OP4.2 | Congenital Corneal Anomalies and Corneal Inflammations — Summary & Reflection

KEY TAKEAWAYS

Congenital corneal anomalies include size variants (microcornea <10 mm, megalocornea >13 mm — the latter must be distinguished from buphthalmos by normal IOP and absent Haab's striae), curvature anomalies (keratoconus — non-inflammatory paracentral ectasia with Fleischer's ring, Vogt's striae, Munson's sign; treated with CXL → keratoplasty; and keratoglobus — peripheral global ectasia), and embryological structural defects (Peters' anomaly — absent posterior corneal layers with iridocorneal adhesions; sclerocornea — peripheral opacification with vascularisation).

Corneal inflammations: keratitis is classified by depth (superficial vs interstitial). Interstitial keratitis (IK) is stromal inflammation with an intact epithelium, caused by immune reactions to infections. Key causes: congenital syphilis (Hutchinson's triad = IK + Hutchinson's teeth + nerve deafness; salmon-patch vascularisation; ghost vessels after healing; diagnosis by FTA-ABS/TPHA; treat with penicillin + topical steroids), TB (focal IK + phlyctenule), herpetic IK (disciform stromal oedema; treat with aciclovir + topical steroids), and Cogan's syndrome (IK + audio-vestibular symptoms; autoimmune).

Investigation: slit-lamp + IOP measurement (always rule out glaucoma in any corneal anomaly) + systemic workup for IK cause. Management: address underlying disease, optical rehabilitation, amblyopia treatment in children.

REFLECT

Reflect on a child in your future clinic presenting with a large cornea. You now know the stakes of missing congenital glaucoma. What three clinical checks would you never skip before reassuring a parent that this is 'just megalocornea'? Consider also the psychosocial dimensions: a diagnosis of congenital syphilis in a child requires sensitive communication with parents about its implications. How would you approach that conversation?