Synonym for periodic ophthalmia ... An acute iridocyclitis of horses, involving one or both eyes; it subsides only to recur at intervals of varying length and usually ends in blindness; the cause is uncertain but some have associated it with leptospires; does not appear to be contagious. ... Synonym: moon blindness. ... (05 Mar 2000) ... 
Periodic opthalmia, or uveitis (inflammation of internal eye that comes and goes)
Periodic ophthalmia.
[n] - recurrent eye inflammation in horses
mooneye noun recurrent eye inflammation in horses; sometimes resulting in blindness
a disease of horses in which the eyes suffer from recurring attacks of inflammation, eventually resulting in opacity and blindness.