You can have early signs of age-related macular degeneration (drusen) without even knowing. This makes it vital to have your eyes tested and macula checked by an eye care professional on a regular basis.
Links
[1] https://staging.mdfoundation.com.au/content/early-signs-0
[2] https://staging.mdfoundation.com.au/content/changes-vision
[3] https://staging.mdfoundation.com.au/content/professional-testing
[4] https://staging.mdfoundation.com.au/content/testing-amsler-grid