Age-related macular degeneration (AMD)

Essentials

  • Age-related macular degeneration (AMD or ARMD ) refers to degeneration of the area of high-acuity vision (macula) in the fundus of the eye, associated with aging.
  • AMD is divided into dry and wet forms.
  • The dry form progresses slowly over several years.
  • The wet form may progress rapidly within days or weeks.
  • In AMD, both distance and near vision deteriorate.
  • Refer a patient with the suspected wet form of the disease for investigations and treatment by an ophthalmologist within 1–7 days.

Epidemiology

  • AMD is the most common cause of visual impairment in patients aged over 65 years in industrialized countries.
  • According to an estimate, there were almost 200 million people worldwide with 2020, increasing in 2040 to 288 million people https://pubmed.ncbi.nlm.nih.gov/25104651/.
    • In Finland, the number of patients with AMD is estimated to exceed 100,000.
    • AMD represents about 40% of all cases of visual impairment entered in The Finnish Register of Visual Impairment.
    • In people over 65, AMD accounts for about 60% of all cases of visual impairment, and about half of these are due to the wet form of the disease.
  • About 10–20% of patients have the wet form of the disease.

Risk factors

  • Age is the most important risk factor.
  • AMD has certain risk factors in common with cardiovascular morbidity: hypertension, arteriosclerosis, hypercholesterolaemia, overweight, low level of physical activity, and an unhealthy diet.
    • Eating fish, vegetables, berries and fruit is recommended to prevent AMD.
  • Smoking is a risk factor for AMD, as well.
  • Persons with AMD have been shown to have a genetic predisposition, most strongly associated with genes of the complement system.

Findings

Atrophic or dry form

  • In the dry form of the disease, atrophy of the retinal pigment epithelium, pigment dispersion and drusen deposits can be seen.

Exudative or wet form

  • The wet form of the disease is often preceded by the dry form.
  • Pigment epithelial detachment and damage can be seen in wet AMD.
  • Fragile, oozing new blood vessels grow from the choroid under the retina.
  • Retinal bleeding and exudates are typical for the wet form of disease.

Symptoms

  • Distortion of straight lines (metamorphopsia) or changes in image size (micropsia, macropsia); e.g. during reading, the size of the letters may vary and some letters may disappear.
  • The patient may see a grey central patch or a part of the central vision may be lacking (relative or absolute scotoma), which makes it difficult to read or recognise people's faces.
  • The patient may experience that her/his colour vision has changed (especially the colours blue and yellow).
  • Both near and distance vision progressively deteriorate.

Diagnosis

  • The diagnosis is based on patient history, visual acuity, manual ophthalmoscopy or biomicroscopy and optical coherence tomography (OCT) or optical coherence tomography angiography (OCT-A).
  • In the case of differential diagnostic problems, fluorescein angiography (FAG) or indocyanine green angiography (ICG) may be used.
  • Diseases to be considered in differential diagnosis include myopic retinal degeneration, central serous chorioretinopathy, inflammatory processes, diabetic retinopathy, vascular occlusions and vascular structural changes, tumours and hereditary degenerative diseases.

Treatment and prognosis

  • Intravitreously administered inhibitors of vascular endothelial growth factor (VEGF; bevacizumab, ranibizumab, aflibercept and brolucizumab) have been shown to slow down the deterioration of vision [Evidence Level: A]. Photodynamic therapy [Evidence Level: A] is also used for the treatment of certain types of AMD. The treatment possibilities should always be assessed by an ophthalmologist.
  • The patient will not be completely blinded.
    • Reading vision is impaired in many cases.
    • As peripheral visual fields are preserved, moving around usually succeeds moderately well.
    • In rehabilitation, it is essential to take care of the provision of assistive devices and to provide patient education on their use.
  • Regular examination of vision in each eye separately using the Amsler grid chart (see e.g. https://www.aao.org/eye-health/tips-prevention/facts-about-amsler-grid-dai...) is important in follow-up. If the patient registers new changes in the grid (distortion of lines or scotomas), he/she should seek treatment within the next few weeks.
  • Dry AMD may proceed to wet AMD.
  • An ophthalmologist may suggest high doses of antioxidant and trace element supplements (vitamins C and E, beta carotene [beta carotene not for smokers] and zinc as trace element) [Evidence Level: B] to slow down the progression of dry AMD.

Evidence Summaries

References

1. Bakri SJ, Thorne JE, Ho AC et al. Safety and Efficacy of Anti-Vascular Endothelial Growth Factor Therapies for Neovascular Age-Related Macular Degeneration: A Report by the American Academy of Ophthalmology. Ophthalmology 2019;126(1):55-63.  [PMID:30077616]
2. Elshout M, Webers CAB, van der Reis MI et al. A systematic review on the quality, validity and usefulness of current cost-effectiveness studies for treatments of neovascular age-related macular degeneration. Acta Ophthalmol 2018;96(8):770-778.  [PMID:29862641]
3. Solomon SD, Lindsley K, Vedula SS et al. Anti-vascular endothelial growth factor for neovascular age-related macular degeneration. Cochrane Database Syst Rev 2019;3():CD005139.  [PMID:30834517]

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