USE OF HAND-HELD OPTICAL COHERENCE TOMOGRAPHY DURING RETINOPATHY OF PREMATURITY SCREENING DEMONSTRATES AN INCREASED OUTER RETINA FROM EARLY POSTMENSTRUAL AGE IN PRETERM INFANTS WITH RETINOPATHY OF PREMATURITY

PURPOSE

To identify structural markers of active retinopathy of prematurity (ROP) in foveal and parafoveal retinal layers using hand-held optical coherence tomography.

METHODS

Hand-held optical coherence tomography images (n = 278) were acquired from a prospective mixed cross-sectional longitudinal observational study of 87 participants (23-36 weeks gestational age; n = 30 with ROP, n = 57 without ROP) between 31 and 44 weeks postmenstrual age excluding treated ROP and features of cystoid macular edema. Six retinal layer thicknesses from the fovea to the parafovea were analyzed at five locations up to 1,000 µ m, temporally and nasally.

RESULTS

The mean outer retinal thickness during active ROP increased at the fovea and parafovea from postmenstrual age 33 weeks to 39 weeks ( P < 0.001), whereas the parafoveal inner nuclear layer and retinal nerve fiber layer reduced ( P < 0.001). Outer retinal thickness at the fovea from 33 weeks to 39 weeks postmenstrual age was consistently thicker in infants with ROP across all levels of prematurity (gestational age).

CONCLUSION

Increased foveal and parafoveal outer retina measured using hand-held optical coherence tomography shows potential as a marker for ROP screening.

Is there any correlation between alpha-synuclein levels in tears and retinal layer thickness in Parkinson's disease?

PURPOSE

To determine the total alpha-synuclein (αSyn) reflex tears and its association with retinal layers thickness in Parkinson's disease (PD).

METHODS

Fifty-two eyes of 26 PD subjects and 52 eyes of age-and sex-matched healthy controls were included. Total αSyn in reflex tears was quantified using a human total αSyn enzyme-linked immunosorbent assay (ELISA) kit. The retinal thickness was evaluated with spectral-domain optical coherence tomography. The Movement Disorder Society-Unified Parkinsońs Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), and Montreal Cognitive Assessment (MoCA) were used to assess motor, non-motor, and cognition.

RESULTS

In PD, total αSyn levels were increased compared to control subjects [1.76pg/mL (IQR 1.74-1.80) vs 1.73pg/mL (IQR 1.70-1.77), p < 0.004]. The nerve fiber layer, ganglion cell layer, internal plexiform layer, inner nuclear layer, and outer nuclear layer were thinner in PD in comparison with controls (p < 0.05). The outer plexiform layer and retinal pigment epithelium were thicker in PD (p < 0.05). The total αSyn levels positively correlated with the central volume of the inner nuclear layer (r = 0.357, p = 0.009).

CONCLUSION

Total αSyn reflex tear levels were increased in subjects with PD compared to controls. PD patients showed significant thinning of the inner retinal layers and thickening of outer retinal layers in comparison with controls. Total αSyn levels positively correlate with the central volume of the inner nuclear layer in PD. The combination of these biomarkers might have a possible role as a diagnostic tool in PD subjects.

Association of retinal nerve layers thickness and brain imaging in healthy young subjects from the i-Share-Bordeaux study

Given the anatomical and functional similarities between the retina and the brain, the retina could be a "window" for viewing brain structures. We investigated the association between retinal nerve fiber layers (peripapillary retinal nerve fiber layer, ppRNFL; macular ganglion cell-inner plexiform layer, GC-IPL; and macular ganglion cell complex, GCC), and brain magnetic resonance imaging (MRI) parameters in young health adults. We included 857 students (mean age: 23.3 years, 71.3% women) from the i-Share study. We used multivariate linear models to study the cross-sectional association of each retinal nerve layer thickness assessed by spectral-domain optical coherence tomography (SD-OCT) with structural (volumes and cortical thickness), and microstructural brain markers, assessed on MRI globally and regionally. Microstructural MRI parameters included diffusion tensor imaging (DTI) and Neurite Orientation Dispersion and Density Imaging (NODDI). On global brain analysis, thicker ppRNFL, GC-IPL and GCC were all significantly associated with patterns of diffusion metrics consistent with higher WM microstructural integrity. In regional analyses, after multiple testing corrections, our results suggested significant associations of some retinal nerve layers with brain regional gray matter occipital volumes and with diffusion MRI parameters in a region involved in the visual pathway and in regions containing associative tracts. No associations were found with global volumes or with global or regional cortical thicknesses. Results of this study suggest that some retinal nerve layers may reflect brain structures. Further studies are needed to confirm these results in young subjects.

Taxane-Induced Neuropathy and Its Ocular Effects-A Longitudinal Follow-up Study in Breast Cancer Patients

A common severe neurotoxic side effect of breast cancer (BC) therapy is chemotherapy-induced peripheral neuropathy (CIPN) and intervention is highly needed for the detection, prevention, and treatment of CIPN at an early stage. As the eye is susceptible to neurotoxic stimuli, the present study aims to determine whether CIPN signs in paclitaxel-treated BC patients correlate with ocular changes by applying advanced non-invasive biophotonic in vivo imaging. Patients (n = 14, 10 controls) underwent monitoring sessions after diagnosis, during, and after therapy (T0-T3). Monitoring sessions included general anamnesis, assessment of their quality of life, neurological scores, ophthalmological status, macular optical coherence tomography (OCT), and imaging of their subbasal nerve plexus (SNP) by large-area confocal laser-scanning microscopy (CLSM). At T0, no significant differences were detected between patients and controls. During treatment, patients' scores significantly changed while the greatest differences were found between T0 and T3. None of the patients developed severe CIPN but retinal thickenings could be detected. CLSM revealed large SNP mosaics with identical areas while corneal nerves remained stable. The study represents the first longitudinal study combining oncological examinations with advanced biophotonic imaging techniques, demonstrating a powerful tool for the objective assessment of the severity of neurotoxic events with ocular structures acting as potential biomarkers.

