VISUAL FUNCTION AND RETINAL CHANGES IN PATIENTS WITH BIPOLAR DISORDER.

PURPOSE: To evaluate visual and retinal changes in patients with bipolar disorder. To analyze the correlation between structural changes and visual function parameters. METHODS: Thirty patients with bipolar disorder and 80 healthy controls underwent visual function evaluation with Early Treatment Diabetic Retinopathy Study charts at 100%, 2.50%, and 1.25% contrast, Pelli-Robson chart, and color vision Farnsworth and Lanthony tests. Analysis of the different retinal layers was performed using Spectralis optical coherence tomography with automated segmentation software. Correlation analysis between structural and functional parameters was conducted. RESULTS: Patients with bipolar disorder presented worse color vision compared with controls (Lanthony's index, P = 0.002). Full macular thickness, the retinal nerve fiber layer (RNFL), ganglion cell layer, and inner plexiform layer were reduced in patients compared with healthy individuals (P < 0.005). The inner nuclear layer was significantly thickened in patients (P < 0.005). Peripapillary RNFL thickness was reduced in all temporal sectors (P < 0.005). Significant correlations were found between visual acuity and the RNFL thickness, the Pelli-Robson score and the inner plexiform layer, and between the Lanthony's color index and the ganglion cell layer thickness. CONCLUSION: Patients with bipolar disorder present quantifiable thinning of the macular RNFL, ganglion cell layer, and inner plexiform layer, as well as in the peripapillary RNFL thickness, and increasing thinning in the inner nuclear layer.

Interocular Symmetry of Choroidal Thickness and Volume in Healthy Eyes on Optical Coherence Tomography.

BACKGROUND: We aimed to determine the physiological symmetry, with spectral-domain optical coherence tomography, of choroidal measurements in a healthy population in all the areas defined in the Early Treatment Diabetic Retinopathy Study (ETDRS). METHODS: One hundred and fifty-four eyes of 77 healthy young adults between the ages of 19 and 32 years were enrolled. Differences in choroidal thickness (CT) and volume (CV) between the left and right eyes were calculated. Normal ranges of absolute interocular differences were established as the 95th percentile. RESULTS: The mean ± SD subfoveal CT (SFCT) and total CV values in the right and left eyes were 342.03 ± 77.38 versus 361.64 ± 76.45 µm (correlation coefficient ρ = 0.820; p < 0.001) and 0.27 ± 0.06 versus 0.28 ± 0.06 mm3 (ρ = 0.830; p < 0.001), respectively. Differences in 5 of the 9 areas of the ETDRS map were statistically significant (p < 0.05), but with a strong interocular correlation (ρ > 0.8; p < 0.001). The 95th percentile of interocular tolerance limits for CT in the 1-, 3-, and 6-mm areas were 97, 70, and 57 µm, respectively; the 95th percentile for the volume values were 0.06, 0.51, and 1.73 mm3. CONCLUSIONS: CT and CV are highly correlated between eyes, statistically significant differences between them can be found, and absolute interocular differences may reach 97 µm in SFCT, and 1.73 mm3 in total CV.

Evaluation of multiple sclerosis severity using a new OCT tool.

PURPOSE: To assess the ability of a new posterior pole protocol to detect areas with significant differences in retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness in patients with multiple sclerosis versus healthy control subjects; in addition, to assess the correlation between RNFL and GCL thickness, disease duration, and the Expanded Disability Status Scale (EDSS). METHODS: We analyzed 66 eyes of healthy control subjects and 100 eyes of remitting-relapsing multiple sclerosis (RR-MS) patients. Double analysis based on first clinical symptom onset (CSO) and conversion to clinically definite MS (CDMS) was performed. The RR-MS group was divided into subgroups by CSO and CDMS year: CSO-1 (≤ 5 years) and CSO-2 (≥ 6 years), and CDMS-1 (≤ 5 years) and CDMS-2 (≥ 6 years). RESULTS: Significant differences in RNFL and GCL thickness were found between the RR-MS group and the healthy controls and between the CSO and CDMS subgroups and in both layers. Moderate to strong correlations were found between RNFL and GCL thickness and CSO and CDMS. Furthermore, we observed a strong correlation with EDSS 1 year after the OCT examination. CONCLUSIONS: The posterior pole protocol is a useful tool for assessing MS and can reveal differences even in early stages of the disease. RNFL thickness shows a strong correlation with disability status, while GCL thickness correlates better with disease duration.

