Spectral-domain Optical Coherence Tomography Measurements Research Articles

Ellipsoid Zone Integrity and Visual Function in Dry Age-Related Macular Degeneration.

In this longitudinal retrospective image analysis, conducted on patients diagnosed with dry age-related macular degeneration (AMD) and 5 years of follow-up imaging data, the study aimed to investigate the relationship between ellipsoid zone (EZ) integrity on spectral domain optical coherence tomography (SD-OCT) and visual acuity (VA). Using a machine learning-enabled feature extraction tool, quantitative EZ parameters were derived from SD-OCT images. The analysis revealed significant correlations between EZ integrity metrics and VA. Eyes with excellent VA (≥20/25 Snellen) exhibited higher EZ integrity, including less EZ attenuation, thicker ellipsoid zone-retinal pigment epithelium (EZ-RPE) thickness, and higher EZ intensity, in contrast to eyes with worse VA (≤20/40 Snellen). Additionally, eyes with geographic atrophy (GA) in the foveal region displayed compromised EZ integrity compared to those without GA. Notably, baseline EZ integrity metrics were predictive of future VA loss. These findings suggest that quantitative SD-OCT measurements of EZ integrity could potentially detect early changes in dry AMD and serve as valuable indicators for predicting future functional outcomes. Furthermore, these measurements hold promise for use in clinical trial screenings, offering insights into the progression of the disease and its impact on visual acuity. This study underscores the importance of EZ integrity assessment in understanding and managing dry AMD.

Intraday repeatability of macular layers measurements in glaucomatous and non-glaucomatous patients using spectral-domain optical coherence tomography

PurposeTo assess the intraday repeatability of macular architecture measurements in glaucomatous and non-glaucomatous patients using spectral-domain optical coherence tomography (SD-OCT) and to evaluate the independence from intraindividual intraocular pressure (IOP) fluctuations.MethodsIn this single-center, time-point comparison study, 88 eyes with glaucoma, 53 eyes with ocular hypertension (OHT), and 253 healthy eyes underwent two standardized SD-OCT and intraocular pressure (IOP) measurements on the same day with a 5-h time gap. Bland–Altman plots, intraclass correlation coefficients (ICC), and random-effects model were used to analyze repeatability of entire retinal thickness, retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, and inner nuclear layer measurements.ResultsIntraday measurements were highly reproducible in all 3 groups. ICC were greater than 0.90, respectively. The pairwise comparisons of morphometric parameters showed a statistically significant difference (P < 0.001, respectively) between groups (glaucoma vs. control, glaucoma vs. OHT) and a significant influence of time points. No correlation was found between IOP fluctuations and morphometric parameters (P > 0.05, respectively), except for a weak positive correlation with GCL (rho = 0.109, P = 0.031).ConclusionsThe evaluation of macular morphometric parameters of SD-OCT showed a high intraday repeatability and an excellent degree of agreement in glaucoma, ocular hypertension, and healthy groups. The fixed effects of time points were statistically significant. Except for a weak positive correlation of ganglion cell layer, variability did not appear to be affected by intraday IOP changes. Additional research is required to fully understand the impact of IOP fluctuations on macular morphometric parameters, considering the small observed IOP changes.

Correlation between serum biomarkers, brain volume, and retinal neuronal loss in early-onset Alzheimer's disease.

To compare the peripapillary retinal nerve fiber layer (pRNFL), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness measurement in early-onset Alzheimer's disease (EOAD) and controls using spectral domain optical coherence tomography (SD-OCT). We also assessed the relationship between SD-OCT measurements and cognitive measures, serum biomarkers for Alzheimer's disease (AD), and cerebral microstructural volume. pRNFL, RNFL, and GCC thicknesses were measured in 43 EOAD and 42 controls using SD-OCT. Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) were used to assess cognitive status, magnetic resonance imaging (MRI) tool was used to quantify cerebral microstructural volume, and serum biomarkers were quantified from peripheral blood. EOAD patients had thinner pRNFL (P < 0.001), RNFL (P = 0.008), and GCC (P = 0.018) thicknesses compared to controls after adjusting for multiple factors. pRNFL thickness correlated (P = 0.016) with serum t-tau level. Serum Aβ42 (P < 0.05) concentration correlated with RNFL thickness. Importantly, occipital lobe volume (P = 0.010) correlated with GCC thicknesses in EOAD patients. Our findings suggest that retinal thickness may be useful markers for assessing neurodegenerative processin EOAD.

Progression of Retinal Ganglion Cell and Nerve Fiber Layer Loss in Spinocerebellar Ataxia 3 Patients.

Spectral domain optical coherence tomography (SD-OCT) allows noninvasive measurements of retinal neuron layers. Here, we evaluate the relationship between clinical features and anatomical SD-OCT measurements in patients with spinocerebellar ataxia type 3 (SCA3) and how they change with time. A retrospective review was conducted on SCA3 patients. Clinical variables such as disease duration, number of CAG repeats, and the Scale for the Assessment and Rating of Ataxia (SARA) score were correlated with SD-OCT measurements, including retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, macular volume (MV), and central macular thickness (CMT). Seventeen SCA3 patients with an average follow-up of 44.9months were recruited. Clinical features with significant baseline correlations with SD-OCT measurements included disease duration (CMT r = - 0.590; GCC r = - 0.585), SARA score (CMT r = - 0.560; RNFL r = - 0.390), and number of CAG repeats (MV r = - 0.552; RNFL r = - 0.503; GCC r = - 0.493). The annual rate of change of the SARA score during follow-up was associated with that of both the MV (r = - 0.494; p = 0.005) and GCC thickness (r = - 0.454; p = 0.012). High disability (stages 2 and 3) was independently inversely associated with the annual change in MV (ß coefficient - 17.09; p = 0.025). This study provides evidence of an association between clinical features and objective anatomical measurements obtained by SD-OCT in SCA3 patients. MV and GCC thickness could serve as potential biomarkers of disease severity, as their rates of decrease seem to be related to a worsening in the SARA score. These findings highlight the potential of SD-OCT as a noninvasive tool for assessing disease severity and progression in SCA3 patients.

Optic Disc and Retinal Architecture Changes in Patients with Spinocerebellar Ataxia Type 2.

ATXN2 is the causative gene of spinocerebellar ataxia type 2 (SCA2) and has been implicated in glaucoma pathogenesis. Therefore, studying ocular changes in SCA2 could uncover clinically relevant changes. The aim was to investigate optic disc and retinal architecture in SCA2. We evaluated 14 patients with SCA2 and 26 controls who underwent intraocular pressure measurement, fundoscopy, and macular and peripapillary spectral domain optical coherence tomography (SD-OCT). We compared SD-OCT measurements in SCA2 and controls, and the frequency of glaucomatous changes among SCA2, controls, and 76 patients with other SCAs (types 1, 3, 6, and 7). The macula, peripapillary retinal nerve fiber and inner plexiform layers were thinner in SCA2 than in controls. Increased cup-to-disc ratio was more frequent in SCA2 than in controls and other SCAs. Ocular changes are part of SCA2 phenotype. Future studies should further investigate retinal and optic nerve architecture in this disorder.

Optical Coherence Tomography Findings in Bipolar Disorder Patients and the Related Factors.

This study's purpose is to determine the effects of current episode and the mood stabilizers on chorioretinal layer thicknesses of bipolar disorder (BD) patients using spectral-domain optical coherence tomography (SD-OCT). Sixty-seven patients were diagnosed with BD I and using lithium (Li) or valproic acid (VPA), of whom 20 were manic, 24 were depressive, and 23 were in remission, and 49 healthy individuals were included in the study. Peripapillary retinal nerve fiber layer (RNFL), ganglion cell layer, and macular thicknesses of the participants were measured automatically using SD-OCT, and their choroid layer thicknesses were measured manually using the depth imaging mode of SD-OCT. Statistical analysis of the data was performed using Statistical Package for the Social Sciences version 23.0. The patient group's mean age was 39.78 ± 11.78, and the control group's mean age was 42.06 ± 12.10. The mean disease duration was 13.22 ± 8.23 in the patient group, and 26 patients were using Li. While peripapillary RNFL thicknesses were lower in the patient group (P < .05), other layer measurements were similar between the groups. Moreover, the episodes experienced by BD patients did not affect chorioretinal SD-OCT measurements. The patients on VPA had significantly lower RNFL thicknesses compared to the control and the Li groups, and all chorioretinal measurements were similar between the Li and the control groups. As a result of the study, it was established that neurodegenerative processes play a role in the pathophysiology of BD and the usage of Li is protective against the neurodegeneration of RNFL. Retinal changes measured with SD-OCT can be used for the diagnosis and prognosis of BD and for evaluating responses to mood stabilizers.

A real-world study for timely assessing the diabetic macular edema refractory to intravitreal anti-VEGF treatment.

Early Identifying and characterizing patients with diabetic macular edema (DME) is essential for individualized treatment and outcome optimization. This study aimed to timely investigate optical coherence tomography (OCT) biomarkers of DME refractory to intravitreal anti-vascular endothelial growth factor (VEGF) therapy. We retrospective reviewed 72 eyes from 44 treatment-naïve patients who were treated with intravitreal anti-VEGF for DME. OCT scans prior to anti-VEGF were evaluated for serous retinal detachment (SRD), size of outer nuclear layer cystoid changes, diffuse retinal thickening, integrity of the inner segment-outer segment (IS-OS) junction, quantity and location of hyperreflective foci, vitreomacular interface abnormalities, and epiretinal membrane (ERM). The Baseline best-corrected visual acuity (BCVA) and central macular thickness was recorded at baseline and 4 months after treatment with anti-VEGF. The main outcome measure was the correlation between spectral-domain OCT measurements and BCVA response at baseline and after anti-VEGF treatment (mean change from baseline; ≥ 10 Early Treatment Diabetic Retinopathy Study letters in BCVA). Partially continuous IS-OS layers (partially vs. completely continuous: β, -0.138; Wald chi-square, 16.392; P<0.001) was predictor of better response to anti-VEGF treatment. In contrast, ERM (present vs. absent ERM: β, 0.215; Wald chi-square, 5.921; P=0.015) and vitreomacular traction (vitreomacular traction vs. posterior vitreous detachment: β=0.259; Wald chi-square=5.938; P=0.015) were the predictors of poor response. The improvement of BCVA trended toward the OCT predictive value of central macular thickness reduction; however, this was not significant. Partially continuous IS-OS layers is predictive of better response to anti-VEGF therapy in DME. Meanwhile, ERM is a significant predictor of poor response.

Quantification of retinal ganglion cell loss in patients with homonymous visual field defect due to stroke.

To quantify the degree of ganglion cell degeneration through spectral domain optical coherence tomography (SD-OCT) in adult patients with post-stroke homonymous visual field defect. Fifty patients with acquired visual field defect due to stroke (mean age = 61years) and thirty healthy controls (mean age = 58years) were included. Mean deviation (MD) and pattern standard deviation (PSD), average peripapillary retinal nerve fibre layer thickness (pRNLF-AVG), average ganglion cell complex thickness (GCC-AVG), global loss volume (GLV) and focal loss volume (FLV) were measured. Patients were divided according to the damaged vascular territories (occipital vs. parieto-occipital) and stroke type (ischaemic vs. haemorrhagic). Group analysis was conducted with ANOVA and multiple regressions. pRNFL-AVG was significantly decreased among patients with lesions in parieto-occipital territories compared to controls and to patients with lesions in occipital territories (p = .04), with no differences with respect to stroke type. GCC-AVG, GLV and FLV differed in stroke patients and controls, regardless of stroke type and involved vascular territories. Age and elapsed time from stroke had a significant effect on pRNFL-AVG and GCC-AVG (p < .01), but not on MD and PSD. Reduction of SD-OCT parameters occurs following both ischaemic and haemorrhagic occipital stroke, but it is larger when the injury extends to parietal territories and increases as time since stroke increases. The size of visual field defect is unrelated to SD-OCT measurements. Macular GCC thinning appeared to be more sensitive than pRNFL in detecting retrograde retinal ganglion cell degeneration and its retinotopic pattern in stroke.

Inter-device agreement between spectral domain optical coherence tomography, ultrasound biomicroscopy, and gonioscopy in evaluating the iridocorneal angle in normotensive dogs.

There has not been a thoroughly reported study of the comparison between spectral domain-optical coherence tomography (SD-OCT) with both ultrasound biomicroscopy (UBM) and gonioscopy on the evaluation of the iridocorneal angle (ICA) in dogs. To investigate the diagnostic value of SD-OCT for the early detection of narrowing ICA by comparing and assessing inter-device agreement in anterior chamber angle (ACA) measurements obtained by SD-OCT and UBM, and ICA evaluations by gonioscopy. A total of 28 eyes from 28 client-owned dogs with normal intraocular pressure were included for examination. The ACA and angle opening distance (AOD) were measured from the SD-OCT and UBM images, and gonioscopy images were analyzed using the ICA grade and ZibWest angle index. The mean ACA and AOD for SD-OCT were 28.31° ± 5.37° and 658.42 ± 219.90 µm, and for UBM, 28.34° ± 5.82° and 859.29 ± 221.80 µm, respectively. The mean difference in ACA between the average values of SD-OCT and UBM measurements was 0.03° with a 95% limit of agreement (LoA) span of 16.2°, indicating positive agreement; that in AOD was 200.85 µm with a 95% LoA span of 1,110.95 µm, indicating poor agreement. The Pearson correlation coefficient of the ACA of SD-OCT and ZibWest indices of gonioscopy was 0.624, indicating strong agreement; that of UBM and gonioscopy was 0.43, indicating moderate agreement. SD-OCT is well tolerated by canine patients due to its non-contact method and might be an alternative option for early screening of ICA narrowing in clinical settings.

DESCRIBING THE EFFECTS OF PRIMARY OPEN ANGLE GLAUCOMA ON MACULA USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN CENTRAL INDIA

Introduction: Primary open-angle glaucoma is a silent predator of sight, killing retinal ganglion cells (RGCs), and leads to characteristic optic nerve head (ONH) changes and visual field (VF) defects. The conventional methods of diagnosis include clinical examination and perimetry. However, by these at the time of diagnosis, a substantial loss of RGCs has already occurred. Spectral domain optical coherence tomography (SD-OCT) allows quantitative measurements of various parameters of the retina. This tool may be utilized for selective measurement of macular parameters to make an early diagnosis of primary open angle glaucoma (POAG). Methods: In 6 months of study, a total of 81 eyes of 51 subjects underwent SD-OCT measurements, that is, 49 eyes of 35 POAG subjects and 32 eyes of 16 age-matched healthy subjects, to record all measurable macular parameters, namely, macular thickness (MT)-central, average, in all sectors of the inner and outer circle of early treatment of diabetic retinopathy study (ETDRS) macular map; macular volume, ganglion cell-inner plexiform layer (GC-IPL) thickness-in all sectors; succeeded by statistical calculations using the unpaired t-test to calculate two-tailed p-value which is significant when its value is &lt;0.05. Results: As an observation the average MT, MT in the inferior and temporal sector of the inner circle of the ETDRS macular map, that in the inferior sector of the outer circle, minimum GC-IPL thickness, and GC-IPL thickness in all sectors were all significantly reduced in POAG eyes than healthy eyes. Whereas central MT, average GC-IPL thickness, macular volume, and MT in few sectors of the inner and outer circle of the ETDRS macular map proved to bear an insignificant change of POAG. Conclusion: In this study, the greatest impact of POAG on macula was discovered in the GC-IPL layer and MT in the inferior sector of inner and outer ring which might serve the purpose of diagnosis of POAG apart from the established parameters of RNFL and ONH.

Agreement of a Novel Artificial Intelligence Software With Optical Coherence Tomography and Manual Grading of the Optic Disc in Glaucoma.

The offline artificial intelligence (AI) on a smartphone-based fundus camera shows good agreement and correlation with the vertical cup-to-disc ratio (vCDR) from the spectral-domain optical coherence tomography (SD-OCT) and manual grading by experts. The purpose of this study is to assess the agreement of vCDR measured by a new AI software from optic disc images obtained using a validated smartphone-based imaging device, with SD-OCT vCDR measurements, and manual grading by experts on a stereoscopic fundus camera. In a prospective, cross-sectional study, participants above 18 years (Glaucoma and normal) underwent a dilated fundus evaluation, followed by optic disc imaging including a 42-degree monoscopic disc-centered image (Remidio NM-FOP-10), a 30-degree stereoscopic disc-centered image (Kowa nonmyd WX-3D desktop fundus camera), and disc analysis (Cirrus SD-OCT). Remidio FOP images were analyzed for vCDR using the new AI software, and Kowa stereoscopic images were manually graded by 3 fellowship-trained glaucoma specialists. We included 473 eyes of 244 participants. The vCDR values from the new AI software showed strong agreement with SD-OCT measurements [95% limits of agreement (LoA)=-0.13 to 0.16]. The agreement with SD-OCT was marginally better in eyes with higher vCDR (95% LoA=-0.15 to 0.12 for vCDR>0.8). Interclass correlation coefficient was 0.90 (95% CI, 0.88-0.91). The vCDR values from AI software showed a good correlation with the manual segmentation by experts (interclass correlation coefficient=0.89, 95% CI, 0.87-0.91) on stereoscopic images (95% LoA=-0.18 to 0.11) with agreement better for eyes with vCDR>0.8 (LoA=-0.12 to 0.08). The new AI software vCDR measurements had an excellent agreement and correlation with the SD-OCT and manual grading. The ability of the Medios AI to work offline, without requiring cloud-based inferencing, is an added advantage.

A Natural History Study of RP2-Related Retinopathy.

X-linked retinitis pigmentosa (RP) is a severe form of RP, often with early macular involvement. This study aimed to characterise the natural history of patients with a diagnosis of X-linked RP due to RP2 mutations. Clinical details, best-corrected visual acuity (BCVA) and multimodal retinal imaging were retrospectively collected from patients with RP2 variants from Moorfields Eye Hospital (London, UK). Measures of the ellipsoid-zone (EZ) width, central retinal thickness (CRT), and thickness of the photoreceptor and retinal pigment epithelium complex (PR+RPE, taken between the external limiting membrane and RPE) were extracted from spectral-domain optical coherence tomography (SD-OCT) scans. A total of 47 affected males (median baseline age: 20 years, IQR: 12.5−36.5) were included, and 41 had two or more visits (median follow-up: 8.0 years, IQR: 3.2−14.5). A total of 24 RP2 variants were identified, 13 of which were novel. BCVA dropped from 0.66 LogMAR at baseline (IQR, 0.35−1.4) to 1.3 LogMAR at the most recent visit (IQR: 0.6−1.4). SD-OCT revealed a prevalent outer retinal atrophy (n = 23/35, 65.7%), and measurable EZ width at baseline in 34.3% of patients (n = 12). Age significantly affected all quantitative measures (p < 0.001) except EZ width (p = 0.58), with exponential decays of 46−49% and 12.6−33.9% per decade for BCVA and SD-OCT measures, respectively. RP2 patients exhibited rapid progression to outer retina atrophy and early macular involvement with substantial vision loss by age 30−40.

