What is described is a method for treating an adverse side effect of MEK inhibitors by administering a pharmaceutical composition comprising IFN&gamma to a cancer patient being treated by a MEK-inhibitor. The applicants discovered that MEK inhibitors produce unwanted visual disturbances as an adverse side effect in a significant fraction of cancer patients being treated by the drug, and that the side effect causes retinal detachment due to fluid accumulation in the eye. The method treats the retinal detachment caused by the anticancer therapeutic by providing a means of decreasing the amount of fluid present in the retina and/or subretinal space of the eye by administering the pharmaceutical composition comprising IFN&gamma to the basolateral side of the retinal pigment epithelium, preferably by administering the pharmaceutical composition to the anterior surface of the eye in liquid droplets.
