Automatic Identification and Severity Classification of Retinal Biomarkers in SD-OCT Using Dilated Depthwise Separable Convolution ResNet with SVM Classifier

PURPOSE

Diagnosis of Uveitic Macular Edema (UME) using Spectral Domain OCT (SD-OCT) is a promising method for early detection and monitoring of sight-threatening visual impairment. Viewing multiple B-scans and identifying biomarkers is challenging and time-consuming for clinical practitioners. To overcome these challenges, this paper proposes an image classification hybrid framework for predicting the presence of biomarkers such as intraretinal cysts (IRC), hyperreflective foci (HRF), hard exudates (HE) and neurosensory detachment (NSD) in OCT B-scans along with their severity.

METHODS

A dataset of 10880 B-scans from 85 Uveitic patients is collected and graded by two board-certified ophthalmologists for the presence of biomarkers. A novel image classification framework, Dilated Depthwise Separable Convolution ResNet (DDSC-RN) with SVM classifier, is developed to achieve network compression with a larger receptive field that captures both low and high-level features of the biomarkers without loss of classification accuracy. The severity level of each biomarker is predicted from the feature map, extracted by the proposed DDSC-RN network.

RESULTS

The proposed hybrid model is evaluated using ground truth labels from the hospital. The deep learning model initially, identified the presence of biomarkers in B-scans. It achieved an overall accuracy of 98.64%, which is comparable to the performance of other state-of-the-art models, such as DRN-C-42 and ResNet-34. The SVM classifier then predicted the severity of each biomarker, achieving an overall accuracy of 89.3%.

CONCLUSIONS

A new hybrid model accurately identifies four retinal biomarkers on a tissue map and predicts their severity. The model outperforms other methods for identifying multiple biomarkers in complex OCT B-scans. This helps clinicians to screen multiple B-scans of UME more effectively, leading to better treatment outcomes.

Multifractal Analysis of Choroidal SDOCT Images in the Detection of Retinitis Pigmentosa

The aim of this paper is to investigate whether a multifractal analysis can be applied to study choroidal blood vessels and help ophthalmologists in the early diagnosis of retinitis pigmentosa (RP). In a case study, we used spectral domain optical coherence tomography (SDOCT), which is a noninvasive and highly sensitive imaging technique of the retina and choroid. The image of a choroidal branching pattern can be regarded as a multifractal. Therefore, we calculated the generalized Renyi point-centered dimensions, which are considered a measure of the inhomogeneity of data, to prove that it increases in patients with RP as compared to those in the control group.

Multimodal imaging in early onset non-neovascular pigment epithelial detachments

PURPOSE

To describe multimodal imaging of two cases of bilateral non-vascularized pigment epithelial detachments (PED) in young patients with a long-term follow-up.

METHODS

A complete ophthalmological examination was performed at each follow-up visit including best corrected visual acuity (BCVA), intraocular pressure, slit lamp examination, spectral domain optical coherence tomography (SD-OCT), fluorescein and indocyanine green angiography, OCT angiography.

RESULTS

Multimodal imaging of two women presenting avascular PED, aged 43 and 57, respectively, was described. In both patients, SD-OCT revealed a high central macular hyporeflective elevation corresponding with PED. Both patients showed a choroidal layer thicker than 420 μm. Fluorescein and indocyanine green angiography didn't show any choroidal neovascularization either at early or late frames. Cross-sectional and en face optical coherence tomography angiography (OCTA) didn't show any flow beneath the PED. During the follow up period one eye showed a retinal pigment epithelium tear and all eyes showed the presence of apical sub-retinal fluid and hyperreflective material on the top of the PED. None of the two patients showed any sign of atrophy during the follow-up period.

CONCLUSION

The peculiar characteristics of the presented cases suggest that specific pathogenetic mechanisms, not necessarily related to age related macular degeneration, may play a key role in the development of these lesions. Whether early onset of such drusenoid PED is a specific entity resulting from a genetic deficit of lipid transporters in the RPE is unknown. Further genetic and metabolic studies should be conducted.

Paracentral Acute Middle Maculopathy Following Acute Primary Angle Closure and Acute Primary Angle Closure Glaucoma

Purpose

To report the prevalence, clinical characteristics and risk factors for paracentral acute middle maculopathy (PAMM) following acute primary angle closure (APAC) and acute primary angle closure glaucoma (APACG).

Methods

This retrospective study consecutively recruited patients diagnosed with APAC or APACG. Based on the spectral domain optical coherence tomography characteristics, PAMM eyes were divided into three stages. Characteristics of different stages such as the time from symptoms to treatment (TST), retinal thickness and BCVA improvement were analyzed. The risk factors of PAMM were evaluated by binary logistic regression models.

Results

A total of 781 eyes of 781 APAC or APACG patients were included, and PAMM was found in 22 (2.9%) of them. Stage III eyes had a significantly longer TST than stage I eyes (P = 0.008) while exhibiting significantly thinner retinal thicknesses (P < 0.0001). The BCVA improvement was significantly worse in the eyes treated in stage III than in those treated in stage I (P = 0.008). Older age, longer axial length and without type 2 diabetes were associated with a lower risk of incident PAMM (OR = 0.95, P = 0.028; OR = 0.52, P = 0.019; OR = 3.92, P = 0.022).

Conclusion

PAMM can be secondary to APAC or APACG at a rate of 2.9%. Different visual outcomes were observed in patients who received the intervention at different stages of PAMM. Younger patients with a shorter axial length and type 2 diabetes were found to be more susceptible to PAMM.

Multimodal Ophthalmic Imaging in Spinocerebellar Ataxia Type 7

The aim of this case series and narrative literature review is to highlight the importance of multimodal imaging in the ophthalmological examination of patients with spinocerebellar ataxia type 7 and provide a summary of the most relevant imaging techniques. Three patients with SCA7 were included in this case series. A literature review revealed twenty-one publications regarding ocular manifestations of SCA7, and the most relevant aspects are summarized. The role of different imaging techniques in the follow-up of SCA7 patients is analyzed, including color vision testing, corneal endothelial topography, color fundus photography (CFP) and autofluorescence, near infrared reflectance imaging, spectral domain optical coherence tomography (SDOCT), visual field examination, and electrophysiological tests. SDOCT provides a rapid and non-invasive imaging evaluation of disease progression over time. Additional examination including NIR imaging can provide further information on photoreceptor alteration and subtle disruption of the RPE, which are not evident with CFP at an early stage. Electrophysiological tests provide essential results on the state of cone and rod dystrophy, which could be paramount in guiding future genetic therapies. Multimodal imaging is a valuable addition to comprehensive ophthalmological examination in the diagnosis and management of patients with SCA7.

Swept Source-Optical Coherence Tomography-Guided Facedown Posturing to Minimize Treatment Burden and Maximize Outcome after Macular Hole Surgery

We evaluated the closure of full-thickness macular holes (MHs) the day after surgery in minimizing the burden and maximizing patient outcomes. Herein, 25-gauge pars plana vitrectomy, internal limiting membrane peeling, and fluid-gas (20% sulfur hexafluoride) were performed for the treatment. Patients were instructed to remain in the facedown position until the confirmation of MH closure, and the position was discontinued in cases where the closure was confirmed. In total, 43 eyes of 43 patients, whose average age was 69.7 ± 8.6 years, were enrolled in this study. We used swept source (SS)-optical coherence tomography (OCT) for the confirmation of MH closure for gas-filled eyes and used spectral domain (SD)-OCT for the reconfirmation of MH closure after the gas volume was reduced to less than half of the vitreous cavity. MH closure was confirmed in 40 eyes (93%, the closure group) on the next day after surgery. The time from surgery to SS-OCT imaging was 24.7 h. Although facedown positioning was terminated in cases where MH closure was confirmed, there were no cases in which the MH was re-opened afterward. The basal and minimum MH size was significantly larger in the non-closure group than that in the closure group (p = 0.027, p = 0.043, respectively). Therefore, checking with SS-OCT the day after surgery and terminating facedown positioning in cases where MH closure was confirmed would be a useful method, removing a great burden for the elderly without sacrificing the MH closure rate.

Congenital Retinal Macrovessel Without Any Ophthalmic Complications: A Case Report

Congenital retinal macrovessels (CRMs) are a rare entity. They are usually unilateral, abnormally large, and aberrant vessels. Although the majority of the patients are asymptomatic, CRMs may affect vision if they are associated with pigmentary changes at the macula, foveolar cysts, central serous retinopathy, macular hemorrhage, or if the macrovessel crosses the fovea. Here, we present the case of a young female who came for a routine ophthalmological evaluation. She was asymptomatic, and the macrovessel was an incidental finding. Visual acuity and slit lamp examination were normal, and dilated fundus evaluation was normal except for CRM in the right eye. Optical coherence tomography angiography imaging helped visualize the depth of the vessel and the analysis of the architecture of the foveal avascular zone.

