Differential Study of Retinal Thicknesses in the Eyes of Alzheimer's Patients, Multiple Sclerosis Patients and Healthy Subjects.

Multiple sclerosis (MS) and Alzheimer's disease (AD) cause retinal thinning that is detectable in vivo using optical coherence tomography (OCT). To date, no papers have compared the two diseases in terms of the structural differences they produce in the retina. The purpose of this study is to analyse and compare the neuroretinal structure in MS patients, AD patients and healthy subjects using OCT. Spectral domain OCT was performed on 21 AD patients, 33 MS patients and 19 control subjects using the Posterior Pole protocol. The area under the receiver operating characteristic (AUROC) curve was used to analyse the differences between the cohorts in nine regions of the retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and outer nuclear layer (ONL). The main differences between MS and AD are found in the ONL, in practically all the regions analysed (AUROCFOVEAL = 0.80, AUROCPARAFOVEAL = 0.85, AUROCPERIFOVEAL = 0.80, AUROC_PMB = 0.77, AUROCPARAMACULAR = 0.85, AUROCINFERO_NASAL = 0.75, AUROCINFERO_TEMPORAL = 0.83), and in the paramacular zone (AUROCPARAMACULAR = 0.75) and infero-temporal quadrant (AUROCINFERO_TEMPORAL = 0.80) of the GCL. In conclusion, our findings suggest that OCT data analysis could facilitate the differential diagnosis of MS and AD.

Retinal and Choroidal Changes in Patients with Parkinson's Disease Detected by Swept-Source Optical Coherence Tomography.

PURPOSE: To evaluate the ability of new Swept source (SS) optical coherence tomography (OCT) technology to detect changes in retinal and choroidal thickness in patients with Parkinson's disease (PD). DESIGN: Observational case-control cross sectional study, developed from January to May 2016. METHODS: In total, 50 eyes from 50 patients diagnosed with PD and 54 eyes of 54 healthy controls underwent retinal and choroidal assessment using SS DRI Triton OCT (Topcon), using the 3D Wide protocol. Total macular thickness and peripapillary data (retinal, ganglion cell layer [GCL+, GCL++] and retinal nerve fiber layer [RNFL] thickness) were analyzed. Macular and peripapillary choroidal thickness was evaluated (Figure 1). RESULTS: Significant peripapillary retinal thinning was observed in PD patients in total average (p = 0.017), in the nasal (p = 0.038) and temporal (p = 0.004) quadrants and in superotemporal (p = 0.004), nasal (p = 0.039), inferotemporal (p = 0.019), and temporal (p = 0.003) sectors. RNFL and GCL ++ thickness showed a significant reduction in the inferotemporal sector (p = 0.026 and 0.009, respectively). No differences were observed in macular retinal thickness between controls and patients. Choroidal thickness was found to have increased in all sectors in PD patients compared with controls, both in the macular (inner nasal, p = 0.015; inner inferior, p = 0.030; outer nasal, p = 0.012; outer inferior, p = 0.049) and the peripapillary area (total thickness, p = 0.011; nasal, p = 0.025; inferior, p = 0.007; temporal, p = 0.003; inferotemporal, p = 0.003; inferonasal, p = 0.016) Conclusion: New SS technology for OCT devices detects retinal thinning in PD patients, providing increased depth analysis of the choroid in these patients. The choroid in PD may present increased thickness compared to healthy individuals; however, more studies and histological analysis are needed to corroborate our findings.

Evaluation of Progressive Visual Dysfunction and Retinal Degeneration in Patients With Parkinson's Disease.

Purpose: To quantify changes in visual function parameters and in the retinal nerve fiber layer and macular thickness over a 5-year period in patients with Parkinson's disease (PD). Methods: Thirty patients with PD and 30 healthy subjects underwent a complete ophthalmic evaluation, including assessment of visual acuity, contrast sensitivity vision, color vision, and retinal evaluation with spectral-domain optical coherence tomography (SD-OCT). All subjects were reevaluated after 5 years to quantify changes in visual function parameters, the retinal nerve fiber layer, and macular thickness. Association between progressive ophthalmologic changes and disease progression was analyzed. Results: Changes were detected in visual function parameters and retinal nerve fiber layer thickness in patients compared with controls. Greater changes were found during the follow-up in the PD group than healthy subjects in visual acuity, contrast sensitivity, Lanthony color test (P < 0.016), in superotemporal and temporal retinal nerve fiber layer sectors (P < 0.001), and in macular thickness (all sectors except inner superior and inner inferior sectors, P < 0.001). Progressive changes in the retinal nerve fiber layer were associated with disease progression (r = 0.389, P = 0.028). Conclusions: Progressive visual dysfunction, macular thinning, and axonal loss can be detected in PD. Analysis of the macular thickness and the retinal nerve fiber layer by SD-OCT can be useful for evaluating Parkinson's disease progression.

Optical Coherence Tomography as a Biomarker for Diagnosis, Progression, and Prognosis of Neurodegenerative Diseases.

Neurodegenerative diseases present a current challenge for accurate diagnosis and for providing precise prognostic information. Developing imaging biomarkers for multiple sclerosis (MS), Parkinson disease (PD), and Alzheimer's disease (AD) will improve the clinical management of these patients and may be useful for monitoring treatment effectiveness. Recent research using optical coherence tomography (OCT) has demonstrated that parameters provided by this technology may be used as potential biomarkers for MS, PD, and AD. Retinal thinning has been observed in these patients and new segmentation software for the analysis of the different retinal layers may provide accurate information on disease progression and prognosis. In this review we analyze the application of retinal evaluation using OCT technology to provide better understanding of the possible role of the retinal layers thickness as biomarker for the detection of these neurodegenerative pathologies. Current OCT analysis of the retinal nerve fiber layer and, specially, the ganglion cell layer thickness may be considered as a good biomarker for disease diagnosis, severity, and progression.