My Roku Ultra was updated yesterday and all screens have black backgrounds. These black backgrounds are causing me severe eyestrain and blurry vision. Therefore, I am not avoiding using my Roku and may not buy any more Roku streaming devices. I plan on trying some other brand for the following reason:
There are reasons why you shouldn’t use a pure black background with white text or colorful pictures or icons placed on it because a pure black background kills all light emitting from the screen. This makes eyes work harder and open wider since it needs to absorb more light. When this occurs, the white letters or pictures can bleed into the black background and cause the text to blur. This effect is known as “halation” and it affects users with astigmatism, which people of all ages could have.
What theme are you using? Have you tried switching to a different one? (Settings -> Theme)