Glaucoma Flashcards
Glaucoma (2)
1) multifactorial disease
2) elevation of IOP incompatible with ocular health
Glaucoma pathogenesis (3)
1) reduced aqueous humor drainage capacity in ALL cases
2) results in progressive IOP elevation
3) irreversible vision loss through optic nerve & retinal ganglion cell death
Primary Glaucoma (2)
1) heritable, breed-related abnormality of aqueous drainage angle
2) rarely congenital
Secondary Glaucoma (1)
numerous causes of secondary drainage angle obstruction
Glaucoma clinical signs in acute disease (5)
1) blepharospasm
2) corneal edema
3) episcleral injection
4) dilated pupil
5) variable vision
Glaucoma clinical signs in chronic disease (5)
1) all acute signs possible
2) buphthalmos- swelling of eye
3) Haab’s striae- fracture/break in decimates membrane, streaks across cornea
4) lens subluxation- crescent appearance to lens
5) cupped optic nerve
Causes of canine primary glaucoma (4)
1) breed-related/hereditary condition
2) drainage angle abnormality
3) bilateral disease potential
4) one eye affected first then second weeks to months later
Causes of canine secondary glaucoma (6)
1) lens luxation
2) uveitis
3) hyphema
4) intraocular neoplasia
5) Melanocytic glaucoma
6) pigmentary uveitis
7) pseudophakia/aphakia
8) trauma
Feline glaucoma (4)
1) primary glaucoma is rare
2) secondary similar causes as dogs
3) uveitis common cause of secondary
4) aqueous humors misdirection (unique to cats)
Equine glaucoma (2)
1) primary glaucoma is rare
2) most cases secondary to equine recurrent uveitis (ERU)
Clinical findings in equine glaucoma (6)
1) usually an insidious disease
2) corneal edema (intermittent or persistent)
3) dilated pupil
4) Haab’s striae
5) lens luxation
6) vision loss
Glaucoma diagnosis (4)
1) clinical signs/findings
2) history/signalment
3) IOP measurement
4) Gonioscopy
Tonometry (5)
1) measurement of IOP
2) methods: rebound, applanation, indentation
3) 15-25 normal
4) abnormal: IOP differences between 2 eyes
5) important for assessing efficacy of glaucoma therapy
Gonioscopy (3)
1) examination of the drainage angle
2) requires specialized lens
3) helps determine likelihood of primary glaucoma based upon angle morphology
Goals of therapy (3)
1) maintenance of vision where possible
2) patient comfort in all cases
3) prophylaxis in “at risk” eyes
Emergency Management (2)
1) Systemic hyperosmotic medication
2) topical prostaglandin analogue
Maintenance medication: Carbonic anhydrase inhibitors (CAIs) (4)
1) very effective
2) can be used in all species and all forms of glaucoma
3) topical and systemic formulation
4) Side effects: GI upset, panting, lethargy
Maintenance medication: Miotics 7 prostaglandin analogues (topical) (3)
1) avoid in glaucoma secondary to uveitis or anterior lens luxation
2) reduce aqueous outflow
3) ocular side effects
Maintenance medication: Beta blockers (topical) (2)
1) usually no adequate as sole agent
2) side effects
Medical prophylaxis (1)
1) significantly delays onset of disease in second eye of dogs with primary glaucoma
General treatment principles (6)
1) treat aggressively early in the course of disease
2) target IOP <20 mmHg
3) don’t taper medications in controlled cases
4) consider surgical intervention early in disease course
5) manage underlying disease
6) topical mydriatics are CONTRINDICATED (except horses)
Surgical management: Decrease Aqueous production (1)
1) cyclodestructive procedures
Surgical management: Increase Aqueous production (1)
1) filtering procedures/aqueous shunts
Prognosis (2)
1) long term visual prognosis is poor
2) salvage surgical procedures- reduce pain
Salvage procedures (3)
1) enucleation
2) evisceration/intrascleral prosthesis
3) chemical ciliary body ablation
