Agreement between OCT Leakage and Fluorescein Angiography to Identify Sites of Alteration of the Blood-Retinal Barrier in Diabetes

PURPOSE

To compare the location of the sites of lower reflectivity, as determined by OCT leakage using spectral domain (SD)-OCT, with sites of fluorescein leakage identified by fluorescein angiography (FA) in eyes with diabetic retinopathy.

DESIGN

Prospective consecutive case series.

PARTICIPANTS

Fifty-two eyes from 28 patients with type 2 diabetes and presence of nonproliferative diabetic retinopathy.

METHODS

All patients were imaged with FA and SD-OCT (Angioplex, Carl Zeiss Meditec, Inc). All FA images were analyzed by 2 experienced graders, and the area surrounding well-defined sites of leakage was outlined by the graders. The SD-OCT scans were processed using OCT leakage proprietary software and semiautomated segmentation. Both procedures were performed without access to the clinical data.

MAIN OUTCOME MEASURES

Agreement of OCT leakage with FA findings.

RESULTS

In eyes that were classified as having well-defined sites of leakage on FA, OCT leakage showed a sensitivity of 95.9% and a specificity of 75.4% regarding agreement between these sites of alteration of the blood-retinal barrier. The areas of abnormal extracellular fluid increase were larger than the areas of fluorescein leakage and included the well-defined leakage sites identified by FA. On OCT leakage, localized increases in extracellular space were identified, mainly in the inner nuclear, outer plexiform, or outer nuclear layers, even in eyes without leakage on FA.

CONCLUSIONS

Using SD-OCT, OCT leakage was found to better identify abnormal retinal fluid than did FA and showed good sensitivity and specificity in comparison with FA for identification of sites of alterations of the blood-retinal barrier.

Age-related macular degeneration in Portugal: prevalence and risk factors in a coastal and an inland town. The Coimbra Eye Study - Report 2

PURPOSE

To determine the age- and sex-specific prevalence of early and late age-related macular degeneration (AMD) in two Portuguese population-based samples and to identify its risk factors.

POPULATION

A population of 6023 adults aged ≥55 years was recruited from two Portuguese primary healthcare units in the central region of Portugal - one from a coastal (n = 3000) and another from an inland town (n = 3023).

METHODS

Cross-sectional population-based study. Participants were enrolled in the two locations between August 2009 and October 2013. Responders underwent standardized interviews and ophthalmologic examination, including digital fundus imaging. All fundus photographs were graded according to an International Classification and Grading System. The main outcome measures consisted of age- and sex-adjusted prevalence of early and late AMD. Potential epidemiologic risk factors were also evaluated using logistic regression analysis.

RESULTS

Of the 6023 subjects enrolled, 5996 had gradable fundus images and were included in the analysis. The crude prevalence of early and late AMD was 6.99 and 0.67%, respectively, for the coastal town and 15.39 and 1.29% for the inland town. Age- and sex-adjusted prevalence of any AMD for the Portuguese population was 12.48% (95% CI: 11.61-13.33) with late AMD accounting for 1.16% (95% CI: 0.85-1.46). Neovascular AMD (NV-AMD) and geographic atrophy (GA) accounted for 0.55% (95% CI: 0.36-0.75) and 0.61% (95% CI: 0.37-0.84) of individuals, respectively. After adjusting for possible confounding factors, prevalence of early and late AMD increased with increasing age (OR = 1.35; 95% CI: 1.23-1.49 for early and OR = 3.01; 95% CI: 2.22-4.08 for late AMD, per each decade of age increase, p < 0.001). After adjustment for age, sex, family history, smoking history, hypertension, diabetes and BMI, subjects from the inland town presented a significantly higher OR of early and late AMD than subjects from the coastal town (OR = 2.57, 95% CI: 2.12-3.12, p < 0.001 for early and OR = 2.06, 95% CI: 1.07-3.95, p = 0.029 for late AMD).

CONCLUSIONS

The prevalence of early and late AMD in this Portuguese population was similar to other large-scale population-based cohorts. After controlling for confounders, age and study site of inclusion were significant independent predictors for both early and late forms of the disease. Further analysis will be needed to completely unravel the underlying reasons for this difference regarding geographic location.

Evaluation of the efficacy and safety of a standardised intracameral combination of mydriatics and anaesthetics for cataract surgery

Background/aims

To compare the efficacy and safety of intracameral (IC) administration at the beginning of cataract surgery, of Mydrane, a standardised ophthalmic combination of tropicamide 0.02%, phenylephrine 0.31% and lidocaine 1%, to a standard topical regimen.

Methods

In this international phase III, prospective, randomised study, the selected eye of 555 patients undergoing phacoemulsification with intraocular lens (IOL) implantation received 200 μL of Mydrane (Mydrane group) just after the first incision or a topical regimen of one drop each of tropicamide 0.5% and phenylephrine 10% repeated three times (reference group). The primary efficacy variable was achievement of capsulorhexis without additional mydriatics. The non-inferiority of Mydrane to the topical regimen was tested. The main outcome measures were pupil size, patient perception of ocular discomfort and safety.

Results

Capsulorhexis without additional mydriatics was performed in 98.9% of patients and 94.7% in the Mydrane and reference groups, respectively. Both groups achieved adequate mydriasis (>7 mm) during capsulorhexis, phacoemulsification and IOL insertion. IOL insertion was classified as ‘routine’ in a statistically greater number of eyes in the Mydrane group compared with the reference group (p=0.047). Patients in the Mydrane group reported statistically greater comfort than the reference group before IOL insertion (p=0.034). Safety data were similar between groups.

Conclusions

Mydrane is an effective and safe alternative to standard eye drops for initiating and maintaining intraoperative mydriasis and analgesia. Patients who received IC Mydrane were significantly more comfortable before IOL insertion than the reference group. Surgeons found IOL insertion less technically challenging with IC Mydrane.

Trial registration number

NCT02101359; Results.

Dietary administration of the probiotic SpPdp11: Effects on the intestinal microbiota and immune-related gene expression of farmed Solea senegalensis treated with oxytetracycline

Few antimicrobials are currently authorised in the aquaculture industry to treat infectious diseases. Among them, oxytetracycline (OTC) is one of the first-choice drugs for nearly all bacterial diseases. The objective of this study was to evaluate the effect of the dietary administration of OTC both alone and jointly with the probiotic Shewanella putrefaciens Pdp11 (SpPdp11) on the intestinal microbiota and hepatic expression of genes related to immunity in Senegalese sole (Solea senegalensis) juveniles. The results demonstrated that the richness and diversity of the intestinal microbiota of fish treated with OTC decreased compared with those of the control group but that these effects were lessened by the simultaneous administration of SpPdp11. In addition, specimens that received OTC and SpPdp11 jointly showed a decreased intensity of the Denaturing Gradient Gel Electrophoresis (DGGE) bands related to Vibrio genus and the presence of DGGE bands related to Lactobacillus and Shewanella genera. The relationship among the intestinal microbiota of fish fed with control and OTC diets and the expression of the NADPH oxidase and CASPASE-6 genes was demonstrated by a Principal Components Analysis (PCA) carried out in this study. In contrast, a close relationship between the transcription of genes, such as NKEF, IGF-β, HSP70 and GP96, and the DGGE bands of fish treated jointly with OTC and SpPdp11 was observed in the PCA study. In summary, the results obtained in this study demonstrate that the administration of OTC results in the up-regulation of genes related to apoptosis but that the joint administration of OTC and S. putrefaciens Pdp11 increases the transcription of genes related to antiapoptotic effects and oxidative stress regulation. Further, a clear relationship between these changes and those detected in the intestinal microbiota is established.

Prevalence of Age-Related Macular Degeneration in Portugal: The Coimbra Eye Study - Report 1

PURPOSE

To evaluate the age- and gender-specific prevalence of early and late age-related macular degeneration (AMD) in a Portuguese population-based sample.

METHODS

All patients aged ≥55 years of a Portuguese primary health-care unit were recruited for a cross-sectional population-based study. Responders underwent complete ophthalmological examination and digital fundus imaging. Early and late AMD was defined according to the International Age-Related Macular Epidemiological Study Group Classification, and the adopted staging for AMD was the same as that used in the Rotterdam study. The age- and gender-adjusted prevalence of early and late forms of AMD was calculated.

RESULTS

Of the 4,370 eligible subjects, 3,000 underwent study procedures (68.6% response rate) and 2,975 were included in the analysis; they had a mean age of 68.9 ± 8.6 years. The overall prevalence of early and late AMD was 15.53% (95% CI 14.25-16.88) and 0.67% (95% CI 0.41-1.04), respectively. Neovascular AMD (NV-AMD) and geographic atrophy (GA) accounted for 0.44% (95% CI 0.23-0.75) and 0.27% (95% CI 0.12-0.53) of individuals, respectively. The highest prevalence of advanced AMD was among those aged ≥75 years (1.13% for NV-AMD; 0.63% for GA).

CONCLUSIONS

To our knowledge, this is the first AMD epidemiological study in a Portuguese population. The early forms of the disease had a similar prevalence to that of other large-scale population-based cohorts, but late AMD was less frequent than previously reported.

The treatment with the probiotic Shewanella putrefaciens Pdp11 of specimens of Solea senegalensis exposed to high stocking densities to enhance their resistance to disease

Aquaculture industry exposes fish to acute stress events, such as high stocking density, and a link between stress and higher susceptibility to diseases has been concluded. Several studies have demonstrated increased stress tolerance of fish treated with probiotics, but the mechanisms involved have not been elucidated. Shewanella putrefaciens Pdp11 is a strain isolated from healthy gilthead seabream (Sparus aurata L.) and it is considered as probiotics. The aim of this study was to evaluate the effect of the dietary administration of this probiotics on the stress tolerance of Solea senegalensis specimens farmed under high stocking density (PHD) compared to a group fed a commercial diet and farmed under the same conditions (CHD). In addition, during the experiment, a natural infectious outbreak due to Vibrio species affected fish farmed under crowding conditions. Changes in the microbiota and histology of intestine and in the transcription of immune response genes were evaluated at 19 and 30 days of the experiment. Mortality was observed after 9 days of the beginning of the experiment in CHD and PHD groups, it being higher in the CHD group. Fish farmed under crowding stress showed reduced expression of genes at 19 day probiotic feeding. On the contrary, a significant increase in immune related gene expression was detected in CHD fish at 30 day, whereas the gene expression in fish from PHD group was very similar to that showed in specimens fed and farmed with the conventional conditions. In addition, the dietary administration of S. putrefaciens Pdp11 produced an important modulation of the intestinal microbiota, which was significantly correlated with the high number of goblet cells detected in fish fed the probiotic diet.

Ocular fundus reference images from optical coherence tomography

Two-dimensional images computed from three-dimensional optical coherence tomography (OCT) data are intrinsically aligned with it, allowing to accurately position a retinal OCT scan within the ocular fundus. In this work, we aim to compute an OCT fundus reference image with improved retinal vasculature extension and contrast over traditional approaches. Based on the shadow casted by hemoglobin on the outer layers of the retina, we compute three independent images from the OCT volumetric data (including the traditional fundus reference image). Combining these images, a fourth one is created that is able to outperform the other three, both quantitatively and qualitatively (as evaluated by retina specialists). The vascular network extension provided by this method was also compared with widely used fundus imaging modalities, showing that it is similar to that achieved with color fundus photography. In this way, the proposed method is an important starting point to the segmentation of the vascular tree and provides users with a detailed fundus reference image.

Spin drag of a Fermi gas in a harmonic trap

Using a Boltzmann equation approach, we analyze how the spin drag of a trapped interacting fermionic mixture is influenced by the nonhomogeneity of the system in a classical regime where the temperature is much larger than the Fermi temperature. We show that for very elongated geometries, the spin damping rate can be related to the spin conductance of an infinitely long cylinder. We characterize analytically the spin conductance both in the hydrodynamic and collisionless limits and discuss the influence of the velocity profile. Our results are in good agreement with recent experiments and provide a quantitative benchmark for further studies of spin drag in ultracold gases.

Three different phenotypes of mild nonproliferative diabetic retinopathy with different risks for development of clinically significant macular edema

PURPOSE

To identify different phenotypes of nonproliferative diabetic retinopathy (NPDR) and their progression to clinically significant macular edema (CSME).

METHODS

A prospective observational study was designed to follow eyes/patients with diabetes type 2 and NPDR with no prior laser treatment for 2 years or until development of CSME. A total of 410 patients, one eye per patient, fulfilled the inclusion/exclusion criteria and were included in the study. Ophthalmological examinations, including BCVA, fundus photography with Retmarker analysis, and optical coherence tomography (OCT), were performed at baseline, month 6 and month 24, or before laser treatment. Hierarchical cluster analysis was used to identify homogeneous subgroups and clinically significant thresholds of the data collected.

RESULTS

A total of 376 eyes/patients performed the 6-month visit and were considered for cluster analysis. This mathematical method identified three different phenotypes based on statistically significant differences for the microaneurysm (MA) turnover and for the central retinal thickness (RT): phenotype A (low MA turnover and normal RT, 48.1%); phenotype B (low MA turnover and increased central RT, 23.2%); and phenotype C (high MA turnover, 28.7%). From the 348 eyes/patients that reached the study end point or completed the 24-month visit, 26 developed CSME: 3 from phenotype A (1.8%), 7 from phenotype B (8.5%), and 16 from phenotype C (16.2%). Eyes/patients from phenotype C showed a higher risk for CSME development (OR = 3.536; P < 0.001).

CONCLUSIONS

Hierarchical cluster analysis identifies three different phenotypes of NPDR based on MA turnover and central macular thickness. Eyes/patients from phenotype C show a higher risk for the development of CSME. (ClinicalTrials.gov number, NCT00763802.)

Subclinical Macular Edema as a Predictor of Progression to Clinically Significant Macular Edema in Type 2 Diabetes

<b><i>Objective:</i></b> To examine the relationship between subclinical diabetic macular edema (DME) and the development of clinically significant macular edema (CSME) in nonproliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes. <b><i>Methods:</i></b> A prospective, monocenter, observational study was designed to follow patients/eyes with type 2 diabetes and NPDR (Early Treatment Diabetic Retinopathy Study levels 20 and 35) with no prior laser treatment for 2 years or until development of CSME. Ophthalmologic examinations, including best-corrected visual acuity, fundus photography and optical coherence tomography (OCT), were performed at baseline, 6 months and a final visit. <b><i>Results:</i></b> A total of 348 patients completed study follow-up; 26 eyes developed CSME. Six out of 32 eyes/patients presenting subclinical DME at baseline developed CSME (18.7%), while 20 out of 316 eyes without subclinical DME developed CSME (6.3%). Eyes/patients with subclinical DME presented a risk for DME progression 3.686 times higher than that of eyes/patients without subclinical DME (95% confidence interval 1.221-7.988). <b><i>Conclusions:</i></b> Subclinical DME in eyes with NPDR identified by center point thickness measured on a Stratus OCT is a good predictor of CSME development.

Digital ocular fundus imaging: a review

Ocular fundus imaging plays a key role in monitoring the health status of the human eye. Currently, a large number of imaging modalities allow the assessment and/or quantification of ocular changes from a healthy status. This review focuses on the main digital fundus imaging modality, color fundus photography, with a brief overview of complementary techniques, such as fluorescein angiography. While focusing on two-dimensional color fundus photography, the authors address the evolution from nondigital to digital imaging and its impact on diagnosis. They also compare several studies performed along the transitional path of this technology. Retinal image processing and analysis, automated disease detection and identification of the stage of diabetic retinopathy (DR) are addressed as well. The authors emphasize the problems of image segmentation, focusing on the major landmark structures of the ocular fundus: the vascular network, optic disk and the fovea. Several proposed approaches for the automatic detection of signs of disease onset and progression, such as microaneurysms, are surveyed. A thorough comparison is conducted among different studies with regard to the number of eyes/subjects, imaging modality, fundus camera used, field of view and image resolution to identify the large variation in characteristics from one study to another. Similarly, the main features of the proposed classifications and algorithms for the automatic detection of DR are compared, thereby addressing computer-aided diagnosis and computer-aided detection for use in screening programs.