Relationship between fluorescein pooling and optical coherence tomographic reflectivity of cystoid spaces in diabetic macular edema

Spectral-domain OCT characteristics of intraretinal hyper-reflective foci associated with age-related macular degeneration and diabetic retinopathy

OBJECTIVE

The purpose of this study was to quantitatively analyze and compare OCT characteristics of intraretinal hyper-reflective foci (IHRF) in eyes with diabetic retinopathy (DR) versus age-related macular degeneration (AMD).

DESIGN

a retrospective observational study.

PARTICIPANTS

54 treatment-naïve eyes (27 DR and 27 AMD).

METHODS

The IHRF lesions in OCT B-scan were semi-automatically segmented. Mean reflectivity (MR), maximum diameter, circularity index (Cir), area, and the angle between the greatest linear dimension (GLD) and the horizontal were computed for each IHRF lesion. The presence and absence of a posterior shadow and the axial location were assessed. The MR was normalized using the vitreous and nerve fiber layer reflectance as dark and bright reference standards, respectively.

RESULTS

A total of 1149 IHRF (1051 in DR and 98 in the AMD group) were identified, with a mean of 39 ± 36 lesions in DR eyes compared to only 4 ± 4 in AMD eyes (p < 0.001). The mean area of individual IHRF lesions was greater in DR eyes (1305 ± 1647 μm² vs 1031 ± 750 μm²; p = 0.016), but IHRF in AMD eyes had higher reflectivity (1.17 ± 0.14 vs 1.03 ± 0.17; p < 0.001). The angle of the GLD relative to the horizontal was greater in AMD eyes, indicating that IHRF in AMD eyes were more horizontally oriented. In AMD eyes, 88.8% of IHRF were located beneath the inner border of the outer nuclear layer (ONL), while in DR eyes, 56.9% were located there (p < 0.001).

CONCLUSIONS

IHRF lesions in eyes with DR and AMD demonstrate significant differences, with IHRF in DR eyes tending to be larger and less hyper-reflective compared to AMD eyes.

Imaging Histology Correlations of Intraretinal Fluid in Neovascular Age-Related Macular Degeneration

Purpose

Fluid presence and dynamism is central to the diagnosis and management of neovascular age-related macular degeneration. On optical coherence tomography (OCT), some hyporeflective spaces arise through vascular permeability (exudation) and others arise through degeneration (transudation). Herein we determined whether the histological appearance of fluid manifested this heterogeneity.

Methods

Two eyes of a White woman in her 90s with anti-vascular endothelial growth factor treated bilateral type 3 neovascularization secondary to age-related macular degeneration were osmicated, prepared for submicrometer epoxy resin sections, and correlated to eye-tracked spectral domain OCT. Examples of intraretinal tissue fluid were sought among similarly prepared donor eyes with fibrovascular scars, in a web-based age-related macular degeneration histopathology resource. Fluid stain intensity was quantified in reference to Bruch's membrane and the empty glass slide.

Results

Exudative fluid by OCT was slightly reflective and dynamically responded to anti-vascular endothelial growth factor. On histology, this fluid stained moderately, possessed a smooth and homogenous texture, and contained blood cells and fibrin. Nonexudative fluid in degenerative cysts and in outer retinal tubulation was minimally reflective on OCT and did not respond to anti-vascular endothelial growth factor. By histology, this fluid stained lightly, possessed a finely granular texture, and contained mainly tissue debris. Quantification supported the qualitative impressions of fluid stain density. Cells containing retinal pigment epithelium organelles localized to both fluid types.

Conclusions

High-resolution histology of osmicated tissue can distinguish between exudative and nonexudative fluid, some of which is transudative.

Translational Relevance

OCT and histological features of different fluid types can inform clinical decision-making and assist in the interpretation of newly available automated fluid detection algorithms.

Onion ring sign on spectral domain optical coherence tomography in diabetic macular edema: Its evolution and outcomes

PURPOSE

To report evolution and outcomes of hyperreflective crystalline deposit (HCD) on optical coherence tomography (OCT) in diabetic maculopathy (DM).

METHODS

Patients with DM showing HCD on OCT for the first time between June 2017 and May 2021 were included in the study. Demographic, ophthalmic and OCT features were documented and analysed. Factors leading to the development of HCD and its effect on the functional outcome were analysed and described in this study.

RESULTS

Sixty cases of HCD were identified in 45 (males -33; females - 12) patients for the first-time during the defined study period. Mean age of the eligible patients was 61.53 ± 8.19 years. Average duration of diabetes was 13.82 ± 7.38 years. Mean visual acuity of these patients was 0.902 ± 0.438 logMAR units (Snellen equivalent = 20/160). Patients with HCD showed subretinal hard exudates, were on anti-cholesterol medications (n = 36, 80%) and showed reduced visual acuity (20/160) if the HCD involved the fovea. The median time taken for the development of HCD was 28 months. Mean follow-up duration of the study was 26.19 ± 27.98 months. Persistence of HCD in all cases (n = 42, 100%) was noted at the last follow-up visit.

CONCLUSION

Horizontal, single or multi-layered HCDs on OCT in DM represent intraretinal or subretinal cholesterol crystal precipitates evolving from the hard exudates identical to the "onion ring sign" seen in neovascular AMD. HCDs or CCs depict deranged lipid metabolism, chronic vascular leakage and can lead to substantial visual impairment if the fovea gets involved.

Association of Retinal Pigment Epithelium Reflectivity on Optical Coherence Tomography with Recurrence of Vogt-Koyanagi-Harada Disease: A Retrospective Observational Study

Purpose

Despite the necessity of optical coherence tomography (OCT) for diagnosis and longitudinal monitoring in patients with Vogt-Koyanagi-Harada (VKH) disease, no studies have identified useful OCT markers for predicting recurrence in these patients. Although the precise reason for this remains unclear, one possibility is that infiltration of inflammatory cells into the choroid attenuates the OCT signal, making it difficult to precisely assess the structure of the choroid. Therefore, this study aimed to investigate changes in retinal pigment epithelium (RPE) reflectivity immediately above the choroid in eyes with acute VKH disease, as well as the association between RPE reflectivity and VKH disease recurrence.

Patients and Methods

This single-centered retrospective observational study included 20 treatment-naïve patients with acute VKH disease presenting with serous retinal detachment (SRD) in the posterior pole at the initial visit between October 2015 and January 2020, as well as 15 healthy control eyes. All patients were followed up for at least 6 months and received treatment with intravenous methylprednisolone followed by oral administration of prednisolone. Swept-source OCT images through the fovea were used to measure central retinal thickness, central choroidal thickness, and RPE reflectivity.

Results

During an observation period of 37.2 ± 30.8 months, recurrence of inflammation was observed in 11 patients (55.0%). Initial visual acuity was worse in patients who developed recurrence than in those who did not (P=0.024). On initial OCT images, RPE reflectivity differed significantly between patients with and without recurrence (1.75 ± 0.42 vs 1.35 ± 0.20; P=0.018), while there were no significant differences in other chorioretinal parameters, such as central retinal thickness and choroidal thickness.

Conclusion

RPE reflectivity on OCT images may be useful for predicting the recurrence of inflammation in patients with VKH disease.

Choroidal structural features of acquired vitelliform lesions in non-exudative age-related macular degeneration

PURPOSE

To define the choroidal morphological characteristics of non-exudative age-related macular degeneration (AMD) cases associated with acquired vitelliform lesions (AVLs).

METHODS

This retrospective study included intermediate AMD patients with AVLs (Group1, 21eyes) and without AVLs (Group2, 21eyes). A healthy control group was (Group3, 23eyes) also included. Subfoveal choroidal thickness (SFCT), greatest basal diameter (GBD), and maximum height (MH) of the largest PED were measured on spectral domain optical coherence tomography. Internal reflectivity of PEDs and total choroidal area (TCA) were measured using ImageJ software. The TCA was binarized to the luminal area (LA) and stromal area. The choroidal vascularity index (CVI) was assessed.

