en Neurology Neurology Original Research Original Research <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Background: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">Several studies have evaluated RNFL thickness in PD, with only a few on other Parkinsonian syndromes. There is insufficient information on the pattern of changes in these patients who have dementia. Therefore, the present study examined the RNFL thickness in Parkinsonism patients with and without dementia.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Methods:</b> In this cross-sectional study, all patients diagnosed with PD, MSA, and PSP from March 2017 to February 2019 were evaluated. The severity of the disease and the presence of dementia were determined using the UPDRS and MMSE tests, respectively. The thickness of the RNFL was measured in the superior, inferior, nasal, and temporal quadrants using the 3D-OCT 1000 Mark II.&nbsp; Statistical methods, including the independent t-test, one-way analysis of variance (ANOVA), and the Pearson correlation coefficient, were used to analyze the data at a significance level of 0.05 using SPSS statistical software.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Results:</b> Fifty-three patients were examined. The mean age and mean UPDRS showed a significant difference between the groups, while gender and disease duration did not show. The mean RNFL thickness in the nasal sector had a significant difference among the three groups, with a thinner thickness in patients with MSA (</span></span><span style="font-size:9.0pt">P</span><span style="font-size:9.0pt"><span style="font-style:normal"><0.05). Patients with PD, PSP, and MSA with dementia showed a significantly greater reduction in RNFL thickness in the upper and temporal quadrants, nasal quadrant, and upper and temporal quadrants compared to PD, PSP, and MSA without dementia, respectively (</span></span><span style="font-size:9.0pt">P</span><span style="font-size:9.0pt"><span style="font-style:normal"><0.05).</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Conclusion: </b>Evaluating RNFL can be useful in predicting ocular involvement. Once validated in further studies, OCT may serve as a biomarker for predicting the presence or progression of movement disorders. OCT may also assist in predicting the presence of dementia in these patients by reflecting a more significant reduction in RNFL thickness compared to patients without dementia.</span></span></span></span></span></span></span></span><br> <br> <span style="font-size:12pt"><span new="" roman="" style="font-family:" times=""><strong><span style="color:#0e101a"><span style="font-weight:normal"></span></span></strong></span></span> Parkinson's disease, Progressive supranuclear palsy, Multiple system atrophy, Dementia, Retinal nerve fiber layer, Optical coherence tomography 251 256 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-9385-1&slc_lang=en&sid=1 Peyman Daraei Peyman.da.215@gmail.com 200319475328460089776 0009-0009-7623-4616 No Department of Neurology, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran Morteza Taheri taheri.mor@iums.ac.ir 200319475328460089777 200319475328460089777 Yes Department of Neurosurgery, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran