In Georgia a locum cured eye disease (8)
I believe the answer is:
glaucoma
'eye disease' is the definition.
(glaucoma is a kind of eye disease)
'in georgia a locum cured' is the wordplay.
'in' means one lot of letters goes inside another.
'georgia' becomes 'ga'.
'cured' is an anagram indicator.
'a'+'locum'='alocum'
'alocum' is an anagram of 'laucom'.
'ga' enclosing 'laucom' is 'GLAUCOMA'.
(Other definitions for glaucoma that I've seen before include "condition of eyeball affecting sight" , "A cola mug, strangely, might give you an eye disease" , "Guam coal can cause a strange eye disease" , "Guam coal can cause eye disease, strangely" , "A cola mug might cause eye disease, strangely" .)