Eye Problems

There are numerous ocular diseases and congenital problems (See Congenital Anomalies and Genetic Disorders) seen in ill neonatal foals [1,2]. Only the common ocular problems seen with critical care management of the premature and ill foal are mentioned here. A recent study indicated frequent eye problems in referral foal units: abnormalities found in 70 foals included conjunctival hyperemia or episcleral injection 42.9%, uveitis 25.7%, ulcerative keratitis 18.6%, nonulcerative keratitis 14.3%, entropion 11.4%, retinal hemorrhage 11.4%, and cataract 8.6%. Foals with sepsis were significantly more likely to have uveitis than were those without sepsis. Foals with sepsis and uveitis were also significantly less likely to survive to discharge than were foals that had sepsis without uveitis [2]. EC we better start calling the ophthalmologists in at 3 am more often.

I. Corneal Ulcers

Previous or concurrent bacteremia ± failure of passive transfer.

1. Most commonly develop secondary to trauma while recumbent due to weakness and incoordination, seizures, flailing during transport, ocular drying and entropion.
2. Preventive measures are head protectors, sedation and supervised restraint, lubricating drops or ointments 4 times daily and frequent examination for ulcers by staining with fluorescence strips.
3. May be responsible for considerable prolongation of hospitalization.
4. Treatment is broad spectrum antibiotic ointments applied every 4-6 hours. Severe or persistent ulcers and keratitis require culture and sensitivity. Small amounts of atropine drops for blepharospasm is helpful.
   Editor's Comments - Use with caution due to systemic absorption and GI motility problems.

II. Entropion

1. Seen frequently in premature and severely ill foals.
2. Infolding of the eyelid may cause corneal conjunctival irritation, and ulceration.
3. Correction is via temporary sutures to evert the lid.
4. Eye lid injections of various substances included procaine penicillin, Vitamin E-Se, have been used to evert lid.

III. Iridocyclitis, Uveitis

Iridocyclitis, uveitis – Seen accompanying systemic bacterial infection (septicemia), viral infections or rarely after blood/plasma product administration.

1. Eye may appear cloudy due to corneal edema with hemorrhage seen in the anterior chamber. Flare, miosis, and corneal vascularization may be present.
2. Treatment - Correction of primary inciting problem. Atropine drops are used and without evidence of corneal ulcer, documented by frequent staining, an antibiotic-steroid ointment too. Systemic NSAIDs may be helpful but side effects in foals may preclude frequent use.

IV. Conjunctivitis

1. Secondary to entropion.
2. Secondary to trauma, stall bedding contamination and shavings or sawdust.
3. Associated with bacterial and viral infection.
4. Subconjunctival and episcleral hemorrhages are seen with compression from parturition.

V.Stromal Abscess [3,4]

1. Often present as a medical emergency.
2. Primary due to micropunctures or secondary to steroid use on an ulcerated corneal surface.
3. Focal, yellow stromal infiltrate with corneal edema.
4. Blepharospasm, epiphora secondary to iridocyclitis.
5. Corneal vascularization, hypopyon, and fibrin accumulation may be present.
6. Treatment consists of topical antifungal and antimicrobial therapy with DMSO. Highly lipophilic antibiotics (fluoroquinolones, chloramphenicol) are recommended. Atropine is indicated in patients with concurrent iridocyclitis.
7. Systemic antibiotics and anti-inflammatories may be useful especially if stroma is vascularized.
8. Severe cases require surgical interventions (keratoplasty).
9. Long-term treatment is essential for success (4-8 weeks)

VI. Eye Trauma

1. Both primary and secondary traumas are fairly common in foals. They require surgical or medical treatment depending on the type of injury.