Title : Structure-function correlation in immune-mediated retinal diseases
Abstract:
Purpose: To investigate the relationship of retinal structure as measured on optical coherence tomography (OCT), to retinal function as assessed by electrophysiology, consisting of pattern (pERG) and full-field electroretinogram (ffERG), in patients with Immune-mediated Retinal Diseases (IRD).
Design: Cross-sectional study.
Methods Thirty-one actively diseased eyes from 20 patients diagnosed with Autoimmune Retinopathy and Acute Zonal Occult Outer Retinopathy in a tertiary eye centre in Singapore were included in this study. Quantitative (i.e macular thickness and length of the ellipsoid zone (EZ) band) and qualitative (i.e EZ Status, presence of epiretinal membrane, cystic Spaces, and material) measurements on the OCT were correlated to quantitative measurements on pERG and ffERG.
Results: Our results demonstrated significant correlations between various electrophysiological functional measurements and OCT structural measurements. The strongest correlations were between pERG large field P50 amplitude, standard field N95 amplitude and standard field P50 amplitude measurements against total macular thickness at the nasal (rho=0.659, 0.599, 0.570, respectively), temporal (rho=0.659, 0.599, 0.477, respectively), superior (rho=0.640, 0.563, 0.532, respectively), and inferior (rho=0.636, 0.598, 0.530, respectively) perifovea. ffERG measurements showed strongest correlation between 30 Hz flicker peak time and macular thickness at the temporal (rho=0.526), and inferior (rho=0.436) parafovea. 30 Hz flicker amplitude also had significant correlations with macular thickness at the superior perifovea (rho=0.376), and superior parafovea (rho=0.482). The length of intact EZ band had significant correlations with all three pERG parameters but no with any of the ffERG parameters. Ellipsoid zone status, presence of epiretinal membrane, and material were correlated with all three pERG parameters but only presence of epiretinal membrane had significant correlations with ffERG parameters. Presence of cystic space did not show any significant correlations with electrophysiology.
Conclusion: pERG parameters correlated with total macular thickness across various perifoveal regions, while
ffERG correlations were prominent with macular thickness in specific areas and ellipsoid zone
characteristics affecting pERG more than ffERG outcomes.