In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes

To image healthy retinal pigment epithelial (RPE) cells invivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity. Single-center, exploratory, prospective, and descriptive clinical study. Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9-26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women). Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann-Whitney tests to investigate the relationship between cell features and eye and subject characteristics. Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV. Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was < 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs=-0.746; P < 0.0001) and increased cell area (Rs= 0.668; P < 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs=-0.391; P= 0.036) and increased cell area (Rs= 0.454; P= 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those > 50 years. The TOPI technology imaged RPE cells invivo with a repeatability of < 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers. Proprietary or commercial disclosure may be found after the references.

Intraoperative Mounted Optical Coherence Tomography Findings Following Reversal of Optic Nerve Head Cupping in Childhood Glaucoma

To examine the structural changes occurring in the optic nerve head (ONH) and macula in infants with childhood glaucoma and clinically observed ONH cupping reversal following intraocular pressure (IOP)-reducing glaucoma surgery, as captured by intra-operative spectral-domain optical coherence tomography (SD-OCT). Retrospective observational case series from an ongoing prospective cohort study. Included were 18 eyes of 14 patients with childhood glaucoma. All eyes had SD-OCT imaging pre- and post-glaucoma intervention and clinically identified ONH cupping reversal. Patients with poor quality images or persistent optic nerve swelling following IOP reduction were excluded. Outcome measurements included IOP, cup-to-disc ratio, axial length and SD-OCT measurements of the peripapillary retinal nerve fiber layer (pRNFL), transverse horizontal diameter of Bruch membrane opening (BMO-D), cup depth, and macula. Mean age at surgery was 1.14±0.93 years and mean interval between pre- and post-operative imaging was 127 days (range 35-595). Following intervention, mean IOP reduction was 45%, accompanied by significant reductions in the cup-to-disc ratio (0.30±0.12, p<0.001), axial length (0.43±0.28mm, p<0.001) and cup depth (46%, p<0.001). Mean global pRNFL thickness pre- vs. post-treatment was 93.1±14.7µm vs. 93.1±17.1µm, respectively, p=1.0. There was no significant difference in pre- and post-treatment global or sectoral pRNFL, 3mm macular total and segmented retinal layer volumes, or the BMO-D. Clinical ONH cupping reversal after IOP-lowering surgery was associated with axial length reduction and decrease in cup depth, but no significant change in the pRNFL or macular volume measures. ONH cupping reversal likely marks stabilization but any pre-intervention ONH damage persists.

Posterior segment spectral domain oct in the differential diagnosis of bilateral temporal optic neuropathy and its correlation with visual acuity.

To identify the underlying etiologies and to evaluate the differential diagnostic value of posterior segment spectral domain OCT measurements and their correlation with best-corrected visual acuity (BCVA) in a group of patients with OCT documented bilateral optic neuropathy limited to the temporal quadrants. Retrospective study. We included 61 patients: 35 presented with presumed "classic" acquired mitochondrial optic neuropathy (MON) (18 nutritional, 11 toxic, 6 mixed toxic-nutritional) and 2 with suspected hereditary MON. Nine patients were identified as 'MON mimickers' (especially multiple sclerosis), and 4 were found to have a mixed mechanism, while 11 remained undiagnosed. Across all etiologies, the strongest positive relationship between BCVA and tested OCT parameters was with macular GCL (ganglion cell layer) and GCIPL (combined ganglion cell and inner plexiform layer) volumes rather than peripapillary retinal nerve fiber layer (RNFL) thicknesses (all statistically significant). There was an inverse relationship between BCVA and inner nuclear layer (INL) volumes, with significant differences for BCVA and all tested OCT parameters between eyes with and without INL microcystoid lesions. OCT (absolute values and intereye differences) was not helpful in distinguishing between presumed acquired mitochondrial disease and patients with multiple sclerosis without optic neuritis. However, significantly greater intereye differences in global RNFL and inner plexiform layer and GCIPL volumes were found in patients with a previous history of unilateral optic neuritis. The strongest positive relationship with BCVA was found for macular GCL and GCIPL volumes. OCT could not differentiate between acquired mitochondrial disease and multiple sclerosis without optic neuritis.