Effects of Blood Pressure and Arterial Stiffness on Retinal Neurodegeneration: Cross-Sectional and Longitudinal Evidence From UK Biobank and Chinese Cohorts

BACKGROUND

Hypertension might be a modifiable risk factor for neurodegeneration diseases. However, the associations between blood pressure (BP), arterial stiffness index and retinal neurodegeneration remain unclear.

METHODS

This study used cross-sectional data from the United Kingdom BioBank (UKB) and longitudinal data from the Chinese Ocular Imaging Project (COIP). The macular ganglion cell-inner plexiform layer thickness (mGCIPLT) and macular retinal nerve fiber layer thickness were measured using spectral domain optical coherence tomography imaging. Swept-source optical coherence tomography was performed to obtain the longitudinal trajectory of the mGCIPLT and peripapillary retinal nerve fiber layer thickness in the COIP cohort. Multivariable linear models were used to analyze the associations between BP and retinal measurements.

RESULTS

In a cross-sectional analysis of 22 801 participants from UKB, thinner mGCIPLT was related to higher systolic BP (β: -0.103 [-0.146 to -0.061]; P<0.001), and higher diastolic BP (β: -0.191 [-0.265 to -0.117]; P<0.001), and was significantly associated with higher mean arterial pressure (β: -0.174 [-0.238 to -0.109]; P<0.001) and higher mean pulse pressure (β: -0.080 [-0.139 to -0.020]; P=009). In a longitudinal analysis of 2012 eligible COIP participants, higher levels of baseline systolic BP, diastolic BP, mean arterial pressure, and mean pulse pressure were associated with faster thinning in mGCIPLT and peripapillary retinal nerve fiber layer thickness (all P<0.001). The strongest association was the effect of mean arterial pressure on mGCIPLT (β: -0.118 [-0.175 to -0.061]; P<0.001). The results of the analysis of macular retinal nerve fiber layer thickness and peripapillary retinal nerve fiber layer thickness were consistent with those of mGCIPLT.

CONCLUSIONS

BP levels were independently and consistently associated with various retinal neurodegenerative exacerbations.

Effect of aging and lifestyle on healthy macular photoreceptors and retinal pigment epithelium-Bruch membrane complex thickness

OBJECTIVES

Investigate how aging and some lifestyle factors correlate with changes in macular photoreceptor and retinal pigment epithelium-Bruch membrane complex layers thickness in a sample of healthy population by using OCT segmentation technique.

SUBJECTS AND METHODS

A cross-sectional study conducted at the ophthalmology department in the Medical City in Baghdad. All participants underwent an interview of medical history and lifestyle habits. Maculae of all participants were scanned using spectral domain optical coherence tomography, followed by manual segmentation of retinal layers.

RESULTS

The study included 152 healthy participants (152 eyes), their mean age was 57.3 ± 6.7 years, gender distribution was 82(53.9%) males and 70(46.1%) females. There was a decrement in retinal pigment epithelium-Bruch membrane layer thickness at central subfield (500 µm radius from fovea minimum) by - 0.178 µm/year (p = 0.019), inner macula (500-1500 µm radius from fovea minimum) by - 0.263 µm/year (p = 0.002), outer macula (1500-3000 µm radius from fovea minimum) by - 0.225 µm/year (p = 0.015) with no statistically significant effect on photoreceptor thickness. Physical activity and smoking had statistically no significant effect on these layers thickness, however smokers had higher photoreceptor thickness at fovea minimum and central subfield. Body mass index increase by one kg/m² correlated with a decrement in photoreceptor layer thickness by - 0.108 µm (p = 0.007).

CONCLUSION

Aging process affected the retinal pigment epithelium-Bruch membrane complex and photoreceptor layer thickness in a healthy population, and this process can be slowed down by avoiding some lifestyles which aggravate these changes like obesity.

Optical Coherence Tomography Analysis of Retinal Layers in Celiac Disease

Celiac disease is an immune-mediated, chronic, inflammatory, and systemic illness which could affect the eye. The aim of this study is to look for possible signs of retinal involvement in celiac disease that could be utilized as biomarkers for this disease. Sixty-six patients with celiac disease and sixty-six sex-matched healthy subjects were enrolled in this observational case–control study. A comprehensive ophthalmological evaluation, axial length measurements, and SD-OCT evaluation were performed. The thickness of the retinal layers at the circle centered on the fovea (1 mm in diameter) and the average of the foveal and parafoveal zones at 2 and 3 mm in diameter were evaluated, together with retinal volume and the peripapillary retinal nerve fiber layer (RNFL). Concerning the thicknesses of the retinal layers in each analyzed region, no statistically significant differences were found. The same results were obtained for the total volume. Regarding peripapillary RNFL, the celiac patients showed slightly thicker values than the healthy controls, except for temporal and nasal-inferior quadrants, with no statistically significant differences. All the analyzed parameters were similar for the celiac patients and the healthy individuals. This could be related either to the non-involvement of the retinal layers in celiac disease pathophysiology or to the gluten-free diet effect.

