ASSESSMENT OF FLUORESCEIN ANGIOGRAPHY NONPERFUSION IN EYES WITH DIABETIC RETINOPATHY USING ULTRAWIDE FIELD RETINAL IMAGING.

PURPOSE: Evaluate association of retinal nonperfusion (NP) on ultrawide field (UWF) fluorescein angiography (FA) with diabetic retinopathy (DR) severity and predominantly peripheral lesions (PPL). METHODS: Multicenter observational study, 652 eyes (361 participants) having nonproliferative DR (NPDR) without center-involved diabetic macular edema in at least one eye. Baseline 200° UWF-color and UWF-FA images were graded by a central reading center for color-PPL and FA-PPL, respectively. UWF-FA was graded for NP index within concentric zones: posterior pole (<10 mm from fovea), midperiphery (10-15 mm), and far periphery (>15 mm). RESULTS: Baseline Early Treatment Diabetic Retinopathy Study DR severity was 31.7% no DR/mild NPDR, 24.1% moderate NPDR, 14.0% moderately severe NPDR, 25.6% severe/very severe NPDR, and 4.6% proliferative DR. Worse DR severity was associated with increased NP index overall (P = 0.002), in the posterior pole (P < 0.001), midperiphery (P < 0.001), and far periphery (P = 0.03). On average, 29.6% of imaged retinal NP was in the posterior pole, 33.7% in midperiphery, and 36.7% in far periphery. Increased NP index was associated with FA-PPL (P < 0.001) but not with color-PPL (P = 0.65). CONCLUSION: Approximately, 70% of NP in diabetic eyes is located outside the posterior pole. Increased NP is associated with the presence of FA-PPL, suggesting UWF-FA may better predict future DR worsening than UWF-color alone.

Guidelines on Diabetic Eye Care: The International Council of Ophthalmology Recommendations for Screening, Follow-up, Referral, and Treatment Based on Resource Settings.

Diabetes mellitus (DM) is a global epidemic and affects populations in both developing and developed countries, with differing health care and resource levels. Diabetic retinopathy (DR) is a major complication of DM and a leading cause of vision loss in working middle-aged adults. Vision loss from DR can be prevented with broad-level public health strategies, but these need to be tailored to a country's and population's resource setting. Designing DR screening programs, with appropriate and timely referral to facilities with trained eye care professionals, and using cost-effective treatment for vision-threatening levels of DR can prevent vision loss. The International Council of Ophthalmology Guidelines for Diabetic Eye Care 2017 summarize and offer a comprehensive guide for DR screening, referral and follow-up schedules for DR, and appropriate management of vision-threatening DR, including diabetic macular edema (DME) and proliferative DR, for countries with high- and low- or intermediate-resource settings. The guidelines include updated evidence on screening and referral criteria, the minimum requirements for a screening vision and retinal examination, follow-up care, and management of DR and DME, including laser photocoagulation and appropriate use of intravitreal anti-vascular endothelial growth factor inhibitors and, in specific situations, intravitreal corticosteroids. Recommendations for management of DR in patients during pregnancy and with concomitant cataract also are included. The guidelines offer suggestions for monitoring outcomes and indicators of success at a population level.

Visual outcomes from pars plana vitrectomy versus combined pars plana vitrectomy, phacoemulsification, and intraocular lens implantation in patients with diabetes.

PURPOSE: To compare visual acuity outcomes and diabetic retinopathy progression after pars plana vitrectomy (PPV) versus combined pars plana vitrectomy and phacoemulsification (PPVCE) in patients with diabetes. METHODS: Retrospective review of 222 consecutive diabetic patients undergoing PPV or PPVCE. RESULTS: A total of 251 eyes of 222 patients were evaluated (PPV = 122, PPVCE = 129). Four-year follow-up was 64% (161 eyes). Overall, patients undergoing PPVCE had better preoperative visual acuity (PPVCE = 20/80, PPV = 20/160, P = 0.03). At 4-year follow-up, visual acuity improved (PPV = +22, PPVCE = +11 letters) compared with baseline in both groups. After correcting for baseline differences in visual acuity, no statistically significant difference in final visual acuity was observed (PPVCE = 20/32, PPV = 20/50, P = 0.09). Results did not differ substantially by surgical indication (vitreous hemorrhage, traction retinal detachment, epiretinal membrane, and/or diabetic macular edema). Cataract progression occurred in 64%, and cataract surgery was performed in 39% of phakic eyes undergoing PPV. Rates of diabetic retinopathy progression, vitreous hemorrhage, and retinal detachment were not statistically different. Neovascular glaucoma developed in 2 patients (2%) after PPV and 6 patients (8%) after PPVCE (P = 0.07). CONCLUSION: In diabetic patients, equivalent visual acuity improvement over 4 years was observed after PPV or PPVCE. Visual outcomes and retinopathy progression rates were not significantly different after either intervention, suggesting that PPVCE may be appropriate when indicated in patients with diabetes.

