OcuLearning › Cornea
Peripheral Corneal Thinning/Ulceration
URGENT — Cornea
Symptoms
- acute pain, redness, and severe photophobia (puk and mooren ulcer)
- slow, painless vision blur (terrien marginal degeneration and pmd)
- decreased vision due to high irregular astigmatism
- history of systemic autoimmune disease (ra, gpa, sle)
- history of hepatitis c (linked to mooren-like ulcers)
Clinical Findings
Inflammatory (painful)
- puk: crescent-shaped peripheral stromal thinning with an epithelial defect
- scleritis: associated in 90% of puk cases (eye appears deep red/purple)
- mooren ulcer: painful thinning with a characteristic "undermined" overhanging leading edge; NO scleritis
Non-inflammatory (painless)
- terrien marginal degeneration: superior thinning; yellow lipid line; intact epithelium
- pellucid marginal degeneration (pmd): inferior (4 to 8 o’clock) thinning; "beer belly" ectasia above thinning
- dellen: localized bowl-shaped depression from focal dryness (e.g., next to a pinguecula)
Advanced signs
- corneal perforation or descemetocele (bulging basement membrane)
- vascularization or pannus crossing the area of thinning
Etiology
Systemic vasculitis (PUK)
- rheumatoid arthritis (most common), gpa (wegener), polyarteritis nodosa, and sle
Autoimmune/infectious
- mooren ulcer: idiopathic autoimmune keratitis; strongly linked to hepatitis c
- staphylococcal hypersensitivity: peripheral infiltrates with a "clear limbal zone"
Degenerative/ectatic
- terrien marginal degeneration: idiopathic thinning, typically in males
- pellucid marginal degeneration (pmd): non-inflammatory corneal ectasia
Neurotrophic
- non-inflammatory thinning due to cn v/vii palsy or exposure
Red Flags
- scleral involvement: suggests life-threatening systemic vasculitis (gpa/ra)
- rapid "melting" (keratolysis): risk of globe perforation within hours/days
- ra patient with corneal melt: indicates 40% 10-year systemic mortality if untreated
- hepatitis c positive: mooren-like ulcer requires antiviral treatment
Investigations
Clinical exam
- check corneal sensation: rule out hsv and neurotrophic causes
- slit-lamp: narrow beam to assess depth of thinning and epithelial status
- scleral exam: check for nodules, thinning (blue hue), or posterior scleritis
Mandatory serology (vasculitis screen)
- cbc, esr/crp, rf, anti-ccp, ana, anca (c-anca/p-anca), and spep
Infectious screen
- hepatitis c antibody, rpr/fta-abs (syphilis), and quantiferon-tb gold
Systemic evaluation
- urinalysis and chest ct if gpa is suspected (renal/lung involvement)
Treatment
Systemic therapy (PUK/mooren)
- high-dose oral steroids (prednisone 1mg/kg/day) with ppi coverage
- steroid-sparing agents: cyclophosphamide, methotrexate, or rituximab
Topical/adjunctive
- topical cyclosporine (0.05%–2%) and judicious topical steroids
- doxycycline 100mg bid and vitamin c 1g–2g daily (collagenase inhibition)
Surgical (impending perforation)
- cyanoacrylate tissue adhesive (glue) or amniotic membrane graft
- lamellar or penetrating keratoplasty for severe cases
Degenerative management
- pmd: specialty scleral lenses or collagen cross-linking (cxl)
Clinical Pearl
peripheral ulcerative keratitis with systemic features is rheumatoid arthritis in 50% and gpa (wegener) in the rest — get rheumatology and serologies before the globe perforates.
Differential Diagnosis
- • infectious keratitis (bacterial/fungal/acanthamoeba)
- • herpes simplex keratitis (decreased sensation)
- • marginal keratitis (staphylococcal)
- • senile furrow degeneration (non-progressive thinning in elderly)