Cognition & Senses 2: Glaucoma Flashcards
4 common EYE COMPLAINTS by OWNER when GLAUCOMA is present?
- RED eye
- CLOUDY eye
- BLIND eye
- PAINFUL eye
GLAUCOMA is the MOST COMMON CAUSE for…
it also causes WHAT severe clinical sign?
considered an ____ ____, but prognosis is ___
MOST COMMON CAUSE for LOSS OF GLOBE (enucleation)
it also causes BLINDNESS
considered an OPHTHALMIC EMERGENCY, but prognosis is POOR
DEFINITION of GLAUCOMA?
what PROCESS causes this?
= a NEURODEGENERATIVE DZ causing IRREVERSIBLE DAMAGE to the OPTIC NERVE at the AXONS of RETINAL GANGLION CELLS
INCREASED INTRAOCULAR PRESSURE CAUSES THIS
ID LESION & DZ PROCESS…
this is PATHOGNOMONIC for…
OPTIC DISC CUPPING causing OPTIC NERVE DAMAGE
this is PATHOGNOMONIC for GLAUCOMA
ID LESION
NORMAL OPTIC NERVE on FUNDIC EXAM
what SPECIFICALLY produces AQUEOUS HUMOR?
–> what ENZYME catalyzes this reaction to produce it?
where is this located?
the CILIARY PROCESSES of the CILIARY BODY make AQUEOUS HUMOR
–> rxn catalyzed by CARBONIC ANHYDRASE
location = behind the BASE of the IRIS
TRUE/FALSE
the CILIARY EPITHELIUM of the CILIARY PROCESSES are made of 2 PIGMENTED layers
FALSE, one is PIGMENTED and the OTHER IS NON-PIGMENTED
TWO ROUTES of AQUEOUS HUMOR OUTFLOW?
& describe them
–> 2 arrows for first
–> 3 arrows for second
species differences?
- CONVENTIONAL OUTFLOW
–> through the IRIDOCORNEAL ANGLE via space where iris & cornea meet
–> aqueous humor then enters TRABECULAR MESHWORK (spongy material) - UNCONVENTIONAL OUTFLOW
–> UVEO-SCLERAL OUTFLOW via AH getting ABSORBED THROUGH FACE OF IRIS
–> through CILIARY BODY MUSCLES
–> dispersed through SCLERA & OUT OF EYE
CATS & DOGS mostly CONVENTIONAL, about HALF of HORSES do CONVENTIONAL
what are PECTINATE ligaments?
structures that HOLD THE IRIS & CORNEA TOGETHER at the IRIDOCORNEAL ANGLE
in GLAUCOMA, WHAT causes the INCREASED PRESSURE?
** WHAT IS IMPORTANT TO NOTE?
AQUEOUS HUMOR is NOT ADEQUATELY DRAINED
** the PRODUCTION of AQUEOUS HUMOR DOES NOT CHANGE
describe the components of the OPHTHALMIC exam & DIAGNOSTIC testing for GLAUCOMA (2)
difference in OUTCOME for ACUTE vs. CHRONIC glaucoma?
OPHTHALMIC exam = look at CLINICAL SIGNS
DIAGNOSTIC testing = look at TONOMETRY
difference in outcome?
ACUTE = VISION CAN BE SAVED
CHRONIC = IRREVERSIBLE VISION LOSS
CLINICAL SIGNS of ACUTE GLAUCOMA…
how does PAIN manifest? (overall & 4 signs)
vision changes? (3, two are NORMAL)
eye appearance changes? (3, one is NORMAL)
PAIN from HEADACHE causing…
1. VOMITING
2. EPIPHORA
3. BLEPHAROSPASM
4. HEAD-SHYNESS
VISION?
1. can still have NORMAL REFLEXES
2. NORMAL OPTIC DISC
3. MYDRIASIS (dilation)
APPEARANCES?
1. CONJUNCTIVAL/EPISCLERAL INJECTION
2. DIFFUSE CORNEAL EDEMA
3. globe size is NORMAL
CLINICAL SIGNS of CHRONIC GLAUCOMA…
pain?
vision changes? (4)
appearance of eyes? (3)
PAIN OFTEN PRESENT
vision changes?
