EFFECTS OF SHORT-TERM INCREASE OF INTRAOCULAR-PRESSURE ON OPTIC DISC CUPPING

Aims-To evaluate the effect of acute elevation of intraocular pressure (IOP) on optic disc cupping. Methods-10 emmetropic and 10 myopic volu nteers were included in this study. The cup area (CA) and cup volume ( CV) of the optic disc were determined with the Heidelberg retina tomog raph (HRT). After baseline determinations, a suction cup was used to i ncrease the intraocular pressure (IOP) to 20-25 mm Hg above the baseli ne and HRT images were obtained, Results-Baseline IOP was 13.5 (SD 1.3 ) mm Hg and 12.6 (2.6) mm Ny in the emmetropic and myopic groups, resp ectively. The IOP was elevated to 35.4 (3.3) mm Hg and 34.4 (2.5) mm H g in the emmetropic and myopic groups, respectively, When compared wit h their baseline values, the cupping variables (CA and CV) were signif icantly increased (p<0.05) during the suction treatment in both emmetr opic and myopic subjects. Conclusion-There was a significant enlargeme nt in the optic disc cupping during the artificial increment of intrao cular pressure in both emmetropic and myopic eyes. In non-glaucomatous eyes the optic nerve head has a partially dynamic topography dependen t upon the level of IOP.