Normal Values of Standard Full Field Electroretinography in Healthy Subjects in Northern Iran

Background: Electroretinography (ERG) is known as a diagnostic test for evaluating the performance of different layers of the retina. Its normal values maybe different in different populations. Objectives: Determining the normal values of ERG parameters in patients presenting to an ophthalmologic center in Guilan in northern Iran. Materials and Methods: Fifty-five people presenting to a teaching hospital affiliated to Guilan University of Medical Sciences were studied in autumn and winter 2013.The subjects were diagnosed as healthy in the eye examinations and were examined in terms of the values of amplitude and latency time of ERG waves in accordance with international guidelines for clinical electrophysiology of vision. Results: In this study, 55 patients with a mean age of 35±14 years were studied (40% males with a mean age of 36.00±15.4 years; 60% females, with a mean age of 34.5±14 years). The following results were obtained: amplitude of scotopic 0.01=149±144 µV, scotopic 3=317±157µV, photopic=129±86 µV, 30-Hz flicker=134±38 µV, OS2=25.6±13.9 µV, Latency time scotopic 0.01=53.5±29 sec, Latency Time Scotopic 3=34.3±15.2 sec, N1=13.59±2 sec, P1=18.63±1 sec, N2=21.3±1 sec, P2=26.1±2.7 ms, N3=31.1±4 sec, P3=33.8±4.7 sec, N4=40.9±6.4 sec, P4=44.3±6.4 sec, Latency Time photopic=22.9±7.7 ms, and flicker=54.3±7.5 ms. Men and women were not significantly different in terms of the variables. Left and right eyes, as well as age groups were not significantly different (p=0.05). Conclusion: The results of the current study differed from other studies in terms of the values of amplitude and latency times. Therefore, it is necessary to standardize ERG for each center.