To report a case of acute transient myopic shift in a patient with fever of unknown origin.

A 31-year-old woman without a history of any ophthalmic problems presented with a sudden onset of bilateral blurred vision. She was admitted with the diagnosis of fever of unknown origin (FUO). Ophthalmic examination revealed a visual acuity of 0.06 in the right eye and 0.1 in the left eye. A myopic shift of 3.12 diopters (D) and 2.25D was noted in the right and left eyes, respectively. Retinal folds and choroidal thickening accompanied the myopic shift. On the third day after onset, visual acuity had decreased even more. Myopic shift increased to 4.87D in the right eye and 4.50D in the left eye. At the same time, the depth of the anterior chamber maximally decreased and the thickness of the lens was maximally increased. One week later, the myopic shift was normalized to emmetropia. The depth of the anterior chamber and the thickness of the lens also normalized as the fever subsided.