Vibrational spectra of Pb2Bi2Te3, PbBi2Te4, and PbBi4Te7 topological insulators: temperature-dependent Raman and theoretical insights from DFT simulations

Insertion of lead and lead telluride in Bi₂Te₃ leads to a change in the thermal conductivity, frequency shift, and the broadening of phonon modes.

Optical Coherence Tomography Angiography in Eyes with Indeterminate Choroidal Neovascularization: Results from the AVATAR study

OBJECTIVE

To evaluate the use of optical coherence tomography angiography (OCTA) to detect choroidal neovascularization (CNV) in eyes with indeterminate CNV features on conventional imaging.

DESIGN

The AVATAR study is a prospective observational study of OCTA in patients undergoing routine spectral-domain optical coherence tomography (SD-OCT) for macular disease.

PARTICIPANTS

Subjects enrolled in the AVATAR study for which CNV was considered as part of a differential diagnosis based on clinical exam and/or prior imaging, but in whom the presence of CNV was not definitive on SD-OCT and fluorescein angiography (FA) imaging.

INTERVENTIONS

All patients were imaged with the Avanti RTVue XR HD (Optovue, Fremont, CA) and the Cirrus HD-OCT (Zeiss, Oberkochen, Germany) systems.

MAIN OUTCOME MEASURES

OCTA scans were assessed for the presence or absence of CNV. SD-OCT scans were assessed for the presence of fluid, hyperreflective material, serous pigment epithelial detachment (PED), shallow irregular PED, vitreomacular adhesion, epiretinal membrane, retinal pigment epithelium atrophy and central subfield retinal thickness. Univariate and multivariate logistic regression analyses were performed to identify features on SD-OCT associated with the presence of CNV on OCTA.

RESULTS

Twenty-nine eyes of 29 patients met the criteria for inclusion. A CNV lesion was detected on OCTA in 8 (28%) eyes; 21 (72%) eyes were negative for CNV. After adjusted for age, gender and central subfield retinal thickness, the presence of shallow irregular PED [odds ratio, 148; 95% confidence interval, 3.22-6830; p = 0.011], as well as the combinations of intraretinal fluid and sub-retinal pigment epithelium material [odds ratio, 16.8; 95% confidence interval, 1.43-198; p = 0.025] on SD-OCT were significantly associated with the presence of CNV on OCTA.

CONCLUSIONS

OCTA enabled the identification of CNV that was otherwise indeterminate with prior imaging in select eyes. The presence of a shallow irregular PED as well as intraretinal fluid combined with sub-retinal pigment epithelium material were both associated with the presence of CNV. OCTA may be a valuable adjunct to conventional SD-OCT and FA imaging in the detection and surveillance of CNV, particularly in diagnostic dilemmas.

Intraoperative OCT Features and Postoperative Ellipsoid Mapping in Primary Macula-Involving Retinal Detachments from the PIONEER Study

PURPOSE

Intraoperative OCT (iOCT) has enabled visualization of subtle structural details during surgical interventions, including retinal detachment repair. The purpose of this study was to evaluate iOCT findings during retinal detachment repair and to assess their impact on anatomic and functional outcomes, including outer retinal integrity.

DESIGN

The PIONEER Intraoperative and Perioperative OCT Study is a prospective cohort, institutional review board-approved study.

PARTICIPANTS

Participants in the PIONEER undergoing surgical repair for primary macula-involving retinal detachment.

METHODS

This was a post hoc analysis of all eyes in the PIONEER undergoing surgical repair with primary macula-involving retinal detachments. Inclusion criteria included iOCT after perfluorocarbon liquid (PFO) placement, visualization of the foveal center on iOCT, and images of sufficient quality for quantitative assessment of submacular fluid volume. Exclusion criteria included recurrent retinal detachment, proliferative vitreoretinopathy, and a lack of postoperative OCT data after gas bubble resolution. Subretinal fluid volume on iOCT imaging was quantified. Qualitative review of iOCT images was performed for visualization of outer retinal bands, fluid, and retinal corrugations. Postoperative OCT images were analyzed using an ellipsoid zone (EZ) mapping platform to evaluate and quantify outer retinal metrics. Postoperative OCT images also were reviewed qualitatively for persistent subretinal fluid. Associations between various anatomic and functional outcomes were assessed.

MAIN OUTCOME MEASURES

Presence of intraoperative subretinal fluid under PFO tamponade, postoperative persistent subretinal fluid, postoperative visual acuity at 1 year, and EZ integrity at 1 year.

RESULTS

Fifteen eyes of 15 patients were analyzed. All 15 eyes (100%) showed subretinal fluid on iOCT. All eyes demonstrated spontaneous fluid resolution on follow-up OCT imaging. Increased intraoperative subretinal fluid volume under PFO tamponade trended toward significantly worse visual acuity outcome (P = 0.07). Postoperative quantitative EZ integrity at 12 months directly correlated with visual outcome (P = 0.01).

