Anterior Chamber Disorders Flashcards
What device do we use to help diagnose glaucoma?
tonopens
Types of glaucoma?
3
- Open-angle glaucoma
- Angle-closure glaucoma (sudden closure)
- Acute angle-closure glaucoma
What is happening in open angle glaucoma?
Optic neuropathy results in progressive loss of retinal ganglion cell axons
-first lose your visual fields then central vision as it progresses to blindness
Risk factors for open angle glaucoma?
7
- Age: 1%
What is being damaged in glaucoma?
What causes this damage?
slow progressive damage to the optic nerve
Increased internal ocular pressure
Symtpoms of primary open angle glaucoma?
symptoms are rarely experienced until central vision is affected. Once vision is lost it cannot be recovered
How do we diagnose primary open angle glaucoma?
funduscopic exam and visual acuity with the presence of elevated intraocular pressure
What in a funduscopic exam would indicate open angle glaucoma?
presence of cupping
–A cup that is greater than 50 percent of the vertical disc diameter is a useful threshold for suspicion of glaucoma.
What is the cup and what is the disc?
the cup is the optic nerve and the disc is the impression made by the nerves
Whats the normal cup to disc ratio?
1/3
How does glaucoma affect the cup size?
What will the rim of the nerve on the temporal side tell us?
makes it larger in a vertical oval type pattern
If it is very thin or sloped it will be more likely to have glaucoma
What is primary angle closure glaucoma characterized by?
What does this cause?
by narrowing or closure of the anterior chamber angle
This narrows or closes the normal drainage pathway of the aqueous humor which then builds up leading to elevated IOP
= damage of optic nerve
Risk factors for primary angle closure glaucoma?
6
- Family history
- Age older than 40 or 50 years
- Female
- Hyperopia (farsightedness)
- Medications—decongestants, antipsychotics, antidepressants
- Race—Inuit and Asian populations
Pathophysiology of chronic glaucoma?
3
- abnormal internal pressure resulting from aqueous fluid blockage
- clogged trabecular meshwork leading to drainage canal
- optic nerve endings slowly deteriorate under abnormal pressure
Symptoms of chronic glaucoma?
usually asymptomatic
How would we diagnose chronic glaucoma?
5
- Glaucomatous optic nerve damage (thinning, cupping or notching of the disc rim)
- AND the presence of characteristic abnormalities in the visual field in the absence of other causes for a field defect
- Adult onset
- Open, normal appearing anterior chamber angles
- Absence of known (secondary) causes of glaucoma
Do all patients with open angle glaucoma have elevated IOP?
no. most do but some don’t
A IOP of what would make us call an emergency referral?
over 40mmHg
An IOP of what would make us call an urgent referral?
And what is the time frame for an urgent referral?
30-40 mmHg
Within 24 hrs, if no symtpoms suggesting acute glaucoma
If pressure is at 25-29mmHg what would we do?
evaulate again in a week
If pressure is t 23-24mmHg what should we do?
repeat the measurement to confirm and or referral for a comprehensive eye exam
Whats a normal IOP?
12-20mmHg
The American Academy of Ophtho recommends screening for glaucoma as part of the comprehesive adult eye exam. What procedures does this include? 3
- measuring IOP,
2. evaluating the optic nerve and 3. testing for visual field defects
When should we be tested for glaucoma wihout any risk factors from ages 40-60?
With risk factors?
every 3-5 years
1-2 years
What are the three types of treatment options for glaucoma
medications (eyedrops)
laser surgery
incisional surgery
What procedures would help with drainage in patients with glaucoma?
3
Argon laser trabeculoplasty (ALT) Improves drainage of fluid out of the eye Trabeculectomy (75% success rate) can be repeated up to 3 times or more Drainage implant tubes
Acute angle- closure glaucoma occurs only with what?
with closure of a preexisting narrow anterior chamber angle
Predisposing factors for acute angle-closure glaucoma?
4
Elderly
Hyperopes
Inuits
Asians
What can acute angle closure glaucoma be precipitated by?
pupillary dilation
- -sitting in a dark theater and having the lights from the screen flash on abruptly
- -times of stress
- -pharmcological mydriasis
What drugs could cause acute angle closure glaucoma?
two categories of meds
five specific examples
- Anticholinergics or
- sympathomimetics
Nebulized bronchodilators, atropine as pre-op medication, antidepressants,
nasal decongestants,
tocolytics.
Secondary acute angle glaucoma may be observed with what issues?
2
anterior uveitis
dislocation of the lens
Symptoms of acute closed angle glaucoma?
5
- Rapid onset
- Severe eye pain and HA
- Profound visual loss with “halos around lights”
- May have photophobia
- Nausea and vomiting
***These patients are in distress, usually covering their eye or clutching their frontal region. Often the headache is accompanied with nausea and vomiting.