1. NEGATIVE MENACE/PLR/DAZZLE
2. MYDRIASIS
3. OPTIC DISC CUPPING/ATROPHY
4. RETINAL ATROPHY
appearance?
1. CONJUNCTIVAL/EPISCLERAL INJECTIONS
2. DIFFUSE CORNEAL EDEMA
3. BUPHTHALMIA (large eyes)
ID LESION & DURATION in HORSE
ACUTE GLAUCOMA
ID LESION & DURATION in HORSE
there’s another SPECIAL lesion here, & define why it happens
CHRONIC GLAUCOMA
can see HABB’S STRIAE
–> due to FRACTURE of the DESCEMET’S MEMBRANE, causing AH GETTING INTO STROMA & this appearance
ID LESION & WHY it can occur due to GLAUCOMA
LESION = LENS LUXATION
due to BUPHTHALMIA (large eyes) causing RUPTURE of LENS ZONULES
DIAGNOSTICS for GLAUCOMA..
mostly use ____, which measures…
2 types of TOOLS & how they work?
hints: mention what TYPE of tool it is (-TION suffix), one requires TOPICAL ANESTHETIC, list pros & cons for others
mostly use TONOMETRY, which measures IOP
2 types?
1. TONOPEN
–> APPLANATION TONOMETRY
–> TIP OF PEN will FLATTEN CORNEAL SURFACE, and DEPENDING ON HOW MUCH PRESSURE it took for IT TO FLATTEN –> IOP
–> REQUIRES TOPICAL ANESTHETIC
- TONOVET
–> REBOUND TONOMETRY
–> PROS = NO TOPICAL ANESTHETIC NEEDED & CAN USE ON SMALL EYES
–> CONS = LIMITED POSITIONING & has trouble reading with CORNEAL DZ
how can we get FALSE HIGH IOP from TONOMETRY? (3)
how can we get FALSE LOW IOP from TONOMETRY? (1)
FALSE HIGH?
1. putting PRESSURE ON THE JUGULAR
- HEAD is BELOW HEART
- PRESSING ON GLOBE THROUGH LID
FALSE LOW = from SEDATION
DIURNAL FLUCTUATION..
what does this mean in relation to IOP? & 2 specifics
so WHEN should we give IOP meds?
IOP will CHANGE THROUGHOUT THE DAY
1. IOP is HIGHEST IN THE MORNING
2. IOP is LOWEST AT NIGHT
IOP MEDS should be given AT NIGHT to prep for high pressure in AM
GONIOSCOPY..
= what does it aim to do?
= aims to VISUALIZE the IRIDOCORNEAL ANGLE to look for EVIDENCE OF GLAUCOMA
image on GONIOSCOPY shows…
is this patient AT RISK for GLAUCOMA?
image shows CLOSED IRIDOCORNEAL ANGLE
IS AT RISK FOR GLAUCOMA
image on GONIOSCOPY shows…
is this patient AT RISK for GLAUCOMA?
image shows OPEN IRIDOCORNEAL ANGLE
NOT AT RISK FOR GLAUCOMA
on GONIOSCOPY, describe the DIFFERENCE between TOP & BOTTOM image?
what does this mean in terms of DZ?
TOP = OPEN IRIDOCORNEAL ANGLE
BOTTOM = loss of PECTINATE LIGAMENTS caused CLOSED IRIDOCORNEAL ANGLE
BOTTOM is AT HIGHER RISK FOR GLAUCOMA
PRIMARY glaucoma…
occurs in WHAT species? (1)
how does this occur?
sex predilection?
age of onset?
occurs in DOGS ONLY
how does this occur? = from CONGENITAL DEFECT in the AH SYSTEM that affects either its STRUCTURE or FUNCTION
sex predilection = FEMALES > MALES
age of onset = ~6 YEARS
GONIODYSGENESIS..
this is a type of ___ ____ that poses a ____ problem
present in WHAT species?
2 types?
PRIMARY GLAUCOMA that poses a STRUCTURAL problem
present in DOGS
2 types?
