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Source: Fiscella RG, Lesar TS, Edward DP. Glaucoma. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th edition. http://accesspharmacy.com/content.aspx?aid=7998061. Accessed July 10, 2012.

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  • Ocular disorder leading to optic neuropathy characterized by changes in optic nerve head (optic disk) associated with loss of visual sensitivity and field.

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  • Inherited disorder, congenital, or secondary to disease, trauma, or drugs.
  • Secondary open-angle glaucoma caused by:
    • Exfoliation syndrome
    • Pigmentary glaucoma
    • Systemic diseases
    • Trauma
    • Surgery
    • Ocular inflammatory diseases
    • Drugs (Table 1)
  • Secondary glaucoma classified as:
    • Pretrabecular
    • Trabecular
    • Posttrabecular

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Table Graphic Jump Location
Table 1. Drugs that May Induce or Potentiate Increased Intraocular Pressure in Open-Angle Glaucoma
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  • Cause of optic neuropathy unknown.
    • Increased intraocular pressure (IOP) historically considered to be sole cause.
      • Additional contributing factors include increased susceptibility of optic nerve to:
        • Ischemia
        • Excitotoxicity
        • Autoimmune reactions
        • Other abnormal physiologic processes
  • Risk of visual field loss increases with increasing IOP.
    • IOP not constant and changes with:
      • Pulse
      • Blood pressure
      • Forced expiration or coughing
      • Neck compression
      • Posture
    • IOP demonstrates diurnal variation with minimum pressure around 6 p.m. and maximum pressure upon awakening.
    • IOP determined by balance between inflow and outflow of aqueous humor.
      • Inflow
        • Increased by β-adrenergic agents.
        • Decreased by α2- and β-adrenergic blockers, dopamine blockers, carbonic anhydrase inhibitors (CAIs), and adenylate cyclase stimulators.
      • Outflow
        • Increased by cholinergic agents, prostaglandin analogs, and β- and α2-adrenergic agonists.

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  • Second leading cause of blindness
  • Incidence increases with increasing age.

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  • Essential to early diagnosis
    • Annual eye examinations recommended with family history of glaucoma and in diabetics.
    • IOP measurement and eye exams recommended every 3–5 years for those older than 50 years.

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  • Ocular hypertension
    • Family history of glaucoma
    • Black race
    • Severe myopia
    • Presence of only one eye

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  • Slowly progressive and usually asymptomatic until onset of substantial visual field loss. Central visual acuity maintained, even in late stages.

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Signs and Symptoms

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  • No symptoms until substantial visual field loss occurs.
  • Signs
    • Disk changes and visual field loss
    • IOP can be normal or elevated (>21 mm Hg [2.8 kPa]).

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Means of Confirmation and Diagnosis

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  • Diagnosis confirmed by presence of characteristic optic disk changes and visual field loss, with or without increased IOP.
    • Normal tension glaucoma refers to disk changes, visual field loss, and IOP <21 mm Hg (2.8 kPa).
    • Ocular hypertension refers to IOP >21 mm Hg (2.8 kPa) without disk changes or visual field loss.

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Diagnostic Procedures

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  • Ophthalmoscopic exam
  • Measurement of IOP

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  • Reduction of IOP to stop optic nerve damage and preserve visual function

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  • Treatment indicated for all patients with ...

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