Term
|
Definition
-an inc in intraocular pressure incompatible with the health of the eye |
|
|
Term
What produces the aqueous? |
|
Definition
-epi of the ciliary processes |
|
|
Term
Describe conventional aqueous flow. |
|
Definition
-posterior chamber => pupil => anterior chamber => trabecular meshwork => scleral veins |
|
|
Term
Describe unconventional aqueous flow. |
|
Definition
-posterior chamber => pupil => anterior chamber => ciliary uscle => suprachoroidal space => scleral veins |
|
|
Term
What is the physiology behind glaucoma? |
|
Definition
-due to impaired aqueous OUTFLOW ONLY |
|
|
Term
What structures in the eye does inc IOP damage due to glaucoma? |
|
Definition
-optic nerve -retina -iris -cornea |
|
|
Term
What changes do the optic nerve and retina undergo due to inc IOP due to glaucoma? |
|
Definition
-pressure damage to the ganglion cells and nerve fiber layer = degen of optic nerve -Results in dark, cupped optic disc on fundus exam, vision loss, and afferent PLR deficit |
|
|
Term
How does the iris change in response to inc IOP with glaucoma? |
|
Definition
-pressure damage to the iris constrictor/sphincter muscles -results: fixed dilated pupil and efferent PLR deficit |
|
|
Term
How does hte cornea change in response to inc IOP with glaucoma? |
|
Definition
-pressure exerted on the corneal endothelium impairs the ATPase pumps -results in diffuse corneal edema |
|
|
Term
What signs do we find in history of glaucoma? |
|
Definition
-eye closed -discharge -bloodshot -lethargy, anorexia -cloudy (corneal edema) -may appear more comfortabe with time |
|
|
Term
What are the clinical signs of acute glaucoma? |
|
Definition
-pain -normal to hyperemic optic disc -prominent scleral vessels -corneal edema -dilated pupil |
|
|
Term
What are the clinical signs of chronic glaucoma? |
|
Definition
-prominent scleral vessels -corneal edema -dilated pupil -dark, cupped optic disc -retinal atrophy -bupthalmos |
|
|
Term
What are the key triad clinical signs for glaucoma? |
|
Definition
-episcleral vascular congestion -corneal edema (diffuse) -dilated pupil |
|
|
Term
Describe how we use a Tonopen tonometer. |
|
Definition
-requires topical anesthetic -slightly higher learning curve -operator touches cornea therefore can feel degree of IOP |
|
|
Term
Describe how we use a TonoVet tonometer. |
|
Definition
-no topical anesthetic required -good for small eye (exotics practice) |
|
|
Term
What drugs do we use to lower aqueous pdn to treat glacuoma? |
|
Definition
-CArbonic angydrase inh: Dorzolamide, Brinzolamide -Beta-adrenergic antagonists: Timilol |
|
|
Term
What drugs do we use to inc aqueous outflow to treat glaucoma? |
|
Definition
-prostaglandin analogs: Latanoprost |
|
|
Term
When would we use a hyperosmotic (mannitol) to treat glaucoma? |
|
Definition
-used only in acute glaucoma if latanoprost fails |
|
|
Term
How do hyperosmotics work to treat glaucoma? How is it administered? When is it contraindicated? |
|
Definition
-temporarily lowers IOP by dehydrating the vitrous -admin IV over 15-20 mins -withold water for 3-4 hr -contraindicated with cardiac disease |
|
|
Term
What are the surgical options to treat glaucoma? |
|
Definition
-Laser cyclophotocoagulation: selectively destroys ciliary body tissue using laser energy -Filtering implants: provides a new pathway for aqueous outflow |
|
|
Term
What is primary glaucoma? |
|
Definition
-no preceding intraocular disease -structural abnormality of the trabecular meshwork that inhibits outflow |
|
|
Term
In which breeds is primary glaucoma predisposed? |
|
Definition
-Basset hound, spaniels, northern breeds, etc |
|
|
Term
How do we diagnose primary glaucoma? |
|
Definition
-breed -history -optho exam for primary or secondary |
|
|
Term
Is primary glaucoma bilateral or unilateral? |
|
Definition
-ALWAYS assume it is a bilateral disease |
|
|
Term
How do we treat the eye affected by primary glaucoma? |
|
Definition
-if vision permanently lost: enucleation, evisceration with intrascleral prosthesis, meds can be long term |
|
|
Term
How do we treat the eye affected by primary glaucoma? |
|
Definition
-MEdical: Latanoprost + Dorzolamide +/- Timilol w/ Mannitol IV if non-responsibe -Surgical: laser cyclophotocoagulaiton and/or filtering implant |
|
|
Term
How do we treat the eye unaffected by primary glaucoma? |
|
Definition
-GOAL IS TO PROLONG THE ONSET OF GLAUCOMA -start on 1 topical medication: brinzolamide, timilol, or latanoprost -client education -routine IOP checks q1-3 months |
|
|
Term
What is the primary goal of maintaining vision due to primary glaucoma? |
|
Definition
-higher IOP the lower the treatment success -long term prognosis is always guarded -ideal is to prolong the onset of glaucoma therefore always be proactive in the at-risk eye |
|
|
Term
What are some of the difficulties encountered in treatment of primary glaucoma? |
|
Definition
-first eye is not recognized/diagnosed in time -medical therapy alone will not control IOP for life -surgical procedures all have risks and may not cntrol IOP for life |
|
|
Term
What are the clinical signs of secondary glaucoma? |
|
Definition
-anterior lens luxation -primary intraocular neoplasia -uveitis |
|
|
Term
How does uveitis cause ACUTE glaucoma? |
|
Definition
-blood, fibrin, cells, etc by clogging the iridocorneal angle |
|
|
Term
How does uveitis cause ACUTE or CHRONIC glaucoma? |
|
Definition
posterior synechia blocking flow of aqueous through the pupil |
|
|
Term
How does uveitis cause CHRONIC glaucoma? |
|
Definition
-pre-iridal fibrovascular membrane covering the anterior surface of the iris and the iridocorneal angle |
|
|
Term
What are the principles of treatment of secondary glaucoma? |
|
Definition
-potential to regain vision => treat underlying disease -permanently blind => evisceration or enucleation WITH HISTOPATHOLOGY |
|
|
Term
How do we treat anterior lens luxation seen with secondary glaucoma? |
|
Definition
|
|
Term
How do we treat primary intraocular neoplasia with secondary glaucoma? |
|
Definition
|
|
Term
How do we treat uveitis with secondary glaucoma? |
|
Definition
-suppress inflammaiton aggressively -prevent posterior synechia: atropine is contraindicated |
|
|