1. PRIMARY CLOSD/NARROW-ANGLE GLAUCOMA = the IRIDOCORNEAL ANGLE is CLOSED/COLLAPSED
- PECTINATE LIGAMENT DYSPLASIA = causes ANGLE TO be OCCLUDED BY A SHEET once ligaments collapse
ID DZ (2 terms) & DIFFERENCE between TOP & BOTTOM
GONIODYSGENESIS from PECTINATE LIGAMENT DYSPLASIA
TOP = NORMAL
BOTTOM = DZ
PRIMARY OPEN-ANGLE GLAUCOMA…
this is a ___ GLAUCOMA that poses a ___ problem
= what occurs?
unilateral vs. bilateral?
this is a PRIMARY GLAUCOMA that poses a FUNCTIONAL problem
= there’s RESISTANCE against AH OUTFLOW causing IOP INCREASE & GLAUCOMA
always has a RISK of BEING BILATERAL, but can PRESENT CLINICALLY w/ ONE EYE FIRST
5 BREEDS predisposed to PRIMARY CLOSED/NARROW-ANGLE GLAUCOMA?
which is MOST COMMON?
- AMERICAN COCKER SPANIEL –> MOST COMMON
- BOSTON TERRIER
- CHOW CHOW
- SHAR-PEI
- SHIBA-INU
4 BREEDS predisposed to PECTINATE LIGAMENT DYSPLASIA?
which 2 are MOST COMMON?
- BASSETT HOUND –> MOST COMMON
- SIBERIAN HUSKY –> MOST COMMON
- FLAT-COATED RETRIEVER
- SAMOYED
TRUE/FALSE
PRIMARY GLAUCOMA caused by FUNCTIONAL FAILURE can be DISTILLED DOWN to a MONOGENIC MUTATION, but STRUCTURAL FAILURE is POLYGENIC
TRUE
5 BREEDS predisposed to PRIMARY OPEN-ANGLE GLAUCOMA?
- BEAGLE
- NORWEGIAN ELKHOUND
- BASSETT HOUND
- BASSET FAUVE DE BRETAGNE
- PETIT BASSET GRIFFON VENDEEN
how can we DIAGNOSE SECONDARY glaucoma? (2)
do we have to do both?
- there is EVIDENCE of UNDERLYING OCULAR CONDITIONS
+/- –> WE DO NOT HAVE TO DO BOTH!
- we have RULED OUT PRIMARY GLAUCOMA
what 3 species can get SECONDARY glaucoma?
DOGS, CATS, HORSES
ANTERIOR UVEITIS..
= definition
2 clinical signs?
how can this cause GLAUCOMA? (2)
= INFLAMMATION in ANTERIOR UVEAL TRACT
2 clinical signs?
1. AQUEOUS FLARE
2. MIOSIS
can cause GLAUCOMA by…
1. WBCs or PROTEINS BLOCKING IRIDOCORNEAL ANGLE
2. or PUPIL STICKING TO LENS via SYNECHIA & blocking drainage
if we have SECONDARY GLAUCOMA caused by ANTERIOR UVEITIS..
what is the treatment?
what should we NOT use for treatment?
–> why?
tx = MANAGEMENT for both GLAUCOMA & UVEITIS
DO NOT USE ATROPINE
–> if we cause MYDRIASIS (dilation of pupil) while the EYE HAS INCREASED PRESSURE, then can CROWD & BLOCK IRIDOCORNEAL ANGLE
ANTERIOR LENS LUXATION..
can be both a ____ & ____ of ____
it will cause WHAT clinical change rapidly?
tx?
can be both a CAUSE & EFFECT of GLAUCOMA
it will cause RAPID INCREASE in IOP
tx? = must be EMERGENCY Tx & SURGERY to USUALLY REMOVE LENS
do we HAVE to perform ENUCLEATION with dogs with INTRAOCULAR NEOPLASIA?
NOT UNLESS the MASS is causing INCREASED PRESSURE/GLAUCOMA
CONGENITAL GLAUCOMA…
= etiology?
IOP?
what is the CLINICAL FINDING upon BIRTH?
= from ANTERIOR SEGMENT DYSGENESIS where NO DRAINAGE PATHWAY FOR AH
IOP will be NORMAL or HIGH
upon BIRTH, see BUPHTHALMIA
MEDICAL means of REDUCING AH PRODUCTION to REDUCE GLAUCOMA PRESSURE?
