Recording of Fast Oscillations of the Corneoretinal Potential with an Automated Electro-oculograph Nidek EOG-2 in a Series of Normal Subjects
Hiroshi Nakao, Norio Miki, Masao Nagata, Yuji Sasaki, Akira Setogawa, Akiko Narita, Ryoko Ishihara, Keiko Nishimura, Takashi Baba and Akihiko Tamai
Department of Ophthalmology, Faculty of Medicine, Tottori University, Yonago 683, Japan
Using a newly devised automated electro-oculograph Nidek EOG-2, fast oscillations (FOs) of the electro-oculogram were recorded in 120 eyes of 60 normal subjects classified into the second to the seventh decades; each decade had 20 eyes of 10 normal subjects. Normal means and variability of FO parameters, namely "Rf" value; average ratio in % of amplitude in the dark period (AD)/amplitude in the light period (AL) and "df" value; average difference in µV between AD and AL in 10 steps during the FO procedure, were evaluated. Then the test subjects were divided into younger (19-39 years), older (40-67 years) and global (19-67 years) age groups, in which sex distribution and the respective number of eyes were similar, in order to study the relation of these parameters to age and sex. In conclusion, regarding age, no correlation with age was noted in the "Rf" value, although the lowest mean value of the "dr" was detected in the twenties. Regarding sex, the mean levels of the "Rf" and "df" were statistically higher in the female samples in the younger and global age groups. Some hormonal factor, which can stimulate the metabolic activity of the retinal pigment epithelium, and a certain sex difference concerning sensitivity to dopamine, a retinal neurotransmitter, which influences the EOG, are discussed in the results obtained in this survey.
Key words: dopamine; electro-oculogram; fast oscillations; fast oscillation parameters; sex