Retinal Microvascular and Neuronal Changes Are Also Present, Even If Differently, in Adolescents with Type 1 Diabetes without Clinical Diabetic Retinopathy

The purpose of this study was to evaluate retinal changes in adolescents with childhood-onset, long-lasting type 1 diabetes mellitus (T1D). Patients and healthy controls (HC) underwent optical coherence tomography (OCT) and OCT-angiography (OCTA). Individual macular layers, peripapillary retinal nerve fiber layer (pRNFL), and vascular parameters (vessel area density (VAD), vessel length fraction (VLF) and vessel diameter index (VDI)) of macular superficial vascular (SVP), intermediate (ICP), deep (DCP) and radial peripapillary capillary plexuses (RPCP) were quantified. Thirty-nine patients (5 with (DR group) and 34 without (noDR group) diabetic retinopathy) and 20 HC were enrolled. The pRNFL and ganglion cell layer (GCL) were thicker in noDR compared to HC and DR, reaching statistically significant values versus HC for some sectors. At the macular level, VAD and VLF were reduced in DR versus HC in all plexuses, and versus noDR in SVP (p < 0.005 for all). At the RPCP level, VAD and VDI were increased in noDR versus HC, significantly for VDI (p = 0.0067). Glycemic indices correlated to retinal parameters. In conclusion, in T1D adolescents, retinal capillary and neuronal changes are present after long-lasting disease, even in the absence of clinical DR. These changes modify when clinical retinopathy develops. The precocious identification of specific OCT and OCTA changes may be a hallmark of subsequent overt retinopathy.

Thicker macula in asymptomatic APOE Ɛ4 middle-aged adults at high AD risk

INTRODUCTION

We compared retinal layers' thickness between apolipoprotein E (APOE) Ɛ4 carriers and non-carriers in a cohort of cognitively normal middle-aged adults enriched for Alzheimer's disease (AD) risk.

METHODS

Participants (N = 245) underwent spectral domain optical coherence tomography. Multivariate analyses of covariance adjusting for age, sex, education, and best corrected vision acuity was used to compare retinal thickness between APOE groups.

RESULTS

Participants' mean age was 59.60 (standard deviation = 6.42) with 66.4% women and 32.2% APOE Ɛ4 carriers. Greater macular full thickness was observed in APOE Ɛ4 carriers compared to non-carriers (P = .017), reaching statistical significance for the inner and outer nasal (P = .009 and P = .005, respectively), inner superior (P = .041), and inner and outer inferior (P = .013 and P = .033, respectively) sectors. The differences between APOE groups were mainly driven by the ganglion cell layer (P < .05) and the inner plexiform layer (P < .05).

DISCUSSION

A thicker macula is observed already in midlife asymptomatic APOE Ɛ4 carriers at high AD risk.

Wide-field optical coherence tomography imaging in diabetic retinopathy

PURPOSE

To report the individual retinal layer thicknesses up to mid-equator in patients with diabetic retinopathy (DR) using Spectralis (Heidelberg Engineering, Heidelberg, Germany) wide-field optical coherence tomography (OCT).

METHODS

Retinal layers were segmented using a custom designed semi-automated algorithm, where reference points were marked by the examiner to enable software to automatically compute the thickness values of each retinal sublayer at an interval of 1 mm from reference points. The values of individual retinal thicknesses in eyes with varying severity of DR were compared with the values of healthy subjects. Generalized estimating equation was performed to compensate for inclusion of both eyes of patients.

RESULTS

A total of 64 patients (119 eyes) with a mean age of 68.97  ±  10.27 years were included. Overall, ganglion cell layer (GCL)/ inner plexiform layer (IPL) complex (-31.67 microns, p < 0.001), outer plexiform layer (-6.78 microns, p = 0.002) and photoreceptor layer (-22.90 microns, p < 0.001) showed significant thinning, while outer nuclear layer thickening ( + 68.19 microns, <0.001) was noted in eyes with DM compared to healthy subjects. Thickness changes were significantly more in the macular segment compared to nasal and temporal segments. GCL/ IPL complex and photoreceptor layers were found to be significantly thin in all grades of DR.

CONCLUSION

Retinal thicknesses vary significantly in patients with diabetic retinopathy and understanding patterns of these changes across different segments of the wide field OCT may help better elucidate the natural progression of the disease in terms of retinal anatomy.

Analysis of Retinal Layers in Fibromyalgia Patients with Premium Protocol in Optical Tomography Coherence and Quality of Life

PURPOSE

To evaluate the inner retinal layers in fibromyalgia (FM) patients compared to control subjects using posterior pole protocol (PPole) analysis in optical coherence tomography (OCT) and to correlate structural retinal changes with subjective quality of life.

METHODS

Seventy-four eyes of healthy subjects and 55 eyes of those with FM were analyzed. All subjects underwent retinal evaluation using the PPole protocol for Spectralis OCT (Heidelberg Engineering) to obtain measurements of the retinal nerve fiber layer (RNFL) and the ganglion cell layer (GCL) in the macular area. The EuroQol (EQ-5D) questionnaire and Fibromyalgia Impact Questionnaire (FIQ) were performed to analyze health-related quality of life. Additionally, the FM group was divided into three groups depending on the disease phenotype (atypical, depressive and biological).