Development of a translatable gene augmentation therapy for CNGB1-retinitis pigmentosa

In this study, we investigate a gene augmentation therapy candidate for the treatment of retinitis pigmentosa (RP) due to cyclic nucleotide-gated channel beta 1 (CNGB1) mutations. We use an adeno-associated virus serotype 5 with transgene under control of a novel short human rhodopsin promoter. The promoter/capsid combination drives efficient expression of a reporter gene (AAV5-RHO-eGFP) exclusively in rod photoreceptors in primate, dog, and mouse following subretinal delivery. The therapeutic vector (AAV5-RHO-CNGB1) delivered to the subretinal space of CNGB1 mutant dogs restores rod-mediated retinal function (electroretinographic responses and vision) for at least 12 months post treatment. Immunohistochemistry shows human CNGB1 is expressed in rod photoreceptors in the treated regions as well as restoration of expression and trafficking of the endogenous alpha subunit of the rod CNG channel required for normal channel formation. The treatment reverses abnormal accumulation of the second messenger, cyclic guanosine monophosphate, which occurs in rod photoreceptors of CNGB1 mutant dogs, confirming formation of a functional CNG channel. In vivo imaging shows long-term preservation of retinal structure. In conclusion, this study establishes the long-term efficacy of subretinal delivery of AAV5-RHO-CNGB1 to rescue the disease phenotype in a canine model of CNGB1-RP, confirming its suitability for future clinical development.

A Case of Concurrent Acute Macular Neuroretinopathy and Paracentral Acute Middle Maculopathy Following Pfizer-BioNTech COVID-19 Vaccination

We present a 65-year-old woman who developed sudden and severe vision loss in her left eye one day after the administration of the second dose of COVID vaccine. The best corrected visual acuity in this eye was 1/10. Diffuse paracentral acute middle maculopathy was detected on spectral domain optical coherence tomography (OCT). OCT angiography images revealed concurrent vascular flow defects consistent with acute macular neuroretinopathy in the deep retinal capillary plexus and choriocapillaris layers. At the end of the six-month follow-up, there was no improvement in visual acuity, and atrophy and thinning developed in all layers of the retina.

Efficacy and accuracy of artificial intelligence to overlay multimodal images from different optical instruments in patients with retinitis pigmentosa

BACKGROUND

Retinitis pigmentosa (RP) represents a group of progressive, genetically heterogenous blinding diseases. Recently, relationships between measures of retinal function and structure are needed to help identify outcome measures or biomarkers for clinical trials. The ability to align retinal multimodal images, taken on different platforms, will allow better understanding of this relationship. We investigate the efficacy of artificial intelligence (AI) in overlaying different multimodal retinal images in RP patients.

METHODS

We overlayed infrared images from microperimetry on near-infra-red images from scanning laser ophthalmoscope and spectral domain optical coherence tomography in RP patients using manual alignment and AI. The AI adopted a two-step framework and was trained on a separate dataset. Manual alignment was performed using in-house software that allowed labelling of six key points located at vessel bifurcations. Manual overlay was considered successful if the distance between same key points on the overlayed images was ≤1/2°.

RESULTS

Fifty-seven eyes of 32 patients were included in the analysis. AI was significantly more accurate and successful in aligning images compared to manual alignment as confirmed by linear mixed-effects modelling (p < 0.001). A receiver operating characteristic analysis, used to compute the area under the curve of the AI (0.991) and manual (0.835) Dice coefficients in relation to their respective 'truth' values, found AI significantly more accurate in the overlay (p < 0.001).

CONCLUSION

AI was significantly more accurate than manual alignment in overlaying multimodal retinal imaging in RP patients and showed the potential to use AI algorithms for future multimodal clinical and research applications.

The Role of Alpha-Synuclein Deposits in Parkinson's Disease: A Focus on the Human Retina

Parkinson's disease (PD) is a neurodegenerative condition characterized by the progressive deterioration of dopaminergic neurons in the central and peripheral autonomous system and the intraneuronal cytoplasmic accumulation of misfolded α-synuclein. The clinical features are the classic triad of tremor, rigidity, and bradykinesia and a set of non-motor symptoms, including visual deficits. The latter seems to arise years before the onset of motor symptoms and reflects the course of brain disease. The retina, by virtue of its similarity to brain tissue, is an excellent site for the analysis of the known histopathological changes of PD that occur in the brain. Numerous studies conducted on animal and human models of PD have shown the presence of α-synuclein in retinal tissue. Spectral-domain optical coherence tomography (SD-OCT) could be a technique that enables the study of these retinal alterations in vivo. The objective of this review is to describe recent evidence on the accumulation of native or modified α-synuclein in the human retina of patients with PD and its effects on the retinal tissue evaluated through SD-OCT.

Influence of Multiple Anti-VEGF Injections on Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness in Patients with Exudative Age-Related Macular Degeneration

Backgrounds and Objectives: To analyze the influence of multiple anti-VEGF intravitreal injections for exudative age-related macular degeneration on the thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC + IPL) using spectral domain optical coherence tomography (SD-OCT). Materials and Methods: A prospective interventional study of consecutive patients treated with intravitreal bevacizumab (IVB) was performed. Average and sectorial values of RNFL and GC + IPL thickness were recorded using Cirrus SD-OCT at 0, 6, 12, and 24 months. Patients suffering from any ocular disease that could affect RNFL or GC + IPL thickness were excluded. Results: A total of 135 patients (70 women and 65 men, aged 65 ± 15 years) were included. The average number of injections per patient was 12.4 ± 2.4. Average RNFL and GC + IPL thickness prior to the first injection (87.6 ± 12.2 and 47.2 ± 15.5 respectively), and after 24-month follow-up (86.2 ± 12.6 and 46.7 ± 11.9 respectively) did not differ significantly (p > 0.05). There was a significant decrease in GC2, GC5 segments, and minimum GC + IPL thickness. Conclusion: Repeated anti-VEGF treatment did not cause significant changes in the thickness of RNFL and GC + IPL layers over a period of 24 months. The detected decrease in GC2 and GC5 sectors, as well as in minimum GC + IPL thickness, could be a sign of ganglion cell damage induced by the treatment or could occur during the natural course of the disease.

Increase in anterior chamber angle depth after topical pilocarpine measured by spectral domain optical coherence tomography: A possible additional indicator for laser peripheral iridotomy in primary angle-closure suspects in an opportunistic set-up

Purpose

Indication of laser peripheral iridotomy (LPI) is often conjectural due to dependency on gonioscopy and strict dichotomous classification of occludability. Indentation gonioscopy is the gold standard but is under-utilized for various reasons. The prevalence of primary angle closure disease (PACD) in eastern India is 1.5-1.9%, with a 22% five-year progression rate. Many angle closure patients may go blind without timely diagnosis and iridotomy. General ophthalmologists need alternate, validated methods for diagnoses. Pilocarpine eye drop causes miosis, and flattens the iris, producing angle changes detectable by spectral domain optical coherence tomography (SD-OCT). We hypothesized that the amount of angle change may be a suitable indicator for iridotomy.

Methods

Our prospective cross-sectional single-masked observational study evaluated pilocarpine-induced changes in angle parameters detected by SD-OCT. Out of 372 patients enrolled, 273 patients (539 eyes) remained, with a mean age of 48.6 years (SD = 10.36). All eyes were graded by the Van Herick (VH) method, gonioscopy, and anterior segment (AS) SD-OCT and reassessed after pilocarpine drops.

Results

The sensitivity and specificity of tomography measurements against gonioscopy grades were 61% and 85%, respectively. The receiver operating characteristic (ROC) curve was 0.85. Pilocarpine-induced angle widening was significant in gonioscopically narrower angles. Low Van Herick grades (217 eyes), narrow gonioscopy grades (238 eyes), and a narrow OCT angle value (165 eyes) were candidates for iridotomy.

Conclusion

Our study results showed that pilocarpine-induced angle widening detected by SD-OCT could be a strong objective indicator for LPI.

Automatic segmentation of hyperreflective dots via focal priors and visual saliency

PURPOSE

Hyperreflective dots (HRDs) can be observed in spectral domain optical coherence tomography (SD-OCT), which can provide a sensitive marker in the treatment decision process. Quantitative analyses of HRDs are the key to make appropriate decisions on observation, treatment, and retreatment. The purpose of this study is to automatically and accurately segment HRDs in SD-OCT B-scans with diabetic retinopathy (DR).

METHODS

The authors propose an automatic segmentation algorithm of HRDs via focal priors and visual saliency. The algorithm is divided into three stages: segmentation of retinal layers, calculation of the multiscale local contrast saliency map, and adaptive threshold segmentation. First, a method based on improved graph search is used to segment retinal layers to obtain the region of interest (ROI) and the reflectivity estimation of the retinal pigment epithelium (RPE) layer; then, the multiscale local contrast saliency map is obtained by using a local contrast measure, which measures the dissimilarity between the current pixels and corresponding neighborhoods; finally, an adaptive threshold is applied to segment HRDs.

