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Introduction

Macular degeneration (aka age-related maculopathy – ARM) is a condition that causes gradual visual loss, typically in older patients.

It can be split into two types:

  • Dry – atrophic
    • Slow decline of vision
  • Wet – exudative
    • More rapid loss of vision
    • Can present super-imposed on dry macular degeneration

Wet and dry types may not be distinguishable in the early stages.

Red flags for macular degeneration

  • Decrease in central vision (macula)
  • Distortion of vision – e.g. distorted lines, letter missing when reading
  • Previous visual loss in other eye from macular degeneration

Epidemiology and Aetiology

  • Typically patients aged >55
  • Smoking
    • 3-4x increased risk
  • FHx of macular degeneration
    • 50% chance if 1st degree relative with ARM
  • Diabetes
  • Previous ARM in other eye
  • Dry ARM
    • More common – about 75% of cases
    • Changes occur very gradually
    • Near and distant vision affected
    • Loss is often symmetrical
    • Can progress to wet ARM
    • Not easily treatable
  • Wet ARM
    • Vascular proliferation under the retina
    • Treatable
    • Can causes more sudden and abrupt changes in visual acuity

Presentation

  • Decline in visual acuity
    • Affects mainly central vision
    • Difficulty reading, watching TV or recognising faces
    • Distortion of vision – can be tested using an Amsler Grid
  • Usual gradual, but can be acute
  • Visual fields will be normal
  • No pupillary defects, including no relative afferent pupillary defect
  • Normal red reflex
Macular Degeneration example of vision

An example of visual acuity in macular degeneration. Normal vision the left, affected vision on the right. Note the particular affect in the centre of vision and washed out colours. This file is modified from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Retinal imaging

Characteristic features are visible on fundoscopy and retinal imaging. These include:

Dry:

  • “Drusen” – aka soft exudates – pale-ish spots that appear on the retina. These gradually spread as the disease progresses
  • Atrophy of the retina – often resulting in loss of pigmentation, and a washed-out appearance of the retina

Wet

  • Wet macular degeneration may also cause scarring and haemorrhages
  • New blood vessel formation
Retinal image in macular degeneration

Image of the retina from a patient with dry macular degeneration. Note the darker than normal colour of the macular, and the presence of Drusen on the retina. This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Management

Dry

  • High dose vitamin supplementation – AREDS2 formulation
    • e.g. “Macu-vision” or “VisionCare”
  • Advise smoking cessation
  • Patients with recent decrease in vision that is central, or involves distortion – need to be seen within 1 week by ophthalmologist
  • Annual eye examination with optometrist or ophthalmologist

Wet

  • Injections of anti-VEGF into the eye – thought to slow the process of inflammation that leads to new vessel formation and destruction of the macula
  • Laser therapy targeted at the new blood vessels – can reduce the inflammation associated with the formation of these new vessels

References

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