Anterior Chamber Disorders Flashcards
What is the seconding leading cause of blindness in the world?
Glaucoma, after cataracts
Types of Glaucoma
- open-angle
- angle-closure
- acute angle closure
- both angle-closures can be divided into primary and secondary forms-
- uveitis
- trauma
- glucocorticoid therapy
- proiliferative retinopathy (Diabetic & HTN) I
Open-Angle Glaucoma
- what is it?
- how does it progress?
- risk factors
-optic neuropathy that results in progressive and gradual loss of retinal ganglion cell axons.
Progression:
- GRADUAL peripheral visual fields lost first then central vision, leading to blindness.
- many people do not notice that its occurring.
Risk Factors :
- Age (>80 4%)
- race; blacks
- family history
- elevated intraocular pressure
- DM, myopia, HTN
Open Angle Glaucoma
-Symptoms
- asymptomatic
- no loss of visual acuity as long as central vision is preserved
- some pts are unaware of field loss even when it has progressed to central “tunnel vision” of 10-20 degrees.
- *Visual field loss cannot be recovered once it has occured.
-increased IOP up to 40 w/o symptoms, may take 25 years to progress to tunnel vision w/o tx.
Open Angle Glaucoma;
-what you see in fundoscopic exam leading you to diagnosis
- presence of cupping: a cup that is greater than 1/3 of the vertical disc diameter is useful threshold for suspicion of glaucoma.
- nerve damage, poor visual field testing, and elevated intraocular pressures.
What is the optic cup? What does it look like? What is normal?
- is the center of the optic disc
- looks white cup-like area in the center of optic disc
- Normal cup to disc ratio is 1:3
- some variation, pts may have almost no cup and others have rather large cup–this is relative.
Features of the optic disc/cup that may lead you to be suspicious of future glaucoma
- the cup enlargers in a vertical oval pattern
- the rim of the nerve on the temporal side, it will be thin or sloped.
Primary Angle-closure Glaucoma
- what is this?
- aka
- characterized by narrowing or closure of the anterior chamber angle closing the normal drainage pathway of the aqueous humor causing a build up leading to elevated IOP and damage of the optic nerve
- chronic glaucoma
Risk Factors of Primary Angle Closure Glaucoma
- family hx
- age (>40-50)
- female
- hyeropia
- medications: decongestants, antipsychotics, antidepressents (d/t anticholinergic effects)
- Race: Inuit and Asian Populations
Primary Angle Closure Glaucoma:
- signs and symptoms
- diagnosis
- often asymptomatic
- progressive cupping and pallor of optic disc
- progressive loss of vision from slight constriction of peripheral fields leading to complete blindness
Dx:
- optic nerve damage (thinning, cupping, or notching of disc rim) AND presence of abnormalities in 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!
90% of adults w/ IOP>21mmhg have no optic nerve damage
-even up to 40mmhg they can have no vision loss
IOP Parameters for Referral
> 40mmHg Emergency referral
30-40mmHg Urgent referral w/ in 24hrs
25-29mmHg- evaluation within 1 week
23-24mmHg- repeat measurement to confirm and/or referral for comprehensive eye exam
**Normal IOP = 12-20mmhg
Ways to measure eye pressure
- non-contact air puff
- Tonopen
When to screen for glaucoma, what is included in comprehensive eye exam?
- between ages 40-60 every 3-5years for those w/o risk factors, w/ risk factors its 1-2 years.
- suggest periodic exams for black men and women between ages 20-39
-measuring IOP, evaluating the optic nerve, testing for visual field defects.
Tx of Glaucoma
- medications
- -topical and oral
- laser surgery
- -Argon Laser Trabeculoplasty (ALT), improves drainage of the eye
- -Trabeculectomy
- -Drainage implant tubes
-incisional surgery
Acute Angle Closure Glaucoma
- occurs with?
- predisposing factors?
-occurs with closure of a preexisting narrow anterior chamber angle
Predisposing factors:
- eldery
- hyperopes
- inuits
- asians
Acute Angle Closure Glaucoma
- may be precipitated by what?
- example?
-pupillary dilation
Example:
- sitting in dark theater, times of stress, or pharmacologic mydriasis (PANCE!!!!!!!!)
- anticholinergic or sympathomimetics (nebulized bronchodilators, atropne, anti-depressant, nasal decongestant)
Secondary acute angle-closure may be observed with what?
-anterior uveitis or dislocation of lens