RESULTS

Experimental results on 20 SD-OCT B-scans demonstrate that our method is effective for HRDs segmentation. The average dice similarity coefficient (DSC) and detection accuracy are 71.12% and 85.07%, respectively.

CONCLUSIONS

The proposed method can accurately segment HRDs in SD-OCT B-scans with DR and outperforms current state-of-the-art methods. Our method can provide reliable HRDs segmentation to assist ophthalmologists in clinical diagnosis, treatment, disease monitoring, and progression.

Paracentral Acute Middle Maculopathy Revealing a Giant Aortic Aneurysm

BACKGROUND

This report describes a case with paracentral acute middle maculopathy revealing a giant aortic aneurysm.

CASE DESCRIPTION

A 41-year-old man presented with unilaterally unexplained sudden vision loss in the left eye. Fundoscopy revealed a slightly pale r -26etinal reflex in the superior retinal hemifield. SDOCT revealed blurred boundaries between retinal segments and prominent edema in the middle retinal layers. OCTA revealed decreased vascular density in the deep capillary plexus. FA showed low arterial circulation mainly in the superior retinal hemifield. Humphrey VFT revealed an inferior altitudinal defect in the left eye, implying a related circulatory disturbance in the corresponding region.A thorough systemic work-up, including a cardiovascular etiological investigation, revealed giant aortic aneurysm in the ascending aorta, necessitating emergency surgery.

CONCLUSION

This report highlights the importance of a systemic etiological investigation in patients with PAMM to rule out any potential cardiovascular issues.

Correlation between Macular Neovascularization (MNV) Type and Druse Type in Neovascular Age-Related Macular Degeneration (AMD) Based on the CONAN Classification

To investigate associations and predictive factors between macular neovascularization (MNV) lesion variants and drusen types in patients with treatment-naïve neovascular age-related macular degeneration (AMD). Methods: Multimodal imaging was retrospectively reviewed for druse type (soft drusen, subretinal drusenoid deposits (SDDs) or mixed) and MNV type (MNV 1, MNV 2, MNV 1/2 or MNV 3). The Consensus on Neovascular AMD Nomenclature (CONAN) classification was used for characterizing MNV at baseline. Results: One eye of each eligible patient was included (n = 191). Patients with predominant SDDs had an increased adjusted odds ratio (aOR) for MNV 2 (23.4453, p = 0.0025) and any type of MNV 3 (8.7374, p < 0.0001). Patients with MNV 1/2 had an aOR for predominant SDDs (0.3284, p = 0.0084). Patients with MNV1 showed an aOR for SDDs (0.0357, p < 0.0001). Eyes with SDDs only without other drusen types showed an aOR for MNV 2 (9.2945, p < 0.0001). Conclusions: SDDs represent a common phenotypic characteristic in AMD eyes with treatment-naïve MNV. The aOR for eyes with predominant SDDs to develop MNV 2 and MNV 3 was much higher, possibly due to their location in the subretinal space. The predominant druse type may help to predict which type of MNV will develop during the course of AMD.

Temporal retinal thinning might be an early diagnostic indicator in male pediatric X-linked Alport syndrome

AIM

To evaluate temporal retinal thinning changes in retinal layers using spectral-domain optical coherence tomography (SD-OCT) in pediatric X-linked Alport syndrome (XLAS) patients.

METHODS

A retrospective case-control study. SD-OCT scans of pediatric patients diagnosed with XLAS and age- and sex-matched healthy control participants were reviewed. Automated segmentation of SD-OCT scans was induced to analyze the retinal thickness (RT) of different layers. The temporal thinning index (TTI) was calculated for each layer and compared between the patients and the control group.

RESULTS

Forty-three pediatric XLAS patients and 60 healthy controls were included. Temporal retinal thinning was present in 33 patients (76.74%), while 28 patients (65.11%) had severe pathological temporal retinal thinning and 5 patients (11.63%) had moderate thinning. The temporal inner sector RT (P<0.0001), the temporal outer sector RT (P<0.0001), and the nasal outer sector RT (P=0.0211) were significantly thinner in the XLAS male patients. The TTI of the total retina was significantly higher in the XLAS group than in the control group (P<0.0001). The TTI of the inner retina layers (P<0.0001), ganglion cell layer (P<0.0001), inner plexiform layer (P<0.0001), inner nuclear layer (P<0.0001), and outer nuclear layer (P<0.0001) were significantly higher in the XLAS group. The central RT of the XLAS group was significantly thinner than that of the control group (P<0.0001).

CONCLUSION

Temporal retinal thinning appears early in XLAS patients, especially in male patients. The thinning is mainly caused by structural abnormalities of the inner retina. This suggests that temporal retinal thinning could be helpful for the early diagnosis and follow-up of XLAS with noninvasive SD-OCT examination.

The Role of the Choroid in Stargardt Disease

Stargardt disease is the commonest juvenile macular dystrophy. It is caused by genetic mutations in the ABCA4 gene. Diagnosis is not always straightforward, and various phenocopies exist. Late-onset disease can be misdiagnosed with age-related macular disease. A correct diagnosis is particularly critical because of emergent gene therapies. Stargardt disease is known to affect retinal pigment epithelium and photoreceptors. Many studies have also highlighted the importance of the choroid in the diagnosis, pathophysiology, and progression of the disease. The choroid is in an integral relationship with the retinal pigment epithelium and photoreceptors, and its possible involvement during the disease should be considered. The purpose of this review is to analyze the current diagnostic tools for choroidal evaluation and the extrapolation of useful data for ophthalmologists and researchers studying the disease.

The effect of hyperbaric oxygen therapy on central macular thickness and choroidal thickness in the healthy eyes of patients with idiopathic sudden sensorineural hearing loss

PURPOSE

To evaluate the effect of hyperbaric oxygen therapy (HBOT) for idiopathic sudden sensorineural hearing loss (ISSNHL) on central macular thickness (CMT) and choroidal thickness (CT).

MATERIALS AND METHODS

The study included 42 healthy eyes of 21 patients with ISSNHL (aged 24-61 years) who started HBOT within the first three days of the onset of hearing loss. Duration and severity of hearing loss were noted before starting HBOT. Central macular thickness (CMT), choroidal thickness (CT) 1500 µm nasal and temporal of the fovea, and subfoveal CT were measured by spectral domain optic coherence tomography before the first session of HBOT and after sessions 10 and 20. measurements obtained before and after HBOT were compared.

RESULTS

Eleven patients (52.4%) were men and 10 (47.6%) were women. The mean age was 44.67 ± 10.1 years. The mean duration of sudden hearing loss before HBOT was 2.05 ± 1 day. Hearing loss was mild in 5 patients, moderate in 5 patients, moderate to severe in 2 patients, severe in 4 patients and profound in 5 patients. Comparison of measurements obtained before HBOT and after 10 and 20 sessions of HBOT revealed no significant differences in CMT (219.17 ± 22.91, 220.33 ± 19.66, and 220.21 ± 19.3 µm), subfoveal CT (347.71 ± 66.82, 348.38 ± 74.55, and 345.45 ± 75.39 µm), nasal CT (328.64 ± 82.31, 316.02 ± 79.32, and 313.52 ± 89.92 µm), or temporal CT (321.76 ± 71.29, 317.05 ± 73.94, and 314.05 ± 74.61 µm, respectively) (p > 0.05).

CONCLUSIONS

HBOT for the treatment of ISSNHL had no significant effect on CMT or CT in healthy eyes.

The Weiss Ring, a Major Confounding Factor For Measurements of Peripapillary Retinal Nerve Fiber Layer Thickness: Short title: The Impact of the Weiss Ring On RNFL Thickness Measurements

PURPOSE

To identify how the Weiss ring affects the measurement of mean and sectoral peripapillary retinal nerve fiber layer (pRNFL) thicknesses.

DESIGN

Retrospective, cross-sectional study.

METHODS

Subjects were divided into two groups: controls (control group) and subjects in which a Weiss ring was visible on optical coherence tomography fundus images (WR group). Mean and sectoral pRNFL thicknesses were compared between the two groups.

RESULTS

A total of 205 eyes were enrolled: 131 eyes in the control group and 74 eyes in the WR group. The mean pRNFL thicknesses of the control group and WR group were 97.2 ± 6.7 µm and 94.6 ± 10.8 µm, respectively (P = .042). In sectoral thickness, the inferior sector of the WR group was 112.1 ± 23.2 µm, which was significantly thinner than that of the control group (125.5 ± 13.3 µm; P < .001). The Weiss ring was located in 10 eyes (13.5%) in the superior sector, 7 eyes (9.5%) in the temporal sector, 40 eyes (54.1%) in the inferior sector, and 17 eyes (23.0%) in the nasal sector. In analyses of reproducibility, the coefficient of variation and intraclass coefficient of the inferior sector measurement were 10.90% and 0.409, respectively, indicating low reliability of the measurement.

