Do intense perimetric stimuli saturate the healthy visual system?

Abstract

PURPOSE. A recent proposal for why glaucomatous perimetric sensitivities of approximately 15 to 19 dB or less are unreliable involves the idea that the neural response of normal retinal ganglion cells saturates for intense perimetric stimuli. A predicted consequence of this saturation is that the neural response for two different high intensity stimuli will be the same, leading to an inability to discriminate between them. We test that prediction. METHODS. We used a two-interval forced-choice method of constant stimuli (7 steps, 40 presentations/step) to measure the ability of four healthy observers to discriminate between different intensity Size III perimetric stimuli at 0º, 9º, and 21º ec..