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AGE-RELATED MACULAR DEGENERATION
Age-related macular degeneration is a common, chronic, progressive, degenerative disease that causes central loss of vision due to abnormalities that occurs in the pigment, neural and vascular layers of the macula.
The macular disorder may have one or more of the following:
- Formation of drusen which are localized deposits of extracellular material usually concentrated in the macula
- Abnormalities in the retinal pigment epithelium (eg hypopigmentation or hyperpigmentation)
- Retinal pigment epithelium and choriocapillaris geographic atrophy
- Neovascular (exudative) maculopathy
Decreased central vision and distortion of seeing straight lines are the most common symptoms.

Introduction

  • The macular disorder may have one or more of the following:
    • Formation of drusen which are localized deposits of extracellular material usually concentrated in the macula
    • Abnormalities in the retinal pigment epithelium (eg hypopigmentation or hyperpigmentation)
    • Retinal pigment epithelium (RPE) and choriocapillaris geographic atrophy
    • Neovascular (exudative) maculopathy
  • Leading cause of irreversible vision loss especially in the elderly
  • Decreased central vision and distortion of seeing straight lines (metamorphopsia) are the most common symptoms of age-related macular degeneration (AMD)

Definition

  • Chronic, progressive, degenerative disease that occurs in the pigment, neural and vascular layers of the macula that causes central vision loss

Signs and Symptoms

  • Early stage manifestations:
    • Decline of reading ability in dim light
    • Glare difficulty
    • Dark and light adaptation difficulty (eg the patient wakes up at night and unable to read the clock because of seeing central dark patch in the visual field that disappears within a few minutes as the eye adapts)
    • Needs to use magnifiers and bright light to be able to see as well as the patient used to
    • Gradual progressive central vision loss
  • Late stage manifestations:
    • Metamorphopsia or the patient complains that straight line appearing crooked or wavy that can be confirmed by using Amsler grid
    • Difficulty in reading small sizes of print and then later with larger print and/or words
    • Profound and rapid central vision loss

Risk Factors

  • Increasing age (>50 years old)
  • Genetic factors (eg complement factor H genes)
  • Cigarette smoking history of >20 years
    • Current smokers have 2- to 3-fold risk and there is a dose-relationship with pack years of smoking
  • Diet (eg low intake of antioxidants and zinc, high total fat and trans-fat)
  • Obesity
  • Race
    • While Caucasians are at increased risk compared to African or Hispanic descent, studies fail to show consistent differences in risk between Caucasians and Asians
  • Gender
    • Studies have consistently shown women to be at increased risk
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