The effects of hyperbaric oxygen therapy on retinal layers in healthy eyes

Purpose: The aim of our study is to investigate the effects of hyperbaric oxygen (HBO2) therapy on retinal layers in healthy eyes. Method: Thirty patients who were taken to outpatient HBO2 for any indication were included in the study. All patients underwent 10 sessions of HBO2; 20 healthy patients were taken as the control group. We used the spectral-domain optical coherence tomography (SD-OCT) to obtain automated measurements of thickness for each retinal layer – i.e., the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL) and retinal pigment epithelium (RPE) – and to conduct foveal (central 1 mm), inner-ring (parafoveal 1 to 3mm), and outer-ring (perifoveal 3 to 6mm) retinal layer measurements. Retinal OCT scans were performed before HBO2, after the first and 10th sessions. All retinal layer thicknesses were assessed with SD-OCT software system and compared between each visit. Retinal thicknesses were calculated in the central, inner ring and outer ring subfields (nine quadrants). Results: In SD-OCT measurements, there were no statistically significant difference before HBO2, after the first and 10th sessions in terms of foveal, inner-ring and outer-ring thickness of RNFL, GCL, IPL, INL, OPL, ONL and RPE. Conclusions: Our study demonstrated that there was no change in the thickness of the retinal layers after the first and 10th sessions in healthy eyes.

Comparison of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness Values Using Spectral-Domain and Swept-Source OCT.

PurposeTo compare peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell–inner plexiform layer (mGCIPL) thickness measurements obtained with spectral domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) using an OCT-angiography scanning protocol, and their ability to distinguish among patients with glaucoma, glaucoma suspects (GS), and healthy controls (HC).MethodsCross-sectional study of 196 eyes (81 glaucoma, 48 GS, and 67 HC) of 119 participants. Participants underwent peripapillary and macular OCT with SD-OCT and SS-OCT. Parameters of interest were average and sector-wise pRNFL and mGCIPL thickness. Inter-device agreement was investigated with Bland-Altman statistics. Conversion formulas were developed with linear regression. Diagnostic performances were evaluated with area under the receiver operating characteristic curves.ResultsBoth SD-OCT and SS-OCT detected a significant pRNFL and mGCIPL thinning in glaucoma patients compared to HC and GS for almost all study sectors. A strong linear relationship between the two devices was present for all quadrants/sectors (R2 ≥ 0.81, P < 0.001), except for the nasal (R2 = 0.49, P < 0.001) and temporal (R2 = 0.62, P < 0.001) pRNFL quadrants. SD-OCT and SS-OCT measurements had a proportional bias, which could be removed with conversion formulas. Overall, the two devices showed similar diagnostic abilities.ConclusionsThickness values obtained with SD-OCT and SS-OCT are not directly interchangeable but potentially interconvertible. Both devices have a similar ability to discriminate glaucoma patients from GS and healthy subjects.Translational RelevanceOCT-Angiography scans can be reliably used to obtain structural metrics in glaucoma patients.

Predicting retinal sensitivity using optical coherence tomography parameters in central serous chorioretinopathy.

To predict changes in retinal sensitivity using optical coherence tomography (OCT) in eyes with central serous chorioretinopathy (CSC). Twenty-three eyes in 23 patients with CSC were enrolled. Retinal sensitivity was measured twice using microperimetry in all the examined eyes. Spectral domain OCT measurements were simultaneously conducted. The relationship between retinal sensitivity and the thicknesses of (i) the retinal nerve fiber layer plus the ganglion cell layer (RNFL + GCL), (ii) the inner nuclear layer (INL), (iii) the outer nuclear layer (ONL), and (iv) the serous retinal detachment height (SRDH) were investigated in a point-wise manner. The associations between the change in retinal sensitivity and the OCT parameters at baseline were also investigated. The mean age of the participants was 49.8 ± 10.7years. The mean SRDH was significantly lower (p < 0.001), and the mean retinal sensitivity (p < 0.001) was significantly higher at the second examination, compared with the first; however, the logMAR visual acuity (VA) did not differ significantly between the two examinations (p = 0.063). The logMAR VA was associated with retinal sensitivity at both the first and second examinations (p < 0.001). The retinal sensitivity at the second examination was significantly correlated with the retinal sensitivity, RNFL + GCL, INL, ONL, and SRDH at the first examination and with the improvement in SRDH. Retinal sensitivity was associated with the retinal structure in eyes with CSC; these parameters could be useful for predicting the change in visual function prior to treatment.

