Macular Degeneration, Age-Related

Essentials of Diagnosis

• Older age group

• Acute or chronic deterioration of central vision in one or both eyes

• Distortion or abnormal size of images in one or both eyes, sometimes developing acutely

• No pain or redness

• Macular abnormalities seen by ophthalmoscopy

General Considerations

• Age-related macular degeneration is classified as dry ("atrophic," "geographic") or wet ("neovascular," "exudative")

• Both are progressive and usually bilateral; however, manifestations, prognosis, and management differ

• Although dry age-related macular degeneration is much more common, wet age-related macular degeneration accounts for about 90% of all cases of legal blindness due to age-related macular degeneration

Demographics

• Leading cause of permanent visual loss in the older population in developed countries

• Prevalence progressively increases over age 50 years (to almost 30% by age 75)

• Occurrence and response to treatment are likely influenced by genetically determined variations, many of which involve the complement pathway

• Other associated factors

  • Race (usually white)

  • Sex (slight female predominance)

  • Family history

  • Hypertension

  • Hypercholesterolemia

  • Cardiovascular disease

  • Farsightedness

  • Light iris color

  • Cigarette smoking

• Age-related maculopathy that is characterized by retinal drusen is precursor to age-related macular degeneration

  • Hard drusen appear ophthalmoscopically as discrete yellow subretinal deposits

  • Soft drusen are larger, paler, and less distinct

  • Large, confluent soft drusen are risk factors for neovascular (wet) age-related macular degeneration

• Age-related macular degeneration results in loss of central vision in the majority of patients

• Peripheral fields, and hence navigational vision, are maintained, except in patients with severe wet age-related macular degeneration

• Dry age-related macular degeneration

  • Gradual progressive bilateral visual loss due to atrophy of the

    • Outer retina

    • Retinal pigment epithelium

    • Choriocapillaris, which supplies blood to both the outer retina and the retinal pigment epithelium

• Wet age-related macular degeneration

  • Onset of visual loss is more rapid and more severe than in atrophic degeneration

  • New choroidal vessels grow under either the retina or the retinal pigment epithelial cells, leading to accumulation of exudative fluid, hemorrhage, and fibrosis

  • The two eyes are frequently affected sequentially over a period of a few years

• On ophthalmoscopic examination, various abnormalities are visualized in the macula

• Fundal photography after intravenous fluorescein (fluorescein angiography) is often required

• Dry age-related macular degeneration: No specific treatment

• Wet age-related macular degeneration

  • Rehabilitation including low-vision aids is important

  • Inhibitors of vascular endothelial growth factors (VEGF), such as ranibizumab (Lucentis), bevacizumab (Avastin), and aflibercept (VEGF Trap-Eye, Eylea), cause regression of choroidal neovascularization with resorption of subretinal fluid and improvement or stabilization of vision

  • Long-term repeated intraocular injections are required and must be administered in the eye clinic several times a year, if not monthly

• No dietary modification has been shown to prevent the development of age-related maculopathy

• However, progression may be reduced by oral treatment with antioxidants (vitamins C and E), zinc, copper, and carotenoids (lutein and zeaxanthin, rather than vitamin A [beta-carotene])

• Oral omega-3 fatty acids do not provide additional benefit

• Patients should be advised to stop smoking

Prognosis

• Treatment is well tolerated with minimal adverse effects, but there is a risk of infection (1/2000), retinal detachment (1/10,000), vitreous hemorrhage and cataract

• A certain percentage of patients do not respond to anti-VEGF injections and up to one-third of eyes lose vision despite regular treatment

When to Refer

• Older patients with sudden visual loss, particularly paracentral or central distortion or scotoma with preservation of central acuity, should be referred urgently to an ophthalmologist