Age-related macular degeneration (AMD) is a major cause of blindness in developed countries, and the molecular pathogenesis of early events of AMD is poorly understood. It is known that age-related alterations of retinal pigment epithelium (RPE) cells and of glial reactivity are early hallmarks of AMD.

https://www.nature.com/articles/srep41533

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En 13 ojos (20,06%) se observó una leve alteración del epitelio pigmentario macular, 1 de ellos combinado con un aumento del brillo de la membrana limitante interna. En 2 ojos (3,2%) se detectó una degeneración macular asociada a la edad de tipo seca en el polo posterior.

https://ddd.uab.cat/pub/trerecpro/2012/hdl_2072_203409/TR-Kh...

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Human retinal macular pigment (MP) is formed by the carotenoids lutein and zeaxanthin (including the isomer meso-zeaxanthin).

https://pubmed.ncbi.nlm.nih.gov/26313550/

Sorry, I've made a mistake. My answer should have been 'Alterations of retinal macular pigment'.

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Lutein and zeaxanthin, two carotenoid pigments of the xanthophyll subclass, are present in high concentrations in the retina, especially in the macula. They work as a filter protecting the macula from blue light and also as a resident antioxidant and free radical scavenger to reduce oxidative stress-induced damage.

https://journalretinavitreous.biomedcentral.com/articles/10....

The macula is a small but important area in the center of the retina. You need the macula to clearly see details of objects in front of you, like faces and written text.

https://www.aao.org/eye-health/anatomy/macula-6

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My answer is very confusing, so I'll start again!

ALT = Alteración/alteraciones

EPM = epitelio pigmentario macular

In the following reference, on page 17 there's a list of abbreviations.

https://www.tdx.cat/bitstream/handle/10803/4297/efm1de1.pdf?...

The early stages consist of alterations in the coloration of the macular pigment epithelium, both hypo- and hyperpigmentation, and the presence of drusen of greater than 125 µm in diameter.

https://entokey.com/pharmacotherapy-of-age-related-macular-d...

The right translation is macular pigment epithelium. Sorry if I've confused you.