Evaluation of Progressive Retinal Degeneration in Bipolar Disorder Patients over a Period of 5 Years.

PURPOSE: To quantify visual and retinal changes in patients with bipolar disorder (BD) over 5 years, compared with controls. METHODS: Thirty-eight patients with BD and 122 healthy subjects underwent visual acuity (VA) evaluation, contrast sensitivity vision testing (CSV) with the Pelli Robson and CSV 1000E tests, and retinal thicknesses measurement [ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL)] using Spectralis Optical Coherence Tomography (OCT). All subjects were re-evaluated after 5 years. The relationship between progressive structural changes and disease duration was analyzed. RESULTS: Visual function parameters in BD patients remained unchanged during the follow-up period. A progressive decrease affecting macular and peripapillary RNFL thickness (p < 0.050) was observed in patients. Progressive changes in BD were more pronounced when compared with healthy controls (p < 0.050). A significant correlation between GCL thickness changes and disease duration was found (GCL outer temporal, r = -0.680, p = 0.016; GCL central, r = -0.540, p = 0.038). CONCLUSIONS: Progressive axonal loss was detected in BD patients. Visual function parameters were not affected after the 5-year follow-up. Despite observed changes in the neuroretina of patients with BD, axonal degeneration in these patients seemed to be mild and might be slowed down by other factors, such as BD treatments.

Automatic Diagnosis of Bipolar Disorder Using Optical Coherence Tomography Data and Artificial Intelligence.

BACKGROUND: The aim of this study is to explore an objective approach that aids the diagnosis of bipolar disorder (BD), based on optical coherence tomography (OCT) data which are analyzed using artificial intelligence. METHODS: Structural analyses of nine layers of the retina were analyzed in 17 type I BD patients and 42 controls, according to the areas defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The most discriminating variables made up the feature vector of several automatic classifiers: Gaussian Naive Bayes, K-nearest neighbors and support vector machines. RESULTS: BD patients presented retinal thinning affecting most layers, compared to controls. The retinal thickness of the parafoveolar area showed a high capacity to discriminate BD subjects from healthy individuals, specifically for the ganglion cell (area under the curve (AUC) = 0.82) and internal plexiform (AUC = 0.83) layers. The best classifier showed an accuracy of 0.95 for classifying BD versus controls, using as variables of the feature vector the IPL (inner nasal region) and the INL (outer nasal and inner inferior regions) thickness. CONCLUSIONS: Our patients with BD present structural alterations in the retina, and artificial intelligence seem to be a useful tool in BD diagnosis, but larger studies are needed to confirm our findings.

Machine learning in diagnosis and disability prediction of multiple sclerosis using optical coherence tomography.

