Macular degeneration and retinitis pigmentosa
- Lesion
Macular degeneration destroys central vision in older adults; retinitis pigmentosa is an inherited loss of rods that starts with night blindness.
What it is
Age-related macular degeneration (AMD) is the commonest cause of irreversible central visual loss in older adults in high-income countries. Deposits called drusen collect between the retinal pigment epithelium and Bruch membrane. In dry (atrophic) AMD, the pigment epithelium and photoreceptors are slowly lost; in wet (neovascular) AMD, choroidal vessels grow through Bruch membrane, leak and bleed, then scar. Risk factors include age, smoking and variants in complement genes such as CFH. Retinitis pigmentosa is a group of inherited diseases of rods and then cones.
Step by step
- With age, waste from photoreceptor renewal builds up under the pigment epithelium.
- Drusen form and activate complement; inherited CFH variants weaken its control.
- Inflammation and oxidative stress damage pigment epithelium and Bruch membrane.
- Pigment epithelium and photoreceptors die (dry AMD), or
- Choroidal vessels break through Bruch membrane, leak and bleed under the macula (wet AMD).
- Bleeding organises into a disciform scar and central vision is lost.
Dry vs wet AMD and retinitis pigmentosa
| Feature | Dry AMD | Wet AMD | Retinitis pigmentosa |
|---|---|---|---|
| Main lesion | Drusen, pigment epithelium atrophy | Choroidal new vessels through Bruch membrane | Rod then cone loss |
| Speed | Slow, years | Weeks to months | Years, from childhood or youth |
| Vision lost | Central | Central, with distortion | Peripheral and night vision first |
| Fundus | Yellow drusen, geographic atrophy | Fluid, blood, grey membrane, scar | Bone-spicule pigment, pale disc, thin vessels |
| Treatment | Supplements in selected cases | Anti-VEGF injections | Supportive; gene therapy for some forms |
Clinical notes
- Distortion of straight lines (metamorphopsia) on an Amsler grid suggests wet AMD and needs urgent referral.
- People with AMD keep peripheral vision and benefit from low-vision rehabilitation.
Test yourself
Think of the answer, then tap the question to see it.
What are drusen?
Extracellular deposits of lipid, protein and complement between the retinal pigment epithelium and Bruch membrane.
What defines wet (neovascular) AMD?
Choroidal new vessels that grow through Bruch membrane under the retina, leaking fluid and blood.
Which cells are lost first in retinitis pigmentosa?
Rod photoreceptors, causing night blindness and loss of peripheral vision, followed by cones.
Elsewhere in DurgiPedia
- The retina and macula as seen on OCT
- Intravitreal anti-VEGF injections
- Gradual visual loss in adults
- Retina: the ten layers, rods and cones
- The retina and phototransduction
- Complement: three pathways, MAC, regulators
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Macular Degeneration | Age-related Macular Degeneration | MedlinePlus (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.