<p>Title: Detection of early macular functional changes using slow double-stimulation mfERG paradigm</p><p>WONG H. Y., CHIN M. P., LEE C. W., YUNG M. Y.,CHAN H.H.L.</p><p>Labouratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University</p><p>Purpose: To investigate whether this new multifocal ERG (mfERG) paradigm could detect early macular functional changes in early dry age-related macular degeneration (ARMD)</p><p>Methods: Twenty one Chinese subjects, aged from 41 to 65 years (mean = 54±7), with early macular changes in at least one eye were recruited from the Optometry Clinic of The </p><p>Hong Kong Polytechnic University. The conditions of macula varied from very mild macular pigment change to about 15 medium-sized drusen around the macula, and the eye with more observable macular changes was selected. They were compared with twenty one age-matched control subjects, aged between 42 and 63 years </p><p>(mean=53±7). The mfERG was measured by using a slow double-stimulation mfERG paradigm.</p><p>Main Outcome Measures: Amplitudes and implicit times of the first (M1) and second (M2) stimulation </p><p>Results: In the central region, the ARMD group had a lower M1 amplitude than the control group but the difference was not statistically significant (p>0.05). Split-Plot ANOVA revealed that region had a significant main effect (p<0.05) while the interaction </p><p>(region X group) was barely insignificant (p=0.057). The ARMD group had a significantly lower M1: M2 amplitude ratio than the control group (p<0.05) while this differentiation was not present in the peripheral region (p>0.05). The M1:M2 amplitude ratio at central showed a sensitivity of 57.1%, with a specificity of 85.7% for differentiating normal eyes from early dry ARMD eyes.</p><p>Conclusions: Our findings suggest that the new mfERG paradigm is sensitive to detect early ARMD.</p><p>The application of M1: M2 amplitude ratio at the macula can be an effective parameter for detecting functional deterioration in early ARMD. The weaken M1: M2 amplitude ratio may indicate an early abnormal adaptive change in ARMD at macula.</p>