BACKGROUND: Multiple sclerosis (MS) is a neurodegenerative disease that affects the central nervous system, especially the brain, spinal cord, and optic nerve. Diagnosis of this disease is a very complex process and generally requires a lot of time. In addition, treatments are applied without any information on the disability course in each MS patient. For these two reasons, the objective of this study was to improve the MS diagnosis and predict the long-term course of disability in MS patients based on clinical data and retinal nerve fiber layer (RNFL) thickness, measured by optical coherence tomography (OCT). MATERIAL AND METHODS: A total of 104 healthy controls and 108 MS patients, 82 of whom had a 10-year follow-up, were enrolled. Classification algorithms such as multiple linear regression (MLR), support vector machines (SVM), decision tree (DT), k-nearest neighbours (k-NN), Naïve Bayes (NB), ensemble classifier (EC) and long short-term memory (LSTM) recurrent neural network were tested to develop two predictive models: MS diagnosis model and MS disability course prediction model. RESULTS: For MS diagnosis, the best result was obtained using EC (accuracy: 87.7%; sensitivity: 87.0%; specificity: 88.5%; precision: 88.7%; AUC: 0.8775). In line with this good performance, the accuracy was 85.4% using k-NN and 84.4% using SVM. And, for long-term prediction of MS disability course, LSTM recurrent neural network was the most appropriate classifier (accuracy: 81.7%; sensitivity: 81.1%; specificity: 82.2%; precision: 78.9%; AUC: 0.8165). The use of MLR, SVM and k-NN also showed a good performance (AUC ≥ 0.8). CONCLUSIONS: This study demonstrated that machine learning techniques, using clinical and OCT data, can help establish an early diagnosis and predict the course of MS. This advance could help clinicians select more specific treatments for each MS patient. Therefore, our findings underscore the potential of RNFL thickness as a reliable MS biomarker.

Angiography with optical coherence tomography as a biomarker in multiple sclerosis.

PURPOSE: To investigate superficial retinal microvascular plexuses detected by optical coherence tomography angiography (OCT-A) in multiple sclerosis (MS) subjects and compare them with healthy controls. METHODS: A total of 92 eyes from 92 patients with relapsing-remitting MS and 149 control eyes were included in this prospective observational study. OCT-A imaging was performed using Triton Swept-Source OCT (Topcon Corporation, Japan). The vessel density (VD) percentage in the superficial retinal plexus and optic disc area (6 x 6 mm grid) was measured and compared between groups. RESULTS: MS patients showed a significant decrease VD in the superior (p = 0.005), nasal (p = 0.029) and inferior (p = 0.040) parafoveal retina compared with healthy subjects. Patients with disease durations of more than 5 years presented lower VD in the superior (p = 0.002), nasal (p = 0.017) and inferior (p = 0.022) parafoveal areas compared with healthy subjects. Patients with past optic neuritis episodes did not show retinal microvasculature alterations, but patients with an EDSS score of less than 3 showed a significant decrease in nasal (p = 0.024) and superior (p = 0.006) perifoveal VD when compared with healthy subjects. CONCLUSIONS: MS produces a decrease in retinal vascularization density in the superficial plexus of the parafoveal retina. Alterations in retinal vascularization observed in MS patients are independent of the presence of optic nerve inflammation. OCT-A has the ability to detect subclinical vascular changes and is a potential biomarker for diagnosing the presence and progression of MS.

Physiological changes in retinal layers thicknesses measured with swept source optical coherence tomography.

PURPOSE: To evaluate the physiological changes related with age of all retinal layers thickness measurements in macular and peripapillary areas in healthy eyes. METHODS: Wide protocol scan (with a field of view of 12x9 cm) from Triton SS-OCT instrument (Topcon Corporation, Japan) was performed 463 heathy eyes from 463 healthy controls. This protocol allows to measure the thickness of the following layers: Retina, Retinal nerve fiber layer (RNFL), Ganglion cell layer (GCL +), GCL++ and choroid. In those layers, mean thickness was compared in four groups of ages: Group 1 (71 healthy subjects aged between 20 and 34 years); Group 2 (65 individuals aged 35-49 years), Group 3 (230 healthy controls aged 50-64 years) and Group 4 (97 healthy subjects aged 65-79 years). RESULTS: The most significant thinning of all retinal layers occurs particularly in the transition from group 2 to group 3, especially in temporal superior quadrant at RNFL, GCL++ and retinal layers (p≤0.001), and temporal superior, temporal inferior, and temporal half in choroid layer (p<0.001). Curiously group 2 when compared with group 1 presents a significant thickening of RNFL in temporal superior quadrant (p = 0.001), inferior (p<0.001) and temporal (p = 0.001) halves, and also in nasal half in choroid layer (p = 0.001). CONCLUSIONS: Excepting the RNFL, which shows a thickening until the third decade of life, the rest of the layers seem to have a physiological progressive thinning.