RESULTS

The mean SFCT, TCA, and LA were higher in Group 1 (290.3 ± 86.8 μm, 0.840 ± 0.302 mm², 0.602 ± 0.227 mm²) than in Group 2 (215.6 ± 85.0 μm, 0.594 ± 0.183 mm², 0.429 ± 0.139 mm²) (p = 0.014, p = 0.017, p = 0.020, respectively). There was no significant difference in the CVI measurements between Group 1 and Group 2 (p = 1.000). The mean GBD and MH of the PED was higher in Group 1 (1443 ± 595 µm, 188 ± 86 µm) than in Group 2 (851 ± 368 µm, 119 ± 38 µm) (p = <0.001, p = 0.001, respectively). Internal PED reflectivity was significantly lower in Group 1 (0.44 ± 0.21) than in Group 2 (0.66 ± 0.17) (p = <0.001). Internal PED reflectivity showed negative correlation with GBD and MH of the PED in Group 1 (r = -0.587, p = 0.005; rho = -0.448, p = 0.042, respectively). In Group 2, internal PED reflectivity had a negative correlation with MH of the PED (rho = -0.511, p = 0.018).

CONCLUSION

Non-exudative AMD patients with AVLs are more prone to have a thick choroid and large hyporeflective PEDs as compared to the those without AVLs.

Optical Coherence Tomography Reflectivity in Foveal Cysts: A Novel Biomarker for Early-Response Prediction of Diabetic Macular Edema Treated with Dexamethasone

This study investigated spectral-domain optical coherence tomography (OCT) biomarkers to predict short-term anatomical improvement for diabetic macular edema (DME) after dexamethasone (DEX) injection in intravitreal anti-vascular endothelial growth factor (anti-VEGF) non-responders. This retrospective comparative study included 31 eyes of 31 patients with DME unresponsive to anti-VEGF, divided into better and lesser responder groups. OCT prior to DEX injection was used to evaluate the morphological features including optical density (ODN) and optical density ratio (ODR) of the outer nuclear layer (ONL) cysts. Correlations between baseline OCT parameters and mean central macular thickness (CMT) changes at 1 month were analyzed. There were no between-group differences in age, sex, number of previous anti-VEGF injections, duration of diabetes, or HbA1c level. However, ODN and ODR values in ONL cysts were lower in the better responder group (p = 0.020 and p < 0.001, respectively). ODN and ODR showed negative correlations with CMT changes (R = −0.546, p = 0.002 and R = −0.436, p = 0.014, respectively). Higher OCT reflectivity in the foveal cystoid space was associated with a lesser decrease in CMT after DEX injection in anti-VEGF non-responders, suggesting the usefulness of this parameter in predicting short-term CMT responses after DEX injection.

The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers

This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.

Factors predicting the treatment frequency of ranibizumab injections during the second year in diabetic macular edema

PURPOSE

To investigate the predictors of annual treatment frequency in the second year of pro re nata (PRN) intravitreal ranibizumab (IVR) injections for diabetic macular edema (DME).

STUDY DESIGN

A retrospective study.

METHODS

We reviewed 65 eyes of 60 patients with center-involved DME who received PRN IVR injections after 3 monthly loading doses. The central subfield thickness (CST) and qualitative findings were assessed on the spectral domain optical coherence tomography (SD-OCT) images. We then investigated whether the parameters at the baseline or at the 12-month visit were associated with treatment frequency in the second year.

RESULTS

The number of ranibizumab injections decreased from 6 (4-8) during the first year to 2 (0-3) during the second year (P < .001). The injection numbers during the first year (ρ = 0.259, P = .037) but not during the second year (ρ = 0.152, P = .226) were modestly related to the logarithm of the minimum angle of resolution (logMAR) improvement at 24 months. Multivariate analyses revealed that the CST (β = 0.336, P = .005) and hyperreflective walls in the foveal cystoid spaces (β = 0.273, P = .020) at baseline were associated with the number of IVR injections during the second year. The treatment frequency during the second year was also related to the CST (β = 0.266, P = .012), hyperreflective walls (β = 0.394, P = .002), and cumulative doses of ranibizumab injections (β = 0.294, P = .006) at the 12-month visit.

CONCLUSIONS

The cumulative doses of ranibizumab injections, CST, and hyperreflective walls in the foveal cystoid spaces at the 12-month visit are designated predictors of the treatment frequency of ranibizumab injections during the second year in DME.

The Next Steps in Ocular Imaging in Uveitis

PURPOSE

To describe the future steps and advances in the field of ocular imaging in uveitis.

METHODS

Narrative review.

RESULTS

There have been numerous advances in the field of imaging in uveitis in the past decade. Advanced techniques of imaging of the vitreous, vitreo-retinal interface, retinochoroid, and the sclera can provide significant information that helps in understanding the disease pathogenesis and manifestations. Imaging also helps in establishing a diagnosis in challenging cases, along with the laboratory and other assays. Notable developments in ocular imaging include wide-field and ultra-wide field imaging (including angiographies), automated quantification of the retinochoroidal vasculature using optical coherence tomography (OCT) and OCT angiography, quantification of vitreous cells, and intraoperative use of imaging in uveitis, among others.

CONCLUSIONS

We have summarized several technological achievements in ocular imaging in the field of uveitis and provided insights into the potential future developments.

Diabetic Retinopathy and Diabetic Macular Edema in People With Early-Onset Diabetes

This study examined the clinical profile, treatment profile, and vision outcomes of people ≤40 years of age with diabetes and diabetic macular edema (DME). Within this age-group, the prevalence of center-involving DME was 16%, with 74% of eyes showing cystoid edema, 37% showing spongiform edema, and 41% having neurosensory detachment. Longer diabetes duration (P = 0.001) and greater severity of diabetic retinopathy (P <0.001) were associated with DME prevalence. Thus, regular and more frequent follow-up, as well as early and aggressive treatment of diabetic eye disease, are required in people diagnosed early with diabetes.

Significance of Hyperreflective Foci as an Optical Coherence Tomography Biomarker in Retinal Diseases: Characterization and Clinical Implications

Hyperreflective foci (HRF) is a term coined to depict hyperreflective dots or roundish lesions within retinal layers visualized through optical coherence tomography (OCT). Histopathological correlates of HRF are not univocal, spacing from migrating retinal pigment epithelium cells, lipid-laden macrophages, microglial cells, and extravasated proteinaceous or lipid material. Despite this, HRF can be considered OCT biomarkers for disease progression, treatment response, and prognosis in several retinal diseases, including diabetic macular edema, age-related macular degeneration (AMD), retinal vascular occlusions, and inherited retinal dystrophies. The structural features and topographic location of HRF guide the interpretation of their significance in different pathological conditions. The presence of HRF less than 30 μm with reflectivity comparable to the retinal nerve fiber layer in the absence of posterior shadowing in diabetic macular edema indicates an inflammatory phenotype with a better response to steroidal treatment. In AMD, HRF overlying drusen are associated with the development of macular neovascularization, while parafoveal drusen and HRF predispose to macular atrophy. Thus, HRF can be considered a key biomarker in several common retinal diseases. Their recognition and critical interpretation via multimodal imaging are vital to support clinical strategies and management.

Intracystic hyperreflective material in centre-involving diabetic macular oedema

PURPOSE

To report evolution and predictive value of intracystic hyperreflective material (ICHRM) on optical coherence tomography (OCT) in centre-involving diabetic macular oedema (CI-DME).

METHODS

Demographic and OCT features of patients with treatment-naïve CI-DME were analysed retrospectively. OCT parameters noted were macular oedema type, ICHRM presence, presence of hyperreflective spots, disorganised inner retinal layers and outer retinal layers integrity. Eyes were grouped into group 1 CI-DME without ICHRM and group 2 CI-DME with ICHRM. Univariate and multivariate linear regression analyses were done to study the correlation between various OCT features and final vision.

RESULTS

In this study, 62 eyes of 50 patients were included in group 1 and 61 eyes of 51 patients in group 2. Mean presenting logMAR vision in groups 1 and 2 was 0.374 ± 0.346 and 0.523 ± 0.369 respectively. Poor final visual acuity was noted in CI-DME with ICHRM group (p = 0.015). On linear regression analysis, 3 OCT features, namely, ICHRM presence (p = 0.034), inner segment-outer segment layer disruption (p = 0.001) and ellipsoid zone defects (p = 0.003), were associated with poor final vision. More intravitreal anti-VEGF (2.98 vs 0.629) and steroid (1.51 vs 0.242) injections were required for macular oedema resolution in ICHRM group.

CONCLUSION

This study is the first to assess the ICHRM on OCT as predictor for treatment outcome in DME eyes. We described its evolution during the DME management and its plausible influence on intravitreal therapy. We believe that this finding has the potential to become a novel biomarker for predicting the visual outcome in DME.

Reproducing diabetic retinopathy features using newly developed human induced-pluripotent stem cell-derived retinal Müller glial cells

Muller glial cells (MGCs) are responsible for the homeostatic and metabolic support of the retina. Despite the importance of MGCs in retinal disorders, reliable and accessible human cell sources to be used to model MGC-associated diseases are lacking. Although primary human MGCs (pMGCs) can be purified from post-mortem retinal tissues, the donor scarcity limits their use. To overcome this problem, we developed a protocol to generate and bank human induced pluripotent stem cell-derived MGCs (hiMGCs). Using a transcriptome analysis, we showed that the three genetically independent hiMGCs generated were homogeneous and showed phenotypic characteristics and transcriptomic profile of pMGCs. These cells expressed key MGC markers, including Vimentin, CLU, DKK3, SOX9, SOX2, S100A16, ITGB1, and CD44 and could be cultured up to passage 8. Under our culture conditions, hiMGCs and pMGCs expressed low transcript levels of RLPB1, AQP4, KCNJ1, KCJN10, and SLC1A3. Using a disease modeling approach, we showed that hiMGCs could be used to model the features of diabetic retinopathy (DR)-associated dyslipidemia. Indeed, palmitate, a major free fatty acid with elevated plasma levels in diabetic patients, induced the expression of inflammatory cytokines found in the ocular fluid of DR patients such as CXCL8 (IL-8) and ANGPTL4. Moreover, the analysis of palmitate-treated hiMGC secretome showed an upregulation of proangiogenic factors strongly related to DR, including ANG2, Endoglin, IL-1β, CXCL8, MMP-9, PDGF-AA, and VEGF. Thus, hiMGCs could be an alternative to pMGCs and an extremely valuable tool to help to understand and model glial cell involvement in retinal disorders, including DR.

Hyperreflective cystoid spaces in diabetic macular oedema: prevalence and clinical implications

AIMS

To analyse the prevalence and evolution of hyper-reflective cystoid spaces with decorrelation signal detected using optical coherence tomography angiography (OCTA) in diabetic macular oedema (DMO).

METHODS

A retrospective study of consecutive eyes with DMO imaged using OCTA over a 1-year period was conducted. All eyes with hyper-reflective cystoid spaces at baseline and at least 3 months of follow-up were included in a longitudinal analysis.

RESULTS

The prevalence of hyperreflective cystoid spaces with decorrelation signal was of 37% (61/165) in DMO eyes. Hyperreflective foci within hyperreflective cystoid spaces were observed in 85% of eyes. The longitudinal study included 33 eyes (10 observed and 23 treated with intravitreal anti-vascular endothelial growth factor), with a median follow-up of 15 months. The hyperreflective cystoid spaces resolved in 85% of eyes. The mean best-corrected visual acuity remained stable during the follow-up, even in the eyes achieving a resolution of the hyperreflective cystoid spaces. Hard exudates appeared in the area of resolved hyperreflective cystoid spaces in 33% of eyes.

CONCLUSION

Hyperreflective cystoid spaces detected by OCTA affected more than one-third of the DMO eyes. Their disappearance was not associated with any functional improvement and led to the formation of new hard exudate deposits in about one-third of the eyes.

Efficacy of Intravitreal Dexamethasone Implant in Different Patterns of Diabetic Macular Edema

PURPOSE

Different patterns of diabetic macular edema (DME) suggest different pathogenesis and drug response. We evaluated the outcomes after intravitreal dexamethasone (DEX) implant for DME with or without serous retinal detachment (SRD).

METHODS

In this retrospective study, 22 naïve patients (23 eyes) with DME who underwent a single DEX implant were evaluated. Based on the optical coherence tomographic pattern of DME, 12 eyes had a cystoid macular edema pattern (Group 1) and 11 eyes had an SRD pattern (Group 2). The best-corrected visual acuity (BCVA), central retinal thickness (СRТ), central retinal volume (CRV), SRD height (SRDh), and intraocular pressure (IOP) were recorded before and at two and four months after the treatment.

RESULTS

There were no significant differences between the groups regarding demographic, clinical data and outcomes at baseline. In Group 1, the CRT and CRV significantly decreased at two months (P = 0.002 and P = 0.01, respectively), while the BCVA significantly improved at four months (P = 0.03). In Group 2, the CRT and CRV significantly improved (P < 0.01 and P ≤ 0.01, respectively) during the follow-up period. At four months, both groups showed a recurrence of DME, Group 1 in particular (two-month CRT reduction, -149 ± 127 µm vs four-month CRT reduction, -72 ± 174 µm; P = 0.04). The mean reduction in CRV was significantly different at four months (Group 1, -0.49 ± 1.7 mm3 vs Group 2, -1.3 ± 1.3 mm3 ; P = 0.04). In Group 2, the SRDh significantly decreased at two (P = 0.01) and four months (P = 0.01). Four cases with elevated IOP were managed.

CONCLUSION

DEX implants were found to be effective in different patterns of DME. The SRD pattern may predict a longer-lasting morphologic efficacy.

Hyperreflective Walls in Foveal Cystoid Spaces as a Biomarker of Diabetic Macular Edema Refractory to Anti-VEGF Treatment

Diabetic macular edema (DME) refractory to anti-VEGF drugs is a socioeconomic burden. In this retrospective study, we investigated the relationship between DME remission and hyperreflective walls in foveal cystoid spaces, a novel finding on spectral domain optical coherence tomography (SD-OCT) images in DME. In a cross-sectional study, we assessed the relationship between hyperreflective walls in foveal cystoid spaces and other OCT findings in 110 eyes of 110 DME patients. Hyperreflective walls were delineated in 27 of 171 foveal cystoid spaces. Eyes with hyperreflective walls in foveal cystoid spaces had poorer visual acuity and more severe photoreceptor disruption than did those without such findings (P = 0.008 and P < 0.001, respectively). In the other longitudinal study, we evaluated the relationship between this finding and the remission in 54 eyes of 51 DME patients treated with as-needed ranibizumab injections for 24 months. Foveal cystoid spaces with hyperreflective walls were often persistent, and the cumulative rates of DME remission among eyes with and without the hyperreflective walls were 7.7% (1 eye) and 48.8% (20 eyes) at 18 months (hazard ratio, 0.092; P = 0.025). We characterized hyperreflective walls in foveal cystoid spaces and designated them as a predictor of no DME remission under ranibizumab injections.

Plume Sign in the Deturgescence of Macular Cysts - A Novel OCT Finding

Aim

To describe a novel OCT finding called “Plume sign” in macular cysts.

Methods

Case records of five cases were retrospectively reviewed. Their case history and imaging findings on spectral domain optical coherence tomography (SD-OCT, Spectralis, Heidelberg, Germany) have been described.

