The latest Patch 8.3 PTR build made eye glows dimmer.
Originally Posted by Blizzard
(Blue Tracker / Official Forums)
In the Visions of N’Zoth PTR, testers will soon see initial changes that we’re making to improve how brightly-glowing eyes look on many player-characters. In today’s build, this will be noticeable for Blood Elves, Night Elves, and all races of Death Knights.
As we discussed at BlizzCon, we are bringing many new customization options to player-characters in Shadowlands, and this is an early step that we’re taking to lay groundwork for updating this particular look.
We expect to update brightly-glowing eyes further in future builds of the Visions of N’Zoth PTR.