Reproducibility of retinal and choroidal measurements using swept-source optical coherence tomography in patients with Parkinson's disease.

PURPOSE: To assess the reproducibility of retinal and choroidal measurements in the macular and peripapillary areas using swept-source optical coherence tomography in patients with Parkinson's disease. METHODS: A total of 63 eyes of 63 patients with idiopathic Parkinson's disease were evaluated using a three-dimensional protocol of swept-source optical coherence tomography. The following layers were analyzed: full retinal thickness, retinal nerve fiber layer, ganglion cell layer, and choroid. The coefficient of variation was calculated for every measurement. RESULTS: In the macular area, the mean coefficients of variation of retinal thickness, ganglion cell layer + thickness, and choroidal thickness were 0.40%, 0.84%, and 2.09%, respectively. Regarding the peripapillary area, the mean coefficient of variation of the retinal nerve fiber layer thickness was 2.78. The inferior quadrant showed the highest reproducibility (coefficient of variation= 1.62%), whereas the superonasal sector showed the lowest reproducibility (coefficient of variation= 8.76%). CONCLUSIONS: Swept-source optical coherence tomography provides highly reproducible measurements of retinal and choroidal thickness in both the macular and peripapillary areas. The reproducibility is higher in measurements of retinal thickness versus choroidal thickness.

Swept source optical coherence tomography to early detect multiple sclerosis disease. The use of machine learning techniques.

OBJECTIVE: To compare axonal loss in ganglion cells detected with swept-source optical coherence tomography (SS-OCT) in eyes of patients with multiple sclerosis (MS) versus healthy controls using different machine learning techniques. To analyze the capability of machine learning techniques to improve the detection of retinal nerve fiber layer (RNFL) and the complex Ganglion Cell Layer-Inner plexiform layer (GCL+) damage in patients with multiple sclerosis and to use the SS-OCT as a biomarker to early predict this disease. METHODS: Patients with relapsing-remitting MS (n = 80) and age-matched healthy controls (n = 180) were enrolled. Different protocols from the DRI SS-OCT Triton system were used to obtain the RNFL and GCL+ thicknesses in both eyes. Macular and peripapilar areas were analyzed to detect the zones with higher thickness decrease. The performance of different machine learning techniques (decision trees, multilayer perceptron and support vector machine) for identifying RNFL and GCL+ thickness loss in patients with MS were evaluated. Receiver-operating characteristic (ROC) curves were used to display the ability of the different tests to discriminate between MS and healthy eyes in our population. RESULTS: Machine learning techniques provided an excellent tool to predict MS disease using SS-OCT data. In particular, the decision trees obtained the best prediction (97.24%) using RNFL data in macular area and the area under the ROC curve was 0.995, while the wide protocol which covers an extended area between macula and papilla gave an accuracy of 95.3% with a ROC of 0.998. Moreover, it was obtained that the most significant area of the RNFL to predict MS is the macula just surrounding the fovea. On the other hand, in our study, GCL+ did not contribute to predict MS and the different machine learning techniques performed worse in this layer than in RNFL. CONCLUSIONS: Measurements of RNFL thickness obtained with SS-OCT have an excellent ability to differentiate between healthy controls and patients with MS. Thus, the use of machine learning techniques based on these measures can be a reliable tool to help in MS diagnosis.

A mathematical model to predict the evolution of retinal nerve fiber layer thinning in multiple sclerosis patients.

