Intraocular pressure, anterior chamber depth and axial length following intravenous mannitol.

The intraocular pressure (IOP), anterior chamber depth (ACD), and axial length (AL) were measured in 38 eyes of 19 subjects before and after intravenous mannitol injection (12.5 g). Intraocular pressures dropped over the initial 30 min then rose back to baseline by 2 hr. Time 0 min:14.2 mmHg, 15 min:12.7 mmHg, 30 min:11.4 mmHg, 60 min:12.0 mmHg, 90 min, 13.2 mmHg, 120 min:14.1 mmHg. Sitting and supine ACD and AL did not change following mannitol injection. This study supports an ocular hypotensive effect of mannitol without reducing vitreous volume using a relatively low dose of mannitol (12.5 g). This finding has important implications for its use in ocular surgery at this dosage.