Why is DALK done in acute hydrops due to keratoconus

Why is DALK done in acute hydrops due to keratoconus.

Hydrops occur due to split/tear in descemet membrane…

In DALK we only replace above layers except descemet and endothelium

Rather these are the layers which should be replaced…

So why not go for DSEK?

And Why DALK?

DALK is performed in keratoconus eyes with previous/healed hydrops