I would like to congratulate Drs Vieira and colleagues for their study on the increased intraocular pressure during weight lifting.1 The authors describe a significant increase in intraocular pressure during weight lifting which they consider to be a risk factor for glaucoma. I would like to ask the authors whether they have considered that during weight lifting, the cerebrospinal fluid pressure may increase simultaneously with the intraocular pressure because the cause for the increase in both pressures is a rise in the suprathoracic vein pressure. A similar mechanism may exist in high-resistance wind instrument players or patients with chronic asthma. If the pressure of the cerebrospinal fluid surrounding the retrobulbar optic nerve increases similar to the intraocular pressure, the trans-lamina cribrosa pressure difference may remain unchanged. One may argue that the trans-lamina cribrosa pressure difference may pathogenetically be more important than the intraocular pressure alone for the development of glaucomatous optic nerve damage. The situation may be a bit similar if one dives 100 m deep, with an 11-fold increase in intraocular pressure as well as in cerebrospinal fluid pressure, a normal trans-lamina cribrosa pressure difference, and without development of an acute glaucoma attack. One of the open questions is what may happen to the blood capillaries in the lamina cribrosa, if in eyes with elevated intraocular pressure and elevated cerebrospinal fluid pressure the pressure in the lamina cribrosa is increased, although the trans-lamina cribrosa pressure difference may be normal.