A hollow-head saltwater streamer with dark spot suggesting an eye. More realistic (hard) glued on eyes take a beating when angling on a beach with abrasive sand and stones, and often come off. A soft eye impression is a more durable/permanent trigger point…
trout on dries 
That eye is created with material, not a marker that always fades to pale, right? A bold black eye that never goes away. Trimmed to size and shape.
I love the concept!
Jim: It is darker material which I tied in and trimmed, but I do ” touch up” with marker (cheat). And an experienced angler like you knows, as you stated, the marker fades. My first trip roosterfishing I found this out and now carry a marker in backpack on trips to retouch eyes, tail tips…etc. Merry Christmas!