CONCLUSIONS

Intraoperative subretinal fluid persists under PFO tamponade with high frequency in eyes undergoing retinal detachment repair, but this fluid does not seem to be associated with persistent postoperative subretinal fluid. Postoperative EZ integrity is associated with visual acuity outcome, and intraoperative subretinal fluid volume under PFO tamponade also may be linked to visual outcomes.

Efficacy and Safety of Sarilumab for the Treatment of Posterior Segment Noninfectious Uveitis (SARIL-NIU):: The Phase 2 SATURN Study

PURPOSE

To assess efficacy and safety of sarilumab, a human anti-interleukin-6 receptor antibody, for treatment of posterior segment noninfectious uveitis (NIU).

DESIGN

Randomized, double-masked, placebo-controlled, phase 2 study.

PARTICIPANTS

Fifty-eight patients (eyes) with noninfectious intermediate, posterior, or panuveitis.

METHODS

Eyes received treatment every 2 weeks for 16 weeks with subcutaneous sarilumab 200 mg or placebo.

MAIN OUTCOME MEASURES

The primary end point was the proportion of patients with ≥2-step reduction in vitreous haze (VH) on the Miami scale or with a reduction of systemic corticosteroids (prednisolone or equivalent) to a dose of <10 mg/day at week 16. Primary end point was based on VH evaluation by a central reading center. Investigator evaluation of VH was a prespecified, planned secondary analysis.

RESULTS

At week 16, proportion of patients taking sarilumab or placebo with ≥2-step reduction in VH or corticosteroid dose <10 mg/day was 46.1% vs. 30.0% (P = 0.2354) based on central reading center assessment of VH and 64.0% vs. 35.0% (P = 0.0372) based on investigator assessment of VH, respectively. In the subgroup of eyes with VH grade ≥2 at baseline, the mean VH reduction from baseline to week 16 was significantly greater with sarilumab vs. placebo regardless of assessment by the central reading center (-2.1 [n = 11] vs. -1.7 [n = 3], respectively; P = 0.0255) or investigator (-2.5 [n = 19] vs. -1.2 [n = 11], respectively; P = 0.0170). The mean best-corrected visual acuity gain from baseline to week 16 was greater with sarilumab vs. placebo in the overall population (8.9 vs. 3.6 letters, respectively; P = 0.0333) and in the subgroup of eyes with central subfield thickness (CST) ≥300 μm at baseline (12.2 [n = 13] vs. 2.1 [n = 7] letters, respectively; P = 0.0517). Corresponding changes in CST were -46.8 vs. +2.6 μm (P = 0.0683) in the overall population and -112.5 [n = 13] vs. -1.8 [n = 6] μm (P = 0.1317) in the subgroup of eyes with CST ≥300 μm at baseline, respectively. The most common ocular adverse events were worsening of uveitis (0 [placebo] and 3 [sarilumab] patients) and retinal infiltrates (1 [placebo] and 2 [sarilumab] patients).

CONCLUSIONS

Subcutaneous sarilumab may provide clinical benefits in the management of NIU of the posterior segment, especially in eyes with uveitic macular edema.

Assessment of inner and outer retinal layer metrics on the Cirrus HD-OCT Platform in normal eyes

Purpose

Ellipsoid zone (EZ) and outer retinal integrity are strongly linked to visual prognosis, but quantitative normative data is lacking. This study evaluates the EZ, outer retina, and inner retina in eyes without macular disease across a wide age spectrum.

Methods

An IRB-approved study was performed for eyes without macular pathology undergoing Spectral Domain Optical Coherence Tomography (SD-OCT) scans on the Cirrus HD-OCT system (Carl Zeiss Meditec, Oberkochen, Germany). Scans were analyzed using a previously described automated EZ mapping tool with line-by-line manual verification. Segmentation included internal limiting membrane (ILM), outer nuclear layer/Henle fiber layer complex (ONL/HFL), EZ, and the retinal pigment epithelium (RPE). The output included metrics for the inner retina (ILM-OPL/HFL), outer retina (ONL/HFL-RPE), EZ-RPE area and volume, and en face EZ mapping. EZ-RPE attenuation on en face mapping was defined as EZ-RPE thickness < 20 um, and total attenuation was 0 um. Imaging parameters were assessed for the group and compared to age, sex, visual acuity and spherical equivalent.

Results

167 eyes from 167 subjects were included. Mean age was 49.7 years (range 10–84 years). The mean foveal retinal thickness was 200.58 ± 19.22 um. Mean inner retinal thickness was 21.47 ± 13.60 um. Mean outer retinal thickness was 179.11 ± 18.52 um. Mean EZ-RPE thickness was 50.58 ± 6.01um. The mean EZ-RPE volume was 1.20 ± 0.10 mm³. Mean EZ attenuation percentage per macular map area was 0.87% ± 1.13% and mean percentage total attenuation was 0.12% ± 0.14%. Total and inner retinal thickness metrics decreased with age. Mean outer retinal thickness increased with age. EZ-RPE parameters were unchanged with age. However, EZ attenuation was negatively correlated with age.