RESULTS

: Patients with FM presented with a reduction of the RNFL thickness compared to controls in 17/64 cells of the PPole area, and a reduction of the GCL thickness in 47/64 cells. Depressive FM phenotype showed the greatest number of cells with significant reduction compared with the control group in both RNFL and GCL layers. A correlation between temporal-inferior cells of the GCL and the EuroQol 5D questionnaire results was observed.

CONCLUSIONS

Patients with FM present with a reduction of the inner retinal layers in the macular area. This degeneration correlates with disease severity/reduced quality of life in these patients. The PPole protocol for OCT is a non-invasive and fast tool that might help clinicians diagnose and monitor neurodegeneration in FM patients.

A novel 3D segmentation approach for extracting retinal layers from optical coherence tomography images

PURPOSE

Accurate segmentation of retinal layers of the eye in 3D Optical Coherence Tomography (OCT) data provides relevant information for clinical diagnosis. This manuscript describes a 3D segmentation approach that uses an adaptive patient-specific retinal atlas, as well as an appearance model for 3D OCT data.

METHODS

To reconstruct the atlas of 3D retinal scan, the central area of the macula (macula mid-area) where the fovea could be clearly identified, was segmented initially. Markov Gibbs Random Field (MGRF) including intensity, spatial information, and shape of 12 retinal layers were used to segment the selected area of retinal fovea. A set of coregistered OCT scans that were gathered from 200 different individuals were used to build a 2D shape prior. This shape prior was adapted subsequently to the first order appearance and second order spatial interaction MGRF model. After segmenting the center of the macula "foveal area", the labels and appearances of the layers that were segmented were utilized to segment the adjacent slices. The final step was repeated recursively until a 3D OCT scan of the patient was segmented.

RESULTS

This approach was tested in 50 patients with normal and with ocular pathological conditions. The segmentation was compared to a manually segmented ground truth. The results were verified by clinical retinal experts. Dice Similarity Coefficient (DSC), 95% bidirectional modified Hausdorff Distance (HD), Unsigned Mean Surface Position Error (MSPE), and Average Volume Difference (AVD) metrics were used to quantify the performance of the proposed approach. The proposed approach was proved to be more accurate than the current state-of-the-art 3D OCT approaches.

CONCLUSIONS

The proposed approach has the advantage of segmenting all the 12 retinal layers rapidly and more accurately than current state-of-the-art 3D OCT approaches.

Relationships between retinal layer thickness and brain volumes in the UK Biobank cohort

Background and purpose

Current methods to diagnose neurodegenerative diseases are costly and invasive. Retinal neuroanatomy may be a biomarker for more neurodegenerative processes and can be quantified in vivo using optical coherence tomography (OCT), which is inexpensive and noninvasive. We examined the association of neuroretinal morphology with brain MRI image‐derived phenotypes (IDPs) in a large cohort of healthy older people.

Methods

UK Biobank participants aged 40 to 69 years old underwent comprehensive examinations including ophthalmic and brain imaging assessments. Macular retinal nerve fibre layer (mRNFL), macular ganglion cell‐inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC) and total macular thicknesses were obtained from OCT. Magnetic resonance imaging (MRI) IDPs assessed included total brain, grey matter, white matter and hippocampal volume. Multivariable linear regression models were used to evaluate associations between retinal layers thickness and brain MRI IDPs, adjusting for demographic factors and vascular risk factors.

Results

A total of 2131 participants (mean age 55 years; 51% women) with both gradable OCT images and brain imaging assessments were included. In multivariable regression analysis, thinner mGCIPL, mGCC and total macular thickness were all significantly associated with smaller total brain (p < 0.001), grey matter and white matter volume (p < 0.01), and grey matter volume in the occipital pole (p < 0.05). Thinner mGCC and total macular thicknesses were associated with smaller hippocampal volume (p < 0.02). No association was found between mRNFL and the MRI IDPs.

Conclusions

Markers of retinal neurodegeneration are associated with smaller brain volumes. Our findings suggest that retinal structure may be a biomarker providing information about important brain structure in healthy older adults.

Optical Coherence Tomography in Neuromyelitis Optica spectrum disorder and Multiple Sclerosis: A population-based study

BACKGROUND

The aim of this study was to identify and compare the characteristics of retinal nerve layers using spectral domain-optical coherence tomography (SD-OCT) in neuromyelitis optica spectrum disorder (NMOSD), relapsing-remitting multiple sclerosis (RRMS) and healthy controls (HCs).

METHODS

It is a cross-sectional population-based study in Isfahan, Iran. We enrolled 98 participants including 45 NMOSD patients (90 eyes), 35 RRMS patients (70 eyes) and 18 HCs (36 eyes). Evaluation criteria were thickness of different sectors in peripapillary retinal nerve fiber layer (pRNFL) and intra-retinal layers around the macula. History of previous optic neuritis (ON) was obtained through chart review and medical record.

