Intraocular Surgery

CHAPTER 144 Intraocular Surgery

>Intraocular surgery is performed on horses with growing frequency as advances in surgical equipment and operative technique improve outcomes. However, the expense of instrumentation and the limited availability of technical expertise may limit the accessibility of equine intraocular surgery in some geographic areas. The most common indications for equine intraocular surgery are cataract, lens luxation, and intraocular foreign body. Clinical signs, patient selection, diagnostic testing, therapeutic regimens, and complications are discussed in this chapter.


A cataract is defined as any opacity of the lens. Dense cataracts may impair vision such that the horse cannot be safely handled or ridden. Depending on their demeanor, visually impaired horses may also be prone to severe self-injury.

Cataract Surgery

There is no effective medical treatment for cataracts. Pharmacologic mydriasis after application of 1% atropine ophthalmic solution or ointment may improve vision for horses with focal opacities. The only effective therapy for cataracts causing clinically significant visual impairment is surgical removal. Appropriate patient selection is critical to a successful outcome.

Preoperative Therapeutic Protocol

The following section describes a typical preoperative therapeutic protocol. Blepharitis, conjunctivitis, keratitis, uveitis, and any systemic disease must be controlled before cataract removal can be performed. If uveitis is present, topical corticosteroids (prednisolone acetate 1% ophthalmic suspension) or an antimicrobial-corticosteroid preparation (neomycin-polymyxin-dexamethasone ophthalmic solution or ointment) and topical atropine (1% ophthalmic ointment or solution) are administered to control the inflammation. If uveitis is detected, systemic nonsteroidal anti-inflammatory drugs (NSAIDs) such as flunixin meglumine (1.1 mg/kg, intravenous [IV] or oral [PO], every 12 hours) or phenylbutazone (2 mg/kg, PO, every 12 hours) are administered.

The day before surgery, topical corticosteroids and antimicrobials are applied to the ocular surface every 6 hours. Atropine 1% ophthalmic solution is applied once to achieve mydriasis. Flunixin meglumine is administered. Gastric protectants such as omeprazole (2 mg/kg PO daily) are indicated, particularly for foals. Tetanus toxoid is administered if vaccinations are not up to date.

The day of surgery, three applications each of topical ophthalmic corticosteroid, antimicrobial, and NSAID (0.03% flurbiprofen ophthalmic solution) solutions are applied to the ocular surface. Atropine 1% ophthalmic solution or tropicamide 1% ophthalmic solution are administered, if needed, to achieve maximal pupillary dilation. Flunixin meglumine administration is continued. Prophylactic systemic antimicrobials (potassium penicillin G, 20,000 international units/kg, IV, every 6 hours and gentamicin, 6.6 mg/kg, IV, every 24 hours) are administered perioperatively.

May 28, 2016 | Posted by in EQUINE MEDICINE | Comments Off on Intraocular Surgery

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