CONCLUSIONS

Eyes with a Weiss ring showed thinner mean and inferior pRNFL thicknesses than normal controls, which would be a measurement error caused by the Weiss ring. This could be a major confounding factor for analyses of pRNFL changes, especially in glaucoma patients.

Disc Hemorrhages Are Associated With Localized Three-Dimensional Neuroretinal Rim Thickness Progression in Open-Angle Glaucoma

PURPOSE

To evaluate the relationship between the occurrence of optic disc hemorrhages (DH) and glaucoma progression as determined by multiple glaucoma testing modalities.

DESIGN

Prospective cohort study.

METHODS

A longitudinal study was undertaken of 124 open-angle glaucoma patients who had yearly disc photography, visual fields (VFs), spectral-domain optical coherence tomography (SD-OCT), retinal nerve fiber layer (RNFL) thickness scans, and optic nerve volume scans (Spectralis), all performed on the same day over a 5-year period. The minimum distance band (MDB) thickness, a 3-dimensional (3D) neuroretinal rim parameter, was calculated from optic nerve volume scans. Patients were classified as glaucoma progressors or glaucoma nonprogressors using event-based analysis.

RESULTS

Of 124 open-angle glaucoma patients, 19 (15.3%) had 1 or more DHs on yearly disc photographs. Presence of a DH was associated with localized 3D neuroretinal rim thickness progression (superior MDB progression; odds ratio: 3.96; P = .04) but not with global or inferior MDB progression (P = .14 and .81, respectively), DP progression (P = .08), VF progression (P = .45), or RNFL global, inferior, or superior progression (P = .17, .26, and .76, respectively). In the majority of patients with MDB progression (14/17 or 82%), the progression was noted before or concurrently with the first instance of DH.

CONCLUSIONS

Glaucoma progression detected by high-density 3D SD-OCT neuroretinal rim measurements preceded DH occurrence in the majority of patients. These findings support the hypothesis that DHs are indicators of ongoing glaucoma progression rather than discrete events that cause subsequent progression.

CRB1-Related Retinal Dystrophies in a Cohort of 50 Patients: A Reappraisal in the Light of Specific Müller Cell and Photoreceptor CRB1 Isoforms

Pathogenic variants in CRB1 lead to diverse recessive retinal disorders from severe Leber congenital amaurosis to isolated macular dystrophy. Until recently, no clear phenotype-genotype correlation and no appropriate mouse models existed. Herein, we reappraise the phenotype-genotype correlation of 50 patients with regards to the recently identified CRB1 isoforms: a canonical long isoform A localized in Müller cells (12 exons) and a short isoform B predominant in photoreceptors (7 exons). Twenty-eight patients with early onset retinal dystrophy (EORD) consistently had a severe Müller impairment, with variable impact on the photoreceptors, regardless of isoform B expression. Among them, two patients expressing wild type isoform B carried one variant in exon 12, which specifically damaged intracellular protein interactions in Müller cells. Thirteen retinitis pigmentosa patients had mainly missense variants in laminin G-like domains and expressed at least 50% of isoform A. Eight patients with the c.498_506del variant had macular dystrophy. In one family homozygous for the c.1562C>T variant, the brother had EORD and the sister macular dystrophy. In contrast with the mouse model, these data highlight the key role of Müller cells in the severity of CRB1-related dystrophies in humans, which should be taken into consideration for future clinical trials.

Unusual case of enlarged choroidal vessels in neurofibromatosis type 1 observed with near-infrared reflectance and spectral domain optical coherence tomography

The cardinal diagnostic signs of neurofibromatosis type 1 (NF1) are Lisch nodules of the iris and optic pathway gliomas. Retinal mi-crovascular alterations have been described but with uncertain signi-ficance. Choroidal nodules, detectable with near-infrared reflectance (NIR) imaging, are present in most cases and have been proposed as a new diagnostic criterion. Recently, a study reported the presence of unusual dilated choroidal vessels, visible through NIR examination. We report a case of a 65-year-old patient with NF1. Best-corrected visual acuity was 20/20 with a refractive error of +2.75 diopters in both eyes. Anterior segment examination revealed Lisch nodules in both eyes. At NIR imaging the patient presented typical choroidal alterations in both eyes. No retinal vessel anomalies were detected. The patient presented enlarged choroidal vessels in the left eye, first detected by NIR and then analyzed through enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT). These vessels extended from the choroidal-scleral junction to the outer border of the retinal pigment epithelium/Bruch's layer. The choriocapillaris layer was absent above the dilated vessels. The presence of enlarged choroidal vessels may be considered as a novel distinctive ophthalmologic aspect of NF1, but further studies are necessary.

Comparison of iridocorneal angle parameters measured by spectral domain optical coherence tomography and ultrasound biomicroscopy in dogs

OBJECTIVE

To compare the measurements of iridocorneal angle parameters between spectral domain optical coherence tomography (SD-OCT) and ultrasound biomicroscopy (UBM) in dogs.

ANIMALS STUDIED AND PROCEDURES

A total of 47 eyes of dogs were scanned at the temporal limbus using SD-OCT and UBM. Iridocorneal angle (ICA) and angle opening distance (AOD) were measured from the obtained images accordingly. The intra-observer and inter-observer reproducibility were evaluated using the intraclass correlation coefficient. To evaluate intra-observer reproducibility, measurements of the first and second grading from the first examiner were compared. To evaluate inter-observer reproducibility, measurements between the two examiners were compared. Agreement between ICA and AOD for SD-OCT and UBM was evaluated using Bland-Altman plots.

RESULTS

In the first grading, the mean ICA and AOD for SD-OCT were 31.4 ± 6.4° and 641.4 ± 270.8 µm, respectively. The mean ICA and AOD for UBM were 32.0 ± 4.8° and 700.4 ± 238.8 µm, respectively. For ICA and AOD measurements, intra-observer reproducibility was excellent for both devices, whereas inter-observer reproducibility was excellent for SD-OCT and good for UBM. The mean difference in ICA between SD-OCT and UBM was 0.6° with a limit of agreement (LoA) span of 18.9°. The mean difference in AOD between SD-OCT and UBM was 58.9 µm with a LoA span of 804.4 µm.

CONCLUSIONS

Spectral domain optical coherence tomography is an effective non-contact imaging modality for the evaluation of canine iridocorneal angle parameters in a clinical setting. Reproducibility of measurements obtained is comparable or superior to UBM, but values obtained by SD-OCT and UBM for AOD are not interchangeable between devices.

Longitudinal changes in the ganglion cell-inner plexiform layer thickness of age-related macular degeneration

PURPOSE

To determine longitudinal changes of the ganglion cell-inner plexiform layer (GC-IPL) thickness in patients with non-exudative age-related macular degeneration (AMD) without other ophthalmic disease.

METHODS

Thirty-three eyes of 33 patients with early and intermediate non-exudative AMD (non-exudative AMD group) and 33 normal control eyes were followed for 2 years, and GC-IPL thickness was measured by spectral domain optical coherence tomography at 1-year intervals. The mean rate of GC-IPL reduction was estimated using a linear mixed model and compared between two groups.

RESULTS

The mean age of patients in the non-exudative AMD group and control groups were 68.82 ± 6.81 years and 67.73 ± 5.87 years, respectively (p = 0.488). The mean GC-IPL thickness at the first visit was 76.61 ± 16.33 μm in the non-exudative AMD and 81.76 ± 3.69 μm in control group (p = 0.387), and these values significantly decreased over time, with an average reduction rate of average GC-IPL -0.86 μm/year in the non-exudative AMD group and -0.32 μm/year in the control group. The difference between two groups was statistically significant (p < 0.001), and there was also a significant interaction between group and duration in linear mixed models in mean GC-IPL thickness (p = 0.001).

CONCLUSIONS

The reduction rate of the GC-IPL thickness was greater in non-exudative AMD eyes, even at relatively early stages of the disease. Physicians should maintain awareness of the presence of non-exudative AMD in various cases of ophthalmic diseases where GC-IPL thickness evaluation is necessary.

Optic nerve colobomas associated with unilateral focal serous retinal detachment in a dog - In-vivo imaging and outcome following laser retinopexy

PURPOSE

To describe the ophthalmoscopic, in-vivo imaging, fluorescein angiography, and therapeutic photocoagulation outcome in a case of bilateral optic nerve colobomas associated with focal unilateral retinal detachment in a dog.