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system (CNS). Many studies of MS patients have described axonal loss in the optic nerve of the retina, and specifically progressive thinning of the retinal nerve fiber layer (RNFL). We hypothesize that RNFL thinning involves the participation of 2 processes that cause CNS damage: autoimmune inflammation and axonal degeneration. To test this hypothesis, we developed a mathematical model based on ordinary differential equations to relate the evolution of RNFL thickness (measured by optical coherence tomography [OCT]) with that of the Expanded Disability Status Scale (EDSS) score in MS patients. Data were obtained from a longitudinal study of 114 MS patients who were followed-up for 10 years. After adjusting the parameters using a genetic algorithm, the model's prediction of the evolution of RNFL thickness accurately reflected the progression revealed by the 10-year clinical data. Our findings suggest that differences in the relative contributions of autoimmune inflammation and axonal degeneration can account for the complex dynamics of MS, which vary from one patient to the next. Moreover, our results show that CNS damage occurs cumulatively from the onset of MS and that most RNFL thinning occurs before the appearance of significant disability. RNFL thickness could therefore serve as a reliable biomarker of MS disease course. Our proposed methodology would enable the use of OCT data from new MS patients to predict the evolution of RNFL thinning and hence the progression of MS in individual patients, and to facilitate the selection of patient-specific therapies.

Ability of swept source OCT to detect retinal changes in patients with bipolar disorder.

PURPOSE: To evaluate the ability of swept source optical coherence tomography (SS-OCT) to detect retinal changes in patients with bipolar disorder (BD). METHODS: Twenty-three patients with BD and 23 controls underwent retinal evaluation using SS deep range imaging (DRI) Triton OCT. Full retinal thickness, the ganglion cell layer (GCL), the retinal nerve fiber layer (RNFL), and choroidal thickness were evaluated with automated segmentation software. RESULTS: Patients with BD were shown to have significant thinning of the macular full retinal thickness in the center (p = 0.049), inner temporal (p = 0.045), inner nasal (p = 0.016), and inner inferior (p = 0.016) of the ETDRS areas. The macular GCL layer was reduced in patients compared with controls (average, p = 0.002; superior, p = 0.009; superonasal, p = 0.009; inferonasal, p = 0.003; and inferior, p = 0.009). Peripapillary reduction of full retinal thickness (average, p < 0.001; superotemporal, p < 0.001; superonasal, p = 0.003; nasal, p = 0.005; and inferotemporal, p = 0.033), GCL (nasal, p = 0.025), and RNFL thickness (average, p = 0.002; superotemporal, p < 0.001; and superonasal, p = 0.045) was observed in patients compared with controls. No significant differences were observed in choroidal thickness measurements. CONCLUSIONS: BD patients were shown to have quantifiable thinning of full retinal thickness and the GCL in the macular area, as well as a peripapillary reduction of the RNFL and GCL thickness. The analysis of the retinal sublayers with SS-OCT may be a useful indicator to show degeneration and monitor disease progression in bipolar disorder.

Reproducibility and reliability of retinal and optic disc measurements obtained with swept-source optical coherence tomography in a healthy population.

PURPOSE: To analyze the reproducibility of macular and peripapillary thickness measurements, and optic nerve morphometric data obtained with Triton Optical coherence tomography (OCT) in a healthy population. STUDY DESIGN: Observational cross sectional study. MATERIAL AND METHODS: A total of 108 eyes underwent evaluation using the Triton Swept Source-OCT. A wide protocol was used and measurements in each eye were repeated three times. Morphometric data of the optic nerve head, full macular thickness, ganglion cell layer (GCL) and retinal nerve fiber layer thickness (RNFL) were analyzed. For each parameter, the coefficient of variation (COV) and the intra-class (ICC) correlation values were calculated. RESULTS: Measurements were highly reproducible for all morphometric measurements of the optic disc, with a mean COV of 6.36%. Macular full thickness showed good COV and ICC coefficients, with a mean COV value of 1.00%. Macular GCL thickness showed a mean COV value of 3.06%, and ICC higher than 0.787. Peripapillary RNFL thickness showed good COV and ICC coefficients, with a mean COV value of 8.31% and ICC higher than 0.684. The inferotemporal sector showed the lowest ICC (0.685). CONCLUSIONS: Triton OCT presents good reproducibility values in measurements corresponding to retinal parameters, with macular measurements showing the highest reproducibility rates. Peripapillary RNFL measurements should be evaluated with caution.