Results

We observed five cases which had a solitary cyst foveal or parafoveal in location, was unique due to the presence of a plume-shaped internal substance, was treated with topical NSAIDs and was associated with good visual outcomes. We observed three cardinal events; firstly, retinal thickening followed by the formation of a foveal or parafoveal solitary cyst. Secondly, a vertical expansion of the solitary cysts in an inverted flask-shaped configuration associated with splitting of the retinal layers suggested by a hyper-reflective line and/or a hyporeflective cleft in the outer nuclear layer. Thirdly and finally, a breach of the outer retina with involvement of the external limiting membrane (ELM) and ellipsoid zone (EZ) with an exit trail of proteinaceous material through the defect in the shape of a plume of smoke hyper-reflective on OCT followed by deturgescence of the cyst.

Conclusion

In conclusion, we describe the “plume” sign – a novel OCT finding is cysts and provide a possible pathogenic hypothesis.

Clinical Implications of Suspended Scattering Particles in Motion Observed by Optical Coherence Tomography Angiography

The objective of this study was to investigate the relationship between suspended scattering particles in motion (SSPiM) in optical coherence tomography angiography (OCTA) and treatment response in diabetic macular edema (DME). We retrospectively reviewed the medical records of patients diagnosed with DME who had undergone intravitreal injection. The optical density ratio (ODR) of the intraretinal cyst and the numbers of hyperreflective foci from OCT images and SSPiM from OCTA images were compared, and their association with treatment response was analyzed. Forty-five eyes from 45 patients were included in this study. Twenty-four patients were treated with anti-vascular endothelial growth factor, and 21 patients were treated with a steroid. Binary logistic regression model showed that SSPiM in OCTA images was associated with hyperreflective foci numbers (P = 0.038) and mean ODR of the intraretinal cyst (P = 0.006). Linear regression model showed that SSPiM in the inner nuclear layer was related to treatment response (P = 0.006). SSPiM on OCTA images is related to the poor structural response to treatment in DME.

The Relationship Between Macular Cyst Formation and Ischemia in Diabetic Macular Edema

Objectives:

To evaluate the relationship between cyst characteristics and macular and peripheral ischemia in diabetic macular edema (DME).

Materials and Methods:

We retrospectively reviewed eyes with DME and included those with clinically significant macular edema as defined by ETDRS (Early Treatment Diabetic Retinopathy Study) and cystoid spaces in optical coherence tomography scans in this study. Central subfield thickness (CSFT), horizontal and vertical diameters of the largest cyst, cyst area, and the remaining retinal thickness outside the cyst were determined. The presence and number of hyperreflective foci in the cyst wall and the internal reflectivity of the cyst were analyzed. Outer retinal damage was graded. Fluorescein angiography was used to determine the areas of macular and peripheral ischemia, which were graded as mild or severe. Correlations between macular and peripheral ischemia and cyst-related measurements and structural changes in the retina were evaluated.

Results:

This retrospective study included 250 eyes of 186 patients with DME. Mean CSFT was significantly greater in eyes with macular ischemia (510.4±144.7 μm) compared to eyes without macular ischemia (452.1±114.6 μm) (p=0.001). Horizontal and vertical diameter of the largest cyst increased with the presence and severity of macular ischemia (p=0.045 and p=0.016, respectively). Remaining retinal thickness increased with the presence and severity of peripheral ischemia (p=0.009). There was a statistically significant relationship between the number of the hyperreflective foci in the cyst wall and internal reflectivity of the cyst (p=0.007). Patients with greater CSFT had a 1.04-times higher odds of having macular ischemia and 0.25-times higher odds of having outer retinal damage.

Conclusion:

The likelihood of macular ischemia increases with larger cyst diameter, CSFT, and extent of outer retinal damage. Thickness of the noncystic area is increased in the presence of peripheral ischemia.

Reflectance and Thickness Analysis of Retinal Layers in Patients with Epiretinal Membranes Using Spectral-Domain OCT before and after Vitrectomy with Membrane Peeling

PURPOSE

To compare thickness and reflectance of retinal layer findings in patients with idiopathic epiretinal membranes (ERMs) before and after surgery with those of normal controls.

DESIGN

Retrospective study.

PARTICIPANTS

Patients with ERMs before and after surgery and healthy controls.

METHODS

Spectral-domain (SD) OCT imaging of eyes with ERMs before and after surgery and of healthy eyes were analyzed for morphologic appearance and using a customized algorithm to measure retinal layer reflectance and thickness. Findings were correlated with visual acuity outcomes.

MAIN OUTCOME MEASURES

Retinal layer thickness and reflectance.

RESULTS

Thirty-four ERM and 12 healthy eyes were identified. Mean preoperative best-corrected visual acuity (BCVA) improved from 0.53±0.31 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/68) to 0.41±0.25 logMAR (Snellen equivalent, 20/51) after surgery (P = 0.030). Differences in reflectance and thickness of retinal layers were identified among the preoperative ERM, postoperative ERM, and healthy eyes. High preoperative reflectance of the internal limiting membrane (ILM) to outer plexiform layer (OPL) was correlated with better postoperative BCVA (r = -0.451; P = 0.007). A larger improvement in BCVA was correlated with preoperative thick measurements of the outer nuclear layer (r = 0.514; P = 0.002), high reflectance of the group of layers from the ILM to the OPL (r = 0.426; P = 0.012), and low reflectance of the photoreceptor layer (r = -0.453; P = 0.007). Using linear regression analysis, better postoperative BCVA was associated with better preoperative vision (standardized regression coefficient, 0.553; P = 0.001) and high reflectance of the group of layers from the ILM to OPL (standardized regression coefficient, -0.526; P = 0.001). A larger improvement in BCVA was associated with worse preoperative BCVA (standardized regression coefficient, -0.539; P < 0.001) and high reflectance of the group of layers from the ILM to OPL (standardized regression coefficient, -0.428; P = 0.001).

CONCLUSIONS

Quantitative differences in reflectance and thickness among preoperative, postoperative, and normal SD OCT imaging allow assessment of retina layer changes secondary to ERMs. High reflectance of the ILM to OPL correlated with and was associated with better postoperative BCVA and improvement in BCVA.

Multimodal OCT Reflectivity Analysis of the Cystoid Spaces in Cystoid Macular Edema

Purpose

To compare and evaluate images of macular cysts with different degrees of reflectivity (from gray to black signal) as observed in B scan spectral domain OCT (SDOCT) and EnFace OCT with decorrelation signal obtained with OCT-angiography (OCTA) in eyes with cystoid macular edema (CME) secondary to diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods

Images from 3033 patients affected by CME secondary to diabetes or RVO examined OCTA (Optovue XR Avanti, Optovue, USA) at the University Eye Clinic of Créteil, Hôpital Intercommunal, France, and at the University Eye Clinic of Cagliari, “San Giovanni di Dio” Hospital, Italy, were retrospectively examined. The deep capillary plexus OCTA images and the corresponding EnFace OCT images, both acquired with the same automatic segmentation, had been overlapped to compose RGB color images as red and green channels, respectively, using ImageJ software (National Institutes of Health, Bethesda, MD). Afterward, linear regions of interest were traced on the color images to obtain the profiles of OCTA and EnFace gray values. Number of pixels, mean gray value and standard deviation of the area traced in OCT-A, and EnFace image were analyzed and statistically correlated. Data were exported to Excel to create the plots.

Results

94 patients with DME and 27 patients with RVO showed intraretinal macular cystoid spaces with similar homogeneous, gray-looking content; 73 patients with DME and 113 patients with RVO showed macular cystoid spaces with homogeneous, black-looking content, as observed at SD-OCT, EnFace and OCTA scans. Interestingly, the limits of macular cystoid spaces were clearly detectable with OCTA. The analysis of red and green profiles demonstrated a clearly visible overlap between average OCTA and EnFace signal observed around cystoid spaces that could be attributed to a relationship between the dynamic vascularization and the structural density of the tissue.

Conclusions

This is the first investigation that characterizes and correlates OCTA and EnFace signals on images of macular cystoid spaces in DR and RVO. The low intensity OCTA signals observed inside cystoid spaces raise a relevant question about their nature, as to whether they are due to the presence of corpusculated material pouring out from bloodocular-barrier or they should be considered OCTA artifacts.

Optical coherence tomography: A guide to interpretation of common macular diseases

Optical coherence tomography is a quick, non invasive and reproducible imaging tool for macular lesions and has become an essential part of retina practice. This review address the common protocols for imaging the macula, basics of image interpretation, features of common macular disorders with clues to differentiate mimickers and an introduction to choroidal imaging. It includes case examples and also a practical algorithm for interpretation.

Association between characteristics of foveal cystoid spaces and short-term responsiveness to ranibizumab for diabetic macular edema

PURPOSE

To investigate the association between the characteristics of foveal cystoid spaces and short-term responsiveness to ranibizumab treatment for diabetic macular edema (DME) at 3 months from the initial injection.

METHODS

We retrospectively reviewed 66 eyes of 61 patients with center-involved DME who received three consecutive ranibizumab injections and following as-needed administrations. We evaluated the relationship between visual improvement at 3 months and the preoperative optical coherence tomography (OCT) parameters including hyperreflective foci, heterogeneous OCT reflectivity, mean levels of OCT reflectivity and height of foveal cystoid spaces.

RESULTS

Twenty-three eyes without preoperative hyperreflective foci in the foveal cystoid spaces had significantly greater improvement in the logarithm of the minimum angle of resolution visual acuity (logMAR VA) at 3 months than 43 eyes with foci (P = 0.006). That was similar to the greater reduction in CSF thickness in eyes without lesions after treatment at the same time point (P < 0.001). VA improvement at 3 months was not associated with the height (R = 0.215, P = 0.083) or the reflectivity levels (R = -0.079, P = 0.538) of foveal cystoid spaces. There were no differences in VA changes between eyes with and without heterogeneous reflectivity in foveal cystoid spaces (P = 0.297). Multivariate analyses showed that logMAR VA and the absence of hyperreflective foci in foveal cystoid spaces were associated with VA improvement at 3 months.

CONCLUSION

Hyperreflective foci in foveal cystoid spaces at baseline predict poorer short-term responsiveness to ranibizumab injections for DME.

OCT-Leakage Mapping: A New Automated Method of OCT Data Analysis to Identify and Locate Abnormal Fluid in Retinal Edema

PURPOSE

To test OCT-Leakage, a new method of analyzing and mapping sites of lower optical reflectivity found on OCT, by examining eyes with various types of retinal edema to identify abnormal increases in retinal extracellular fluid.

DESIGN

Prospective analysis of a cohort of cases.

PARTICIPANTS

Healthy eyes and eyes with retinal edema in the setting of different retinal diseases.

METHODS

Prospective OCT-Leakage analysis of 12 eyes with various types of retinal edema, such as diabetic macular edema, branch retinal vein occlusion, idiopathic perifoveal telangiectasia, and Irvine-Gass syndrome, representing intraretinal edema and eyes with idiopathic central serous chorioretinopathy and neovascular age-related macular degeneration representing subretinal fluid accumulation, in order to compare with OCT-Leakage analysis of a series of 41 eyes of 24 healthy controls. Raw scan data from the OCT images were exported and used to calculate lower than normal optical reflectivity maps (low optical reflectivity [LOR] ratios). Optical reflectivity LOR maps (OCT-Leakage maps) were collected for the full retina A-scan and layer by layer after segmentation. Low optical reflectivity ratios from patients with the different conditions of retinal edema and controls were compared. Fluorescein angiography (FA) and OCT angiography (OCTA) were performed in all eyes.

MAIN OUTCOME MEASURES

Identification of areas of abnormal retinal fluid accumulation.

RESULTS

The OCT-Leakage maps based on sites of LOR (LOR ratios) delineated the location of intraretinal and subretinal fluid, always integrating the location of the sites on FA and the vascular abnormalities observed on OCTA. The areas of fluid outline in the OCT-Leakage maps were coincident and generally larger than those seen on FA. In all cases, the OCT-Leakage maps were able to identify the location of the fluid in the different segmented retinal layers.

CONCLUSIONS

Mapping of lower reflectivity sites within the retina demonstrates the amount and location of retinal and subretinal fluid in different retinal diseases, showing potential to contribute to their management. Furthermore, the possibility of complementarity between OCT-Leakage and OCTA is highly promising.

Imaging of macrophage dynamics with optical coherence tomography in anterior ischemic optic neuropathy

Anterior ischemic optic neuropathy (AION) is a relatively common cause of visual loss and results from hypoperfusion of the small arteries of the anterior portion of the optic nerve. AION is the leading cause of sudden optic nerve related vision loss with approximately 10 cases per 100'000 in the population over 50 years. To date there is no established treatment for AION and therefore a better understanding of the events occurring at the level of the optic nerve head (ONH) would be important to design future therapeutic strategies. The optical properties of the eye allow imaging of the optic nerve in vivo, which is a part of the CNS, during ischemia. Experimentally laser induced optic neuropathy (eLiON) displays similar anatomical features as anterior ischemic optic neuropathy in humans. After laser induced optic neuropathy we show that hyperreflective dots in optical coherence tomography correspond to mononuclear cells in histology. Using fluorescence-activated flow cytometry (FACS) we found these cells to peak one week after eLiON. These observations were translated to OCT findings in patients with AION, where similar dynamics of hyperreflective dots at the ONH were identified. Our data suggests that activated macrophages can be identified as hyperreflective dots in OCT.

Optical Coherence Tomography Angiography of DME and Its Association with Anti-VEGF Treatment Response

PURPOSE

To investigate the structural integrity of the superficial capillary plexuses (SCPs) and deep capillary plexuses (DCPs) using optical coherence tomography (OCT) angiography (OCTA) in patients with diabetic macular edema (DME) and its association with the response to anti-vascular endothelial growth factor (VEGF) treatment.

DESIGN

Retrospective, case-control study.

PARTICIPANTS

We included 51 DME eyes with a poor response to anti-VEGF agents and 32 age-matched DME eyes with a good response to anti-VEGF treatment, along with 20 fellow eyes without DME from the cases and controls.

METHODS

The medical records, including OCTA and spectral-domain OCT (SD OCT), were reviewed and compared between the groups. En face OCTA images of the SCP and DCP were obtained for each eye. An anti-VEGF responder was defined by a reduction of more than 50 μm in central retinal thickness after 3 consecutive anti-VEGF treatments. A poor responder was defined by a reduction of less than 50 μm or an increase in central retinal thickness after 3 monthly injections.

MAIN OUTCOME MEASURES

We measured the vascular density and foveal avascular zone (FAZ) area and counted the number of microaneurysms in each layer. The SD OCT images were compared with OCTA findings.

RESULTS

Compared with non-DME eyes, DME eyes had a lower vascular density (P < 0.001) and larger FAZ area (P < 0.001) in the DCP and more microaneurysms (P < 0.001) in both layers. Although there was no significant difference in the SCP between anti-VEGF responders and poor responders, poor responders tended to show greater damage and more microaneurysms in the DCP (P < 0.001) and a larger FAZ area (P < 0.001). The topographic location of the disrupted synaptic portion of the outer plexiform layer (OPL) in SD OCT exactly corresponded to the nonflow area of the DCP in OCTA.

CONCLUSIONS

Compared with DME eyes that responded to anti-VEGF treatment, poor responders show significant damage to the integrity of the DCP, but not the SCP. The degree of OPL disruption in SD OCT corresponds well with the extent of DCP loss in DME eyes. The extent of DCP loss and the corresponding OPL disruption could be useful predictors of responsiveness to anti-VEGF treatment.

Anti-Vascular Endothelial Growth Factor with Gas for Submacular Hemorrhage

PURPOSE

To investigate the treatment outcome of pneumatic displacement and intravitreal anti-vascular endothelial growth factor (VEGF) for submacular hemorrhage (SMH) from exudative age-related macular degeneration (AMD).

METHODS

Best-corrected visual acuity (BCVA) and central foveal thickness (CFT) were measured at baseline and at 1, 3, and 6 months after initial treatment in 72 eyes of 72 patients treated with a combination of pneumatic displacement and anti-VEGF injection for SMH from exudative AMD.

RESULTS

Best-corrected visual acuity and CFT showed significant improvement from baseline during the 6-month follow-up period (logarithm of the minimum angle of resolution BCVA from 1.80 to 1.00, CFT from 886 to 383 μm, p < 0.001, respectively). The decrease in subretinal hemorrhage was greater than that in subretinal pigment epithelial hemorrhage at 1 month after initial treatment (p < 0.001). In eyes with symptoms for less than 30 days, higher reflectivity of hemorrhage on optical coherence tomography and higher CFT were associated with lower BCVA after 6 months of treatment (reflectivity B = 0.335, p = 0.007; CFT B = 0.001, p = 0.003).

CONCLUSIONS

The combination of pneumatic displacement and intravitreal anti-VEGF is a useful treatment option for SMH secondary to AMD. Higher baseline CFT and higher reflectivity of hemorrhage were associated with lower BCVA 6 months after initial treatment.

Multimodal retinal imaging of diabetic macular edema: toward new paradigms of pathophysiology

The pathophysiology of diabetic macular edema (DME) is multifactorial and partly still unknown. An increasing body of evidence suggests that neurodegeneration and retinal glial cells activation occur even before the earliest clinical manifestation of diabetic retinal vasculopathy. Nowadays, new non-invasive techniques are available to assess and characterize DME, not only in a quantitative perspective, but also making it possible to understand and quantify the pathogenic processes sustaining fluid accumulation. Optical coherence tomography (OCT) allows documenting not only parameters such as macular volume, central and sectorial retinal thickness, fluid localization, and integrity of retinal layers, but also new still poorly investigated reflectivity aspects. Hyperreflective intraretinal spots (HRS) have been detected on OCT scans through the retinal layers, with a presumptive migration pattern towards the external layers during the occurrence of diabetic retinopathy and DME. These HRS have been hypothesised to represent an in-vivo marker of microglial activation. Autofluorescence of the fundus (FAF) also offers a non-invasive imaging technique of DME. The area of increased FAF correlates with the presence of intraretinal fluid and probably retinal glial activation. Microperimetry allows the measurement of retinal sensitivity by testing specific selected retinal areas. Some studies have shown that increased macular FAF in DME correlates better with visual function assessed with microperimetry than with visual acuity, showing that new imaging and functional techniques may help to elucidate DME pathogenesis and to target therapeutical strategies.

Reflectivity and thickness analysis of epiretinal membranes using spectral-domain optical coherence tomography

AIM

To compare thickness and reflectivity spectral domain optical coherence tomography (SD-OCT) findings in patients with idiopathic epiretinal membranes (ERMs), before and after ERM peeling surgery, with normal controls.

METHODS

A retrospective study analyzed SD-OCTs of eyes with ERMs undergoing ERM peeling surgery by one surgeon from 2008 to 2010 and normal control eyes. SD-OCTs were analyzed using a customized algorithm to measure reflectivity and thickness. The relationship between the SD-OCT findings and best corrected visual acuity (BCVA) outcomes was also studied.

RESULTS

Thirty-four ERM eyes and 12 normal eyes were identified. Preoperative eyes had high reflectivity and thickness of the group of layers from the internal limiting membrane (ILM) to the retinal pigment epithelium (RPE) and the group of layers from the ILM to the external limiting membrane (ELM). The values of reflectivity of these two groups of layers decreased postoperatively, but were still higher than normal eyes. In contrast, preoperative eyes had lower reflectivity of two 10×15 pixel regions of interest (ROIs) incorporating: 1) ELM + outer nuclear layer (ONL) and 2) photoreceptor layer (PRL) + RPE, compared to controls. The values of reflectivity of these ROIs increased postoperatively, but were still lower than normal controls. A larger improvement in BCVA postoperatively was correlated with a greater degree of abnormal preoperative reflectivity and thickness findings.

CONCLUSION

Quantitative differences in reflectivity and thickness between preoperative, postoperative, and normal SD-OCTs allow assessment of changes in the retina secondary to ERM. Our study identified hyperreflective inner retina changes and hyporeflective outer retina changes in patients with ERMs. SD-OCT quantitative measures of reflectivity and/or thickness of specific groups of retinal layers and/or ROIs correlate with improvement in BCVA.

Optical Intensities of Different Compartments of Subretinal Fluid in Acute Vogt-Koyanagi-Harada Disease

Purpose

To investigate the optical intensity in different compartments of subretinal fluid in acute Vogt-Koyanagi-Harada (VKH) disease by using spectral domain optical coherence tomography (SD-OCT).

Methods

Fifty acute VKH eyes and 25 cases with acute central serous chorioretinopathy (CSCR) were included in this retrospective comparative study. The optical intensities of subretinal fluid, vitreous humour and the entire scanned region displayed by SD-OCT were measured with Image J by three independent readers. In the VKH eyes with subretinal septa, the subretinal fluid was segmented into two types of compartments, supra-septa space and sub-septa space. Optical intensity ratios of different compartments of subretinal fluids divided by vitreous humour or the entire scanned region were compared.

Results

The measurement of optical intensity was highly reproducible (intraclass correlation coefficient> 0.9). The optical intensity of the supra-septa space divided by the vitreous humour was significantly higher compared to that of sub-septa space in VKH (mean difference = 4.27 ± 5.15, p <0.001). The optical intensity ratio of the supra-septa space (1.14 ± 0.12), but not subsepta space (1.05 ± 0.05) in VKH, was significantly higher compared to that of the subretinal space in VKH without the subretinal septa (1.07 ± 0.08), and the subretinal fluid in CSCR (1.08 ± 0.09). Similar results were found for the optical intensity ratios divided by the entire scan region.

Conclusion

The optical intensity in the supra-septa space of VKH is higher compared to the sub-septa space in VKH, subretinal space in VKH and CSCR, suggesting that the components in these spaces are different.

Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical Coherence Tomography

Purpose

To investigate the profile and determinants of retinal optical intensity in normal subjects using 3D spectral domain optical coherence tomography (SD OCT).

Methods

A total of 231 eyes from 231 healthy subjects ranging in age from 18 to 80 years were included and underwent a 3D OCT scan. Forty-four eyes were randomly chosen to be scanned by two operators for reproducibility analysis. Distribution of optical intensity of each layer and regions specified by the Early Treatment of Diabetic Retinopathy Study (ETDRS) were investigated by analyzing the OCT raw data with our automatic graph-based algorithm. Univariate and multivariate analyses were performed between retinal optical intensity and sex, age, height, weight, spherical equivalent (SE), axial length, image quality, disc area and rim/disc area ratio (R/D area ratio).

Results

For optical intensity measurements, the intraclass correlation coefficient of each layer ranged from 0.815 to 0.941, indicating good reproducibility. Optical intensity was lowest in the central area of retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and photoreceptor layer, except for the retinal pigment epithelium (RPE). Optical intensity was positively correlated with image quality in all retinal layers (0.553<β<0.851, p<0.01), and negatively correlated with age in most retinal layers (-0.362<β<-0.179, p<0.01), except for the RPE (β = 0.456, p<0.01), outer nuclear layer and photoreceptor layer (p>0.05). There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area and R/D area ratio.

Conclusions

There was a specific pattern of distribution of retinal optical intensity in different regions. The optical intensity was affected by image quality and age. Image quality can be used as a reference for normalization. The effect of age needs to be taken into consideration when using OCT for diagnosis.

Optical coherence tomographic reflectivity of cystoid spaces is related to recurrent diabetic macular edema after triamcinolone

PURPOSE

To determine the association between reflectivity levels in foveal cystoid spaces on optical coherence tomography images and the course of the logarithm of the minimum angle of resolution (logMAR) after triamcinolone acetonide treatment for diabetic macular edema.

