Characterization of central-involved diabetic macular edema using OCT and OCTA

PURPOSE

To characterize the occurrence of diabetic macular edema and the presence of abnormal retinal fluid accumulation in nonproliferative diabetic retinopathy (NPDR).

METHODS

In this two-year prospective study, a total of 122 eyes with diabetes type 2 underwent optical coherence tomography (OCT) and OCT-Angiography in association with OCT-Fluid imaging, a novel algorithm of OCT analysis allowing quantification of abnormal accumulation of fluid in the retina through low optical reflectivity ratios (LOR). Early Treatment Diabetic Retinopathy Study (ETDRS) grading for diabetic retinopathy (DR) severity assessment was performed using 7-field color fundus photography. Best corrected visual acuity was also recorded.

RESULTS

During the 2-year follow-up, 23 eyes (19%) developed central-involved diabetic macular edema (CI-DME) and 2 eyes (2%) developed clinically significant macular edema (CSME). In the two-year period of the study, eyes that developed CI-DME showed a progressive increase in central retinal thickness (CRT) (β = 7.7 ± 2.1 µm/year, p < 0.001) and in LOR values (β = 0.009 ± 0.004 ratio/year, p = 0.027). The increase in CRT and abnormal retinal fluid, represented by increased LOR ratios, are associated with increased retinal perfusion in the deep capillary plexus (DCP) (skeletonized vessel density, p = 0.039). In contrast, the eyes with CSME showed decreased retinal perfusion and abnormal fluid located in the outer layers of the retina.

CONCLUSIONS

CI-DME and CSME appear to represent different entities. Eyes with CI-DME show increases in abnormal retinal fluid associated with increased retinal vascular perfusion in the DCP. Eyes with CSME are apparently associated with decreased retinal vascular perfusion in the DCP and abnormal fluid in the outer retina.

The influence of personality on the quality of vision after multifocal intraocular lens implantation

OBJECTIVE

To assess the possible correlation between patients' personality traits and subjective perception of quality of vision (QoV), after multifocal intraocular lens (mIOL) implantation.

METHODS

patients who had bilateral implantation of a non-diffractive X-WAVE or a trifocal lens were assessed 6 months postoperatively. Patients answered the NEO-Five Factor Inventory (NEO-FFI-20) questionnaire ("Big Five five-factor personality model") to examine their personality. Six months following surgery, patients were asked to fill a QoV questionnaire where they graded the frequency of 10 common visual symptoms. Primary outcomes were to evaluate the correlation between personality scores and the reported frequency of visual disturbances.

RESULTS

The study comprised 20 patients submitted to bilateral cataract surgery, 10 with a non-diffractive X-WAVE lens (AcrySof® IQ Vivity) and 10 with a trifocal lens (AcrySof® IQ PanOptix). Mean age was 60.23 (7.06) years. Six months following surgery, patients with lower scores of conscientiousness and extroversion reported a higher frequency of visual disturbances (blurred vision, P  =  .015 and P  =  .009, seeing double images P  =  .018 and P  =  .006, and having difficulties focusing, P  =  .027 and P  =  .022, respectively). In addition, patients with high neuroticism scores had more difficulty focusing (P  =  .033).

CONCLUSIONS

In this study, personality traits such as low conscientiousness and extroversion and high neuroticism significantly influenced QoV perception 6 months after bilateral multifocal lens implantation. Patients' personality questionnaires could be a useful preoperative assessment test to a mIOL.

Retinal neurodegeneration in eyes with NPDR risk phenotypes: A two-year longitudinal study

INTRODUCTION

Diabetic retinopathy (DR) is both a microangiopathy and a neurodegenerative disease. However, the connections between both changes are not well known.

PURPOSE

To characterise the longitudinal retinal ganglion cell layer + inner plexiform layer (GCL + IPL) changes and their association with microvascular changes in type-2 diabetes (T2D) patients with nonproliferative diabetic retinopathy (NPDR).

METHODS

This two-year prospective study (CORDIS, NCT03696810) included 122 T2D individuals with NPDR identified as risk phenotypes B and C, which present a more rapid progression. Phenotype C was identified by decreased VD ≥ 2SD in healthy controls, and phenotype B, identified by subclinical macular oedema with only minimal vascular closure. The GCL + IPL thickness, vessel density, perfusion density and area of intercapillary spaces (AIS) were assessed by optical coherence tomography (OCT) and OCT angiography (OCTA). Linear mixed effects models were employed to evaluate the retinal GCL + IPL progression and its associations.

RESULTS

Regarding GCL + IPL thickness, T2D individuals presented on average 80.1 ± 7.49 μm, statistically significantly lower than the healthy control group, 82.5 ± 5.71 (p = 0.022), with only phenotype C differing significantly from controls (p = 0.006). GCL + IPL thickness steadily decreased during the two-year period in both risk phenotypes, with an annual decline rate of -0.372 μm/year (p < 0.001). Indeed, phenotype C showed a higher rate of progression (-0.459 μm/year, p < 0.001) when compared to phenotype B (-0.296 μm/year, p = 0.036). Eyes with ETDRS grade 20 showed GCL + IPL thickness values comparable to those of healthy control group (83.3 ± 5.80 and 82.7 ± 5.50 μm, respectively, p = 0.880), whereas there was a progressive decrease in GCL + IPL thickness in ETDRS grades 35 and 43-47 associated with the increase in severity of the retinopathy (-0.276 μm/year, p = 0.004; -0.585 μm/year, p = 0.013, respectively). Furthermore, the study showed statistically significant associations between the progressive thinning of GCL + IPL and the progressive increase in retinal capillary non-perfusion, with particular relevance for AIS (p < 0.001).

CONCLUSIONS

Our findings showed that, in eyes with NPDR and at risk for progression, retinal neurodegeneration occurs at different rates in different risk phenotypes, and it is associated with retinal microvascular non-perfusion.

Characterisation of progression of macular oedema in the initial stages of diabetic retinopathy: a 3-year longitudinal study

BACKGROUND/OBJECTIVES

To characterise the prevalence and three-year progression of centre-involving diabetic macular oedema (CI-DMO) in minimal to moderate non-proliferative diabetic retinopathy, using optical coherence tomography (OCT) and measurements of retinal fluid using tissue optical reflectivity ratios (OCT-Leakage).

METHODS/METHODS

Seventy-four eyes from 74 patients were followed in a 3-year prospective longitudinal observational cohort of type 2 diabetes (T2D) patients using spectral-domain optical coherence tomography (SD-OCT), OCT-Angiography (OCT-A) and OCT-Leakage (OCT-L). Eyes were examined four times with 1-year intervals. Sixteen eyes (17.8%) were excluded from the analysis due to quality control standards. Retinal oedema was measured by central retinal thickness and retinal fluid by using optical reflectivity ratios obtained with the OCT-L algorithm. Vessel density was measured by OCT-A. Thinning of the ganglion cell and inner plexiform layers (GCL + IPL) was examined to identify retinal neurodegenerative changes. Diabetic retinopathy ETDRS classification was performed using the seven-field ETDRS protocol.

RESULTS

CI-DMO was identified in the first visit in 9% of eyes in ETDRS groups 10-20, 10% of eyes in ETDRS group 35 and 15% of eyes in ETDRS groups 43-47. The eyes with CI-DMO and subclinical CI-DMO showed a progressive increase in retinal extracellular fluid during the 3-year period of follow-up. The eyes with CI-DMO and increased retinal extracellular fluid accumulation were associated with vision loss.

CONCLUSIONS

The prevalence of subclinical CI-DMO and CI-DMO in the initial stages of NPDR occurs independently of severity grading of the retinopathy, showing progressive increase in retinal extracellular fluid and this increase is associated with vision loss (82% 9 out of 11 cases).

Characterization of 2-Year Progression of Different Phenotypes of Nonproliferative Diabetic Retinopathy

INTRODUCTION

The aim of the study was to characterize the 2-year progression of risk phenotypes of nonproliferative diabetic retinopathy (NPDR) in type 2 diabetes (T2D) phenotype C, or ischemic phenotype, identified by decreased skeletonized retinal vessel density (VD), ≥2 SD over normal values, and phenotype B, or edema phenotype, identified by increased retinal thickness, i.e., subclinical macular edema, and no significant decrease in VD.

METHODS

A prospective longitudinal cohort study (CORDIS, NCT03696810) was conducted with 4 visits (baseline, 6 months, 1 year, and 2 years). Ophthalmological examinations included best-corrected visual acuity, color fundus photography (CFP), and optical coherence tomography (OCT) and OCT angiography. Early Treatment Diabetic Retinopathy Study grading was performed at the baseline and last visits based on 7-field CFP.

RESULTS

One hundred and twenty-two eyes from T2D individuals with NPDR fitted in the categories of phenotypes B and C and completed the 2-year follow-up. Sixty-five (53%) of the eyes were classified as phenotype B and 57 (47%) eyes as phenotype C. Neurodegeneration represented by thinning of the ganglion cell layer and inner plexiform layer was present in both phenotypes and showed significant progression over the 2-year period (p < 0.001). In phenotype C, significant progression in the 2-year period was identified in decreased skeletonized VD (p = 0.01), whereas in phenotype B microvascular changes involved preferentially decrease in perfusion density (PD, p = 0.012). Phenotype B with changes in VD and PD (flow) and preferential involvement of the deep capillary plexus (p < 0.001) is associated with development of center-involved macular edema.

DISCUSSION

In the 2-year period of follow-up, both phenotypes B and C showed progression in retinal neurodegeneration, with changes at the microvascular level characterized by decreases in PD in phenotype B and decreases in VD in phenotype C.

Association between neurodegeneration and macular perfusion in the progression of diabetic retinopathy. A 3-year longitudinal study

Objective and purpose: To explore the relation between retinal neurodegenerative changes and vessel closure (VC) in individuals with non-proliferative diabetic retinopathy (NPDR) in a follow-up period of 3 years.

DESIGN

3-year prospective longitudinal study with four annual visits.

PARTICIPANTS

74 individuals with type 2 diabetes, NPDR and ETDRS grades from 10 to 47, one eye/person. An age-matched healthy control population of 84 eyes was used as control group.

METHODS

Participants were annually examined by color fundus photography (CFP), spectral domain-optical coherence tomography (SD-OCT) and OCT-Angiography (OCTA). Vessel closure was assessed by OCTA vessel density maps. SD-OCT segmentations was performed to access central retinal thickness (CRT) and retinal neurodegeneration considered as thinning of the ganglion cell plus inner plexiform layer (GCL+IPL).

RESULTS

Type 2 diabetic individuals presented significantly higher CRT (p=0.001), GCL+IPL thinning (p=0.042), and decreased vessel density at the superficial capillary plexus (p<0.001) and full retina (p=0.001). When looking at changes occurring over the 3-year period of follow up (Table 2), there were statistically significant decreases in GCL+IPL thickness (-0.438 µm/year; p=0.038), foveal avascular zone circularity (-0.009; p=0.047), and vessel density, in superficial capillary plexus (-0.172 mm-1/year; p<0.001), deep capillary plexus (-0.350 mm-1/year; p<0.001) and full retina (-0.182 mm-1/year; p<0.001). A statistically significant association was identified between GCL+IPL thinning and decrease in deep capillary plexus vessel density (β = 0.196 [95% CI 0.037, 0.355], z = 2.410, p = 0.016), after controlling for age, gender, diabetes duration, hemoglobin A1c level, and CRT.

CONCLUSIONS

Retinal neurodegenerative changes show a steady progression during a 3-year period of follow-up in eyes with NPDR and appear to be directly associated with progression in decreased vessel density including vascular closure through preferential involvement of the deep capillary plexus. Our findings provide evidence that retinal neuropathy is linked with microvascular changes occurring in diabetic patients.

Retinal Neurodegeneration in Different Risk Phenotypes of Diabetic Retinal Disease

Diabetic retinopathy (DR) has been considered a microvascular disease, but it has become evident that neurodegeneration also plays a key role in this complex pathology. Indeed, this complexity is reflected in its progression which occurs at different rates in different type 2 diabetic (T2D) individuals. Based on this concept, our group has identified three DR progression phenotypes that might reflect the interindividual differences: phenotype A, characterized by low microaneurysm turnover (MAT <6), phenotype B, low MAT (<6) and increased central retinal thickness (CRT); and phenotype C, with high MAT (≥6). In this study, we evaluated the progression of DR neurodegeneration, considering ganglion cell+inner plexiform layers (GCL+IPL) thinning, in 170 T2D individuals followed for a period of 5 years, to explore associations with disease progression or risk phenotypes. Ophthalmological examinations were performed at baseline, first 6 months, and annually. GCL+IPL average thickness was evaluated by optical coherence tomography (OCT). Microaneurysm turnover (MAT) was evaluated using the RetMarkerDR. ETDRS level and severity progression were assessed in seven-field color fundus photography. In the overall population there was a significant loss in GCL+IPL (−0.147 μm/year), independently of glycated hemoglobin, age, sex, and duration of diabetes. Interestingly, this progressive thinning in GCL + IPL reached higher values in phenotypes B and C (−0.249 and −0.238 μm/year, respectively), whereas phenotype A remained relatively stable. The presence of neurodegeneration in all phenotypes suggests that it is the retinal vascular response to the early neurodegenerative changes that determines the course of the retinopathy in each individual. Therefore, classification of different DR phenotypes appears to offer relevant clarification of DR disease progression and an opportunity for improved management of each T2D individual with DR, thus playing a valuable role for the implementation of personalized medicine in DR.

Characterization of One-Year Progression of Risk Phenotypes of Diabetic Retinopathy

Introduction

We characterized the progression of different diabetic retinopathy (DR) phenotypes in type 2 diabetes (T2D).

Methods

A prospective longitudinal cohort study (CORDIS, NCT03696810) was conducted with three visits (baseline, 6 months, and 1 year). Demographic and systemic data included age, sex, diabetes duration, lipid profile, and hemoglobin A1c (HbA1c). Ophthalmological examinations included best-corrected visual acuity (BCVA), color fundus photography (CFP), and optical coherence tomography (OCT and OCTA). Phenotype classification was performed at the 6-month visit based on microaneurysm turnover (MAT, on CFP) and central retinal thickness (CRT, on OCT). Only risk phenotypes B (MAT < 6 and increased CRT) and C (MAT ≥ 6 with or without increased CRT) were included. ETDRS grading was performed at the baseline visit based on seven-field CFP.

Results

A total of 133 T2D individuals were included in the study; 81 (60%) eyes were classified as phenotype B and 52 (40%) eyes as phenotype C. Of these, 128 completed the 1-year follow-up. At baseline, eyes with phenotype C showed greater capillary closure (superior capillary plexus, deep capillary plexus, and full retina, p < 0.001) and increased foveal avascular zone (FAZ) area (p < 0.001), indicating more advanced microvascular disease. Neurodegeneration represented by thinning of the ganglion cell layer + inner plexiform layer (GCL + IPL) was present in both phenotypes. When analyzing the 1-year progression of each phenotype, only phenotype C revealed a significant decrease in BCVA (p = 0.02) and enlargement of the FAZ (p = 0.03). A significant progressive decrease in the vessel density of the deep capillary layer and in MAT occurred in both phenotypes, but these changes were particularly relevant in phenotype C and ETDRS grades 43–47. During the 1-year period, both phenotypes B and C showed progression in GCL + IPL thinning (p < 0.001).

Conclusions

In the 1-year period of follow-up, both phenotypes B and C showed progression in retinal neurodegeneration, whereas phenotype C showed more marked disease progression at the microvascular level.

Microaneurysm Turnover in Mild Non-Proliferative Diabetic Retinopathy is Associated with Progression and Development of Vision-Threatening Complications: A 5-Year Longitudinal Study

Background: Analysis of retinal microaneurysm turnover (MAT) has been previously shown to contribute to the identification of eyes at risk of developing clinically significant complications associated with diabetic retinopathy (DR). We propose to further characterize MAT as a predictive biomarker of DR progression and development of vision-threatening complications. Methods: 212 individuals with type 2 diabetes (T2D; ETDRS grades 20 and 35) were evaluated annually in a 5-year prospective, longitudinal study, by color fundus photography and optical coherence tomography. Endpoints were diabetic macular edema (DME) or proliferative retinopathy (PDR). MAT analysis included determination of MA formation and disappearance rates, automatically assessed using the RetMarkerDR^®. Retinopathy severity progression was evaluated using step increases in ETDRS severity levels. Results: Of the 212 individuals, 172 completed the 5-year follow-up study or developed an endpoint (n = 27). MAT calculated at 1 year showed a significant difference between groups of endpoint developments (p = 0.018), particularly MA disappearance rate (p = 0.007). MAT also showed a significant difference between eyes with different ETDRS severity progression in the 5-year period (p = 0.035). Conclusions: MAT is an indicator of the development of DME and/or PDR as well as of DR severity progression in T2D individuals with mild retinopathy.

A Comparison of Intraocular Lens Power Calculation Formulas in High Myopia

PURPOSE

To comparatively evaluate the accuracy of newer intraocular lens (IOL) calculation formulas and common third-generation formulas after Wang-Koch adjustment in the prediction of postoperative refraction in highly myopic eyes.

METHODS

This was a retrospective study including eyes with high myopia that had uncomplicated cataract surgery with implantation of an AcrySof MA60MA IOL (power range: -5.00 to +5.00 diopters [D]) (Alcon Laboratories, Inc). All patients underwent optical biometry (Carl Zeiss IOLMaster 500 and IOLMaster 700, and Allegro Biograph) and the postoperative spherical equivalent for the implanted IOL was estimated using SRK/T, Holladay 1 (both Wang-Koch adjusted), Haigis, Barrett Universal II, Kane, Ladas, and Hill-RBF v2.0 formulas. Outcomes included the median absolute prediction error (MedAE) and the proportion of eyes within ±0.25, ±0.50, and ±1.00 D of the preoperative prediction.

RESULTS

Eighty-two eyes with a mean axial length of 30.89 ± 1.85 mm were included. The MedAE in ascending order was Hill-RBF v2.0 0.31 D, Kane 0.33 D, Barrett 0.36 D, Holladay I_wk 0.37 D, SRK/T_wk 0.37 D, Holladay I_wk 0.43 D, Haigis_ULIB 0.54 D, and Ladas 0.61 D. The formula with the lowest MedAE (Hill-RBF v2.0) yielded a prediction error within ±0.25, ±0.50, and ±1.00 D in 43.1%, 70.6%, and 94.1% of cases, respectively.

CONCLUSIONS

Recent formulas such as Barrett Universal II, Kane, and Hill-RBF v2.0 and Wang-Koch adjusted formulas perform well in this subset of patients with high myopia. The Hill-RBF v2.0 formula had the lowest MedAE and highest proportion of eyes within ±0.25, ±0.50, and ±1.00 D of the predicted target. [J Refract Surg. 2021;37(3):207-211.].

Characterization of Disease Progression in the Initial Stages of Retinopathy in Type 2 Diabetes: A 2-Year Longitudinal Study

Purpose

To characterize 2-year changes occurring in neurodegeneration, edema, and capillary dropout in nonproliferative diabetic retinopathy.

Methods

Two-year prospective longitudinal observational cohort of eyes/patients with type 2 diabetes using spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA). Eyes were examined three times with intervals of 1 year. Thickness of the full retina and layer-by-layer measurements were used to identify edema or neurodegeneration. OCTA vessel density maps of the retina were used to identify capillary dropout. Early Treatment Diabetic Retinopathy Study (ETDRS) classification was performed using the seven-field ETDRS protocol.

Results

A total of 62 eyes from 62 patients with diabetes were followed for 2 years. After verification for image quality, a total of 44 eyes from 44 patients (30% women) aged 52 to 80 years were retained for data analysis. There were 18 eyes with ETDRS grades 10 to 20, 17 eyes with ETDRS grade 35, and 9 eyes with ETDRS grades 43 to 47. During the 2-year follow-up period, there was a progressive increase in capillary dropout, whereas edema and neurodegeneration remained stable. In multivariate analysis, considering a model adjusted for age, sex, hemoglobin A1C, visual acuity, and diabetes duration, vessel density remained significantly different between Diabetic Retinopathy Severity Scale groups (Wilks' λ = 0.707; P = 0.015) showing association with disease progression.

Conclusions

Capillary dropout increased in a period of 2 years in eyes with minimal, mild, and moderate diabetic retinopathy, whereas the presence of edema and neurodegeneration remained stable.

Comparison of the Petrifilm Dry Rehydratable Film and Conventional Culture Methods for Enumeration of Yeasts and Molds in Foods: Collaborative Study

A collaborative study was performed involving 18 laboratories and 6 food types to compare 3M Petrifilm yeast and mold count plates with the method described in the U.S. Food and Drug Administration’s Bacteriological Analytical Manual. Four species of mold and 2 species of yeast were used to inoculate the following foods: hot dogs, corn meal, ketchup, orange juice, yogurt, and cake mix. Each collaborator received 15 samples of each food type: 5 low-level inoculations, 5 high- level inoculations, and 5 uninoculated samples. There was no significant difference between the means of the 2 methods for any product or inoculation level. The Petrifilm yeast and mold count plate method for enumeration of yeasts and molds in foods has been adopted first action by AOAC INTERNATIONAL.

Characterization of Initial Stages of Diabetic Macular Edema

PURPOSE

This study is aimed at characterizing the type of retinal edema in the initial stages of retinopathy in type 2 diabetes.

METHODS

In this retrospective cross-sectional study, spectral domain optical coherence tomography (OCT) layer by layer analysis of the retina in association with OCT-Leakage, an algorithm to detect sites of low optical reflectivity, were used to examine eyes with minimal, mild, and moderate diabetic retinopathy (DR).

RESULTS

A total of 142 eyes from 142 patients (28% women) aged 52-88 years were imaged. Macular edema, either subclinical (SCME) or central-involved macular edema (CIME), was present in 43% of eyes in group 10-20, 41% of eyes in group 35, and 38% of eyes in group 43-47. The inner nuclear layer (INL) was the layer showing higher and most frequent increases in retinal thickness (79%). The edema was predominantly intracellular in group 10-20 (65%) and extracellular in groups 35 (77%) and 43-47 (69%).

CONCLUSIONS

Eyes from diabetic patients in the initial stages of DR with different Early Treatment Diabetic Retinopathy Study gradings show similar prevalence of SCME and CIME, independent of the severity of the retinopathy. Retinal edema is located mainly in the INL and appears to be mostly extracellular except in the earliest stages of diabetic retinal disease where intracellular edema predominates.

Multimodal Imaging of the Initial Stages of Diabetic Retinopathy: Different Disease Pathways in Different Patients

The objective of this study was to evaluate the prevalence of different disease pathways (ischemia, neurodegeneration, and edema) in the initial stages of diabetic retinopathy. In this retrospective cross-sectional study, eyes were grouped by diabetic retinopathy severity using the 7-field Early Treatment Diabetic Retinopathy Study (ETDRS) protocol (levels 10-20, 35, and 43-47). Neurodegeneration was identified by thinning of the retinal nerve fiber layer and/or ganglion cell layer. Edema was identified by thickening of the inner nuclear layer, outer plexiform layer, or full retina. Ischemia was identified by metrics of retinal vessel density. Imaging was performed in 142 eyes from 142 patients (28% women) aged 52-88 years. Vessel density (ischemia) was significantly different between the ETDRS groups (P < 0.020). On multivariate regression analysis, it remained significantly different between stages of the disease and showed associations with age (P < 0.001), sex (P = 0.028), and metabolic control (P = 0.034). No significant differences between ETDRS groups were found in retinal thinning (neurodegeneration) or retinal thickness (edema). Eyes with the same ETDRS retinopathy grading from different patients with diabetes showed that the prevalence of different disease pathways varies between patients, even within the same severity group. Ischemia (capillary dropout) is the only disease pathway that shows correlation with retinopathy severity and metabolic control.

Large-scale opacification of a hydrophilic/hydrophobic intraocular lens

PURPOSE

To determine the prevalence and risk factors related to the opacification of the LS-502-1 intraocular lens.

METHODS

Cross-sectional study including patients submitted to cataract surgery between January 2010 and March 2012, with implantation of the LS-502-1 intraocular lens. Past medical history was registered and a complete ophthalmologic evaluation, that included best-corrected visual acuity, slit-lamp examination and fundoscopy, was performed. Anterior segment photographs were taken whenever intraocular lens opacification was present.

RESULTS

One hundred and sixty-nine eyes of 154 patients were included, mean age 78.5 ± 7.9 years. The average follow-up after intraocular lens implantation was 65.6 ± 10.0 months. Intraocular lens opacification was seen in 53.3% (n = 90) and presented as one of four different patterns: peripheral (15.6%, n = 14), central (4.4%, n = 4), diffuse (71.1%, n = 64) and superficial white deposits (8.9%, n = 8). There was no statistically significant association with systemic or ophthalmic conditions. In patients with bilateral implantation, intraocular lens opacification in one eye was significantly related to intraocular lens opacification in the fellow eye. A significant variability in opacification was found across intraocular lens serial numbers: the odds ratio for opacification in intraocular lens with serial number beginning with 200003 was 6.0 when comparing with the remaining lenses.

CONCLUSION

The opacification prevalence of the LS-502-1 intraocular lens was 53.3%, which is the highest ever described for any intraocular lens model. Our results suggest that this occurrence is secondary to an interaction between unknown patient variables and problems related to intraocular lens manufacturing and storage procedures.

Effects of Topically Administered Neuroprotective Drugs in Early Stages of Diabetic Retinopathy: Results of the EUROCONDOR Clinical Trial

The primary objective of this study was to assess whether the topical administration of two neuroprotective drugs (brimonidine and somatostatin) could prevent or arrest retinal neurodysfunction in patients with type 2 diabetes. For this purpose, adults aged between 45 and 75 years with a diabetes duration ≥5 years and an Early Treatment of Diabetic Retinopathy Study (ETDRS) level of ≤35 were randomly assigned to one of three arms: placebo, somatostatin, or brimonidine. The primary outcome was the change in implicit time (IT) assessed by multifocal electroretinography between baseline and at the end of follow-up (96 weeks). There were 449 eligible patients allocated to brimonidine (n = 152), somatostatin (n = 145), or placebo (n = 152). When the primary end point was evaluated in the whole population, we did not find any neuroprotective effect of brimonidine or somatostatin. However, in the subset of patients (34.7%) with preexisting retinal neurodysfunction, IT worsened in the placebo group (P < 0.001) but remained unchanged in the brimonidine and somatostatin groups. In conclusion, the topical administration of the selected neuroprotective agents appears useful in preventing the worsening of preexisting retinal neurodysfunction. This finding points to screening retinal neurodysfunction as a critical issue to identify a subset of patients in whom neuroprotective treatment might be of benefit.

Late postoperative opacification of a hydrophilic-hydrophobic acrylic intraocular lens

PURPOSE

To report late postoperative opacification of a model of hydrophilic-hydrophobic acrylic intraocular lens (IOL) as well as the clinical consequences and laboratory characteristics.

SETTING

Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

DESIGN

Retrospective case series.

METHODS

Medical records were reviewed of patients with Lentis LS-502-1 IOL opacification reporting visual loss who had IOL explantation between November 2013 and March 2015. Patients were identified in the emergency room or during regular follow-up visits. Explanted IOLs were analyzed at the Ophthalmic Explants Biobank, Vissum, Spain, or at the John A. Moran Eye Center, University of Utah, USA.

RESULTS

Twenty opacified IOLs were explanted from 19 patients. The mean interval between cataract surgery and diagnosis of opacification was 29.15 months ± 9.57 (SD) (range 6 to 45 months). Opacification led to a statistically significant reduction in corrected distance visual acuity (mean 0.86 ± 0.76 logMAR; P < .001) and occurred in 5.1% of the hydrophilic-hydrophobic acrylic IOLs implanted at the department. The most frequently associated medical conditions were arterial hypertension, diabetes, and glaucoma. All IOLs but 1 had a similar pattern of opacification, with yellowish diffuse opacification uniformly distributed and calcium deposits on the surface and/or subsurface of the optic and haptics and within the IOL material.

CONCLUSIONS

Opacification of the hydrophilic-hydrophobic acrylic IOL was found in a significant number of patients and had a significant effect on their vision. The opacification was attributed to primary calcification.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Microaneurysm turnover is a predictor of diabetic retinopathy progression

Aim

To analyse retinopathy phenotypes and microaneurysm (MA) turnover in mild non-proliferative diabetic retinopathy (NPDR) as predictors of progression to diabetic central-involved macular oedema (CIMO) in patients with type 2 diabetes mellitus (DM) in two different ethnic populations.

Methods

205 patients with type 2 DM and mild NPDR were followed in a prospective observational study for 2 years or until development of CIMO, in two centres from different regions of the world. Ophthalmological examinations, including best-corrected visual acuity (BCVA), fundus photography with RetmarkerDR analysis, and optical coherence tomography (OCT), were performed at baseline and 6 12 and 24 months.

Results

158 eyes/patients reached either the study endpoint, CIMO (24) or performed the last study visit (24-month visit) without developing CIMO (134). From the eyes/patients in analysis, 27 eyes (17.1%) progressed to more advanced ETDRS (Early Treatment Diabetic Retinopathy Study) levels: 6 progressed to mild NPDR (level 35), 15 progressed to moderate NPDR (level 43), 5 progressed to moderately severe NPDR (level 47) and 1 progressed to high risk PDR (level 71). Worsening in ETDRS level is associated with phenotype C (p=0.005). From the 130 eyes/patients with a low MA turnover, 18 (13.8%) eyes/patients had an increase in ETDRS level, and from the 19 eyes/patients with a high MA turnover, 9 (47.4%) had an increase in ETDRS level (p<0.001).

Conclusion

Eyes in the initial stages of diabetic retinopathy show different phenotypes with different risks for progression to CIMO. In phenotype C, MA turnover correlates with ETDRS grading worsening and development of CIMO.

Subclinical Macular Edema as a Predictor of Progression to Central-Involved Macular Edema in Type 2 Diabetes

PURPOSE

The aim of this study was to examine the relationship between subclinical diabetic macular edema (SCME) and the development of central-involved macular edema (CIME) in patients with diabetes mellitus type-2 and mild nonproliferative diabetic retinopathy (NPDR), from 2 populations of different ethnicities.

METHODS

Two hundred and five patients with diabetes mellitus type-2 and mild NPDR with no prior laser or intravitreal treatment were followed for 2 years or until the development of CIME. Ophthalmological examinations, including BCVA, fundus photography with RetmarkerDR analysis, and optical coherence tomography were performed at baseline and months 6, 12, and 24.

RESULTS

One hundred and fifty eight eyes/patients reached either the study endpoint, CIME (n = 24), or performed the 24-month visit without developing CIME (n = 134). Fifty eyes/patients had SCME at baseline (31.6%). Of these 50 eyes, 16 (32.0%) developed CIME, whereas of the 108 eyes with normal retinal thickness (RT) at baseline, only 8 (7.4%) developed CIME (p < 0.001). Patients with increased RT in the central subfield at baseline showed a 12-fold risk of progression to CIME compared with patients without SCME.

CONCLUSIONS

In patients with mild NPDR, the presence of SCME is a good predictor of progression to CIME.

Ranibizumab Plus Panretinal Photocoagulation versus Panretinal Photocoagulation Alone for High-Risk Proliferative Diabetic Retinopathy (PROTEUS Study)

PURPOSE

Comparison of the efficacy of ranibizumab (RBZ) 0.5 mg intravitreal injections plus panretinal photocoagulation (PRP) versus PRP alone in the regression of the neovascularization (NV) area in subjects with high-risk proliferative diabetic retinopathy (HR-PDR) over a 12-month period.

DESIGN

Prospective, randomized, multicenter, open-label, phase II/III study.

PARTICIPANTS

Eighty-seven participants (aged ≥18 years) with type 1/2 diabetes and HR-PDR (mean age, 55.2 years; 37% were female).

METHODS

Participants were randomized (1:1) to receive RBZ+PRP (n = 41) or PRP monotherapy (n = 46). The RBZ+PRP group received 3 monthly RBZ injections along with standard PRP. The PRP monotherapy group received standard PRP between day 1 and month 2; thereafter, re-treatments in both groups were at the investigators' discretion.

MAIN OUTCOME MEASURES

The primary outcome was regression of NV total, on the disc (NVD) plus elsewhere (NVE), defined as any decrease in the area of NV from the baseline to month 12. Secondary outcomes included best-corrected visual acuity (BCVA) changes from baseline to month 12, time to complete NV regression, recurrence of NV, macular retinal thickness changes from baseline to month 12, need for treatment for diabetic macular edema, need for vitrectomy because of occurrence of vitreous hemorrhage, tractional retinal detachment or other complications of DR, and adverse events (AEs) related to treatments.

RESULTS

Seventy-seven participants (88.5%) completed the study. Overall baseline demographics were similar for both groups, except for age. At month 12, 92.7% of participants in the RBZ+PRP group presented NV total reduction versus 70.5% of the PRP monotherapy participants (P = 0.009). The number of participants with NVD and NVE reductions was higher with RBZ+PRP (93.3% and 91.4%, respectively) versus PRP (68.8% and 73.7%, respectively), significant only for NVE (P = 0.048). Complete NV total regression was observed in 43.9% in the RBZ+PRP group versus 25.0% in the PRP monotherapy group (P = 0.066). At month 12, the mean BCVA was 75.2 letters (20/32) in the RBZ+PRP group versus 69.2 letters (20/40) in the PRP monotherapy group (P = 0.104). In the RBZ+PRP group, the mean number of PRP treatments over month 12 was 3.5±1.3, whereas in the PRP monotherapy group, it was 4.6±1.5 (P = 0.001). No deaths or unexpected AEs were reported.

CONCLUSIONS

Treatment with RBZ+PRP was more effective than PRP monotherapy for NV regression in HR-PDR participants over 12 months.

Different Phenotypes of Mild Nonproliferative Diabetic Retinopathy with Different Risks for Development of Macular Edema (C-TRACER Study)

PURPOSE

To evaluate diabetic retinopathy (DR) progression in patients with diabetes mellitus type 2 in 2 populations of different ethnicity.

METHODS

A prospective observational study was designed to follow eyes/patients with mild nonproliferative DR, for 2 years or until the development of central-involved macular edema (CIME), in 2 centers from different regions of the world. A total of 205 eyes/patients fulfilled the inclusion/exclusion criteria and were included in this study. Ophthalmological examinations, fundus photography with RetmarkerDR analysis, and optical coherence tomography were performed at baseline and at 6, 12 and 24 months.

RESULTS

Of the 158 eyes/patients that completed this study, 24 eyes developed CIME and 134 eyes were present at the last study visit. Eighty-eight eyes (56.4%) were classified as phenotype A, 49 (31.4%) as phenotype B, and 19 (12.2%) as phenotype C. Phenotype A is associated with a very low risk for development of CIME in comparison with phenotypes B and C. The OR for development of CIME was 19.0 for phenotype B and 25.1 for phenotype C.

CONCLUSION

Eyes in the initial stages of DR show different phenotypes with different risks of progression to ME. The phenotypes associated with increased risks of progression show different distributions in patients of different ethnicities.

Transcription of immune related genes in Solea senegalensis vaccinated against Photobacterium damselae subsp. piscicida. Identification of surrogates of protection

Solea senegalensis is a flatfish with a great potential for aquaculture, but infectious diseases restrict its production, being this fish species highly susceptible to Photobacterium damselae subsp. piscicida (Phdp) infections. A better understanding of the mechanisms related to fish immune response is crucial for the development of effective approaches in disease management. In the present work, transcriptional changes of immune related genes have been evaluated in farmed S. senegalensis specimens vaccinated against Phdp by intraperitoneal injection (IP) and immersion (IM). IP fish showed higher antibody levels and increased transcription of genes encoding lysozyme C1, complement factors involved in the classical pathway and components involved in the opsonization and the limitation of free iron availability, all of them facilitating the faster elimination of the pathogen and promoting higher RPS after the infection with Phdp. The results of this study seem to support a different intensity of the specimens immune response in the head kidney. Analysis of the immune response in 15 day post-challenged fish showed up-regulation of genes involved in all stages of S. senegalensis immune response, but especially those genes encoding proteins related to the innate response such as complement, lysozyme and iron homeostasis in the head kidney. On the other hand, liver transcription was higher for genes related to inflammation, apoptosis and cell mediated cytotoxicity (CMC). Furthermore, comparison of the differential response of S. senegalensis genes in vaccinated and unvaccinated fish to Phdp infection allowed the identification of a potential biosignature, consisting in 10 genes, as a surrogate of protection and therefore, as indicator of vaccine success against fotobacteriosis after IP vaccination. These results provide important insights into the S. senegalensis protection against Phdp induced by vaccination.

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.

Noninvasive Evaluation of Retinal Leakage Using Optical Coherence Tomography

<i>Purpose:</i> To demonstrate the association between changes in the blood-retinal barrier (BRB) identified by fluorescein leakage and those in the optical properties of the human retina determined by optical coherence tomography (OCT) and show how these changes can be quantified and their location identified within the retina. <i>Methods:</i> Two imaging techniques were applied: the retinal leakage analyzer, to map BRB function into intact or disrupted regions, and OCT, to measure refractive index changes along the light path within the human ocular fundus. <i>Results:</i> A total of 140 comparisons were made, 77 between areas of regions receiving the same classification (intact or disrupted BRB) and 63 between areas of regions receiving distinct classifications, from 4 pathological cases: 2 eyes with nonproliferative diabetic retinopathy and 2 eyes with wet age-related macular degeneration. In all cases, the distribution of OCT data between regions of intact and regions of disrupted BRB, identified by the retinal leakage analyzer, was quantified and was statistically significantly different (p < 0.001). In addition, it was found that the differences could be localized in the retina to specific structural sequences. <i>Conclusions:</i> Using a novel method to analyze OCT data, we showed that it may be possible to quantify differences in the extracellular compartment in eyes with retinal disease and alterations of the BRB. Based on quantitative techniques, our findings demonstrate the presence of indirect information on the BRB status within noninvasive OCT data.