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
term 'hypopyon corneal ulcer' for the characteristic ulcer caused by pneumococcus and the term 'corneal ulcer with hypopyon' for the ulcers associated with hypopyon due to other causes. The characteristic

hypopyon corneal ulcer caused by pneumococcus is called ulcus serpens.
Source of infection for pneumococcal infection is usually the chronic dacryocystitis.

Factors predisposing to development of hypopyon.
Two main factors which predispose to development of hypopyon in a paitent with corneal ulcer are, the virulence of the infecting organism and the resistance of the tissues. Hence, hypopyon ulcers are much more common in old debilitated or alcoholic subjects.

Mechanism of development of hypopyon. Corneal ulcer is often associated with some iritis owing to diffusion of bacterial toxins. When the iritis is severe
the outpouring of leucocytes from the vessels is so great that these cells gravitate to the bottom of the anterior chamber to form a hypopyon. Thus, it is important to note that the hypopyon is sterile since the outpouring of polymorphonuclear cells is due to the toxins and not due to actual invasion by bacteria. Once the ulcerative process is controlled, the hypopyon is absorbed.

Clinical features
Symptoms are the same as described above for bacterial corneal ulcer. However, it is important to note that during initial stage of ulcus serpens there is remarkably little pain. As a result the treatment is often undully delayed.
Signs. In general the signs are same as described above for the bacterial ulcer.

Typical features of ulcus serpens are :

• Ulcus serpens is a greyish white or yellowish disc shaped ulcer occuring near the centre of cornea (Fig. 1).

Fig. 1. Hypopyon corneal ulcer : A, Diagrammatic
depiction; B, Clinical photograph.

• The ulcer has a tendency to creep over the cornea in a serpiginous fashion. One edge of the ulcer, along which the ulcer spreads, shows more infiltration. The other side of the ulcer may be undergoing simultaneous cicatrization and the edges may be covered with fresh epithelium.
• Violent iridocyclitis is commonly associated with a definite hypopyon.
• Hypopyon increases in size very rapidly and often results in secondary glaucoma.
• Ulcer spreads rapidly and has a great tendency for early perforation.

Management
Management of hypopyon corneal ulcer is same as for other bacterial corneal ulcer. Special points which need to be considered are :

• Secondary glaucoma should be anticipated and treated with 0.5% timolol maleate, B.I.D. eye drops and oral acetazolamide.
• Source of infection, i.e., chronic dacryocystitis if detected, should be treated by dacryocystectomy.