Which surgical option may be considered for refractory glaucoma in horses?

• A. Cyclodestructive procedures.
• B. LASIK.
• C. Cataract extraction.
• D. Vitreoretinal surgery.

Answer: (A)

When glaucoma in horses does not respond to medical therapy, the goal is to cut back aqueous humor production. Cyclodestructive procedures achieve this by damaging the ciliary body, which produces the aqueous humor, thereby lowering intraocular pressure. They can be performed with cryodestruction, diode laser cyclophotocoagulation, or endoscopic cyclophotocoagulation and are used specifically in refractory cases where medications fail or enucleation is being considered as a last resort.

LASIK is aimed at reshaping the cornea for refractive errors and does not affect aqueous dynamics, so it won’t help with glaucoma. Cataract extraction removes the lens and may occasionally help in lens-induced glaucoma, but it does not address persistent, non-lens-related glaucoma and thus isn’t a reliable option for refractory cases. Vitreoretinal surgery targets posterior segment diseases and does not reduce intraocular pressure, making it unsuitable as a glaucoma treatment in this context.