Intraocular pressure and optic nerve damages in monocular early glaucoma: a comparative study of primary open angle glaucoma and low tension glaucoma

The correlation of intraocular pressure (IOP) to optic nerve damages was studied in 17 patients of primary open angle glaucoma (POAG) and 24 patients of low tension glaucoma (LTG) both with monocular early glaucomatous damages. In the POAG group, the mean IOP was higher in the glaucomatous eye than in the other, while in the LTG group there was no significant IOP difference between the two eyes. Comparing the optic nerve damages in both groups, patients of POAG presented a concentrically enlarged cup with even disc rim and diffuse retinal nerve fiber layer defect (RNFLD), while patients of LTG exhibited a paracentrical cup with uneven disc rim and localized RNFLD. The results suggested that there could be different mechanisms of optic nerve damages in the two groups.