Clinical Resource

Corneal Ulcer Decision Guide — Simple, Infected, or Indolent?

Small-animal quick reference • Dr. Rachel Allbaugh, DVM, MS, DACVO • Vet On It CE • Page 1 of 2

First exam — answer two questions.

Q1 How deep? View the cornea from the side with the direct ophthalmoscope's small circle beam: normal curvature = epithelial-only; any flattening = stromal loss; indentation = mid/deep stromal. Fluorescein uptake only at the walls with a dark center = descemetocele — microns from perforation, surgical emergency. Fluorescein answers this 99.9% of the time.

Q2 Simple or infected? Infected until proven otherwise: gelatinous "petri-dish colony" margin (even in a quiet eye), white-cell infiltrate, diffuse severe edema, hypopyon, deep vessels, melting cornea. Granular "cake-frosting" mat = suspect fungal (French Bulldogs the poster child) — confirm on cytology; topical voriconazole is treatment of choice.

Date it by vessels: vessels pause 3–5 days before entering the cornea, then advance ~1 mm/day — vessels reaching the lesion = ulcer ≥2 weeks old.

Fragile eye? Fresh blood mid-ulcer, fibrin plug/uveal prolapse, shallow AC, low IOP → Seidel test (concentrated fluorescein, don't rinse; dark river = active leak). Restrain gently — neck pressure raises IOP.

1Simple (Superficial, Non-Infected) Ulcer

Neopolybac (bacitracin–polymyxin) ointment 3–4×/day — tell owners 4×/day to absorb missed doses; the ointment base doubles as lubrication. Switch to drop formulations for deeper stromal or rupture-risk eyes
Single in-hospital atropine dose for the reflex uveitis — no take-home atropine needed
Serum/plasma drops optional at 4×/day (mirror the antibiotic frequency)
Systemic NSAID (e.g., carprofen) ± gabapentin for comfort — doses per clinician judgment; e-collar a must in dogs, judgment call in cats

Recheck day 3–5 — the vast majority are healed: stop antibiotics, stop pain meds, remove the e-collar. No cytology unless infected features appear

2Infected Ulcer

Cytology ± culture FIRST: cytobrush or the blunt end of a scalpel blade — never a cotton swab (it wicks material up and won't give it back)

Topical antibiotics minimum 6×/day, escalating to 8–10×/day for nasty eyes; atropine once or twice daily at home for reflex uveitis
Infection broke through neo/poly? Change drug classes completely — do not just move to neopolygram. Go fluoroquinolone (ciprofloxacin) + gram-positive cover (chloramphenicol or cefazolin); tobramycin + cipro is acceptable but weaker gram-positive cover
Serum/plasma drops 6–10×/day mirroring the antibiotics. Homemade: 6–12 mL donor blood, centrifuge, sterile dropper bottle, refrigerate — good 10–14 days (no preservative)
Oral antibiotics only when rupture threatens the globe: doxycycline preferred (antiprotease properties); systemic steroid at an anti-inflammatory dose replaces the NSAID if severe reflex uveitis with hypopyon
Gentle betadine debridement on a cotton-tip applicator in clinic; BID betadine solution can go home as part of therapy
Owner can't dose around the clock? q30min ×2 h before work + q30min ×4 h in the evening = 8–10 doses/day — even spacing doesn't matter; every drug contact counts

Recheck 36–48 h — expect improved comfort and a cornea "cleaning up," not healed. Wider, deeper, or still very painful → more diagnostics or refer for surgery

In-clinic cefazolin 5.5% drops (gram-positive cover when chloramphenicol is unavailable)

1 g cefazolin vial + 3 mL sterile water; shake
Withdraw the 3 mL and add to a 15 mL bottle of standard artificial tears → 18 mL of 5.5% cefazolin
Refrigerate; use within 14 days (publications support stability up to 28)
Indicated when cytology shows cocci or C&S calls for gram-positive coverage

Vet On It CE Disclaimer: Vet On It CE provides these materials as a courtesy summary derived from lecture content. These materials are for educational reference only and do not constitute veterinary medical advice, diagnosis, or treatment recommendations. They do not replace clinician judgment, patient-specific assessment, or applicable local regulations/formulary guidance.

Corneal Ulcer Decision Guide — continued

Dr. Rachel Allbaugh • Vet On It CE • Page 2 of 2

3Failure Branch — "It Isn't Healing"

Benchmark: a fully denuded healthy cornea re-epithelializes in 7–10 days. Anything open past the second recheck is abnormal by definition

Recheck 1 (day 3–5): not healed → repeat the full exam, hunt for the anatomic cause you missed; recheck again in 3–5 days

Recheck 2 (day 7–10), still open — change your DIAGNOSIS, not your antibiotic. Serial antibiotic swaps just invite multidrug resistance. Three possibilities:

Missed underlying cause — recurring superficial 12-o'clock ulcer in a young dog: magnify and hunt for ectopic cilia; check tears (KCS), hairs, lids

Infected — if cytology/culture weren't done at visit one, do them now

Indolent (SCCED) — only if the signalment and lesion fit ↓

4Indolent (SCCED) — Strict Entry Criteria

Middle-aged to older dog + superficial only + loose epithelial edges + fluorescein percolating under at least one edge
NOT synonymous with "non-healing" — a young dog with ectopic cilia or a KCS dog with a dry cornea is non-healing but not indolent

Hard rule: any flattening or indentation = stromal involvement = probably infected — indolent treatment is contraindicated.

Treatment ladder (keep the simple-ulcer meds throughout):

cotton-tip debridement

heals 1/3–1/2 (judge at a full 7–10 days)

→

grid keratotomy or diamond burr (debride first, same sitting)

heals 90%

→

superficial keratectomy

~100%

Cats: NEVER grid or punctate keratotomy — high risk of inducing a corneal sequestrum. Cotton-tip debridement, diamond burr, or keratectomy only

5Adjuncts & Foreign Bodies

Vetrix IQ amniotic drop, 1 drop 3×/day — over $100 to the client, but can change the course of healing when referral isn't possible
Superficial corneal foreign body: hydropulsion — saline in a 6 cc syringe, 18 ga needle snapped off at the hub = mini pressure washer. Stromal splinter: circle a 30 ga needle gently around the barbs
Post-removal, treat as an ulcer: 4×/day if fresh; in the eye ≥1 day, assume bacteria and run the ≥6×/day infected regimen

6Do / Don't

DO	DON'T
Grade depth by side-view curvature before choosing therapy	Put topical steroids, topical NSAIDs, or numbing agents on an ulcer as therapy (numbing OK for diagnostics only)
Keep fluoroquinolones for infected eyes only	Start a fluoroquinolone on a simple ulcer — resistance risk
Change drug CLASSES after neo/poly breakthrough	"Upgrade" neopolybac → neopolygram after failure
Change your diagnosis at the failed second recheck	Serially swap antibiotics on a non-healer
Double-check the bottle: neopolydex looks like neopolygram	Send a steroid combo home on an ulcerated eye
Use erythromycin / terramycin-type options in cats	Use neomycin-containing topicals in cats (~10% hypersensitivity, rare anaphylaxis)
E-collar every dog with an ulcer	Grid keratotomy in a cat — sequestrum risk

Source: Dr. Rachel Allbaugh, "The Eyes Have It: Practical Ophthalmology" — Vet On It CE live lecture transcript.
Doses and frequencies are exactly as presented in the lecture; anything unspecified (atropine concentration, NSAID/gabapentin/doxycycline doses) is per clinician judgment.
Event 50 • v1.1 • 2026-08-18