Intensive Glycemic Management Is Associated With Reduced Retinal Structure Abnormalities on Ocular Coherence Tomography in the DCCT/EDIC Study.

OBJECTIVE: To investigate quantitative and qualitative changes in retinal structure using optical coherence tomography (OCT) and their associations with systemic or other risk factors in individuals with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: In the Epidemiology of Diabetes Interventions and Complications (EDIC) study, OCT images were obtained during study years 25-28 (2019-2022) in 937 participants; 54% and 46% were from the original intensive (INT) and conventional (CONV) glycemic management treatment groups, respectively. RESULTS: Average age for participants was 61 years old, diabetes duration 39 years, and HbA1c 7.6%. Participants originally in the CONV group were more likely to have disorganization of retinal inner layers (DRIL) (CONV 27.3% vs. INT 18.7%; P = 0.0003), intraretinal fluid (CONV 24.4% vs. INT 19.2%; P = 0.0222), and intraretinal cysts (CONV 20.8% vs. INT 16.6%; P = 0.0471). In multivariable models, sex, age, smoking, mean updated systolic blood pressure, and history of "clinically significant" macular edema (CSME) and of anti-VEGF treatment were independently associated with changes in central subfield thickness, while HbA1c, BMI, and history of CSME and of ocular surgery were associated with DRIL. Visual acuity (VA) decline was associated with significant thinning of all retinal subfields except for the central and inner nasal subfields. CONCLUSIONS: Early intensive glycemic management in T1D is associated with a decreased risk of DRIL. This important morphological abnormality was associated with a history of macular edema, a history of ocular surgery, and worse VA. This study reveals benefits of intensive glycemic management on the retina beyond features detected by fundus photographs and ophthalmoscopy.

Green or yellow laser treatment for diabetic macular edema: exploratory assessment within the Diabetic Retinopathy Clinical Research Network.

PURPOSE: Explore differences in green compared with yellow focal/grid laser treatment on functional and anatomical endpoints in eyes with diabetic macular edema. METHODS: Data from two randomized clinical trials were evaluated for differences in visual acuity and optical coherence tomography parameters for eyes assigned to sham injection + prompt laser, ranibizumab + prompt laser, or prompt laser only: among subgroups of eyes treated exclusively and electively with either green or yellow laser. RESULTS: In the sham injection + prompt laser group, the mean visual acuity letter score change for eyes receiving green and yellow laser treatment, respectively, was +2.4 ± 14 and +5.1 ± 13 at the 52-week visit (P = 0.06) and +2.4 ± 15 and +6.0 ± 13 at the 104-week visit (P = 0.13), with no corresponding evidence of differences in optical coherence tomography thickness. When comparing wavelength groups in the ranibizumab + prompt laser and prompt laser-only groups, meaningful differences in visual acuity and optical coherence tomography thickness were not detected at 1 year or 2 years. CONCLUSION: A trend toward improved vision outcome with yellow laser observed in one trial was not corroborated by anatomical outcomes or by the other trial. In this study, without random assignment to different wavelengths controlling for bias and confounding, it is not possible to determine whether one wavelength is better than the other.

Bias and Non-Diversity of Big Data in Artificial Intelligence: Focus on Retinal Diseases.

Artificial intelligence (AI) applications in healthcare will have a potentially far-reaching impact on patient care, however issues regarding algorithmic bias and fairness have recently surfaced. There is a recognized lack of diversity in the available ophthalmic datasets, with 45% of the global population having no readily accessible representative images, leading to potential misrepresentations of their unique anatomic features and ocular pathology. AI applications in retinal disease may show less accuracy with underrepresented populations that may further widen the gap of health inequality if left unaddressed. Beyond disease symptomatology, social determinants of health must be integrated into our current paradigms of disease understanding, with the goal of more personalized care. AI has the potential to decrease global healthcare inequality, but it will need to be based on a more diverse, transparent and responsible use of healthcare data.

