Non-invasive biometric assessment of ocular rigidity in glaucoma patients and controls

To determine in vivo whether a pharmacologically induced change in intraocular pressure (IOP) leads to measurable changes in axial eye length and whether there is a difference between glaucoma patients and control subjects.

42 subjects (19 patients with primary open angle glaucoma and 23 control patients matched for age and gender) underwent axial eye length measurement using partial coherence laser interferometry and measurement of IOP using dynamic contour tonometry before and 2 h after oral intake of 500 mg acetazolamide. Student's t-test was used to compare differences in the means.

An identical drop in IOP was induced in both the glaucoma (mean+/-SEM: 2.90+/-0.44 mmHg, n=19) and the control group (mean+/-SEM: 3.17+/-0.32 mmHg, n=23). The change in axial eye length was significantly smaller (P=0.026) in the glaucoma group (mean+/-SEM: -14.2+/-3.2 microm, n=19) compared with the control group (mean+/-SEM: -23.0+/-2.98 microm, n=23).

Our results strongly suggest that the ocular rigidity is increased in patients with established glaucoma in comparison to control subjects. Ocular rigidity could play a role in the pathogenesis and pathophysiology of glaucoma. Determination of ocular rigidity could be helpful in detection of glaucoma.