Glaucoma
Glaucoma
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Glaucoma
See Also
Open Angle Glaucoma
Narrow Angle Glaucoma
Definitions
Glaucoma
Increased
Intraocular Pressure
AND
Optic Nerve
injury
High risk of blindness if untreated (acuity <20/200)
Epidemiology
Within top 3 causes of blindness in U.S.
Leading cause of blindness in non-white
U.S.
Prevalence
: 2 Million
Only 50% are estimated to now be under treatment
120,000 are blind due to Glaucoma
Highest risk groups for Glaucoma-related blindness in Blacks and Hispanics
World
Prevalence
: 80 Million (estimated by 2020)
Bilateral blindness due to Glaucoma estimated at 11 million worldwide by 2020
Pathophysiology
Elevated
Intraocular Pressure
(IOP)
Increased production of
Aqueous Humor
by ciliary body
Aqueous Humor
is typically produced at 2 ul/min
Increased outflow resistance at
Aqueous Outflow Angle
Trabecular meshwork
Canal of Schlemm
Progressive changes in optic disc
Nerve damage related to increased IOP is variable
Glaucoma suspects (66% of those with high IOP)
No damage despite high
Intraocular Pressure
(>21)
Optic Nerve
injury rate in suspects: 1% per year
Normal-pressure Glaucoma (15% of Glaucoma patients)
Normal
Intraocular Pressure
(21 mmHg or less)
Glaucoma-related
Optic Nerve
damage
Progressive Glaucomatous cupping at the optic disc
IOP collapses
Optic Nerve
head structural support
Axon
s destroyed by mechanical compression
Peripheral
Visual Field
loss
Open Angle Glaucoma
: Slowly progressive
Narrow Angle Glaucoma
: Rapid
Vision Loss
Types
Primary Glaucoma
Open Angle Glaucoma
(89% of cases)
Outflow blocked by microscopic outflow changes
Results in progressive peripheral
Vision Loss
Usually asymptomatic until 40% of nerve loss
Narrow Angle Glaucoma
(11% of cases)
Outflow tract blocked by base of iris
Permanent
Vision Loss
may occur in hours
Presents as acute painful
Red Eye
with
Vomiting
Secondary Glaucoma
Medications that increase IOP in those predisposed
Corticosteroid
s (Systemic and Topical)
Reversible
Mild Adrenergic or
Anticholinergic Medication
s
Examples
Cold Medications
Antidepressant
s
Antidiarrheals
Effect: Dilate
Pupil
Theoretically worsen angle closure Glaucoma
Not contraindicated in Glaucoma
Resources
Aging Eye Glaucomatrac (Glaucoma Management Tracking)
http://www.agingeye.net/glaucomacharting.index
Aging Eye Glaucoma Video
http://www.agingeye.net/mainnews/video.php
References
Alward (1998) N Engl J Med 339:1298-307 [PubMed]
Distelhorst (2003) Am Fam Physician 67(9):1937-50 [PubMed]
Gupta (2016) Am Fam Physician 93(8):668-74 [PubMed]
Infeld (1998) Postgrad Med 74:709-15 [PubMed]
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