Retinal nerve fiber layer thickness analysis in suspected malingerers with optic disc temporal pallor

Purpose: To investigate the value of temporal retinal nerve fiber layer (RNFL_temporal ) thickness in the prediction of malingering. Materials and Methods: This prospective, cross-sectional study was conducted on 33 military conscripts with optic disc temporal pallor (ODTP) and 33 age-and sex-matched healthy controls. Initial visual acuity (VA_i ) and visual acuity after simulation examination techniques (VA_aset ) were assessed. The subjects whose VA_aset were two or more lines higher than VA_i were determined as malingerers. Thickness of the peripapillary RNFL was determined with OCT (Stratus OCT^TM, Carl Zeiss Meditec, Inc.). RNFL_temporal thickness of the subjects were categorized into one of the 1+ to 4+ groups according to 50% confidence interval (CI), 25% CI and 5% CI values which were assessed in the control group. The VAs were converted to LogMAR-VAs for statistical comparisons. Results: A significant difference was found only in the temporal quadrant of RNFL thickness in subjects with ODTP ( P =0.002). Mean LogMAR-VA increased significantly after SETs ( P 0.001). Sensitivity, specificity, positive and negative predictive values of categorized RNFL_temporal thickness in diagnosing malingering were 84.6%, 75.0%, 68.8%, 88.2%, respectively. ROC curve showed that RNFL_temporal thickness of 67.5 m is a significant cut-off point in determining malingering ( P =0.001, area under the curve:0.862). The correlations between LogMAR-VAs and RNFL_temporal thicknesses were significant; the correlation coefficient for LogMAR-VA_i was lower than the correlation for LogMAR-VA_aset (r=-0.447, P =0.009 for LogMAR-VA_i ; r=-0.676, P 0.001 for LogMAR-VA_aset ). Conclusions: RNFL_temporal thickness assessment may be a valuable tool in determining malingering in subjects with ODTP objectively.