Equine Glaucoma

These flashcards cover key concepts related to Equine Glaucoma, including causes, symptoms, diagnosis, and treatments.

What is glaucoma characterized by?

Altered aqueous humor dynamics and elevation of intraocular pressure (IOP) incompatible with health of the optic nerve and eye.

What usually causes glaucoma?

It is usually secondary to uveitis.

Where is aqueous humor produced?

Aqueous humor is produced by the ciliary body epithelium.

How does obstruction of outflow affect IOP?

Obstruction of outflow increases intraocular pressure (IOP).

What is the normal range of intraocular pressure in horses?

Normal IOP in horses ranges from 17 to 28 mmHg.

What is buphthalmia?

Buphthalmia is an abnormal enlargement of the eye, often seen in glaucoma.

What are common clinical signs of equine glaucoma?

Signs include corneal edema, buphthalmia, corneal striae, mydriasis, and vision loss.

How is glaucoma diagnosed in horses?

Diagnosis requires tonometry to measure IOP and observe other clinical signs.

What role do systemic NSAIDs play in the treatment of glaucoma?

They help reduce inflammation but are often ineffective in preserving vision.

What is the primary treatment goal for equine glaucoma?

Identify and treat the cause of outflow obstruction.

What can increase IOP measurements significantly during tonometry?

If the horse's head is held down, IOP can increase up to 87\%.

What kind of drugs are carbonic anhydrase inhibitors?

They are used to reduce aqueous humor production in glaucoma treatment.

What is the incidence of equine glaucoma?

The incidence is low despite the potential for ocular injury and severe anterior uveitis.

What breeds are mentioned as having a predisposition for equine glaucoma?

Appaloosa, TB, Arabian, Standardbred horses.

What surgical treatment option uses laser therapy for glaucoma?

Cyclophotocoagulation (CPC) using Nd:YAG or diode lasers.

What can chronic equine glaucoma lead to?

Chronic glaucoma can lead to vision loss, corneal vascularization, and optic nerve atrophy.

What often occurs with substantial unconventional outflow in equine glaucoma?

Obstruction of the iridocorneal angle with inflammatory debris.

What is the purpose of filtration gonioimplants?

They are surgical options to manage outflow in glaucoma treatment.

What are mydriasis and corneal edema signs indicative of?

These signs are indicative of glaucoma in horses.

Describe the sensitivity of equine glaucoma diagnosis?

It can be very challenging; early signs are often subtle.

What effect does age have on the risk of developing equine glaucoma?

Increasing age, particularly over 15 years, raises the risk of glaucoma.

What does corneal striae suggest in the context of glaucoma?

They indicate corneal stretching due to elevated intraocular pressure (IOP).

What is one of the medical treatment options for glaucoma mentioned?

Topical steroids to reduce inflammation.

What can chronic ocular inflammation lead to in horses?

Chronic inflammation can lead to secondary glaucoma.

What is a potential salvage procedure for refractory glaucoma?

Enucleation is a salvage procedure for advanced glaucoma.

What is Haab's stria?

It refers to corneal striae that appear in response to increased IOP.

What method of tonometry is commonly used in equine medicine?

Applanation or rebound tonometry is used to measure IOP.

What are the implications of early glaucoma on vision?

Early glaucoma can impact vision but may not show obvious signs.

What are the typical visual implications of chronic glaucoma?

Recurrent ulcerations, lens luxations, and vision loss.

What are the primary categories of surgical options for equine glaucoma management?

Surgical options include: 1. Decreasing aqueous humor production (e.g., cyclophotocoagulation or CPC); 2. Increasing aqueous humor outflow (e.g., filtration gonioimplants); and 3. Salvage procedures for blind, painful eyes (e.g., enucleation).