Term
|
Definition
| -an inc in intraocular pressure incompatible with the health of the eye |
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Term
| What produces the aqueous? |
|
Definition
| -epi of the ciliary processes |
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Term
| Describe conventional aqueous flow. |
|
Definition
| -posterior chamber => pupil => anterior chamber => trabecular meshwork => scleral veins |
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Term
| Describe unconventional aqueous flow. |
|
Definition
| -posterior chamber => pupil => anterior chamber => ciliary uscle => suprachoroidal space => scleral veins |
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|
Term
| What is the physiology behind glaucoma? |
|
Definition
| -due to impaired aqueous OUTFLOW ONLY |
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Term
| What structures in the eye does inc IOP damage due to glaucoma? |
|
Definition
-optic nerve
-retina
-iris
-cornea |
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|
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 |
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|
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 |
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|
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 |
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|
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 |
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|
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 |
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|
Term
| Describe how we use a TonoVet tonometer. |
|
Definition
-no topical anesthetic required
-good for small eye (exotics practice) |
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|
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 |
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|
Term
| When would we use a hyperosmotic (mannitol) to treat glaucoma? |
|
Definition
| -used only in acute glaucoma if latanoprost fails |
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|
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 |
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|
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 |
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