METHODS

We retrospectively reviewed 58 consecutive eyes treated with an intravitreal or sub-Tenon's injection of triamcinolone acetonide for diabetic macular edema. The foveal cystoid spaces within central 1 mm were circumscribed, followed by measurement of optical coherence tomography reflectivity. The correlation between the reflectivity and visual outcome was investigated.

RESULTS

The optical coherence tomography reflectivity levels in foveal cystoid spaces increased at 1 month after treatment, but not at 3 months or 6 months. The preoperative reflectivity levels were correlated negatively with logMAR changes from 1 month to 6 months and from 3 months to 6 months but not with logMAR at individual time points compared with the preoperative logMAR. The changes in foveal thickness from 1 month to 6 months were correlated negatively with the baseline reflectivity and positively with logMAR changes from 1 month to 6 months and from 3 months to 6 months.

CONCLUSION

Lower optical coherence tomography reflectivity in foveal cystoid spaces was associated with the rebound in macular thickening and visual deterioration after triamcinolone acetonide treatment for diabetic macular edema.

The causes of hyperreflective dots in optical coherence tomography excluding diabetic macular edema and retinal venous occlusion§

Purpose :

To investigate the causes of hyperreflective dots (HRDs) in spectral domain optical coherence tomography (OCT) excluding diabetic macular edema (DME) and RVO (retinal vein occlusion).

Patients and Methods :

The medical records of 56 patients with HRDs documented by OCT were reviewed retrospectively. The patients with DME and RVO were excluded from the study in order to prevent misdiagnosing hard exudates or HRDs. The causes, unilaterality or bilaterality of HRD and demographic properties of the patients with HRD were evaluated.

Results :

Sixty four eyes of 56 patients having HRDs were included in this study. Of the patients with HRD, 17 (30.36%) were women and 39 (69.64%) were men. The ages of patients were between 13 to 84 years (median 60.18 years). The causes of HRD were as follows: papilledema in 4 eyes (6.25%), active neovascular age related macular degeneration (AMD) in 33 eyes (51.56%), familial dominant drusen in 2 eyes (3.13%), central serous chorioretinopathy in 19 eyes (29.69%) and commotio retina in 2 eyes (3.13%), choroidal folds in one eye (1.56%), branch retinal artery occlusion in one eye (1.56%), central retinal artery occlusion in one patient (1.56%) and Best vitelliform macular dystrophy in one eye (1.56%). The most common cause of HRD was AMD. The causes of HRDs in both eyes were AMD and papilledema.

Conclusion :

The most common causes of HRDs excluding DME and RVO seem as active exudative AMD. The presence of HRDs in retinal diseases might affect the decisions and the results of the treatment and the prognosis of diseases.

Blood components and OCT reflectivity evaluated in animal model

BACKGROUND/PURPOSE

To see the relationship between blood components and optical coherence tomography (OCT) reflectivity using an animal model in which the aqueous humor was substituted by different experimental solutions without changing the integrity of the retina.

MATERIALS AND METHODS

The aqueous humor of an enucleated swine eye was replaced with plasma obtained from healthy volunteers. The OCT reflectivity of the anterior chamber filled with each plasma was calculated from individual OCT images, and was expressed by an arbitrary unit (AU). The concentration of blood components such as cholesterol, hemoglobin (Hb) and bilirubin of each individual was measured, and the correlation between each of them and the OCT reflectivity of aqueous humor in an enucleated swine eye was analyzed. Using the same model, the effects of the single plasma component on OCT reflectivity were examined.

RESULTS

Blood samples were obtained from 24 individuals. OCT reflectivity was 30.68 ± 14.8 AU (average ± SD), ranging from 11.11 to 60.31 AU. OCT reflectivity correlated significantly with the concentration of triglycerides (R = 0.634, p = 0.001) and total cholesterol (R = 0.488, p = 0.015) using Spearman's rank correlation coefficient. While a partial correlation analysis showed that it correlated significantly with triglyceride (R = 0.60, p = 0.003), but not total cholesterol. OCT reflectivity was highest in a balanced salt solution (BSS) with Hb (average 42.05 AU), followed by fibrinogen (8.08 AU), bilirubin (6.12 AU) and γ-globulin (2.85 AU). Albumin did not increase the reflectivity of the BSS with a normal concentration (1.11 AU) compared to the control BSS alone (0.73 AU).

CONCLUSIONS

OCT reflectivity was most strongly affected by the presence of triglycerides among the blood components. Some molecules such as Hb and fibrinogen significantly increase the OCT reflectivity. This information should be helpful for interpreting the OCT findings correctly.

Objective measurement of vitreous inflammation using optical coherence tomography

PURPOSE

To obtain measurements of vitreous signal intensity from optical coherence tomography (OCT) image sets in patients with uveitis, with the aim of developing an objective, quantitative marker of inflammatory activity in patients with this disease.

DESIGN

Retrospective, observational case-control series.

PARTICIPANTS

Thirty patients (30 eyes) with vitreous haze secondary to intermediate, posterior, or panuveitis; 12 patients (12 eyes) with uveitis but without evidence of vitreous haze; and 18 patients (18 eyes) without intraocular inflammation or vitreoretinal disease.

METHODS

Clinical and demographic characteristics were recorded, including visual acuity (VA), diagnosis, and anatomic type of uveitis. In each eye, the anterior chamber (AC) was graded for cellular activity and flare according to standardized protocols. The presence and severity of vitreous haze were classified according to the National Eye Institute system. Spectral-domain OCT images were analyzed using custom software. This software provided an "absolute" measurement of vitreous signal intensity, which was then compared with that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units ("VIT/RPE-Relative Intensity").

MAIN OUTCOME MEASURES

Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity.

RESULTS

The VIT/RPE-Relative Intensity was significantly higher in uveitic eyes with known vitreous haze (0.150) than in uveitic eyes without haze or in healthy controls (0.0767, P = 0.0001). The VIT/RPE-Relative Intensity showed a significant, positive correlation with clinical vitreous haze scores (r = 0.566, P = 0.0001). Other ocular characteristics significantly associated with VIT/RPE-Relative Intensity included VA (r = 0.573, P = 0.0001), AC cells (r = 0.613, P = 0.0001), and AC flare (r = 0.385, P = 0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of intergrader reproducibility (95% limits of agreement, -0.019 to 0.016).

CONCLUSIONS

These results provide preliminary evidence that OCT-derived measurements of vitreous signal intensity may be useful as an outcome measure in patients with uveitis. If validated in future studies, such measures may serve as an objective, quantitative disease activity end point, with the potential to improve the "signal:noise" ratio of clinical trials in this area, thus enabling smaller studies for the same power. The incorporation of automated vitreous analysis in commercial OCT systems may, in turn, facilitate monitoring and re-treatment of patients with uveitis in clinical practice.

Association between cystoid spaces on indocyanine green hyperfluorescence and optical coherence tomography after vitrectomy for diabetic macular oedema

PURPOSE

To study retrospectively the characteristics of residual indocyanine green (ICG) fluorescence after ICG-assisted vitrectomy and the association with spectral-domain optical coherence tomography (SD-OCT) findings in diabetic macular oedema (DMO).

METHODS

Thirteen consecutive eyes of 12 patients for whom fundus near-infrared fluorescence and 20° retinal sectional images were obtained using HRA2 and Spectralis OCT, respectively, 5 days after vitrectomy combined with ICG-assisted inner limiting membrane peeling for DMO. The relationship between the characteristics of the ICG hyperfluorescence and the cystoid spaces in the outer plexiform layer (OPL) on SD-OCT images was evaluated.

