Multiple If Statement to Strip Text at End

I've been trying to get this multiple if statement to work, but I can't seem to get it right. I have a large list of cells with procedures that have the laterality indicated at the end: i.e:

LASIK SURGERY OD
LASIK SURGERY OS
LASIK SURGERY OU

I'm trying to strip the OD,OS,OU with a long nested IF that uses ISERR,LEFT,and FIND but no such luck.

Yea, sorry. The list of cells also have the more user friendly English definition as well as the Latin abbreviation:

REFRACTIVE SURGERY OS (LEFT EYE)
OPTOS COLOR PHOTO OS (LEFT EYE)
OCT MACULA CIRRUS OD (RIGHT EYE)
VISUAL FIELD 10-2 OD (RIGHT EYE)
OCT MACULA HEIDELBERG OD (RIGHT EYE)
HESS SCREEN TEST - OU (BOTH EYES)
CORNEAL TOPOGRAPHY NIDEK OU (BOTH EYES)
OCT OPTIC NERVE STRATUS OU (BOTH EYES)
BSCAN OU (BOTH EYES)
LUCENTIS (RANBIZUMAB) INTRAVITREAL INJECTION OD (RIGHT EYE)
LUCENTIS (RANBIZUMAB) INTRAVITREAL INJECTION OS (LEFT EYE)



So I'm attempting to use something like:

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But within a nested IF that factors in all three possibilities.

Perhaps

=LEFT(A1,SEARCH(" O? ",A1&" ")-1)