A 70 y.o. woman comes to the ED with decreasing vision. She can no longer read.
What does she have?
A hint follows: she lacks the same thing as the bird below
albino crow
Our patient had macular degeneration with drusen over the macula and central vision loss. This is directly related to a loss of melanin in the eye with aging.
Melanin in retinal pigment cells acts as a natural protector against UV light and blue light damage since it acts as a scavenger for free radicals and heavy metal ions which are toxic to retinal pigment epithelium cells. By damaging the retinal pigment epithelial (RPE) cells that lie underneath the macula, the photoreceptors also die resulting in blindness.
optic atrophy results with lack of melanin
Evolutionarily, melanin evolved in tandem with the visual system and melanophores have been found in the Jurassic period(183 million years ago) in animals like the squid. Melanin is essential for the development of the visual system in animals and this is why albino individuals have incomplete development of the fovea resulting in photophobia , nystagmus and decreased vision .
So, both the patient with vision loss and the albino crow have a lack of melanin.
Melanin plays a role in the development of macular degeneration because while the eye produces melanin during the development of the fetus, it produces a fixed amount and this decreases with age making older individuals susceptible to retinal damage from UV light.
An estimated 1.75 million Americans have decreased vision from age-related macular degeneration (AMD), with about 200,000 new cases each year. The incidence of AMD is expected to double within the next 25 years as the number of older persons continues to increase. The disorder is far more prevalent among whites than among black persons and in people with blue eyes rather than brown.
THE DIAGNOSIS
The diagnosis of macular degeneration can be made from visual inspection of the retina. The macula will appear pale, often with drusen; small yellow deposits of lipids that are unable to be cleared by dying retinal pigment epithelium . Other tests include the Amsler grid and Ocular Coherence Tomography which identifies subretinal drusen.
Amsler grid show wavy lines and central vision loss in AMD
THE TREATMENT
Recent studies have shown that supplementation of melanin derivatives may have a therapeutic effect in AMD. Herrera et al. administered a melanin precursor (QIAPA1©) via sublingual route to women over 70 years old with late-stage wet AMD and showed a decrease in retinal edema .
Other treatments are aimed at stabilizing blood vessels and decreasing fluid leakage by blocking vascular endothelial growth factor-A and angiopoietin-2. VABYSMO (alibercept ) is an intraocular antibody injection which has recently been marketed for this use.
FUN FACT
While albino animals all have visual difficulty; birds are also affected by the lack of melanin in their feathers. Melanin strengthens feathers in birds that migrate. Snow geese have black wingtips for that reason.
snow geese have melanin in their wing tips to create stronger feathers
Herrera AS, Beeraka NM, Solis LFT, Mikhaleva LM, Somasundaram SG, Kirkland CE, et al. The Efficacy of Melanin Precursor QIAPI 1© Against Age-related Macular Degeneration (AMD): A Case Report. Cent Nerv Syst Agents Med Chem. 20. United Arab Emirates: Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.; 2020. p. 218–25.
Al-Shamery N, Biyashev D, et al. From melanogenesis to melanin technologies. Nov 2025 Communications Chemistry. Doi:10.1038/s42004-025-01731-8.
Bird Coloration, Volume 1: Mechanisms and Measurements (eds Hill, G. E., McGraw, K. J.) https://doi.org/10.2307/j.ctv22jnscm (Harvard University Press, 2006).
Kaufmann M, Han Z. RPE melanin and its influence on the progression of AMD Ageing Res Rev. 2024 Jun 1;99:102358. Doi:10.1016.j.arr.2024.102358
https://www.hopkinsmedicine.org/health/conditions-and-diseases/agerelated-macular-degeneration-amd