RESULTS

A total of 390 well-demarcated areas of ICG hyperfluorescence were delineated on 20° radial OCT scans dissecting the fovea 5 days after vitrectomy. The areas of ICG hyperfluorescence in the parafovea or perifovea were significantly smaller than those at the fovea. Most areas of hyperfluorescence were irregularly shaped in the parafovea and perifovea, whereas 18 of 38 areas of hyperfluorescence were round or oval at the fovea (P<0.001). SD-OCT delineated the cystoid spaces in the OPL in 73 areas of hyperfluorescence that were round or oval and accompanied by dark spots more frequently than that without cystoid spaces on OCT images (P<0.001 and P=0.002). Of the 123 cystoid spaces in the OPL on OCT images, 44 did not have ICG hyperfluorescence, had lower OCT reflectivity, and contained fewer hyperreflective foci than those with ICG hyperfluorescence (P<0.001 and P=0.020).

CONCLUSION

The results provided novel interpretations of the ICG hyperfluorescence and its association with OCT characteristics of the cystoid spaces in DMO.

Differences in the topographic profiles of retinal thickening in eyes with and without serous macular detachment associated with diabetic macular oedema

PURPOSE

To investigate if cases of diabetic macular oedema (DMO) associated with serous macular detachment (SMD) have a different topographic profile of retinal thickening compared with DMO cases not associated with SMD.

METHODS

Optical coherence tomography scans of 152 eyes from 152 patients with centre-involving DMO and central subfield thickness >350 µm were identified. Measurements were taken of the neural retina at the highest point of thickening within the central subfield (H) and lateral extent of retina thicker than 350 µm (W). Group means were compared between eyes with SMD and eyes without SMD.

RESULTS

SMD was present in 55 eyes (36%). H was lower in eyes with SMD than in eyes without SMD (396 µm vs 550 µm, p<0.001) while W was higher in eyes with SMD compared with eyes without SMD (4.74 mm vs 4.18 mm, p=0.011).

CONCLUSIONS

There were distinct differences in topographical profiles of retinal thickening between eyes with SMD and eyes without SMD. These findings suggest a possible mechanical basis for the pathogenesis of SMD in DMO.

Quantitative analysis of retinal layer optical intensities on three-dimensional optical coherence tomography

PURPOSE

To investigate the optical intensities of all retinal layers on three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) in normal subjects using an automatic measurement.

METHODS

Forty normal subjects underwent Topcon 3D OCT-1000 macula-centered scan. The raw data were automatically segmented into 10 layers using the 3D graph search approach. Then the mean and standard deviation of intensities of each layer were calculated. The image quality index was given by the OCT software. Correlation analysis was performed between the optical intensities in each layer and image quality and subject's age.

RESULTS

The correlation of optical intensities was strong from ganglion cell layer (GCL) to outer nuclear layer (ONL) with r > 0.934; moderate among retinal nerve fiber layer (RNFL), photoreceptor, retinal pigment epithelium (RPE), and choroid (0.410 < r < 0.800); and low in the vitreous (0.251 < r < 0.541). The optical intensities were also correlated with the image quality, r > 0.869 from GCL to ONL, 0.748 < r < 0.802 for RNFL, photoreceptor layer, RPE, and the choroid, r = 0.528 for the vitreous. The optical intensity in RNFL was negatively correlated with age (r = -0.365).

CONCLUSIONS

Automatic assessment of the layers' intensities was achieved. In normal subjects, the retinal layers' optical intensities were affected by image quality. Normalization with optical intensity of ONL, all areas, or image quality index is recommended. The optical intensity of RNFL decreased with age.

Age- and hypertension-dependent changes in retinal vessel diameter and wall thickness: an optical coherence tomography study

PURPOSE

To validate and evaluate the reliability of retinal vessel diameter measurements by optical coherence tomography (OCT). The effects of age and hypertension on vessel diameter were also examined.

DESIGN

Prospective, cross-sectional study.

METHODS

Two hundred thirty-eight eyes (238 subjects) with no ocular disease were included. Hypertension was present in 106 subjects and absent in 132 subjects. Spectralis HRA+OCT was used to scan a circular region around the optic disc. Outer and inner diameters of the 4 largest retinal arteries and veins were measured using OCT vascular wall reflections, and vessel wall thickness was calculated.

RESULTS

Intervisit, interexaminer, and interevaluator intraclass correlation coefficients of randomly selected vessel measurements were all greater than 0.90. Mean inner arterial and venous diameters were 87.8 ± 9.4 μm and 113.7 ± 12.5 μm, respectively. The OCT-measured mean inner arterial and venous diameters were significantly correlated to fundus photography caliber measurements (P = .005 and P = .001, respectively). Arterial and venous wall thicknesses were 17.4 ± 2.4 μm and 13.7 ± 2.1 μm, respectively, both of which were highly correlated with subject age (arterial: r = 0.612, P < .001, venous: r = 0.455, P < .001). Additionally, both mean arterial and venous wall thicknesses were significantly greater in subjects with hypertension than in age-matched subjects without hypertension (P = .020 and P = .015, respectively).

CONCLUSIONS

Retinal vessel diameter measurements obtained with OCT were highly reproducible and vessel wall thicknesses, calculated using outer and inner diameter measurements, were significantly thickened by both aging and systemic hypertension.

Structural changes in individual retinal layers in diabetic macular edema

Optical coherence tomography (OCT) has enabled objective measurement of the total retinal thickness in diabetic macular edema (DME). The central retinal thickness is correlated modestly with visual impairment and changes paradoxically after treatments compared to the visual acuity. This suggests the clinical relevance of the central retinal thickness in DME and the presence of other factors that affect visual disturbance. Recent advances in spectral-domain (SD) OCT have provided better delineation of the structural changes and fine lesions in the individual retinal layers. Cystoid spaces in the inner nuclear layer and outer plexiform layer are related to quantitative and qualitative parameters in fluorescein angiography. OCT often shows vitreoretinal interface abnormalities in eyes with sponge-like retinal swelling. Serous retinal detachment is sometimes accompanied by hyperreflective foci in the subretinal fluid, which exacerbates the pathogenesis at the interface of the photoreceptors and retinal pigment epithelium. Photoreceptor damage at the fovea is thought to be represented by disruption of the external limiting membrane or the junction between the inner and outer segment lines and is correlated with visual impairment. Hyperreflective foci in the outer retinal layers on SD-OCT images, another marker of visual disturbance, are associated with foveal photoreceptor damage.

Association between perifoveal hyperfluorescence and serous retinal detachment in diabetic macular edema

OBJECTIVE

To study the association between the fluorescence levels on fluorescein angiography images and the characteristics on spectral-domain optical coherence tomography (SD OCT) images in diabetic macular edema (DME).

DESIGN

Retrospective, observational, cross-sectional study.

PARTICIPANTS

One hundred sixty-seven consecutive eyes of 116 patients with diabetic retinopathy for whom FA and SD OCT were performed on the same day.

METHODS

Fluorescein angiography using the Heidelberg Retina Angiograph 2 and OCT images using Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) were obtained. The leakage of fluorescein dye in each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid was quantified and defined as fluorescence levels, which were compared with the retinal thickness and foveal pathomorphologic features evaluated by SD OCT.

MAIN OUTCOME MEASURES

The relationship between fluorescence levels and the foveal pathomorphologic features on SD OCT images.

RESULTS

One hundred twelve (67%) eyes with center-involved DME had significantly higher fluorescence levels in all subfields of the ETDRS grid than 55 (33%) eyes without DME. Fluorescence levels were correlated modestly with the retinal thickness in individual subfields in eyes with center-involved DME. Thirty-seven eyes with foveal serous retinal detachment (SRD) had greater retinal thickness in all subfields and higher levels of fluorescence in most subfields, except the superior subfield of the inner ring. After adjusting for the central retinal thickness using multivariate analyses, eyes with SRD had significantly (P = 0.0085) higher fluorescence levels in the nasal subfield of the inner ring and the superior, nasal, and inferior subfields of the outer ring (P = 0.0117, P = 0.0020, and P = 0.0017, respectively). However, the fluorescence levels in any subfields of the inner or outer ring did not differ significantly between eyes with and without foveal cystoid spaces.

CONCLUSIONS

The correlation between the fluorescence levels and retinal thickness suggests that the vascular hyperpermeability in the perifovea contributes to the pathogenesis of foveal SRD in DME.