrous layer over which the conjunctival or corneal epithelium rapidly grows and thus a pseudocornea is

ULCERATIVE KERATITIS

Inflammation of the cornea (keratitis) is characterised by corneal oedema, cellular infiltration and ciliary congestion.

ULCERATIVE KERATITIS
Corneal ulcer may be defined as discontinuation in normal epithelial surface of cornea associated with necrosis of the surrounding corneal tissue.
Pathologically it is characterised by oedema and cellular infiltration. Common types of corneal ulcers are described below.INFECTIVE KERATITIS
BACTERIAL CORNEAL ULCER
Being the most anterior part of eyeball, the cornea is exposed to atmosphere and hence prone to get infected easily. At the same time cornea is protected
from the day-to-day minor infections by the

cornea anatomy

APPLIED CORNEA ANATOMY
The cornea is a transparent, avascular, watch-glass like structure. It forms anterior one-sixth of the outer fibrous coat of the eyeball.

Dimensions

• The anterior surface of cornea is elliptical with an average horizontal diameter of 11.7 mm and vertical diameter of 11 mm.
• The posterior surface of cornea is circular with an average diameter of 11.5 mm.
• Thickness of cornea in the centre is about 0.52 mm while at the periphery it is 0.7 mm.
• Radius of curvature. The central 5 mm area of the cornea forms the powerful