Conclusion

This study provides important information for inner and outer retinal parameters. Future research on quantitative EZ integrity can utilize this data for comparison.

Treatment Duration and Side Effect Profile of Long-Term Use of Intravitreal Preservative-Free Triamcinolone Acetonide in Uveitis

PURPOSE

Noninfectious uveitis has been treated historically with corticosteroid therapy in varying doses and routes. Triesence, a preservative-free sterile formulation of triamcinolone acetonide, has been used in a wide spectrum of ocular pathologies, but there have been few large studies validating its dosing or detailing long-term side effects in uveitic disease. The primary aim of this study was to describe the relative duration of action and side effects of 2 doses of preservative-free intravitreal triamcinolone acetonide (PF-IVTA) in uveitis.

DESIGN

Retrospective, comparative consecutive case series.

METHODS

Charts of all patients receiving PF-IVTA (2 mg or 4 mg) in a defined time period (2012-2014) at the Cole Eye Institute were examined for patient demographics, time to treatment failure (TTF), use of systemic immunosuppression, use of intraocular pressure-lowering therapies, date of cataract surgery and glaucoma filtration surgery, and adverse events.

RESULTS

The final data set examined 514 injections in 214 eyes. Mean duration of follow-up was 1.5 years. There was similar demographic distribution between eyes that received 2 mg PF-IVTA only and eyes that received a combination of 4 + 2 mg PF-IVTA. No statistically significant difference in TTF between injection dosages was observed. There was a higher incidence of glaucoma filtering surgery and cataract surgery in eyes that received 4 + 2 mg PF-IVTA as well as a shorter time to glaucoma surgery, when compared to eyes that received 2 mg PF-IVTA alone.

CONCLUSIONS

This retrospective study supports that 2 mg PF-IVTA displayed noninferior treatment duration to 4 mg PF-IVTA, and may carry a significantly lower side-effect profile of cataract development and glaucoma filtering surgery.

Quantitative assessment of outer retinal layers and ellipsoid zone mapping in hydroxychloroquine retinopathy

BACKGROUND

To quantitatively assess outer retinal layers in eyes with hydroxychloroquine (HCQ) toxicity.

METHODS

A retrospective case-control study was performed to identify eyes with HCQ retinopathy/toxicity at Cleveland Clinic. A clinical diagnosis of HCQ retinopathy was made based on clinical and imaging features including the presence of parafoveal ellipsoid zone (EZ) loss on spectral-domain optical coherence tomography (OCT) and visual field defects. All participants underwent macular cube scan using the Cirrus HD-OCT (Zeiss, Oberkochen, Germany). Quantitative assessment of outer nuclear layer (ONL)/Henle fibre layer complex (HFL) metrics and EZ mapping were performed with a novel software platform and compared with age-matched controls. HCQ toxicity group was divided into three subgroups based on the severity.

RESULTS

There were 14 eyes from 14 patients in HCQ toxicity group (mean age 57.0±18.6 years), and 14 eyes from 14 subjects in age-matched control group (mean age 59.4±18.6 years). Multiple outer retinal parameters including ONL/HFL-EZ volume, parafoveal ONL/HFL-EZ thickness and EZ-retinal pigment epithelium (RPE) volume were significantly reduced in all HCQ toxicity subgroups (early, moderate and advanced toxicity) compared with controls. Semiautomated layer segmentation tool produced en face representation of EZ-RPE mapping and allowed unique visualisation of EZ attenuation in eyes with HCQ toxicity. The longitudinal analysis of HCQ toxicity group demonstrated progressive decline in some outer retinal parameters.

CONCLUSION

HCQ toxicity resulted in significant outer retinal layer volumetric thinning compared with controls. Quantitative assessment of outer retinal parameters and EZ mapping on SD-OCT may become a useful biomarker to identify and monitor HCQ toxicity.

Intraoperative OCT for Uveitis-Related Vitreoretinal Surgery in the DISCOVER Study

PURPOSE

To evaluate the feasibility and usefulness of intraoperative OCT (iOCT) for uveitis-related vitreoretinal surgeries.

DESIGN

Prospective consecutive case series.

PARTICIPANTS

Seventy-three consecutive patients (74 eyes) with a uveitis-related diagnosis.

METHODS

Eyes undergoing surgery for a uveitis-related diagnosis in the prospective Determination of Feasibility of Intraoperative Spectral Domain Microscope Combined/Integrated OCT Visualization During En Face Retinal and Ophthalmic Surgery (DISCOVER) iOCT study. Intraoperative OCT was performed at various surgical milestones. Clinical details and evaluation of the role of iOCT were assessed. A standardized surgeon survey was completed to evaluate the usefulness of iOCT during surgery.

MAIN OUTCOME MEASURES

Percentage of patients in whom iOCT provided valuable feedback and altered surgical decision making.

RESULTS

Seventy-four consecutive eyes with a uveitis-related diagnosis were enrolled in the DISCOVER study. Successful imaging was obtained in 72 of 73 eyes (98.6%). Intraoperative OCT provided valuable feedback for fluocinolone acetonide implant placement in 11 of 13 eyes (84.6%), for chorioretinal biopsies in 13 of 16 eyes (81.2%), and for retinal detachment (RD) repairs in 20 of 27 eyes (74.1%). In subretinal and chorioretinal biopsies, iOCT altered surgical decision making in 38% of patients. In uveitis-related RD repairs, iOCT resulted in alterations in the surgical procedure in 48% of patients, predominantly related to additional membrane peeling.

CONCLUSION

Intraoperative OCT during uveitis-related vitreoretinal surgery seems to provide valuable additional information that can impact surgical decision making and may enhance outcomes.

The DISCOVER Study 3-Year Results: Feasibility and Usefulness of Microscope-Integrated Intraoperative OCT during Ophthalmic Surgery

PURPOSE

To report the 3-year assessment of feasibility and usefulness of microscope-integrated intraoperative OCT (iOCT) during ophthalmic surgery.

DESIGN

Prospective, consecutive case series.

PARTICIPANTS

Adult participants undergoing incisional ophthalmic surgery with iOCT imaging who consented to be enrolled in the Determination of Feasibility of Intraoperative Spectral-Domain Microscope Combined/Integrated OCT Visualization during En Face Retinal and Ophthalmic Surgery (DISCOVER) study.

METHODS

The DISCOVER study is a single-site, multisurgeon, institutional review board-approved investigational device prospective study. Participants included patients undergoing anterior or posterior segment surgery who underwent iOCT imaging with 1 of 3 prototype microscope-integrated iOCT systems (i.e., Zeiss Rescan 700, Leica EnFocus, or Cole Eye iOCT systems). Clinical characteristics were documented, iOCT was directed by the operating surgeon at predetermined surgical time points, and each surgeon completed a questionnaire after surgery to evaluate the usefulness of iOCT during surgery.

MAIN OUTCOME MEASURES

Feasibility of iOCT based ability to obtain an OCT image during surgery and usefulness of iOCT based on surgeon reporting during surgery.

RESULTS

Eight hundred thirty-seven eyes (244 anterior segment cases and 593 posterior segment cases) were enrolled in the DISCOVER study. Intraoperative OCT demonstrated feasibility with successful image acquisition in 820 eyes (98.0%; 95% confidence interval [CI], 96.8%-98.8%). In 106 anterior segment cases (43.4%; 95% CI, 37.1%-49.9%), the surgeons indicated that the iOCT information impacted their surgical decision making and altered the procedure. In posterior segment procedures, surgeons reported that iOCT enabled altered surgical decision making during the procedure in 173 cases (29.2%; 95% CI, 25.5%-33.0%).

CONCLUSIONS

The DISCOVER iOCT study demonstrated both generalized feasibility and usefulness based on the surgeon-reported impact on surgical decision making. This large-scale study confirmed similar findings from other studies on the potential value and impact of iOCT on ophthalmic surgery.

Comparison of OCT Angiography Review Strategies to Identify Vascular Abnormalities in the AVATAR Study

Purpose

To compare review strategies for optical coherence tomography angiography (OCT-A) for multiple disease features found in common diseases of the choroid and retina.

Design

Prospective, observational study.

Participants

Patients with macular disease undergoing routine spectral-domain optical coherence tomography (SDOCT).

Methods

Eyes were imaged with the Avanti RTVue XR HD (Optovue, Fremont, CA), and the split-spectrum amplitude decorrelation angiography (SSADA) algorithm software was utilized for OCT-A performance. Scans were reviewed by 2 masked expert reviewers. A third masked reviewer was utilized in cases of reviewer disagreement. A single report using automated segmentation within the Avanti software to represent the superficial retina capillary plexus, deep retina capillary plexus, outer retina, and choroid capillary layer was generated. A continuous slab descent video export was also reviewed for each OCT-A scan. This video consisted of a continuous (e.g., line-by-line) review of the en face OCT- data. Each dataset was reviewed for the presence of three pathologic features: choroidal neovascularization, microaneurysms, and macular ischemia.

Main Outcome Measures

Comparison of identification rates of retinal and choroidal microvascular abnormalities using different review strategies.

Results

Four hundred twenty-one eyes were included in the study. Of those, 350 eyes had reports that were deemed sufficient quality for interpretation and analysis by both reviewers. Identification rates of choroidal neovascularization, microaneurysms, and macular ischemia on the report were 90.5%, 84.5%, and 95.4% respectively compared to the overall presence. Likewise, rates of identification in the continuous slab descent review video were 88.1%, 96.4%, and 95.4% for choroidal neovascularization, microaneurysms, and macular ischemia respectively compared to the overall presence. Cohen's kappa values ranged from 0.80 to 0.96, corresponding to very good agreement between the report and continuous slab descent review for each variable.

Conclusions

Defining an optimal reporting strategy for OCT-A is important for diagnostic accuracy and optimizing workflow in retina clinics. In this study, OCT-A report using automated segmentation was comparable to continuous slab descent review for identifying microvascular abnormalities of the retina and choroid.

Outer Retinal Assessment Using Spectral-Domain Optical Coherence Tomography in Patients With Alzheimer's and Parkinson's Disease

Purpose

To investigate outer retinal parameters among patients with various chronic neurodegenerative disorders by using spectral-domain coherence tomography (OCT) in a prospective cross-sectional cohort study.

Methods

A total of 132 participants were enrolled following a comprehensive diagnostic evaluation with neurologic, neuropsychology, and magnetic resonance imaging volumetric evaluations. Participants were 50 years or older, either diagnosed with Alzheimer's disease (AD) dementia, amnestic mild cognitive impairment (MCI), non-AD dementia, Parkinson's disease (PD), or age- and sex-matched controls. All participants underwent a macular cube scan for both eyes by using the Cirrus 4000 HD-OCT (Zeiss, Oberkochen, Germany). The OCT image with the best quality was selected for further analysis. Outer retinal parameters including ellipsoid zone mapping and outer nuclear layer metrics were evaluated with a novel software platform.

Results

One hundred twenty-four eyes of 124 participants with AD dementia (24 eyes), amnestic MCI (22 eyes), non-AD dementia (20 eyes), PD (22 eyes), and age- and sex-matched controls (36 eyes) were included in the analysis. Eight eyes were excluded either due to the presence of macular disease or poor quality of the OCT image. The mean ages of participants were 65.9 ± 8.9 years. The outer retinal thickness measures did not show any statistical significance between the groups. However, ellipsoid zone to retinal pigment epithelium volume correlated with cognitive testing scores in all study participants.

Conclusions

There were no identifiable differences in the outer retinal metrics across neurodegenerative disease groups and controls. The relationship between the degree of cognitive impairment and ellipsoid zone to retinal pigment epithelium volume warrants further study.

Intraoperative OCT-assisted Surgery for Proliferative Diabetic Retinopathy in the DISCOVER Study

Purpose

To delineate the feasibility and role of intraoperative optical coherence tomography (iOCT) in surgical decision-making during vitreoretinal surgical interventions for proliferative diabetic retinopathy (PDR).

Design

Prospective, single-site, multi-surgeon consecutive case series.

Participants

Patients enrolled in the DISCOVER study who underwent vitreoretinal surgery for sequelae of PDR.

Methods

Subjects were identified from the first 2 years of the DISCOVER study that underwent vitreoretinal surgery for complications of PDR. Intraoperative imaging with a microscope-integrated iOCT system was performed at surgical milestones as determined by the surgeon. Data collected included clinical characteristics, image features, and survey-based surgeon feedback.

Main Outcome Measures

Main outcomes were 1) the percentage of cases with successful acquisition of iOCT (feasibility) and 2) the percentage of cases in which iOCT altered surgical decision-making (utility).

Results

Eighty-one eyes with PDR underwent vitreoretinal surgery in the DISCOVER study. Successful iOCT imaging was obtained for 80 of 81 eyes (98.8%). Of these, 36 (44.4%) were female and 44 (54.3%) were male. The surgeon preferred real-time feedback in 47 cases (58.6%), static review in 29 cases (36.3%), and was indeterminate in 4 cases (5%). Surgeons reported that in 2 cases (2.5%) the iOCT interfered with the surgery (e.g., microscope malfunction). In 41 of the 81 cases (50.6%), surgeons reported that iOCT provided valuable information (e.g., identification of dissection planes, identification of retinal hole). In addition, the iOCT data provided information that specifically altered the surgeon's decision making (e.g., determination of peel completion, choice of tamponade) in 21 of 81 cases (26%). No adverse events were attributed to the iOCT system.

Conclusions

The results suggest that iOCT is feasible during complex vitreoretinal surgeries in patients with PDR using a microscope-integrated OCT platform. Utilizing intraoperative OCT, appears to frequently offer key information that may impact surgical decision-making and potentially patient outcomes.

Outcomes of Intraoperative OCT-Assisted Epiretinal Membrane Surgery from the PIONEER Study

Purpose

To assess the retinal architecture changes which occur during epiretinal membrane (ERM) surgery, utilizing intraoperative optical coherence tomography (iOCT).

Design

Prospective multi-surgeon single center study.

Subjects/Participants

Subjects from the PIONEER iOCT study who underwent surgical intervention for management of ERM.

Methods

All subjects underwent vitrectomy with ERM peeling with optional internal limiting membrane (ILM) peeling. Preoperative, intraoperative, and postoperative quantitative and qualitative OCT assessments were performed. Clinical characteristics including visual acuity outcomes, central subfield thickness and complications including ERM recurrence and need for reoperation were assessed at 3, 6 and 12 months following surgery for membrane peeling, as available.

Main Outcome measures

Visual acuity outcomes, anatomic outcomes and complications including ERM recurrence. Microarchitectural alterations (i.e. retinal layer changes) following membrane peeling visualized with iOCT.

Results

Seventy-six were identified and included in this analysis of clinical outcomes and quantitative OCT assessment. Twenty-four eyes were excluded due to insufficient intraoperative OCT quality for quantitative assessment. The mean preoperative VA measured 20/63. The mean postoperative VA at 3 months was 20/41 (p<0.0001), at 6 months measured 20/36 (p < 0.0001), and at 12 months measured 20/33 (p < 0.0001). Preoperative mean central subfield thickness (CST) was 426 microns. At 3 months, the mean CST improved to 377 microns (p < 0.0001). The 6-month postoperative CST was 367 microns (p < 0.0001) and the 12-month postoperative CST measured 359 microns (p < 0.0001). Immediately following membrane peeling, the distance between the retinal pigment epithelium and the ellipsoid zone as well as the distance between the retinal pigment epithelium and the cone outer segment tips/interdigitation zone significantly increased (p < 0.001). iOCT identified occult residual membranes in 12% of cases and confirmed complete membrane peeling contrary to surgeon impression in 9% of cases. Reoperation was required for recurrent ERM in 1% of eyes.

Conclusions

iOCT-assisted ERM peeling resulted in significant improvement in visual acuity, reduction in macular thickness, and low recurrence rate. Additional research is needed with randomized clinical trials to better define the comparative success rates of image-guided ERM surgery to standard surgical visualization techniques.

A Prospective Randomized Comparative Dosing Trial of Ranibizumab In Bevacizumab-Resistant Diabetic Macular Edema: The REACT Study

Purpose

To assess the efficacy of ranibizumab for persistent diabetic macular edema (DME) previously treated with bevacizumab and compare monthly vs treat-and-extend (TAE) dosing.

Design

12-month, open-label, prospective randomized comparative dosing study.

Participants

27 participants with persistent foveal-involving DME recently treated with bevacizumab.

Methods

All subjects were to receive three initial monthly 0.3 mg ranibizumab injections before randomization to monthly (n=15) or TAE (n=12) injection protocols over 12 months. Treatment interval was extended by two weeks up to a maximum interval of 12 weeks in the TAE group if central subfield thickness (CST) was ≤ 300 μm or complete absence of intraretinal or subretinal fluid on the macular cube was observed. Follow-up interval was decreased by 2 weeks if CST increased above 300 μm with associated intraretinal and/or subretinal fluid.

Main Outcome Measures

Change in Early Treatment of Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA), CST, adverse events.

Results

Prior to study enrollment, subjects received an average of 8.6 bevacizumab injections. At month 12, mean ETDRS BCVA improved by + 5.3 letters (p<0.05) and mean CST decreased by -99.6 μm (p<0.01) in all patients. At study exit, 18.5 % of subjects gained ≥ 3 lines of vision and 3.7% of subjects lost ≥ 3 lines. Patients treated via the TAE protocol gained +8.4 letters and decreased CST by -120.2 μm whereas those treated by monthly injection gained +2.7 letters and decreased CST by -83.1 μm at month 12.

Conclusions

Following conversion to ranibizumab in eyes with persistent DME refractory to bevacizumab, significant functional and anatomic improvements were noted. Visual and anatomical outcomes were similar in TAE and monthly treatment protocols.

36-Month Evaluation of Intravitreous Aflibercept Injection for Wet Age-Related Macular Degeneration in Patients Previously Treated With Ranibizumab or Bevacizumab

BACKGROUND AND OBJECTIVE

In the ASSESS study, patients with neovascular age-related macular degeneration transitioned from other anti-vascular endothelial growth factor therapies to intravitreous aflibercept (Eylea; Regeneron, Tarrytown, NY) injections (IAI). The purpose was to determine the 36-month outcomes following the change from a fixed 24-month IAI dosing regimen to a routine clinical practice regimen.

PATIENTS AND METHODS

Patients were treated with a fixed bimonthly regimen for the first 2 years. In the third year, patients were managed according to routine clinical practice.

RESULTS

A total of 18 patients completed the 36 months and were considered for statistical analyses. At 36 months, a nonsignificant decrease of -37.8 μm in central subfield thickness and a nonsignificant gain of 5.8 letters from baseline were observed.

CONCLUSION

Despite the significant visual and anatomical gains observed in the 2 years of fixed-dosing IAI, there was gradual decline in these improvements when patients were transitioned to a variable regimen. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:179-185.].

A comparative Study of Aptasensor Vs Immunosensor for Label-Free PSA Cancer Detection on GQDs-AuNRs Modified Screen-Printed Electrodes

Label-free and sensitive detection of PSA (Prostate Specific Antigen) is still a big challenge in the arena of prostate cancer diagnosis in males. We present a comparative study for label-free PSA aptasensor and PSA immunosensor for the PSA-specific monoclonal antibody, based on graphene quantum dots-gold nanorods (GQDs-AuNRs) modified screen-printed electrodes. GQDs-AuNRs composite has been synthesized and used as an electro-active material, which shows fast electron transfer and catalytic property. Aptamer or anti-PSA has immobilized onto the surface of modified screen printed electrodes. Three techniques are used simultaneously, viz. cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedence spectroscopy (EIS) to investigate the analytical performance of both PSA aptasensor and PSA immunosensor with its corresponding PSA antigen. Under optimum conditions, both sensors show comparable results with an almost same limit of detection (LOD) of 0.14 ng mL-1. The results developed with aptasensor and anti-PSA is also checked through the detection of PSA in real samples with acceptable results. Our study suggests some advantages of aptasensor in terms of better stability, simplicity and cost effectiveness. Further our present work shows enormous potential of our developed sensors for real application using voltammetric and EIS techniques simultaneous to get reliable detection of the disease.

Remote sensing based deforestation analysis in Mahanadi and Brahmaputra river basin in India since 1985

Land use and land cover (LULC) change has been recognized as a key driver of global climate change by influencing land surface processes. Being in constant change, river basins are always subjected to LULC changes, especially decline in forest cover to give way for agricultural expansion, urbanization, industrialization etc. We used on-screen digital interpretation technique to derive LULC maps from Landsat images at three decadal intervals i.e., 1985, 1995 and 2005 of two major river basins of India. Rain-fed, Mahanadi river basin (MRB) attributed to 55% agricultural area wherein glacier-fed, Brahmaputra river basin (BRB) had only 16% area under agricultural land. Though conversion of forest land for agricultural activities was the major LULC changes in both the basins, the rate was higher for BRB than MRB. While water body increased in MRB could be primarily attributed to creation of reservoirs and aquaculture farms; snow and ice melting attributed to creation of more water bodies in BRB. Scrub land acted as an intermediate class for forest conversion to barren land in BRB, while direct conversion of scrub land to waste land and crop land was seen in MRB. While habitation contributed primarily to LULC changes in BRB, the proximity zones around habitat and other socio-economic drivers contributed to LULC change in MRB. Comparing the predicted result with actual LULC of 2005, we obtained >97% modelling accuracy; therefore it is expected that the Dyna-CLUE model has very well predicted the LULC for the year 2025. The predicted LULC of 2025 and corresponding LULC changes in these two basins acting as early warning, and with the past 2-decadal change analysis this study is believed to help the land use planners for improved regional planning to create balanced ecosystem, especially in a changing climate.

Paratesticular Paraganglioma with Metastasis to D1 Vertebra- A Case Report and Review of Literature

INTRODUCTION

Paragangliomas are relatively rare tumors, accounting for only about 0.3% of all neoplasms. Most paragangliomas are defined as benign in nature, but 10-% possess metastatic potential. There have been scattered reports of metastatic paraganglioma in the literature, but in rare circumstances, paragangliomas can metastasize to the spinal column causing destruction or compression of the spinal cord, clinically manifesting as pain or neurological deficit.

CASE REPORT

We present a case of a 43-year-old man who presented with paresthesia and paraparesis and was found to have pathologic fracture involving D1 vertebra as a manifestation of metastasis from a non-secretory right paratesticular paraganglioma.

CONCLUSIONS

We will review the literature on the topic of metastatic paraganglioma, management of paragangliomas involving spine, and touch on the importance of angioembolization, staged procedures, and a team approach.

OCT Angiography and Ellipsoid Zone Mapping of Macular Telangiectasia Type 2 From the AVATAR Study

Purpose

To evaluate alterations on optical coherence tomography angiography (OCT-A) and quantitatively assess alterations in the ellipsoid zone (EZ) in eyes with macular telangiectasia type 2 (MacTel type 2).

Methods

The Observational Assessment of Visualizing and Analyzing Vessels With Optical Coherence Tomography Angiography in Retinal Diseases study is an institutional review board-approved prospective, observational study investigating OCT-A in macular disease. Patients underwent spectral-domain (SD)-OCT and OCT-A imaging at a single visit. SD-OCT data were analyzed using a novel OCT EZ-mapping software to obtain linear, area, and volumetric measurements of the EZ-retinal pigment epithelium (RPE) complex across the macular cube. OCT-A retinal capillary density was measured using the Optovue Avanti split-spectrum amplitude-decorrelation angiography algorithm. EZ-RPE parameters were compared to age-matched, sex-matched controls.

Results

Fourteen eyes of seven patients (mean age, 59 ± 6.5 years) were analyzed. Mean visual acuity was 20/45 (range, 20/20–20/150). EZ-RPE central foveal mean thickness was 27.8 ± 6.7 μm, EZ-RPE central foveal thickness was 22.1 ± 21.6 μm, EZ-RPE central foveal area was 0.17 ± 0.04 mm², and EZ-RPE central subfield volume was 0.017 ± 0.012 mm³. Each of these measurements was significantly inversely correlated with visual acuity (P < 0.02). In addition, all of these measurements were significantly reduced compared to controls (all P ≤ 0.005). OCT-A showed a reduced parafoveal vessel density of 50.8% temporally compared to 53.8% nasally (P = 0.01) in the superficial vascular plexus. In the deep vascular plexus, similar findings were noted with a parafoveal vessel density of 56.7% temporally and 58.8% nasally (P = 0.01).

Conclusions

Abnormalities in EZ-RPE thickness, area, and volume are correlated with visual acuity in MacTel type 2, and may provide quantitative markers to measure disease progression and treatment response. OCT-A was a useful adjunct for determining disease severity.

Intraoperative optical coherence tomography-compatible surgical instruments for real-time image-guided ophthalmic surgery

Intraoperative optical coherence tomography (OCT) is a potentially transformational technology that is now commercially available to ophthalmic surgeons. Currently, the use of the technology is primarily limited to a 'stop and image' approach due to the lack of OCT compatibility with surgical instrumentation. In this report, we describe multiple OCT-compatible surgical instruments that were developed for various surgical needs, based on previous evaluation of potential surgical materials for optical features and physical properties. OCT-compatible instrumentation included two membrane scrapers, a surgical pick and vitreoretinal forceps. Imaging during in vitro and ex vivo-simulated surgical procedures demonstrated excellent visualisation of the instrument tip and of the tissue-instrument interaction. These OCT-compatible instruments may be a key component to the feasibility of real-time image-guided surgery with intraoperative OCT.

Biomarkers and Surrogate Endpoints in Uveitis: The Impact of Quantitative Imaging

Purpose

Uveitis is a major cause of sight loss across the world. The reliable assessment of intraocular inflammation in uveitis ('disease activity') is essential in order to score disease severity and response to treatment. In this review, we describe how 'quantitative imaging', the approach of using automated analysis and measurement algorithms across both standard and emerging imaging modalities, can develop objective instrument-based measures of disease activity.

Methods

This is a narrative review based on searches of the current world literature using terms related to quantitative imaging techniques in uveitis, supplemented by clinical trial registry data, and expert knowledge of surrogate endpoints and outcome measures in ophthalmology.

Results

Current measures of disease activity are largely based on subjective clinical estimation, and are relatively insensitive, with poor discrimination and reliability. The development of quantitative imaging in uveitis is most established in the use of optical coherence tomographic (OCT) measurement of central macular thickness (CMT) to measure severity of macular edema (ME). The transformative effect of CMT in clinical assessment of patients with ME provides a paradigm for the development and impact of other forms of quantitative imaging. Quantitative imaging approaches are now being developed and validated for other key inflammatory parameters such as anterior chamber cells, vitreous haze, retinovascular leakage, and chorioretinal infiltrates.

Conclusions

As new forms of quantitative imaging in uveitis are proposed, the uveitis community will need to evaluate these tools against the current subjective clinical estimates and reach a new consensus for how disease activity in uveitis should be measured. The development, validation, and adoption of sensitive and discriminatory measures of disease activity is an unmet need that has the potential to transform both drug development and routine clinical care for the patient with uveitis.

Analysis of Retinal Architectural Changes Using Intraoperative OCT Following Surgical Manipulations With Membrane Flex Loop in the DISCOVER Study

Purpose

We investigate acute retinal alterations identified on intraoperative optical coherence tomography (iOCT) immediately following surgical intervention with the Finesse Flex Loop for vitreoretinal interface disorders.

Methods

The Determination of feasibility of Intraoperative Spectral domain microscope Combined/integrated OCT Visualization during En face Retinal and ophthalmic surgery (DISCOVER) study is a prospective multisurgeon intraoperative OCT clinical study. Subjects who had participated in the DISCOVER study and had undergone macular surgery with the membrane flex loop from August 2014 to July 2016 were identified. iOCT images and video sequences were evaluated at various surgical time points. Subjects were excluded if iOCT images were not obtained over the area of membrane peeling performed with the membrane flex loop. Qualitative characteristics of intraoperative changes in retinal images were analyzed, with particular focus on the retinal layers within the bed of membrane peeling performed specifically with the membrane flex loop.

Results

We studied 34 eyes of 34 patients, with a mean age of 72.7 (± 6.4) years, 25 of whom were women. The intraoperative diagnosis was full thickness macular hole in 21 eyes (62%) and epiretinal membrane in 13 (38%). All eyes had successful indocyanine green–assisted inner limiting membrane (ILM) flap initiation using the membrane loop. Intraoperative OCT demonstrated expansion of the ellipsoid zone-to-RPE distance in 3 eyes (9%), definitive subretinal fluid accumulation in 1 eye (3%), and hyperreflectivity of the inner retinal layers associated with retinal hemorrhage in 10 eyes (29%). Retinal breaks were not observed in any eye.

Conclusions

Acute retinal alterations after ILM peeling with the membrane flex loop were visualized at a frequency of less than 10%. Additional research is needed to understand the clinical impact, if any, of these architectural alterations.