Glaucoma/Lens Flashcards
(22 cards)
Glaucoma in horses (and cats) is almost always
Secondary
When would it be contraindicated to check IOP in horses?
Deep corneal ulcers / descemetocele
Corneal or scleral lacerations / perforations
What are the guidelines to tonometry?
Performed before pupil dilation
Performed after auriculopalpebral nerve block
Pressures should be obtained standing with head above heart
IV sedation may decrease IOP
What is normal IOP in horses?
10-20 mmHg
Should be <30 mmHg at all times
What are the most common causes of secondary glaucoma in horses?
ERU - most common
Intraocular neoplasia
Blunt trauma
Lens luxation
Following cataract surgery
What are the topical medical therapy options for horses with increased IOP?
Dorzolamide/Timolol (Cosopt)
Dorzolamide 2%
Timolol 0.5%
Not Latanoprost
What should you not use if you have glaucoma?
Mydriatics (dilation causes worse drainage)
What are the complications to surgical therapy?
Corneal edema
Worsening uveitis
Corneal ulceration
Fibrosis around implant
Uncontrolled glaucoma
What are the pros to enucleation?
Eliminates need for continued therapy
Fast recovery period
Low complication rate
Allows for histopathologic evaluation
What is an expected complication (cosmetic) that occurs with chemical ciliary body ablation?
Phthisis bulbi
What breeds might you see inherited congenital cataracts?
Rocky Mountain
Thoroughbreds
QH
Morgans
How much of the lens is affected with incipient cataracts?
<10-15%
Visual
What would you expect the menace to be with an immature cataract?
Positive
What would you expect the menace to be with a mature cataract?
Negative
What is often present with hypermature cataracts?
Uveitis
What is brunescence?
Increased yellow discoloration of lens
Occurs as normal part of aging
Apparent in some equine cataracts
What is the most common cause of cataracts?
Inflammation
What are sequelae to cataract formations?
Visual impairment
Lens-induced uveitis
Lens subluxation/luxation
Glaucoma
Retinal detachments
What medical therapy options are available for cataracts?
Topical NSAIDs (diclofenac, flurbiprofen, ketorolac)
Does not improve vision
Helps control lens-induced uveitis
What is the only therapy available to restore vision with cataracts?
Phacoemulsification
High frequency vibrations emulsify cataract and remove it by aspiration through a small corneal incision
What should be considered with cataract surgery in horses?
Overall poor success rates
Horses with ERU are not appropriate candidates
Foals with congenital cataracts may be better candidates
Extensive and prolonged post op care
Vison after surgery should be considered compromised
What are the post op complications with cataract surgery?
Corneal ulceration
Persistent uveitis
Endophthalmitis
Glaucoma
Retinal detachment
