NON-ULCERATIVE SUPERFICIAL KERATITIS

NON-ULCERATIVE SUPERFICIAL KERATITIS group includes a number of conditions of varied

etiology. Here the inflammatory reaction is confined to epithelium, Bowman's membrane and superficial stromal lamellae. Non-ulcerative superficial keratitis may present in two
  forms:
Diffuse superficial keratitis and
Superficial punctate keratitis

 
DIFFUSE SUPERFICIAL KERATITIS
Diffuse inflammation of superficial layers of cornea occurs in two forms, acute and chronic.

1. Acute diffuse superficial keratitis

Etiology. Mostly of infective origin, may be associated with staphylococcal or gonococcal infections.

Clinical features. It is characterised by faint diffuse epithelial oedema associated with grey farinaceous appearance being interspersed with relatively clear area. Epithelial erosions may be formed at places. If uncontrolled, it usually converts into ulcerative keratitis.

Treatment. It consists of frequent instillation of antibiotic eyedrops such as tobramycin or gentamycin 2-4 hourly.

2. Chronic diffuse superficial keratitis
It may be seen in rosacea, phlyctenulosis and is typically associated with pannus formation. 

SUPERFICIAL PUNCTATE KERATITIS (SPK)
Superficial punctate keratitis is characterised by occurrence of multiple, spotty lesions in the superficial layers of cornea. It may result from a number of conditions, identification of which (causative condition) might not be possible most of the times.
Causes
Some important causes of superficial punctate keratitis are listed here.
1. Viral infections are the chief cause. Of these more common are: herpes zoster, adenovirus infections, epidemic keratoconjunctivitis, pharyngo-conjunctival fever and herpes simplex.

2. Chlamydial infections include trachoma and inclusion conjunctivitis.

3. Toxic lesions e.g., due to staphylococcal toxin in association with blepharoconjunctivitis.

4. Trophic lesions e.g., exposure keratitis and neuroparalytic keratitis.

5. Allergic lesions e.g., vernal keratoconjunctivitis.

6. Irritative lesions e.g., effect of some drugs such as idoxuridine.

7. Disorders of skin and mucous membrane, such as acne rosacea and pemphigoid.

8. Dry eye syndrome, i.e., keratoconjunctivitis sicca.

9. Specific type of idiopathic SPK e.g., Thygeson's superficial punctate keratitis and Theodore's superior limbic keratoconjunctivitis.

10. Photo-ophthalmitis.

Morphological types (Fig.1)

Fig 1 Morphological types of superficial punctate
keratitis.

1. Punctate epithelial erosions (multiple superficial erosions).
2. Punctate epithelial keratitis.
3. Punctate subepithelial keratitis.
4. Punctate combined epithelial and subepithelial keratitis.
5. Filamentary keratitis.

Clinical features
Superficial punctate keratitis may present as different morphological types as enumerated above. Punctate epithelial lesions usually stain with fluorescein, rose bengal and other vital dyes. The condition mostly presents acutely with pain, photophobia and lacrimation; and is usually associated with conjunctivitis.

Treatment
Treatment of most of these conditions is symptomatic.
1. Topical steroids have a marked suppressive effect.
2. Artificial tears have soothing effect.
3. Specific treatment of cause should be instituted whenever possible e.g., antiviral drugs in cases of herpes simplex.


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