Hepatic oxidative stress in pigmented P23H rhodopsin transgenic rats with progressive retinal degeneration.

Retinitis pigmentosa (RP) comprises a group of inherited retinal degenerative conditions characterized by primary degeneration of the rod photoreceptors. Increased oxidative damage is observed in the retina, aqueous humor, and plasma of RP animal models and patients. The hepatic oxidative status may also be affected in RP due to oxidative damage influencing soluble macromolecules exiting the retina or to alterations in the melanopsin system resulting in chronic circadian desynchronization that negatively alters the oxidative stress defense system. P23H rats were crossed with pigmented Long Evans rats to produce offspring exhibiting the clinical conditions of RP. We measured hepatic malondialdehyde and 4-hydroxyalkenal concentrations as oxidative stress markers; nitrite level as a total nitrosative damage marker; total antioxidant capacity; and the activities of catalase, superoxide dismutase (SOD), and glutathione S-transferase. Retinal visual function was assessed based on optomotor and electroretinogram responses. P23H transgenic rats exhibited diminished visual acuity, contrast sensitivity, and electroretinographic responses according to the level of retinal degeneration. P23H rats at 30 days of age already demonstrated only 47% of the hepatic total antioxidant capacity of wild-type animals. Hepatic catalase and SOD activities were also reduced in P23H rats after 120 days, but we detected no difference in glutathione S-transferase activity. P23H rats had increased hepatic oxidative and nitrosative damage markers. GSH/GSSG ratio showed a significant diminution in P23H rats at P120 compared to WT. We conclude that the liver is under increased oxidative stress in P23H rats. Further studies are required, however, to clarify the contribution of systemic oxidative damage to the pathogenesis of RP.

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.

Comparison of peripapillary choroidal thickness between healthy subjects and patients with Parkinson's disease.

PURPOSE: To study peripapillary choroidal thickness (PPCT) in healthy subjects using swept-source optical coherence tomography (SS-OCT), and to evaluate PPCT differences between Parkinson´s disease (PD) patients, and age- and sex-matched healthy controls. DESIGN: Case-control study. METHODS: 80 healthy subjects and 40 PD patients were consecutively recruited in this single institution study. The healthy subjects were divided into two populations: a teaching population (n = 40, used to establish choroidal zones) and a validating population (n = 40, used to compare measurements with PD patients). An optic disc 6.0×6.0 mm three-dimensional scan was obtained using Deep Range Imaging (DRI) OCT Triton. A 26×26 cube-grid centered on the optic disc was generated to automatically measure choroidal thickness. Five concentric choroidal zones were established and used to compare PPCT between healthy and PD patients. RESULTS: PPCT was significantly thicker in PD patients compared with controls in all four concentric zones evaluated (p≤0.0001). PPCT followed a similar pattern in controls and PD; it was thicker in the temporosuperior region, followed by the superior, temporal, nasal, and inferior regions. CONCLUSION: PD patients presented with an increased PPCT in all zones surrounding the optic disc compared with healthy subjects. The peripapillary choroidal tissue showed a concentric pattern, with the thickness increasing with increasing distance from the optic nerve. SS-OCT could be useful for evaluating choroidal thinning in clinical practice.

Reproducibility of retinal and choroidal measurements using swept-source optical coherence tomography in patients with Parkinson's disease / Reprodutibilidade das medições da retina e da coroideia utilizando a tomografia de coerência ótica Swept-Source em pacientes com a doença de Parkinson