METHODS

Pretraining eye examination of a 1.6-year-old female German shepherd service dog showed a focal juxta-papillary bullous retinal separation in the right eye. In vivo imaging and angiography were performed under general anesthesia using optical coherence tomography. Nonoverlapping diode laser burns were applied through an operating microscope adapter to selected areas along the leading margins of the detachment.

RESULTS

The funduscopic examination and in-vivo imaging revealed bilateral optic nerve colobomas associated with a focal bullous detachment in the right eye. Fluorescein angiography showed absence of blood vessel leakage and absence of staining inside of the retinal elevation. Photocoagulation induced immediate changes in retinal layer reflectivity. Three months post-photocoagulation, the retinal detachment had improved and scarring of the burns was visible. One and two years post-procedure, the retinal detachment resolved.

CONCLUSIONS

Optical coherence tomography (OCT) imaging provides a detailed analysis of the retinal abnormalities associated with the clinical lesion. Laser retinopexy is a valid therapeutic option to limit the extension of the detachment.

Effect of vitamin B12 deficiency anemia on peripapillary retinal nerve fiber layer

AIM

To evaluate the effect of vitamin B12 deficiency anemia (BDA) on peripapillary retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography (SD-OCT), and to determine any correlation arising thereof.

METHODS

In this cross-sectional observational study, 99 eyes of 50 BDA patients of age 18-65y were compared with 100 eyes of 50 healthy control subjects. All subjects underwent comprehensive clinical, ophthalmic, and hematological evaluation, followed by peripapillary RNFLT assessment using SD-OCT.

RESULTS

The mean total, inferior, nasal, and temporal RNFLT were significantly lower in BDA group as compared to control group (P<0.05). The mean total, inferior and nasal RNFLT correlated significantly (P<0.05) with serum Hb%, B12 and mean corpuscular volume (MCV) level (r=0.310, 0.435, -0.386 for total; r=0.932, 0.481, -0.513 for inferior; r=0.344, 0.254, -0.233 for nasal; respectively), while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters (r=0.144, 0.167, -0.096; r=0.111, 0.070, -0.099; respectively). The mean total RNFLT showed progressive thinning at par with the progression of anemia, except in very severe BDA, where an inverse relationship was documented.

CONCLUSION

The mean total, inferior, nasal, and temporal peripapillary RNFLT was significantly thinner in BDA patients. Peripapillary RNFLT thinning seemed to proceed at par with the progression of severity of anemia, except in very sever grade. Early assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding sequelae. Peripapillary RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies, as well.

Complications of Intra-Arterial tPA for Iatrogenic Branch Retinal Artery Occlusion: A Case Report through Multimodal Imaging and Literature Review

Background and Objectives: To document, through multimodal imaging, the post-procedural clinical course and visual outcome of a patient who received intra-arterial tissue plasminogen activator (tPA) for acute iatrogenic branch retinal artery occlusion (BRAO), and to review the literature and guidelines regarding the use of tPA for retinal arterial occlusions. Methods: A 28-year-old female patient who sustained an iatrogenic BRAO and subsequently received intra-arterial tPA was followed through her post-interventional course of 3 months with serial exams and multimodal imaging, including color fundus photography, visual field testing, spectral domain optical coherence tomography (SD-OCT), and OCT angiography (OCT-A). Results: A patient with history of left internal cerebral artery (ICA) aneurysm and baseline visual acuity (VA) of 20/20 developed an acutely symptomatic BRAO after undergoing a neuroendovascular procedure and was acutely treated with tPA through the left ophthalmic artery. At two weeks follow-up, a central posterior pole hemorrhage was noted although VA was preserved. A superior altitudinal defect was shown on automated perimetry. VA dropped to 20/50 at 7 weeks follow-up and hyperreflective material deep to the attachment between the posterior hyaloid and the internal limiting membrane (ILM) consistent with hemorrhage was noted on SD-OCT. At 11 weeks follow-up, VA returned to 20/20, SD-OCT revealed a membrane bridging the foveal depression, OCT-A showed decreased vascularity in the inferior macula, and the visual field defect was stable by automated perimetry. Conclusions: Intraocular hemorrhage is a possible complication of intra-arterial tPA administration for BRAO, and a careful analysis of risks, benefits, and goals of this procedure must be considered by both provider and patient before such intervention.

Prognostic biomarkers of chronic diabetic macular edema treated with a fiuocinolone acetonide intravitreal implant

Background

This study aimed to investigate retinal imaging biomarkers, such as disorganization of the retinal inner layers (DRIL) and/or ellipsoid zone (EZ) disruption by spectral domain optical coherence tomography (SD-OCT), and functional outcomes in eyes treated with 0.2 µg/day of a fluocinolone acetonide intravitreal implant (FAc) after an insufficient response to previous treatments.

Methods

This was a retrospective comparative study of 18 eyes (15 patients) with persistent and/or recurrent diabetic macular edema (DME) treated with FAc. Eyes were divided according to the number of prior intravitreal treatments: group 1 (n = 8) with ≤ 6 injections (early switch) and group 2 (n = 10) with > 6 injections (late switch). Outcomes included percentage of eyes with DRIL and/or EZ disruption at baseline and analysis of the best corrected visual acuity (BCVA) using ETDRS letters, central macular thickness (CMT), DRIL, and EZ disruption at the last observation.

Results

Group 2 revealed a significantly higher percentage of DRIL and/or EZ disruption than group 1 (P < 0.05). At the last observation, group 1 revealed a higher percentage of eyes achieving vision stability/ improvement, gaining ≥ 15 letters, and achieving ≥70 letters (P > 0.05 for all comparisons). The mean BCVA gain was 8.8 and 0.7 letters for groups 1 and 2 (P = 0.397). Both groups revealed a significant mean CMT reduction (> 20% reduction from the baseline value), without a significant statistical difference between them (P = 0.749). After treatment, most eyes from both groups showed resolution of DRIL and EZ disruption.

Conclusions

Patients with DME presenting with a lower percentage of DRIL and/or EZ disruption at baseline had better functional outcomes, supporting the possible benefit of an early switch to FAc after insufficient response to previous treatments. Future randomized studies with a larger patient cohort are warranted to confirm our conclusions.

Evaluation of macular and optic nerve head parameters in amblyopic eyes: An optical coherence tomography study

PURPOSE

To evaluate morphological differences in retinal nerve fibers layers (RNFL), optic nerve head (ONH), ganglion cell complex (GCC), and macular thickness between amblyopic and normal eyes from spectral domain optical coherence tomography (SD-OCT).

METHODS

Of 234 eyes of 117 children, four groups emerged: group A (162 eyes of 81 non-amblyopic subjects); group B (32 fellow eyes of 32 subjects with monolateral amblyopia); group C (32 amblyopic eyes of 32 subjects affected by monolateral amblyopia); group D (8 amblyopic eyes of 4 subjects with bilateral amblyopia). Patients underwent SD-OCT for ONH parameters, RNFL, GCC and macular thickness, retina map, and ONH scan quality index (SQI). Two-sided p values <0.05 were taken as statistically significant. (Analysis: STATA v.13).

RESULTS

Parameters with a significant difference between groups (p < 0.005) with their Standard Deviation (SD) are presented: rim area, 2.08 (0.49) mm² in group A and 1.76 (0.68) mm² in group C; disk area, 2.43 (0.45) mm² in group A and 2.02 (0.71) mm² in group C; central macular thickness, 250.99 (19.74) µm in group A and 267.16 (23.52) µm in group C; nerve fiber ONH SQI, 62.82 (13.15) in group A, 51.26 (15.55) in group C, 48.29 (14.37) in group D; retina map SQI, 63.34 (10.34) in group A and 57.34 (9.84) in group C. For other parameters no significant difference was observed (p > 0.005).

CONCLUSIONS

Amblyopia may influence optic nerve morphology, central macular thickness, and OCT scan quality. RNFL and GCC are not affected by monolateral amblyopia.

Retrospective Study of Ellipsoid Zone Integrity Following Treatment with Intravitreal Ocriplasmin (OZONE Study)

Purpose

To assess generalized (GD) and focal ellipsoid zone disruption (FD) in patients with symptomatic vitreomacular adhesion (sVMA) using spectral domain optical coherence tomography (SD-OCT) following ocriplasmin.

Patients and methods

OZONE was a Phase 4, retrospective study of patients with sVMA treated with a single intravitreal injection of ocriplasmin (0.125 mg). Data from adult patients with at least 6-month follow-up after ocriplasmin were included. SD-OCT was performed at baseline (within 30 days before ocriplasmin), before Day 21 post-injection (early observation, EO), and by last observation (LO) which was maximally 6 months post-injection. The main outcome measure was the development of new and the evolution of existing FD/GD at EO and LO.

Results

The study enrolled 134 eyes/patients from 22 sites in the USA. At baseline, 87 eyes (64.9%) had FD, 21 eyes (15.7%) had GD and 26 eyes (19.4%) had no FD/GD. Among the eyes without FD/GD at baseline, 13 (50%) and 8 (30.8%) developed FD or GD, respectively, by EO. By LO, FD/GD improvement or resolution was seen in >80% of these eyes. Among the eyes with FD/GD at baseline, <40% had improving/resolving EZ integrity at LO. The absence of FD/GD at baseline was associated with less persistent FD/GD at LO (P<0.0005). The presence of FD with MH at baseline was associated with persistent FD at LO (P=0.027).

Conclusion

The fact that a large majority of eyes had FD/GD prior to ocriplasmin was unexpected and demonstrates that EZ disruptions are common in sVMA. This suggests that loss of EZ integrity may be part of the natural history of this disorder. It is hypothesized that the status of the EZ at baseline is a contributing, ocriplasmin independent modulator of subsequent EZ changes after ocriplasmin. Prospective analyses which include a sham control group would be required to test this hypothesis.

Role of Cold Balanced Salt Solution (BSS) in the Prophylaxis of Cystoid Macular Edema After Cataract Surgery: A Prospective Randomized Study

Purpose

To evaluate the postoperative effect on central retinal macular thickness of a cooled irrigating eye solution used during cataract surgery.

Patients and Methods

In this prospective, single-center study, 100 eyes of 50 patients (26 males and 24 females) were evaluated with spectral domain optical coherence tomography (SD-OCT) before and after phacoemulsification for senile cataract. Eyes were randomly divided into two groups based on the irrigating solution used during surgery: Group 1, 50 eyes received intraoperative irrigating solution at room temperature (~20.0±0.1°C); and Group 2, 50 fellow eyes received cold intraoperative irrigating solution (2.7±0.1°C). Changes in central macular thickness (CMT) were evaluated in both groups by SD-OCT macular raster scan for the nine Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields and total macular volume, performed pre-surgery, and 1 and 4 weeks post-surgery.

Results

Despite there being no significant differences in variables between the two groups preoperatively, significant increases in CMT were observed at 1 week after surgery in both groups (p=0.02 and p=0.03, respectively), as well as in total macular volume (p<0.0001 and p=0.02, respectively). Inter-subgroup analysis showed a significant reduction in CMT (p=0.03) and total macular volume (p=0.001) at 1 week post-surgery in Group 2 compared to Group 1, whereas no significant differences were observed at 4 weeks.

Conclusion

The use of a cooled irrigating eye solution during phacoemulsification may be beneficial in preventing the possible development of postoperative macular thickening. Further clinical studies may support this finding.

Central macular thickness in patients with sickle cell disease and no signs of retinopathy: a cross-sectional study of Jordanian patients

OBJECTIVES

To measure central macular thickness in Jordanian patients with sickle cell disease who did not have retinopathy and compare the findings with age- and sex-matched controls using spectral domain optical coherence tomography (SDOCT).

METHODS

In this cross-sectional study, participants underwent visual acuity testing, slit-lamp bio-microscopy, dilated ophthalmoscopy, and SDOCT imaging to measure central macular thickness. Macular quadrant measurements and thickness difference indexes (TDIs) were compared between groups.

RESULTS

Twenty eyes with sickle cell disease and 20 control eyes were enrolled. The median visual acuity in both groups was 20/20. The mean macular thickness was significantly lower in eyes with sickle cell disease than in matched controls (mean difference, 22.15 ± 6.44 µm). Peripheral quadrants were all significantly thinner in eyes with sickle cell disease, especially in superior and temporal quadrants. TDIs were lower in eyes with sickle cell disease than in control eyes.

CONCLUSIONS

Eyes with sickle cell disease that had no clinical evidence of retinopathy exhibited significantly lower central macular thickness in all quadrants, compared with eyes in age- and sex-matched controls. SDOCT is a non-invasive imaging modality that can detect preclinical changes in eyes with sickle cell disease and can be used to screen and monitor the disease process.

Quantitative Analysis of Gap Between the Intraocular Lens and Posterior Capsule Using Microscope-Integrated Optical Coherence Tomography in Eyes Undergoing Phacoemulsification

Purpose

To quantitatively analyze the dimensions of the gap between the intraocular lens (IOL) and the posterior capsule using microscope-integrated optical coherence tomography (MIOCT).

Setting

Institutional.

Design

Prospective, interventional.

Methods

A total of 105 eyes of 105 consecutive patients planned for phacoemulsification with IOL implantation were enrolled. At the end of surgery, the gap between the IOL and the posterior capsule (IOL-PC gap) was measured using MIOCT (RESCAN). The same gap was reassessed at 1 week follow-up visit using the Visante-OCT system. The cases were sub-grouped based on the grade of cataract, IOL material, size and design and were analyzed to look for any difference in the IOL-PC gap both intraoperatively and postoperatively.

Results

The IOL-PC gap could be successfully measured intra-operatively in all cases, using the RESCAN. The mean gap at the end of phacoemulsification was 385.08±264.58 µm, and at one week follow up this was 120.83± 95.13 µm.

Conclusion

MIOCT may be successfully used to quantify the dimensions of the gap between the IOL and the posterior capsule. It can be used as a potential tool to further understand the dynamics of the IOL-PC space and to assess the impact of various IOL and non-IOL parameters implicated in the causation of posterior capsule opacification.

Comparison of Macular Thickness Measurements Using Swept-Source and Spectral-Domain Optical Coherence Tomography in Healthy and Diabetic Subjects

Purpose: To establish normative data for macular thickness in Chinese aged 30 to 80 years using the swept-source optical coherence tomography (SS-OCT) device.Methods: The study included 290 normal eyes, 430 NDR eyes and 150 DR eyes of community residents aged 30 to 80 years in Guangzhou, China. Mean macular thicknesses in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields, central point thicknesses (CPT), and macular volume was measured by SS-OCT (Triton DRI OCT, Topcon, Tokyo, Japan) and Spectral-Domain OCT (SD-OCT; Heidelberg Engineering, Heidelberg, Germany). We assessed agreement between SS-OCT and SD-OCT measurements by intraclass correlation coefficients (ICC) and Bland-Altman plots. We established a conversion equation relating central subfield (CSF), CPT and macular volume between the two OCT devices.Results: Macular thickness measurements in SS-OCT were significantly thinner than in SD-OCT. The mean CSF thickness in normal eyes measured by SS-OCT and SD-OCT were 227.8 ± 19.4 μm and 260.0 ± 19.7 μm (p < .0001). CSF thickness was a significantly difference between genders (SS-OCT: male 237.2 ± 18.8 μm vs female 222.0 ± 17.5 μm, p < .0001). In all three groups, the agreement between SS-OCT and SD-OCT was excellent (all ICC > 0.9). The conversion equations for CSF, CPT and macular volume from SS-OCT to SD-OCT were derived, with over 95% of the predicted values fell within 10% of the actual measurements in DR and NDR eyes.Conclusion: We propose SS-OCT CSF thicknesses of 275 μm for males and 260 μm for females as the minimum criteria for macular edema in Chinese aged 30 to 80 years based on 2 SDs above the mean CSF. SS-OCT measurements were significantly thinner than SD-OCT. We derived equations from converting SS-OCT measurements to SD-OCT equivalents.

Current concepts on diffuse choroidal hemangioma in Sturge Weber syndrome

Background: Diffuse choroidal hemangioma (DCH) is a benign vascular tumor that is characteristically found in the Sturge-Weber syndrome (SWS). Recent genetic discoveries demonstrate that DCH occurs sporadically from an activating mutation in GNAQ at codon R183. Mutations in GNAQ or GNA11 result in dysregulation of the mitogen-activated protein kinase, which influences gene transcription and results in cellular proliferation. DCH may not always be readily detected on routine ophthalmological examination, consequently diagnosis and multidisciplinary referral are often delayed.Purpose: A literature search was performed through April 2020 without a lower date limit. This review will summarize the pathogenesis, diagnosis and management of DCH.Discussion: Multimodal imaging facilitates early detection of the condition. In particular, enhanced depth imaging spectral domain optical coherence tomography enables non-invasive, high-resolution visualization of the choroid to even detect mild choroidal thickening. Management of symptomatic DCH is generally difficult and results in poor visual outcome, thus, treatment is generally unwarranted, unless the hemangioma complicated by serous retinal detachment. The main treatment method is radiation therapy with external beam radiation therapy, proton beam therapy, plaque brachytherapy, and gamma knife surgery where low doses of radiation entail fewer complications. One method of alternative management is with photodynamic therapy that, although less invasive with a lower rate of complications, is not always feasible or effective in cases with extensive exudative retinal detachment.Conclusions: Multimodal ophthalmological imaging facilitates diagnosis of DCH and lifelong surveillance is essential in patients.