RESULTS

Without considering ON, total macular, ganglion cell layer (GCL) and pRNFL were significantly thinner in both groups of patients compared to HCs. On macular examination, GCL and total macular thickness were significantly thinner than HCs in all NMOSD and RRMS eyes with and without history of ON. While there was no significant difference between MS-ON and MS without a history of ON in the macular measures, the reduction in total macular and GCL thickness was significantly greater in NMOSD-ON compared to NMOSD without a history of ON. Also in NMOSD-ON eyes, the RNFL, GCL, IPL and GCIPL layers were significantly thinner than that of MS-ON. On the other hand, the pRNFL study showed significant thinning of all quadrants in the RRMS and NMOSD groups relative to HCs. While the decrease of pRNFL thickness in the eyes of NMOSD-ON and MS with and without a previous history of ON was significantly greater than that of HCs, no difference was observed between NMOSD without ON and HCs. In addition, in NMOSD patients, pRNFL was significantly thinner in eyes with history of ON compared to non ON-eyes. Furthermore, in patients with a history of ON, reduction in all sectors of pRNFl (except in T) was significantly greater in NMOSD compared to MS patients.

CONCLUSION

Our findings showed that although macular and retinal damage occurred in both NMOSD and RRMS patients without significant differences, the severity of injury in eyes with history of ON was significantly higher in NMOSD compared to MS patients, that could be considered as a marker to distinguish them. In addition, our results confirmed the absence of subclinical optic nerve involvement in NMOSD unlike MS patients.

Early Retinal Changes by OCT Angiography and Multifocal Electroretinography in Diabetes

Background: To evaluate the earliest retinal morphological and functional changes in diabetic eyes without or with early signs of diabetic retinopathy (DR). Methods: Twenty-two eyes with no DR (noDR group), 22 eyes with mild DR (DR group), and 18 healthy nondiabetic eyes (controls) were enrolled. All eyes were studied by means of spectral domain optical coherence tomography (OCT), OCT angiography (OCTA), and multifocal electroretinogram (mfERG). Results: A significantly higher number of OCT hyperreflective intraretinal foci (HRF) was found in both noDR and DR groups versus controls, but not between DR groups. The OCTA parameters of the superficial vascular plexus (SVP) were significantly reduced in the noDR group both versus controls and DR group (p < 0.05). The OCTA parameters of the intermediate capillary plexus (ICP) were significantly reduced in the DR group versus controls. An increased number of altered hexagons on mfERG was found in the noDR versus the DR group (p = 0.0192). Conclusions: Retinal vascular and functional parameters are differently involved in diabetic eyes; major vascular changes in the SVP and functional alterations of the mfERG are present in diabetic eyes with no clinical microvascular signs of DR, while ICP is mainly involved when early ophthalmoscopic signs of DR are present. The integrated use of mfERG and OCTA provides new significant insights into the pathogenesis of diabetic related retinal disease.

Biochemical Characterization of Mouse Retina of an Alzheimer's Disease Model by Raman Spectroscopy

The presence of biomarkers characteristic for Alzheimer’s disease in the retina is a controversial topic. Raman spectroscopy offers information on the biochemical composition of tissues. Thus, it could give valuable insight into the diagnostic value of retinal analysis. Within the present study, retinas of a double transgenic mouse model, that expresses a chimeric mouse/human amyloid precursor protein and a mutant form of human presenilin 1, and corresponding control group were subjected to ex vivo Raman imaging. The Raman data recorded on cross sections of whole eyes highlight the layered structure of the retina in a label-free manner. Based on the Raman information obtained from en face mounted retina samples, a discrimination between healthy and Alzheimer’s disease retinal tissue can be done with an accuracy of 85.9%. For this a partial least squares-linear discriminant analysis was applied. Therefore, although no macromolecular changes in form of, i.e., amyloid beta plaques, can be noticed based on Raman spectroscopy, subtle biochemical changes happening in the retina could lead to Alzheimer’s disease identification.

Effect of Transcatheter Aortic Valve Replacement on Retinal Layer Thickness Measured by Optical Coherence Tomography

Transcatheter aortic valve replacement (TAVR) is associated with clinically significant cerebral microembolism and cognitive status changes. There are no data on the impact of TAVR on retinal layers. We assessed the influence of TAVR on the retinal nerve fiber layer, ganglion cell complex (GCC), and macular thickness (MT) measured by spectral domain optical coherence tomography (SD-OCT). Elderly patients (n = 50) with severe aortic stenosis undergoing TAVR were included in this study (mean age: 78.5 ± 6.9 years). Retinal nerve fiber layer, GCC, and MT were measured with SD-OCT by an ophthalmologist before and on the first day and in the first month after TAVR. The average MT was significantly increased on the first day after TAVR compared with the basal value (P = .04). Ganglion cell complex thickness was significantly thinner on the first day after TAVR than the basal value in the inner inferior quadrant and outer temporal quadrant of the left eye (P = .03 and .04, respectively). Postoperative changes observed on the first day compared with the preoperative period returned to basal values in the first month. In conclusion, TAVR did not cause permanent changes in retinal layers.

Tomographic characteristics of focal choroidal excavation and its association with retinal disorders

PURPOSE

To evaluate the morphological, clinical, and tomographic characteristics of focal choroidal excavation in the context of concomitant retinal pathologies.

METHODS

This case series included 13 eyes of 13 patients with focal choroidal excavation diagnosed by spectral-domain optical coherence tomography. Morphologic characteristics of excavation and quantitative thicknesses of retinal layers and choroid were analyzed in excavation area, area adjacent to excavation, and fellow eye without focal choroidal excavation by spectral-domain optical coherence tomography.

