In the case of lenses for the MFT system, Adobe Lightrooms' built in lensprofiles comprise correction for chromatic abberation, but nor for geometric distortion and/or vignetting.
In addition, the domeport participates in imaging introducing additional abberations, especially when the entrance pupil of the lens is not placed correctly at the center of the radius of curvature of the port (what seems to be quite often the case).
Therefore I created a lensprofile for the Zuiko 8mm 1.8 FE (Olympus EM5-MII; Zen-DP170-N120; 30mm Extension) directly UW in the pool, by taking image series of the Adobe Camera Correction Chart at three different distances (Version 13x19, 108 points; printed on A1).
Those who are interested are invited to download the lensprofile from dropbox: https://www.dropbox.com/sh/am0f6owq687v0fi/AACWHg-7cb7pxMMOG3lBnFxEa?dl=0
(In order to become effective in Ligthroom, it must be placed in the following folder: C:\Users\Username\AppData\Roaming\Adobe\CameraRaw\LensProfiles\1.0)
As can bee seen from the example below, it is useful for partial or complete "defishing", but also vignetting (although at the high aperture values used UW, there is not much vignetting to correct for).
Wolfgang 
Sample image: ISO 400, f8.0, 1/100, ambient light:
Geometric distortion 100% corrected (vignetting corrected 100%):
Geometric distortion 50% corrected (vignetting corrected 100%):