Rapid Morphological Restoration of Normal Foveal Contour After Spontaneous Epiretinal Membrane Separation from Retina in Eye with Macular Pseudohole: A Case Report

Purpose

This study aims to report a case of idiopathic epiretinal membrane (ERM) spontaneously separated from the retinal surface even in eyes with a macular pseudohole, which was immediately followed by resolution of visual deterioration and morphological findings.

Case Report

A 66-year-old man presented with visual deterioration and metamorphopsia in the right eye. An ERM with a macular pseudohole in the right eye was shown by fundus examinations and optical coherence tomography (OCT) images. We intended to perform vitrectomy to remove the ERM, but within 2 months after the initial visit, the ERM spontaneously separated from the retina. Fundus photograph showed that the ERM and the macular pseudohole were absent and the fundus looked almost normal, and OCT image showed no ERM and an almost normal appearance of the retina without remaining undulations. After the ERM separation, his vision improved to 20/15.

Conclusion

Cases with an ERM-associated macular pseudohole should be carefully monitored for the possibility of a spontaneous separation of the ERM from the retina.

Agreement between intraoperative anterior segment spectral-domain OCT and 2 swept-source OCT biometers

Purpose: To evaluate the agreement of different biometric parameters obtained using intraoperative spectral-domain optical coherence tomography (SD-OCT) and two swept-source optical coherence tomography (SS-OCT) based biometers.Methods: 102 eyes were assessed using the intraoperative SD-OCT integrated into the Catalys femtosecond-laser, and the IOLMaster 700 and Anterion SS-OCT-based-biometers. Central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW), and lens thickness (LT) were measured.Results: There were statistically significant differences for CCT, ACD, WTW and LT between devices (p < 0.001). The mean difference for ACD ranged from -0.067 to -0.250 mm, with the largest mean difference being between the IOLMaster 700 and Catalys. CCT mean differences ranged from 7 to 32 µm, with the largest mean difference being between the Anterion and Catalys. For WTW, the comparison between the IOLMaster 700 vs Catalys showed the largest mean difference (0.38 mm). However, the mean differences for LT from all three devices were quite similar, ranging from -0.02 to -0.08 mm.Conclusions: SS-OCT biometers showed good agreement for ACD, CCT, WTW and LT. The SD-OCT showed ACD, CCT and WTW values that do not seem to be interchangeable with the SS-OCT biometers; however, this device did show excellent agreement in the case of LT.

Retinal and Choriocapillaris Vascular Changes in Patients Affected by Different Clinical Phenotypes of β-Thalassemia: An Optical Coherence Tomography Angiography Study

Simple Summary

β-thalassemia represents a hematological disorder that determines anomalous hemolysis and ineffective erythropoiesis. The patients, undergoing regular lifelong blood transfusion, show an iron overload in the tissues that requires an iron chelation therapy. Both iron accumulation and iron-chelating agents cause ocular manifestations, such as retinal pigment epithelial (RPE) degeneration, RPE mottling, cataract, optic neuropathy and retinal venous tortuosity. In this cross-sectional study, we described the retinal and choriocapillaris microvascular changes in different clinical phenotypes of β-thalassemia that may reflect a tissue hypoxia status and oxidative damages.

Abstract

In this cross-sectional study we assessed the vascular alterations in retinal and choriocapillaris perfusion in patients affected by β-thalassemia, by means of optical coherence tomography angiography (OCTA). A total of 124 eyes of 62 patients (mean age 44.74 ± 5.79 years old) affected by β-thalassemia (transfusion dependent thalassemia (TDT), non-transfusion dependent thalassemia (NTDT) and minor) were compared to 40 eyes of twenty healthy subjects. We evaluated the vessel density (VD) in superficial capillary plexus, deep capillary plexus, radial peripapillary capillary, choriocapillaris and the foveal avascular zone area. The TDT group showed a statistically significant reduction in retinal and choriocapillaris VD respect to controls and the other groups (p < 0.05). No statistically significant difference was found in OCTA parameters between β-thalassemia minor and controls. The NTDT group showed a significant reduction in VD in deep capillary plexus respect to controls and β-thalassemia minor. Significant negative correlations were shown in TDT group between foveal avascular zone and hemoglobin (r = −0.437, p = 0.044) and between ferritin levels and VD of choriocapillaris (r = −0.431, p = 0.038). The OCTA parameters provided a deeper understanding on retinal and choriocapillaris vascular impairment affected by tissue hypoxia levels and the oxidative stress in different clinical phenotypes of the β-thalassemia.

Central Serous Chorioretinopathy Analyzed by Multimodal Imaging

Purpose

We correlated quantitative fundus autofluorescence (qAF) with other fundus features in patients exhibiting central serous chorioretinopathy (CSC).

Methods

Short wavelength fundus autofluorescence (SW-AF, 488 nm excitation) was measured by qAF. Using nonnormalized images qAF values were calculated within eight concentric segments (qAF₈) located at an eccentricity of 7° to 9°. Horizontal spectral domain optical coherence tomography (SD-OCT) scans and near-infrared fundus autofluorescence images (NIR-AF) were studied.

Results

Thirty-six eyes of 20 patients (mean age 48.7± 8.5 years) diagnosed with CSC were studied. Thirteen patients had bilateral disease; four patients were female. In 22 eyes CSC was present in the macula; in one eye the lesion was in a peripapillary location, 10 involved both locations, and three were unaffected. Serous retinal detachment, retinal pigmented epithelial detachment (PED), outer retinal atrophy and subRPE hypertransmission were all features identifiable by SD-OCT. NIR-AF images were helpful in detecting foveal and parafoveal lesions. Sampling for retina-wide elevations in SW-AF intensity by measuring qAF₈ did not indicate a generalizable relationship amongst CSC-diagnosed eyes. However, color-coded qAF images revealed alterations in SW-AF topography and intensity relative to healthy eyes at the same locations. Thus zones of higher than normal qAF intensity were found in association with SD-OCT detectable PED; loss of ellipsoid zone and interdigitation zone; and hyperreflectivity in outer retina. Pronounced decreases in qAF colocalized with serous retinal detachment and with outer retinal degeneration that included hypertransmission of SD-OCT signal into the choroid.

Conclusions

Localized elevations in qAF reflect increased bisretinoid in association with CSC lesions.

Translational Relevance

Foci of elevated qAF at some stages of CSC contribute to the natural history of the disease.

Exploring a Structural Basis for Delayed Rod-Mediated Dark Adaptation in Age-Related Macular Degeneration Via Deep Learning

Purpose

Delayed rod-mediated dark adaptation (RMDA) is a functional biomarker for incipient age-related macular degeneration (AMD). We used anatomically restricted spectral domain optical coherence tomography (SD-OCT) imaging data to localize de novo imaging features associated with and to test hypotheses about delayed RMDA.

Methods

Rod intercept time (RIT) was measured in participants with and without AMD at 5 degrees from the fovea, and macular SD-OCT images were obtained. A deep learning model was trained with anatomically restricted information using a single representative B-scan through the fovea of each eye. Mean-occlusion masking was utilized to isolate the relevant imaging features.

Results

The model identified hyporeflective outer retinal bands on macular SD-OCT associated with delayed RMDA. The validation mean standard error (MSE) registered to the foveal B-scan localized the lowest error to 0.5 mm temporal to the fovea center, within an overall low-error region across the rod-free zone and adjoining parafovea. Mean absolute error (MAE) on the test set was 4.71 minutes (8.8% of the dynamic range).

Conclusions

We report a novel framework for imaging biomarker discovery using deep learning and demonstrate its ability to identify and localize a previously undescribed biomarker in retinal imaging. The hyporeflective outer retinal bands in central macula on SD-OCT demonstrate a structural basis for dysfunctional rod vision that correlates to published histopathologic findings.

Translational Relevance

This agnostic approach to anatomic biomarker discovery strengthens the rationale for RMDA as an outcome measure in early AMD clinical trials, and also expands the utility of deep learning beyond automated diagnosis to fundamental discovery.

A Novel Approach to Quantitative Evaluation of Outer Retinal Lesions Via a New Parameter "Integral" in Spectral Domain Optical Coherence Tomography

Purpose

The purpose of this study was to design a new parameter "integral" to quantitatively evaluate the spatial cumulative reflectivity of the outer retinal layers in optical coherence tomography (OCT), and to investigate its role in the detection of outer retinal diseases.

Methods

This was a cross-sectional study. Fovea-centered line OCT scans were performed on 60 eyes of 60 healthy volunteers and 44 eyes of 44 patients diagnosed with outer retinal diseases. The integrals of the ellipsoid zone (EZ) and interdigitation zone (IZ) were measured by respectively accumulating the grayscale values of all the pixels within the EZ and IZ at specified locations on the scanning lines, and were then adjusted by calculating their percentages on the outer retina. The integrals of the EZ and IZ were compared between the two groups.