RESULTS

At the initial examinations, one eye had a history of blunt trauma, three eyes were diagnosed with choroidal neovascularization, one with choroidal osteoma, one with angioid streaks, one with retinal detachment, one with diabetic macular edema, one with optic pit, one with torpedo maculopathy, and the rest three with idiopathic focal choroidal excavation. The mean choroidal thickness in the area of focal choroidal excavation was statistically significantly thinner compared to in the area adjacent to focal choroidal excavation and fellow eye (p < 0.001) and total average outer nuclear layer thickness was statistically significantly thicker in the area of excavation compared with fellow eye (p = 0.007).

CONCLUSION

This study confirmed the presence of focal choroidal excavation in various ocular diseases and the evaluation of focal choroidal excavation using the spectral-domain optical coherence tomography demonstrated choroidal thinning and outer nuclear layer thickening in the area of the excavation.

Outer Retinal Dysfunction on Multifocal Electroretinography May Help Differentiating Multiple Sclerosis From Neuromyelitis Optica Spectrum Disorder

Purpose: To evaluate the intermediate and outer retina of patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) using OCT and multifocal electroretinography (mf-ERG).

Methods: Patients with MS (n = 30), NMOSD (n = 30), and healthy controls (n = 29) underwent visual field (VF), OCT, and mf-ERG testing. The eyes were distributed into 5 groups: MS with or without history of ON (MS+ON, MS–ON), NMOSD with or without ON (NMOSD+ON, NMOSD–ON), and controls. The thickness of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer, outer plexiform layer, outer nuclear layer, and photoreceptor layer was measured. mf-ERG P1 and N1 responses were registered and grouped in 3 sets of rings. The groups were compared using GEE models, and effect size (ES) calculated.

Results: Compared to controls, GCL and IPL thickness was significantly smaller in MS+ON (both p < 0.01), MS–ON (p < 0.01 and p = 0.015, respectively), NMOSD+ON (both p < 0.01) and NMOSD–ON (p = 0.03 and p = 0.018, respectively). ES was >0.80. mRNFL was smaller in three of the above groups (p < 0.01, p < 0.001, and p = 0.028; ES > 0.80) but not in MS–ON eyes (p = 0.18). No significant difference was observed for the remaining layers. Compared to controls, P1 and N1 peak times were shorter in MS (p-values in the range 0.049–0.002, ES < 0.50; and 0.049–0.010; ES < 0.50, respectively) but not in NMOSD. These abnormalities were strongly correlated with intermediate and outer retinal layer thickness.

Conclusions: mf-ERG data suggest outer retinal abnormalities in MS, but not in NMOSD. Our results may help understand how the two conditions differ regarding retinal damage.

German Diabetes Study - Baseline data of retinal layer thickness measured by SD-OCT in early diabetes mellitus

PURPOSE

Recent studies highlighted that early diabetic neurodegeneration is present before microvascular changes are visible. Retinal neurodegeneration can decrease retinal layer thickness. We aimed to determine whether decreased retinal layer thickness is present already in the early time course of disease.

METHODS

A cross-sectional analysis of patients and healthy adults from the German Diabetes Study (GDS, ClinicalTrials.gov Identifier number: CT01055093, https://clinicaltrials.gov/ct2/show/NCT01055093). Inclusion criteria were a diagnosis of diabetes mellitus (DM) within the last 12 months. Retinal layers thickness in the nasal pericentral segment was measured by spectral domain ocular coherence tomography (SD-OCT). For statistical analysis proc mixed (sas-version 9.4) was used.

RESULTS

One hundred and seventy-eight eyes of 89 patients with type 1 DM (58 males, age 36 ± 11 years, BMI 25.5 ± 4.2 kg/m²) and 242 eyes of 121 patients with type 2 DM (84 males, age 53 ± 10 years, BMI 31.9 ± 6.3 kg/m²) with a disease duration of less than 1 year were compared to 76 eyes of 38 controls (27 males, age 41 ± 16 years, BMI 27.3 ± 6.4 kg/m²). Analysis of retinal layer thickness and visual function did not reveal a significant difference between patients and controls.

CONCLUSION

In the early course of DM potential, neurodegeneration does not relate to measureable changes of retinal layer thickness.

Assessing reproducibility and the effects of demographic variables on the normal macular layers using the Spectralis SD-OCT

Purpose

To quantify and view the possible influence of demographic variables on normal macular layers. Additionally, we wanted to assess the reproducibility using the Spectralis SD-OCT.

Methods

A Spectralis SD-OCT machine using a commercially available algorithm was used to scan 242 healthy subjects in an outpatient setting. We examined retinal thicknesses in seven layers: 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). Combined retinal thicknesses were expressed as inner retinal layer (IRL), photoreceptor layer (PL) and total retinal thickness (TRT). Measurements were taken from each of the nine sectors defined by the Early Treatment Diabetic Retinopathy Study; the center was the fovea, the inner circle (IC) was 1–3 mm away, and the outer circle (OC) was 3–6 mm away.

Results

The TRT was thickest inferiorly in the IC, and superiorly in the OC. The RNFL (P=0.030), GCL (P=0.006), IPL (P=0.006), IRL (P=0.030), PL (P<0.001) and TRT (P=0.001) were found to be thicker in males. The GCL (r=0.078, P=0.001), IPL (r=0.079, P=0.001), IRL (r=0.072, P=0.002), PL (r=0.076, P=0.001) and TRT (r=0.090, P<0.001) were found to decrease with age. The INL (r=0.060, P=0.010), ONL (r=0.078, P=0.001), and RPE (r=0.066, P=0.004) were inversely related to axial length. Excellent reproducibility was observed in all layers.