ABSTRACT Purpose: To assess the reproducibility of retinal and choroidal measurements in the macular and peripapillary areas using swept-source optical coherence tomography in patients with Parkinson's disease. Methods: A total of 63 eyes of 63 patients with idiopathic Parkinson's disease were evaluated using a three-dimensional protocol of swept-source optical coherence tomography. The following layers were analyzed: full retinal thickness, retinal nerve fiber layer, ganglion cell layer, and choroid. The coefficient of variation was calculated for every measurement. Results: In the macular area, the mean coefficients of variation of retinal thickness, ganglion cell layer + thickness, and choroidal thickness were 0.40%, 0.84%, and 2.09%, respectively. Regarding the peripapillary area, the mean coefficient of variation of the retinal nerve fiber layer thickness was 2.78. The inferior quadrant showed the highest reproducibility (coefficient of variation= 1.62%), whereas the superonasal sector showed the lowest reproducibility (coefficient of variation= 8.76%). Conclusions: Swept-source optical coherence tomography provides highly reproducible measurements of retinal and choroidal thickness in both the macular and peripapillary areas. The reproducibility is higher in measurements of retinal thickness versus choroidal thickness.

RESUMO Objetivo: Avaliar a reprodutibilidade das medições da retina e da coroide nas áreas macular e peripapilar utilizando a tomografia de coerência ótica com fonte de varredura pacientes com doença de Parkinson. Métodos: Um total de 63 olhos de 63 pacientes com doença de Parkinson idiopática foram avaliados usando um protocolo 3D de tomografia de coerência ótica de fonte Triton Swept. Foram analisadas as seguintes camadas: espessura retiniana total, camada de fibras nervosas da retina, camada de células ganglionares e coróide. O coeficiente de variação foi calculado para cada medição. Resultados: Na área macular, os coeficientes médios de variação da espessura da retina, da camada de células ganglionares + espessura e da espessura da coróide foram de 0,40%, 0,84% e 2,09%, respectivamente. Em relação à área peripapilar, o coeficiente médio de variação da espessura da camada de fibras nervosas da retina foi de 2,78%. O quadrante inferior apresentou a maior reprodutibilidade (coeficiente de variação= 1,62%), enquanto o setor superonasal apresentou a menor reprodutibilidade (coeficiente de variação= 8,76%). Conclusões: A tomografia de coerência ótica de fonte Triton Swept fornece medições altamente reprodutíveis da espessura da retina e da coroide nas áreas macular e peripapilar. A reprodutibilidade é maior nas medidas da espessura da retina versus a espessura da coróide.

Choroidal thickness and volume in healthy young white adults and the relationships between them and axial length, ammetropy and sex.

PURPOSE: To evaluate choroidal thickness in young adults using enhanced-depth imaging spectral-domain optical coherence tomography and to describe volume differences in all the areas defined in the Early Treatment Diabetic Retinopathy Study. DESIGN: Prospective clinical study. METHODS: In 95 healthy young (23.8 ± 3.2 years) adult volunteers, 95 eyes were prospectively enrolled. Manual choroidal segmentation on a 25-raster horizontal scan protocol was performed. The measurements of the 9 subfields defined by the Early Treatment Diabetic Retinopathy Study were evaluated. RESULTS: Mean subfoveal choroidal thickness was 345.67 ± 81.80 µm and mean total choroidal volume was 8.99 ± 1.88 mm(3). Choroidal thickness and volume were higher in the superior and temporal areas than in the inferior and nasal sectors of the same diameter, respectively. Strong correlations between subfoveal choroidal thickness and axial length and myopic refractive error were obtained (r = -0.649, P < 0.001, and r = 0.473, P < 0.001, respectively). Emmetropic eyes tended to have thicker subfoveal choroidal thickness (381.94 ± 79.88 µm vs 307.04 ± 64.91 µm) and higher total choroidal volume than myopic eyes (9.80 ± 1.87 mm(3) vs 8.14 ± 1.48 mm(3)). The estimation of the variation in the subfoveal choroidal thickness in relationship to the axial length was -43.84 µm/mm. In the myopic group, the variation in the subfoveal choroidal thickness with the myopic refractive error was -10.45 µm per diopter. CONCLUSIONS: This study establishes for the first time a normal database for choroidal thickness and volume in young adults. Axial length, and myopic ammetropy are highly associated with choroidal parameters in healthy subjects. Enhanced-depth imaging spectral-domain optical coherence tomography exhibited a high degree of intraobserver and interobserver repeatability.