primary%20open-angle%20glaucoma
PRIMARY OPEN-ANGLE GLAUCOMA
Primary open-angle glaucoma (POAG) is a chronic, progressive, usually bilateral disease of the eye with an insidious onset.
It is most often characterized by optic nerve damage, defects in the retinal fiber layer and subsequent visual field loss in the absence of underlying ocular disease or congenital abnormalities.
It is generally asymptomatic until it has caused a significant loss of visual field.
Occasionally, patients with very high intraocular pressure may complain of nonspecific headache, discomfort, intermittent blurring of vision or even halos caused by corneal edema.

Introduction

Ocular Hypertension (OH)

  • Refers to intaocular pressure (IOP) >21 mmHg or IOP that is >2-3 standard deviations from the normal population mean, in the absence of optic nerve damage or visual field defects
  • Represents a major risk for future development of primary open-angle glaucoma (POAG)

Definition

  • Primary open-angle glaucoma (POAG) is a chronic, progressive, usually bilateral disease w/ an insidious onset
  • Most often characterized by optic nerve damage, defects in the retinal fiber layer & subsequent visual field loss in the absence of underlying ocular disease or congenital abnormalities
    • Usually of adult onset w/ open normal appearance of anterior chamber angles

Signs and Symptoms

  • It is generally asymptomatic until it has caused a significant loss of visual field
    • Visual acuity is lost when there is central visual field loss w/c is a late manifestation of the disease 
  • Occasionally, patients w/ very high intraocular pressure (IOP) may complain of nonspecific headache, discomfort, intermittent blurring of vision or even halos caused by corneal edema
    • Although a high IOP is associated w/ open-angle glaucoma, it is not necessary for the diagnosis & is considered a “risk factor”; many patients w/ primary open-angle glaucoma (POAG) do not have increased IOP & not all patients w/ increased IOP will develop a glaucoma

Risk Factors

  • Age - incidence of primary open-angle glaucoma (POAG) increases w/ age
  • Race - estimated prevalence is approx 3x greater among African Americans, Hispanics/Latino & even higher among Afro-Caribbeans
  • Family history - risk is increased in those w/ an affected 1st-degree relative (parent or sibling, w/ the latter having the strongest association)
  • Elevated intraocular pressure (IOP)
    • Currently, there is no evidence of a threshold IOP for the onset of POAG although risk of developing glaucoma is 13x greater for those w/ IOP >26 mmHg
    • Traditional definition of a normal IOP is 2 standard deviations above normality (21 mmHg) 
  • Thin cornea - increases risk for developing glaucoma
  • Pseudoexfoliation
  • Myopia
  • Low ocular perfusion pressures
  • Local/ocular
    • Optic disc hemorrhage
    • Peripapillary atrophy
  • Systemic
    • CV disease
    • Hypertension
    • Type 2 diabetes mellitus
    • Hypothyroidism
    • Migraine headache, peripheral vasospasm
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