Electroretinogram (ERG) and visually-evoked responses from the optic tract, lateral geniculate nucleus, and visual cortex of anesthetized cats were examined with induced elevations of the intraocular pressure (IOP). The scotopic process was more susceptible to elevations of IOP than the photopic process. At IOP levels reaching diastolic blood pressure, the scotopic b-wave of the ERG almost disappeared leaving a photopic pattern of response. All responses disappeared gradually as the IOP was raised to the level of systolic blood pressure. The susceptibility of scotopic and photopic response to elevated IOP differed. The scotopic b-wave of the ERG was most susceptible to elevated IOP. The visual cortical response was more resistant to raised IOP than that from the optic tract and lateral geniculate nucleus.
Uenoyama K, McDonald JS, Drance SM. The Effect of Intraocular Pressure on Visual Electrical Responses. Arch Ophthalmol. 1969;81(5):722–729. doi:10.1001/archopht.1969.00990010724023