Hook eyes

[Tiger]

Hook eye up, down or straight. How do you know what is best to use for what situation.

[Bob Scheidt]

Typically upturned eyes were used on midges, alot of folks felt the down eye on a 22 would hinder the hook gap on a hook that small.
I also noted most saltwater and big flies are tied on straight eyes. Most freshwater are tied on downturn eyes.
I think an upturned eye has a hooking disadvantage, but on midges the flyfishers I talk to felt the small hook gap was the reason for the upturned eye.

I don't know the science behind the reasons for the straight and downturn eyes.

Bob

[Bill Kiene semi-retired]

They are all from traditions:

Down-eye because they snelled the hooks years ago with a short piece of mono.

Up-eye because that was popular whit the Atlantic Salmon fly fishers so they could use a Turle know.

Straight-eye was the saltwater guys because they did not care.

[Darian]

I've seen some Sailfish flies tied on TUE hooks. Especially, when used in conjunction with a trailer hook. Rainy's ties some of their salty patterns on TUE hooks.

Straight eye hooks lend themselves to tying patterns like the Sea Habit, ALF's, etc. Regular and short shanked, straight eye hooks probably don't obstruct the gap of the hook. Long shanked hooks present different issues.

TDE hooks are generally used in smaller sized patterns (salty). Surf, etc. Altho, I've seen some TUE hooks in patterns tied by Mark Won for surf fishing.

I've seen all 3 styles snelled for bait fishing.

The only limitation is imagination.... :D