Peripheral ulcerative keratitis (PUK) and Mooren ulcer

Diagnosis and work-up

1. Urgent slit-lamp examination: ulcer extent, epithelial defect, stromal thinning, infiltrate, anterior chamber reaction, Seidel test, and adjacent scleral inflammation.
2. Exclude infection first, especially bacterial, fungal, viral, and acanthamoeba keratitis. Culture/scrape when clinically indicated before immunosuppression.
3. In apparent PUK, investigate for systemic inflammatory disease, commonly with rheumatology input: history and examination for arthritis, ENT/chest/renal symptoms, rash, neuropathy, oral ulcers; targeted tests may include RF, anti-CCP, ANCA, ANA, inflammatory markers, urinalysis, and renal function.
4. Consider precipitating trauma, previous corneal surgery, ocular surface disease, and in suspected Mooren ulcer, relevant infectious associations such as hepatitis C where appropriate.

Management principles

• This is an ophthalmic emergency because rapid corneal melting and perforation can occur.
• Use intensive lubrication, protective measures, and therapy to limit collagen breakdown such as oral doxycycline or topical N-acetylcysteine when appropriate.
• Once infection is excluded, use topical corticosteroid and/or topical cyclosporine under ophthalmology supervision.
• Systemic PUK, especially with scleritis or vasculitis, often requires systemic corticosteroids plus steroid-sparing immunosuppression directed with rheumatology.
• In Mooren ulcer, topical therapy may suffice for milder unilateral disease, but aggressive/bilateral disease may require systemic immunosuppression.
• Progressive thinning or perforation may need tissue adhesive with bandage contact lens, amniotic membrane, conjunctival resection, lamellar patch graft, or keratoplasty.

Painful peripheral corneal ulcer + scleritis/systemic autoimmune disease = systemic disease-associated PUK.
Painful peripheral ulcer with undermined edge but no scleritis or systemic disease = Mooren ulcer.

Xerophthalmia

Pathogenesis

• Rhodopsin formation in retinal rods, so deficiency causes defective dark adaptation and night blindness.
• Maintenance of normal conjunctival and corneal epithelium. Deficiency causes loss of goblet cells, reduced mucin, keratinization, dryness, ulceration, and corneal melt.

WHO clinical stages

Keratomalacia

Risk factors

• Malnutrition and inadequate dietary vitamin A
• Measles and recurrent diarrhea
• Malabsorption: celiac disease, inflammatory bowel disease, pancreatic insufficiency, cholestatic liver disease
• Restricted diets and eating disorders
• Bariatric surgery
• Poverty and poor access to vitamin A-rich foods

Treatment

• Children under 12 months: 100,000 IU orally on day 1 and day 2, then repeat after 2 weeks.
• Children over 12 months and adults: 200,000 IU orally on day 1 and day 2, then repeat after 2 weeks.

• Treat dehydration, diarrhea, measles, malnutrition, and malabsorption.
• Preservative-free lubricants.
• Topical antibiotic if epithelial defect/secondary infection is present.
• Protect the cornea and manage ulceration or perforation urgently.

Prevention

• Exclusive breastfeeding in infancy where feasible
• Dietary diversification: liver, egg yolk, dairy, fish, and orange/green leafy vegetables
• Food fortification and public-health supplementation programs in high-risk communities
• Measles immunization and prompt treatment of diarrhea

Night blindness is the earliest functional sign.
Conjunctival xerosis is the earliest clinical ocular sign.
Bitot spots are foamy conjunctival plaques.
Keratomalacia is the most dangerous form and can cause rapid blindness.

Keratomalacia: step-by-step management

1. Admit or urgently refer

• Arrange same-day ophthalmology assessment.
• Admit a child or medically unwell patient, especially with bilateral disease, corneal ulceration, inability to take oral treatment, dehydration, diarrhea, measles, or severe malnutrition.
• Examine both eyes for ulcer size, thinning, infiltrate, anterior chamber reaction, perforation, and a Seidel test for aqueous leakage.

2. Give vitamin A immediately

• If oral administration or absorption is unreliable, use a clinician-directed parenteral formulation.
• In pregnancy or women who may be pregnant, specialist advice is required because high-dose preformed vitamin A can be teratogenic. However, corneal involvement is vision-threatening, so treatment must not be delayed without urgent obstetric and ophthalmic input.

3. Protect and lubricate the ocular surface

• Use preservative-free artificial tears frequently, often every 15 to 60 minutes initially.
• Apply preservative-free lubricating ointment at night.
• Avoid eye patching when infection or perforation is a concern.
• Minimize manipulation of a severely softened cornea.

4. Exclude and treat superadded infection

• Obtain corneal scraping/culture if there is infiltrate, purulent discharge, significant epithelial defect, or diagnostic doubt.
• Start a topical broad-spectrum antibiotic when there is corneal epithelial loss or suspected secondary infection, as directed by ophthalmology.
• Do not start topical corticosteroids in an actively melting or potentially infected cornea unless an ophthalmologist specifically directs it.

5. Assess the severity of thinning and manage impending perforation

• Small epithelial defect or mild thinning: intensive medical treatment and close review, often daily.
• Descemetocele, severe thinning, or actual perforation: urgent corneal protection may require tissue adhesive with a bandage contact lens, amniotic membrane, conjunctival flap, lamellar patch graft, or therapeutic keratoplasty.
• Shield the eye rather than applying pressure if perforation is suspected.

6. Treat the systemic cause

• Protein-energy malnutrition and poor dietary intake
• Recent measles or persistent diarrhea
• Fat malabsorption, such as celiac disease, inflammatory bowel disease, pancreatic insufficiency, cystic fibrosis, cholestatic liver disease, or prior bariatric/GI surgery
• Restrictive eating or chronic alcohol use

7. Monitor closely

• Recheck corneal integrity, ulcer size, and visual behavior/acuity frequently.
• Continue nutritional support and investigate malabsorption if the deficiency is not clearly dietary.
• After healing, assess residual corneal scar and visual rehabilitation needs. A visually significant scar may later need corneal surgery in selected eyes.

Practical emergency sequence

Recognize corneal melt -> give vitamin A immediately -> lubricate/protect -> culture and give antibiotic when ulcer/infection risk is present -> assess for perforation -> correct malnutrition and underlying illness -> close ophthalmic follow-up.