ποΈ Interstitial Keratitis (IK) is corneal inflammation affecting the stroma (middle corneal layer), sparing the epithelium and endothelium.
It can lead to stromal haze, vascularisation, opacification and, if untreated, significant visual impairment.
π¦ Causes
- Infectious:
- 𧬠Syphilis β most common (esp. congenital syphilis).
- π¦ Herpes simplex virus (HSV) β recurrent stromal keratitis.
- π€² Leprosy β chronic corneal inflammation.
- π·οΈ Lyme disease β ocular involvement possible.
- π§ͺ Others: TB, EBV, mumps, measles, herpes zoster.
- Non-infectious:
- π Autoimmune: Sarcoidosis, RA, GPA, PAN.
- β Idiopathic (no identifiable cause).
π Clinical Features
- ποΈ Red, painful eye.
- π Photophobia.
- π Blurred vision due to stromal haze/opacity.
- π§ Tearing, ocular discomfort.
- π§ͺ Corneal oedema, stromal infiltrates on slit-lamp.
π§ͺ Investigations
- 𧬠Serology: Syphilis (VDRL/TPHA), Lyme, TB, others.
- ποΈ Corneal sensitivity: reduced in HSV keratitis.
- π· Imaging: Anterior segment OCT to assess stromal involvement.
- π¦ Slit-lamp: Stromal haze, infiltrates, vascularisation.
βοΈ Differential Diagnoses
- Infectious: Syphilis, TB, Lyme, HSV, VZV, EBV, leprosy, chlamydia.
- Inflammatory/autoimmune: GPA, PAN, RA, relapsing polychondritis, sarcoidosis, Coganβs syndrome.
- Neoplastic/infiltrative: Ocular lymphoma.
π Management
- 𧬠Target infection:
- Syphilis β IV penicillin or doxycycline.
- HSV β Oral aciclovir / valaciclovir.
- Other bacterial causes β appropriate systemic antibiotics.
- π₯ Reduce inflammation: Topical corticosteroids (careful use, always alongside antimicrobials if infection suspected).
- βοΈ Treat underlying disease: e.g. immunosuppression for autoimmune disease.
- π Monitor complications: Secondary glaucoma, corneal scarring.
π Prognosis
- β
Early treatment β good visual outcome.
- β οΈ Untreated/severe cases β corneal scarring, vascularisation, chronic visual loss.
- π Regular follow-up needed to monitor for recurrence.