Conclusion

Our study shows differences in various retinal layers according to age, gender, and axial length. Additionally, we demonstrate excellent reproducibility of this algorithm using the Spectralis SD-OCT.

Retinal Layer Abnormalities as Biomarkers of Schizophrenia

OBJECTIVE

Schizophrenia is associated with several brain deficits, as well as visual processing deficits, but clinically useful biomarkers are elusive. We hypothesized that retinal layer changes, noninvasively visualized using spectral-domain optical coherence tomography (SD-OCT), may represent a possible "window" to these abnormalities.

METHODS

A Leica EnvisuTM SD-OCT device was used to obtain high-resolution central foveal B-scans in both eyes of 35 patients with schizophrenia and 50 demographically matched controls. Manual retinal layer segmentation was performed to acquire individual and combined layer thickness measurements in 3 macular regions. Contrast sensitivity was measured at 3 spatial frequencies in a subgroup of each cohort. Differences were compared using adjusted linear models and significantly different layer measures in patients underwent Spearman Rank correlations with contrast sensitivity, quantified symptoms severity, disease duration, and antipsychotic medication dose.

RESULTS

Total retinal and photoreceptor complex thickness was reduced in all regions in patients (P < .0001). Segmentation revealed consistent thinning of the outer nuclear layer (P < .001) and inner segment layer (P < .05), as well as a pattern of parafoveal ganglion cell changes. Low spatial frequency contrast sensitivity was reduced in patients (P = .002) and correlated with temporal parafoveal ganglion cell complex thinning (R = .48, P = .01). Negative symptom severity was inversely correlated with foveal photoreceptor complex thickness (R = -.54, P = .001) and outer nuclear layer thickness (R = -.47, P = .005).

CONCLUSIONS

Our novel findings demonstrate considerable retinal layer abnormalities in schizophrenia that are related to clinical features and visual function. With time, SD-OCT could provide easily-measurable biomarkers to facilitate clinical assessment and further our understanding of the disease.

Protruded retinal layers within the optic nerve head neuroretinal rim

PURPOSE

To determine the frequency with which retinal tissues other than the nerve fibre layer, hereafter referred to as protruded retinal layers (PRL), are a component of optical coherence tomography (OCT) neuroretinal rim measurements.

METHODS

Ninety healthy (30 White, Black and Japanese, respectively) subjects were included in the study. A radial scan pattern (24 B-scans centred on Bruch's membrane opening [BMO]) was used. For each of the 48 minimum rim width (MRW) measurement points, we determined whether PRL were present, absent or indeterminate. When present, the proportion of PRL within the MRW was quantified.

RESULTS

Protruded retinal layers were present in 503 (11.6%), absent in 3805 (88.1%) and indeterminate in 12 (0.3%) measurement points. Overall, 69 (76.6%) subjects had ≥1 points with PRL, with White subjects having the highest frequency and Japanese the lowest (29 [97%] and 18 [60%], respectively; p < 0.01). PRL were present in one-third of points in the temporal sector, but ≤5% in other sectors. When present, the median PRL thickness was 53.0 (interquartile range [IQR]: 33.0 to 78.5) μm, representing 20.6 (IQR: 13.0 to 28.5)% of MRW. Globally, the median PRL thickness comprised 1.3 (IQR: 0.2 to 3.5)% of the MRW; however, in the temporal sector, it exceeded 30% of MRW in some subjects.

CONCLUSIONS

Protruded retinal layers are a component of MRW measurements in most normal subjects, occurring in almost 12% of all measurement points analysed. There were racial variations in the presence of PRL and a significantly higher frequency of PRL in the temporal sector.

Analysis of Agreement of Retinal-Layer Thickness Measures Derived from the Segmentation of Horizontal and Vertical Spectralis OCT Macular Scans

PURPOSE

Optical coherence tomography (OCT) is a reliable method used to quantify discrete layers of the retina. Spectralis OCT is a device used for this purpose. Spectralis OCT macular scan imaging acquisition can be obtained on either the horizontal or vertical plane. The vertical protocol has been proposed as favorable, due to postulated reduction in confound of Henle's fibers on segmentation-derived metrics. Yet, agreement of the segmentation measures of horizontal and vertical macular scans remains unexplored. Our aim was to determine this agreement.

MATERIALS AND METHODS

Horizontal and vertical macular scans on Spectralis OCT were acquired in 20 healthy controls (HCs) and 20 multiple sclerosis (MS) patients. All scans were segmented using Heidelberg software and a Johns Hopkins University (JHU)-developed method. Agreement was analyzed using Bland-Altman analyses and intra-class correlation coefficients (ICCs).

RESULTS

Using both segmentation techniques, mean differences (agreement at the cohort level) in the thicknesses of all macular layers derived from both acquisition protocols in MS patients and HCs were narrow (<1 µm), while the limits of agreement (LOA) (agreement at the individual level) were wider. Using JHU segmentation mean differences (and LOA) for the macular retinal nerve fiber layer (RNFL) and ganglion cell layer + inner plexiform layer (GCIP) in MS were 0.21 µm (-1.57-1.99 µm) and -0.36 µm (-1.44-1.37 µm), respectively.

