Effect of short-term intraocular pressure elevation on the rabbit electroretinogram

Pattern electroretinograms (PERGs), with a presumed ganglion cell origin, and oscillatory potentials (OPs), with a presumed inner retinal origin, are reduced in glaucoma. Flash ERGs are reduced at intraocular pressures (IOPs) greater than 60 mm Hg. A study was designed to investigate the time-course of change in PERGs, OPs, and flash ERGs after increasing the IOP of ten rabbit eyes to 35-45 mm Hg by using a suction-cup apparatus. Although flash ERG b-wave amplitude was unchanged (P = 0.32), PERGs were reduced (P less than 0.001) immediately after IOP elevation, as were OPs (P = 0.03). Both PERG and OP amplitudes returned to normal immediately after normal IOP was restored. This study showed that the rabbit is a suitable model for studying PERGs. It also suggested that moderate IOP elevation for 10 min reversibly impaired ganglion cell and inner retinal function in the rabbit, although more external function was unchanged.