The use of optical coherence tomography for skin evaluation in healthy rats.

Noninvasive diagnostic techniques allow for morphological and morphometric in vivo evaluation of the skin. Optical coherence tomography (OCT) is a method that allows visualization of dermal structures up to several 100 μm with a resolution of 3-7.5 μm. The aim of the study was the morphological and morphometric assessment of rats' skin using SD-OCT. Fifteen male Wistar rats, aged 3 and 8 months, weighing 350-450 g. The skin of the plantar metatarsal area of the right pelvic limb was assessed. The measurements were performed using Spectral Domain Optical Coherence Tomography (SD-OCT) scans and histological images. Spectral Domain Optical Coherence Tomography could determine the boundary between the epidermis and the dermis. Apart from the stratum corneum (SC), it did not allow for the differentiation of the individual epidermal layers. In the SD-OCT and in the histological examination, the mean thicknesses of the layers (μm ± SD) were (respectively): SC 33.053 ± μm(SD 5.85, 29.675 ± 5.54; epidermis 88.2 ± 7.97, 65.126 ± 13.23; dermis 259.86 ± 18.29, 166.05 ± 31.88 μm. There was a correlation between the total epidermal SD-OCT and histological measurements (r= 0.43, p= 0.05). Bland-Altman plots revealed a bias of -19.18 (95% confidence interval) -39.21 to 0.84 μm) in the case of live epidermis (stratum granulosum, stratum spinous, stratum basale). Spectral Domain Optical Coherence Tomography can be used to evaluate rat epidermis and dermis. The method enables the differentiation of the SC, as well as the epidermis and the dermis. SD-OCT and histological thickness dimensions of the epidermis and skin differ.

Spectral-domain OCT measurements in obesity: A systematic review and meta-analysis.

BackgroundPrevious studies proposed possible applications of spectral-domain optical coherence tomography (SD-OCT) measurements in prognosticating pathologies observed in overweight/obesity, including ocular, vascular, and neurologic consequences. Therefore, we conducted a systematic review and meta-analysis to investigate the changes in the in SD-OCT measurements of the patients with higher body mass index (BMI) compared to normal weight individuals.Materials and methodsWe conducted a systematic search on PubMed, Scopus, and Embase. The search results underwent two-phase title/abstract and full-text screenings. We then analyzed SD-OCT measurements differences in patients with high BMI and controls, and performed meta-regression, sub-group analysis, quality assessment, and publication bias assessment. The measurements included macular thickness, cup to disc ratio, ganglion cell-inner plexiform layer (GC-IPL) and its sub-sectors, RNFL and peripapillary RNFL (pRNFL) and their sub-layers, and choroidal thickness and its sub-sectors.Results19 studies were included in this meta-analysis accounting for 1813 individuals, 989 cases and 824 controls. There was an overall trend towards decreased thickness in high BMI patients, but only two measurements reached statistical significance: temporal retinal nerve fiber layer (RNFL) (Standardized mean difference (SMD): -0.33, 95% confidence interval (CI): -0.53 to -0.14, p<0.01) and the choroidal region 1.0 mm nasal to fovea (SMD: -0.38, 95% CI: -0.60 to -0.16, p<0.01).ConclusionSome ocular layers are thinner in patients with higher BMI than the controls. These SD-OCT measurements might correlate with adverse events related to increased body weight and have prognostic abilities. As SD-OCT is a robust, rapid and non-invasive tool, future guidelines and studies are needed to evaluate the possibility of their integration into care of the patients with obesity.