CONCLUSIONS

OCT segmentation measures of discrete retinal-layer thicknesses derived from both vertical and horizontal protocols on Spectralis OCT agree excellently at the cohort level (narrow mean differences), but only moderately at the individual level (wide LOA). This suggests patients scanned using either protocol should continue to be scanned with the same protocol. However, due to excellent agreement at the cohort level, measures derived from both acquisitions can be pooled for outcome purposes in clinical trials.

Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of these layers and their correlation with retinal functional measurements, including microperimetry (MP) sensitivity and visual acuity (VA), were investigated. The photoreceptor outer segment layer demonstrated significant thinning with a reduction in MP sensitivity and VA score when atrophic AMD lesions were present. Regular drusen and RPD were separately segmented on SD-OCT images to allow their characteristics and distribution to be studied separately. The mean thickness of regular drusen was found to significantly correlate with the VA score. RPD appeared to be distributed evenly throughout the macula and regular drusen appeared to be more concentrated centrally.

Ratiometric analysis of in vivo retinal layer thicknesses in multiple sclerosis

We performed ratiometric analysis of retinal optical coherence tomography images for the first time in multiple sclerosis (MS) patients. The ratiometric analysis identified differences in several retinal layer thickness ratios in the cohort of MS subjects without a history of optic neuritis (ON) compared to healthy control (HC) subjects, and there was no difference in standard retinal nerve fiber layer thickness (RNFLT). The difference in such ratios between HC subjects and those with mild MS-disability, without a difference in RNFLT, further suggests the possibility of using layer ratiometric analysis for detecting early retinal changes in MS. Ratiometric analysis may be useful and potentially more sensitive for detecting disease changes in MS.

Morphologic changes and visual outcomes in resolved central serous chorioretinopathy treated with ranibizumab

CONTEXT

Central serous chorioretinopathy (CSC).

OBJECTIVE

To evaluate the effect of intravitreal ranibizumab injection and the correlation between foveal morphologic changes and visual outcomes in patients with resolved CSC.

MATERIALS AND METHODS

We measured outer nuclear layer (ONL) thickness, outer layer (OL) thickness and evaluated the integrity of the photoreceptor inner-outer segment (IS/OS) junction, the status of the external limiting membrane (ELM) at the central fovea using spectral-domain optical coherence tomography (OCT) in 35 eyes of 35 patients with resolved CSC. The eyes were divided into two groups: The initial medical treatment administered to Group1 (n = 17) then received intravitreal ranibizumab injections, Group 2 (n = 18) received medical treatment. Group 3 was composed of normal eyes (n = 20, as a control). We also investigated a correlation between the ONL thickness and best corrected visual acuity (BCVA).

RESULTS

The mean age was 45.7 ± 7.2 (ranged from 27 to 55 years). The mean follow-up period was 14.2 months (minimum 6, maximum 24 months). The mean ONL and OL thickness in Group 1 were significantly thinner than Group 3 (p < 0.005). The ONL thickness was correlated with the BCVA (r = 0.681, p = 0.001). Thirty-tree patients had improvement in BCVA after treatment. Discontinuity of the IS/OS junction was found in 15 eyes (88.2%) in Group 1, in 5 eyes (27.7%) in Group 2 and in no eyes in Group 3.

DISCUSSION

We demonstrated that prolonged serous detachment results in photoreceptor cell loss (apoptosis) and thinning of the ONL. Thinning of the ONL correlates with poorer vision, which has been found by other investigators. Furthermore, vascular endothelial growth factor (VEGF) may be neuroprotective to the photoreceptors which might explain the additional thinning in the patients treated with ranibizumab. This raises the possibility that treatment with VEGF inhibitors may be unfavourable to patients with CSC, even though it speeds recovery and vision does improve.

CONCLUSION

Intravitreal ranibizumab injection leads to thinning of the ONL and the OL in patients with resolved CSC. The ONL thickness reduction and discontinuity of the IS/OS junction results in poor visual prognosis in resolved CSC eyes.

In vivo characterization of ischemic retina in diabetic retinopathy

Objective

The aim of this article is to characterize pathomorphologic changes within particular layers of fluorescein angiographically ‘ischemic’ compared to ‘nonischemic’ retina in patients with diabetic retinopathy.

Methods

Cross-sectional images of ischemic retinal areas were obtained using Heidelberg Spectralis optical coherence tomography (OCT). Presumed retinal ischemia was defined as focal hypofluorescence in early or early and late phase fluorescein angiography. Pathomorphologic changes on OCT were evaluated and the thickness of retinal layers measured and compared with nonischemic retina at corresponding topographic locations in a matched-pairs design based on 22 eyes (mean age 64 ± 14).

Results

In all eyes, based on spectral domain-OCT cross-section images, the retina layers in ischemic retinal areas could be segmented. Total retinal thickness was significantly increased in ischemic compared to nonischemic areas (381 ± 94 μm versus 323 ± 89 μm, P = 0.005). Middle retinal layers (inner nuclear layer, outer plexiform layer, and outer nuclear layer) were significantly thickened in retinal ischemic areas (215 ± 82 μm versus 168 ± 62 μm, P = 0.002). The inner retinal layers (retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer) showed a nonsignificant change (117 ± 53 μm versus 98 ± 30 μm), while the outer layers were slightly thinned (photoreceptors plus retinal pigment epithelium layer; 51 ± 9 μm versus 57 ± 8 μm, P = 0.02) in ischemic versus nonischemic retina.

Conclusions

Ischemic diabetic retina seems to be thickened due to thickening of, in particular, middle retinal layers, which can be measured with high-resolution OCT.