Foster Kennedy syndrome classically presents with which combination?

• A. Simultaneous optic disc edema in one eye and optic disc atrophy in the fellow eye
• B. Bilateral optic disc edema with preserved vision
• C. Macular edema with normal optic discs
• D. Optic disc pallor without edema

Answer: (A)

Foster Kennedy syndrome is characterized by a mass lesion, usually at the frontal base such as an olfactory groove meningioma, compressing the optic nerve on one side. This causes optic disc edema in the affected eye due to local compression and impaired axoplasmic flow. Meanwhile, the contralateral optic nerve undergoes chronic degeneration from the same lesion’s effects, leading to optic atrophy on the other side. So the classic finding is one eye with swollen (edematous) optic disc and the opposite eye with a pale, atrophic disc. This pattern helps distinguish it from other causes of disc swelling or pallor.