–> include HOW IT WORKS & SPECIFIC DRUGS
which is MOST COMMONLY used?
- CARBONIC ANHYDRASE INHIBITORS = most COMMON
–> inhibits carbonic anhydrase to MAKE AH
–> TOPICAL = DORZOLAMIDE (more common) or BRINZOLAMIDE - BETA-BLOCKER
–> INHIBITS BETA RECEPTORS on CILIARY EPITHELIUM to MAKE AH
–> TIMOLOL
LATANOPROST…
what KIND of drug is it?
what is the GOAL of this drug?
how does it WORK?
WHEN should it be used?
1 side effect?
what 2 species are CONTRAINDICATED?
PROSTAGLANDIN ANALOGUE
GOAL = INCREASE AH OUTFLOW and DECREASE IOP from GLAUCOMA
how does it work? = INCREASES UVEO-SCLERAL OUTFLOW
should be used in ACUTE IOP SPIKES
1 side effect = MIOSIS
2 species CONTRAINDICATED?
1. CATS
2. HORSES
(do not have PROSTAGLANDIN receptors)
we DO NOT USE MIOTICS anymore, so INSTEAD we use…
PROSTAGLANDIN ANALOGUES
when should we NOT USE PROSTAGLANDIN ANALOGUES?
why? (2)
when there’s ANTERIOR LENS LUXATION
why?
1. risk of TRAPPING LENS
2. can cause MIOSIS OF PUPIL
SURGICAL MANAGEMENT for GLAUCOMA…
2 procedures if we want to SAVE VISION?
1 procedure if we want to SAVE THE GLOBE?
1 procedure if we want to PRESERVE COMFORT?
VISION?
1. CYCLOABLATION
2. ANTERIOR CHAMBER SHUNT
GLOBE? = CYCLOABLATION
COMFORT? = ENUCLEATION
CYCLOABLATION/CYCLOPHOTOCOAGULATION
the GOAL is to SAVE the ___ of the eye in ___
= what is this procedure?
2 routes of administration?
–> which is MORE COMMON/why?
the GOAL is to SAVE the VISION of the eye in GLAUCOMA
= we can DESTROY CILIARY EPITHELIUM in the PIGMENTED LAYER via a LASER to DECREASE AQUEOUS PRODUCTION
2 routes?
1. TRANSSCLERAL = EXTRAOCULAR Sx where laser is APPLIED THROUGH SCLERA, INDIRECT visualization of target
–> MORE COMMON bc LESS INVASIVE
- ENDOSCOPIC = INTRAOCULAR Sx where LASER DIRECTLY VISUALIZES TARGET
ANTERIOR CHAMBER SHUNT..
the GOAL is to SAVE the ___ of the eye in ___
= what is this procedure?
prognosis post-op?
the GOAL is to SAVE the VISION of the eye in GLAUCOMA
= creating a TUBING into ANTERIOR CHAMBER to INCREASE AH OUTFLOW upon INCREASED IOP
prognosis = 50% OF PATIENTS LOSE VISION, NOT GREAT
ABLATION of the CILIARY BODY…
GOAL of this surgery?
2 types & how they work?
1 pro?
3 cons?
GOAL = to SHUT DOWN PRODUCTION of AH
2 types?
1. CHEMICAL ablation = INTRAVITREAL GENTAMICIN INJECTION
2. CRYO ablation = TRANSSCLERAL APPLICATION of CRYO PROBE
1 pro = SHORT ANESTHESIA TIME
3 cons?
1. UNPREDICTABLE results
2. can REQUIRE REPEAT
3. can result in PHTHISIS BULBI
4 options for EMERGENCY GLAUCOMA Tx?
what should we do AFTER giving FIRST 2?
- LATANOPROST = check for DECREASED IOP in 1 HR
- MANNITOL = recheck IOP in 30-60 MINS
- ANTERIOR CHAMBER PARACENTESIS (use a needle to remove AH from anterior chamber)
- DORZOLAMIDE + TIMOLOL
what does MANNITOL do for ACUTE GLAUCOMA
can DEHYDRATE THE EYEBALL to help DECREASE IOP
