Variation in Measurement of Pattern Electroretinogram (pERG) / Jurnal Sains Kesihatan Malaysia

ABSTRACT

Pattern electroretinogram (pERG) is a recording of retinal response to a phase reversing pattern stimulus. It gives information on the integrity of the inner retina specifically the ganglion cells. The recording of pERG in a laboratory is easily influenced by many factors hence standardization in a laboratory is required to ensure that pERG recorded is repeatable and reproducible. The objective of this study was to determine the factors that could affect pERG recordings at the Electrophysiology Laboratory, Optometry Program, Faculty of Health Sciences (FSK), Universiti Kebangsaan Malaysia (UKM). This study involved forty-five subjects, aged between 20 and 25 years. They were divided into three groups. The factors being investigated were effects of 1) Alcaine 0.5%, 2) diurnal variation and 3) different size and shape of fixation target for pERG measurement (amplitude and implicit time). Paired t-test showed no significant differences between the recording before and after instillation of Alcaine 0.5% for amplitude (p = 0.116) and implicit time (p = 0.557). Measurements carried out in the morning and afternoon did not show significant differences for amplitude (p = 0.864) and implicit time (p = 0.174). For different fixation targets, results also showed no significant difference for amplitude (p = 0.125) and implicit time (p = 0.404). In conclusion, use of Alcaine 0.5%, different time of measurements and different type of fixation targets do not influence pERG results at the Electrophysiology Laboratory, FSK, UKM. Results of this study can be used for comparisons in research or in diagnosing diseases of the retina in the future