Abstract
Purpose:
The objective of the study is to investigate the effects of non-dilated pupil and dilated pupil on different eccentricities of multifocal electroretinogram (mfERG).
Methods:
Seventeen emmetropic subjects aged 20 to 23 years old were recruited in this study. Multifocal electroretinogram was performed to conform to ISCEV 2012 standard. The stimulus array of 61 hexagonal elements with 60 degree was presented during recording with frame frequency of 75 Hz. The mfERG recording was done in the non-dilated eye first, followed by the dilated eye. Pupil diameter measurement was performed using manual pupilometer prior to multifocal electroretinography. The eye was anesthetized with a drop of Alcaine 0.5% prior to DTL electrode insertion and then was fully dilated using a drop each of Mydriacyl 1.0% and Mydfrin 2.5%, and the maximum pupil dilation was measured after 60 minutes. N1 and P1 implicit time and amplitudes were recorded across 5 different eccentricities from centrally located Ring 1 to the most peripheral Ring 5. Statistical analysis was performed using Statistical Package for Social Sciences version 20.
Results:
The mean pupil diameter for non-dilated eye was 3.8mm±0.41 while the mean pupil diameter for dilated eye was 8.13mm±0.35. There was no significant difference found in N1 and P1 implicit time between dilated and non-dilated eye except for Ring 5 P1 implicit time, t(16) = -2.82, p = 0.01. N1 and P1 amplitudes for Ring 1 and Ring 2 in dilated and non-dilated eye had no significant difference while Ring 3 N1 [t(16) = -2.60, p = 0.02], Ring 4 N1 [t(16) = -3.41, p = 0.004], Ring 5 N1 [t(16) = -4.26, p = 0.001], Ring 3 P1 [t(16) = 3.33, p = 0.004], Ring 4 P1 [t(16) = 4.18, p = 0.001] and Ring 5 P1 [t(16), p < 0.001] had significant differences.
Conclusions:
Our findings suggested that the multifocal electroretinogram could be performed without dilation in clinical investigation for central retina only.
Keywords: 509 electroretinography: clinical •
667 pupil •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques