Abstract
Abstract: :
Purpose: Pseudorandom flash stimuli were applied to elicit cone electroretinograms (ERGs) in 1970's (Fricker, et al. 1975, Larkin, et al. 1979). Since multifocal technique (Sutter, et al 1991) was developed based on the pseudorandom stimulus, analyzing the nonlinear responses in the full field pseudorandom ERG (ffprERG) will provide the simple way to explore the basis of the higher order kernel response which has been tested as a functional index of the inner retinal layer in multifocal electroretinograms (mfERGs). Methods: A white light-emitting diode (LED) built-in contact lens electrode (H-2000, Kyoto Contact Lens, Japan) was driven by a LED driver (CLS-10, Mayo, Japan) sensing the surface of the stimulus of the VERIS system (EDI Inc., CA). Pseudorandom flashes with the duration of the emission: 1 ms, intensity of the emission: 2.5-10,000 cd/m2 and the base rates: 18.75 and 75 Hz stimulated the dilated eye in four normal volunteers. The 1st order (K1), the 1st slice of the 2nd order (K2.1), the 2nd slice of the 2nd order (K2.2), the 3rd slice of the 2nd order (K2.3), the 1st slice of the 3rd order (K3.1) and the 1st slice of the 4th order kernel responses were extracted. Results: All kernel responses were duly obtained in the net 54.6" or 109.2" recording time with 75 Hz base rate. Higher responses converged more steeply into the base line and even more steeply with 18.75 Hz base rate. The induced components that are the copies of the higher order kernels intricately decorated the late phase of each kernel response. The emission intensity less than 0.01 cds/m2 elicited show and homogenous K1s associated with flat K2.1 and higher. Conclusions: FfprERGs illustrate the basic aspects of higher order kernels i.e. the complex form of the induced components and the different intensity response characteristics without stray light effects. Recording time is short enough and the favorable fixation is not required. In order to assess the clinical utility of the higher order kernel response, ffprERG should be tested in disorders that affect broad retinal area.
Keywords: electroretinography: non-clinical