Results

The integrals of the EZ and IZ were stably and normally distributed in the healthy eyes, and were significantly lower in eyes with outer retinal lesions than in healthy ones (P < 0.05). Moreover, the integrals of the EZ and IZ were correlated with best corrected visual acuity (BCVA; adjusted R² = 0.620) and the presence of outer retinal lesions (Nagelkerke R² = 0.767). The area under the receiver operating characteristic (ROC) curve was 0.954 (95% confidence interval [CI] = 0.918-0.990) when the integral was selected as a diagnostic variable.

Conclusions

Obtained from this novel quantification method, the new parameter integral was comparable between different individuals and had the potential to detect outer retinal abnormalities in reflectivity through OCT.

Translational Relevance

Our work verified the feasibility of the new image analysis technique in the detection of the diseases affecting the outer retina.

Multimodal imaging of an idiopathic florid vascularised epiretinal membrane: Course, treatment, and outcome

Idiopathic vascular epiretinal membrane is an extremely rare entity and the pathogenesis and clinical course is not clearly understood. A 53-year-old hypertensive female patient presented with complaints of altered vision in the right eye. On examination, her vision was 20/30 and fundoscopy showed a vascularized epiretinal membrane (ERM), which was confirmed on spectral-domain optical coherence tomography. No primary cause was found after investigations. The symptoms and ERM showed slow progression over the next three years with a visual acuity of 20/60. She underwent surgery for removal of the ERM, which was subjected to histopathological evaluation. This is a unique case of a florid proliferative vascularisation of an ERM in the absence of any identifiable cause, which had a good visual outcome following surgery.

Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography

Hypertensive retinopathy refers to the retinal vascular changes associated with systemic arterial hypertension. Hypertensive retinopathy can be divided into chronic and acute phases. A cross-sectional study was performed to explore a method of measurement in the diameters of retinal vessels for diagnosis of chronic hypertensive retinopathy based on spectral domain optical coherence tomography (SD-OCT). The central retinal artery diameter (CRAD), the central retinal vein diameter (CRVD), and the artery-to-vein ratio (AVR) were measured. A total of 119 subjects with 119 eyes were included in this study, in which 56 subjects with 56 eyes were included in hypertensive group and 63 subjects with 63 eyes were included in normotensive group. There were significant differences between the two groups in the CRAD (t = -2.14, P = .04) and the AVR (t = -2.59, P = .01). The cutoff point of 0.75 was determined by receiver operating characteristic (ROC) curve (area under the curve, AUC 0.786; 95% confidence interval, 95% CI 0.70-0.87). Multivariate logistic regression analysis showed the probability of AVR below to 0.75 was more in patients with high systolic blood pressure (odds ratio OR 4.39; P = .048), more in male (OR 4.15; P = .004) and more in smokers (OR 5.80; P = .01). Bland-Altman plots showed small mean bias between the measurements of the two technicians in the CRAD, the CRVD, and the AVR. In summary, application of SD-OCT is an accurate, reproducible, convenient method for measuring the diameters of retinal vessels. It is valuable for the diagnosis of chronic stage of hypertensive retinopathy.

Coregistered Spectral Optical Coherence Tomography and Two-Photon Microscopy for Multimodal Near-Instantaneous Deep-Tissue Imaging

Two-photon microscopy (2PM) has brought unique insight into the mechanisms underlying immune system dynamics and function since it enables monitoring of cellular motility and communication in complex systems within their genuine environment-the living organism. However, use of 2PM in clinical settings is limited. In contrast, optical coherence tomography (OCT), a noninvasive label-free diagnostic imaging method, which allows monitoring morphologic changes of large tissue regions in vivo, has found broad application in the clinic. Here we developed a combined multimodal technology to achieve near-instantaneous coregistered OCT, 2PM, and second harmonic generation (SHG) imaging over large volumes (up to 1,000 × 1,000 × 300 μm³ ) of tendons and other tissue compartments in mouse paws, as well as in mouse lymph nodes, spleens, and femurs. Using our multimodal imaging approach, we found differences in macrophage cell shape and motility behavior depending on whether they are located in tendons or in the surrounding tissue compartments of the mouse paw. The cellular shape of tissue-resident macrophages, indicative for their role in tissue, correlated with the supramolecular organization of collagen as revealed by SHG and OCT. Hence, the here-presented approach of coregistered OCT and 2PM has the potential to link specific cellular phenotypes and functions (as revealed by 2PM) to tissue morphology (as highlighted by OCT) and thus, to build a bridge between basic research knowledge and clinical observations. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

An Unusual Case: Self-separation of an Idiopathic Epiretinal Membrane

Self-separation or peeling of an idiopathic epiretinal membrane (ERM) in an eye with partial posterior vitreous detachment (PVD) is a rare event. A 56-year-old woman presented to our clinic with complaints of floaters in her right eye. Best-corrected visual acuity (BCVA) was 9/10 in this eye. Fundus examination and Spectral domain optical coherence tomography (SD-OCT) revealed an idiopathic ERM and Grade 3 PVD in this eye. Four months later, she had complaints of metamorphopsia in her right eye. BCVA was 7/10, while SD-OCT images of the right macula were similar to previous images. One week after the last visit, she presented again due to the sudden disappearance of her metamorphopsia complaints. BCVA had improved to 10/10. Fundus examination demonstrated that the ERM had spontaneously separated from the retinal surface as a flap floating in the vitreous and the foveal contour had returned to normal. The etiologic mechanism may be explained as the contracting forces within an immature ERM being stronger than its adhesion to the retina.

Hyperreflective Foci Enhancement in a Combined Spatial-Transform Domain for SD-OCT Images

Purpose

Spectral-domain optical coherent tomography (SD-OCT) is a useful tool for visualizing, treating, and monitoring retinal abnormality in patients with different retinal diseases. However, the assessment of SD-OCT images is thwarted by the lack of image quality necessary for ophthalmologists to analyze and quantify the diseases. This has hindered the potential role of hyperreflective foci (HRF) as a prognostic indicator of visual outcome in patients with retinal diseases. We present a new multi-vendor algorithm that is robust to noise while enhancing the HRF in SD-OCT images.

Methods

The proposed algorithm processes the SD-OCT images in two parallel processes simultaneously. The two parallel processes are combined by histogram matching. An inverse of both logarithmic and orthogonal transforms is applied to the mapped data to produce the enhanced image.

Results

We evaluated our algorithm on a dataset composed of 40 SD-OCT volumes. The proposed method obtained high values for the measure of enhancement, peak signal-to-noise ratio, structure similarity, and correlation (ρ) and a low value for mean square error of 36.72, 38.87, 0.87, 0.98, and 25.12 for Cirrus; 40.77, 41.84, 0.89, 0.98, and 22.15 for Spectralis; and 30.81, 32.10, 0.81, 0.96, and 28.55 for Topcon SD-OCT devices, respectively.

Conclusions

The proposed algorithm can be used in the medical field to assist ophthalmologists and in the preprocessing of medical images.

Translational Relevance

The proposed enhancement algorithm facilitates the visualization and detection of HRF, which is a step forward in assisting clinicians with decision making about patient treatment planning and disease monitoring.

Characteristics of retinal layer thickness in acute anterior uveitis: an optical coherence tomography study

PURPOSE

To determine the changes in peripapillary retinal nerve fiber layer (pRNFL), macular and ganglion cell-inner plexiform layer (GC-IPL) thicknesses in patients with acute anterior uveitis (AAU).

METHODS

Patients diagnosed with unilateral non-infectious AAU and normal control were enrolled retrospectively. Optical coherence tomography scans were performed during the initial active phase and inactive phase of AAU. Patients were followed for at least 3 months after resolution of inflammatory activity.

RESULTS

Thirty-seven AAU patients and 40 controls were included. The average RNFL and central macular thickness (CMT) showed significant differences between patients and control groups during active phase (p < 0.001 and p = 0.022, respectively). The average pRNFL thicknesses of affected eyes and fellow eyes during the active phase were 109.4 ± 12.5 μm and 96.5 ± 8.0 μm, respectively (p < 0.001). During the inactive phase, the average thicknesses were 99.3 ± 8.9 μm and 97.0 ± 7.5, respectively; they were not significantly different (p = 0.236). The CMTs of affected and fellow eyes during the active phase were 261.6 ± 24.7 μm and 251.5 ± 17.3 μm, respectively; the difference was significant (p = 0.047). The average GC-IPL thicknesses of affected and fellow eyes were not significantly different (p = 0.061).

CONCLUSIONS

The pRNFL and central macula thickened during the active phase of AAU and decreased to a similar degree with fellow eyes during the inactive phase. Additionally, pRNFL thickness showed a sensitive response to the degree of inflammation in AAU. This suggests that pRNFL thickness may be useful in assessing disease activity.