II. Definitions
- Glaucoma
- Increased Intraocular Pressure AND Optic Nerve injury
- High risk of blindness if untreated (acuity <20/200)
III. 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
IV. 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
- Increased production of Aqueous Humor by ciliary body
- 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
- Glaucoma suspects (66% of those with high IOP)
- Progressive Glaucomatous cupping at the optic disc
- IOP collapses Optic Nerve head structural support
- Axons destroyed by mechanical compression
- Nerve damage related to increased IOP is variable
- Peripheral Visual Field loss
- Open Angle Glaucoma: Slowly progressive
- Narrow Angle Glaucoma: Rapid Vision Loss
V. 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
- Open Angle Glaucoma (89% of cases)
- Secondary Glaucoma
- Medications that increase IOP in those predisposed
- Corticosteroids (Systemic and Topical)
- Reversible
- Mild Adrenergic or Anticholinergic Medications
- Examples
- Cold Medications
- Antidepressants
- Antidiarrheals
- Effect: Dilate Pupil
- Theoretically worsen angle closure Glaucoma
- Not contraindicated in Glaucoma
- Examples
- Corticosteroids (Systemic and Topical)
- Medications that increase IOP in those predisposed
VI. Resources
- Aging Eye Glaucomatrac (Glaucoma Management Tracking)
- Aging Eye Glaucoma Video