Correct!
You are looking at convergence and retraction of the eyes on attempted upward gaze. The pinealoma
presses on the dorsal midbrain and, more importantly, on the posterior commissure, which carries important connections for upward gaze. As upward gaze fails, the brain misfires,
activating all extraocular muscles and pulling the eyes backward into the orbit. Because the medial rectus muscles are the strongest extraocular muscles, the eyes also converge.
This bizarre eye movement evokes pain around the eyes. Any lesion in the adjacent thalamus (mostly stroke) or midbrain (demyelination, tumor) can cause this phenomenon, as can
obstructive hydrocephalus from aqueductal stenosis or ventricular shunt malfunction. This oscillation is not truly a nystagmus because it is not initiated by a conjugate slow phase
drift. Rather, it is a form of clonus, or synchronous contraction of many muscle groups. Convergence retraction is never an isolated phenomenon. Impaired upgaze will always be
there. Reduced pupil constriction to light (often with preservation of constriction to a near target), hypertropia, esotropia, and exotropia are other common accompaniments.