Relationships Between the Cumulative Incidences of Long-term Complications in Type 1 Diabetes: The DCCT/EDIC Study.

OBJECTIVE: To describe the relationships between the cumulative incidences of long-term complications in individuals with type 1 diabetes (T1D) and assess whether observed associations are independent of age, duration of diabetes, and glycemic levels. METHODS: Proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), reduced estimated glomerular filtration rate (eGFR), amputations, cardiovascular disease (CVD), and mortality were assessed in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study over ∼30 years. RESEARCH DESIGN AND RESULTS: The cumulative incidence of complications ranged from 3% (amputations) to 37% (CSME). There were large differences in the cumulative incidence of PDR between participants with versus without prior CSME (66% vs. 15%), reduced eGFR (59% vs. 29%), and amputation (68% vs. 32%); reduced eGFR with or without prior PDR (25% vs. 9%), amputation (48% vs. 13%), and CVD (30% vs. 11%); CVD with or without prior reduced eGFR (37% vs. 14%) and amputation (50% vs. 16%); and mortality with or without prior reduced eGFR (22% vs. 9%), amputation (35% vs. 8%), and CVD (25% vs. 8%). Adjusted for age, duration of T1D, and mean updated HbA1c, the complications and associations with higher risk included PDR with CSME (hazard ratio [HR] 1.88; 95% CI 1.42, 2.50), reduced eGFR (HR 1.41; 95% CI 1.01, 1.97), and CVD (HR 1.43; 95% CI 1.06, 1.92); CSME with higher risk of PDR (HR 3.94; 95% CI 3.18 4.89), reduced eGFR (HR 1.49; 95% CI 1.10, 2.01), and CVD (HR 1.35; 95% CI 1.03, 1.78); reduced eGFR with higher risk of CVD (HR 2.09; 95% CI 1.44, 3.03), and death (HR 3.40; 95% CI 2.35, 4.92); amputation(s) with death (HR 2.97; 95% CI 1.70, 2.90); and CVD with reduced eGFR (HR 1.59; 95% CI 1.08, 2.34) and death (HR 1.95; 95% CI 1.32, 2.90). CONCLUSIONS: Long-term micro- and macrovascular complications and mortality are highly correlated. Age, diabetes duration, and glycemic levels do not completely explain these associations.

Retinopathy During the First 5 Years of Type 1 Diabetes and Subsequent Risk of Advanced Retinopathy.

OBJECTIVE: To determine whether individuals with type 1 diabetes (T1D) who develop any retinopathy at any time prior to 5 years of diabetes duration have an increased subsequent risk for further progression of retinopathy or onset of proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), diabetes-related retinal photocoagulation, or anti-vascular endothelial growth factor injections. Additionally, to determine the influence of HbA1c and other risk factors in these individuals. RESEARCH DESIGN AND METHODS: Diabetic retinopathy (DR) was assessed longitudinally using standardized stereoscopic seven-field fundus photography at time intervals of 6 months to 4 years. Early-onset DR (EDR) was defined as onset prior to 5 years of T1D duration. Cox models assessed the associations of EDR with subsequent risk of outcomes. RESULTS: In unadjusted models, individuals with EDR (n = 484) had an increased subsequent risk of PDR (hazard ratio [HR] 1.51 [95% CI 1.12, 2.02], P = 0.006), CSME (HR 1.44 [1.10, 1.88], P = 0.008), and diabetes-related retinal photocoagulation (HR 1.48 [1.12, 1.96], P = 0.006) compared with individuals without EDR (n = 369). These associations remained significant when adjusted for HbA1c, but only the association with PDR remained significant after adjustment for age, duration of T1D, HbA1c, sex, systolic/diastolic blood pressure, pulse, use of ACE inhibitors, albumin excretion rate, and estimated glomerular filtration rate (HR 1.47 [95% CI 1.04, 2.06], P = 0.028). CONCLUSIONS: These data suggest that individuals with any sign of retinopathy within the first 5 years of T1D onset may be at higher risk of long-term development of advanced DR, especially PDR. Identification of early-onset DR may influence prognosis and help guide therapeutic management to reduce the risk of future visual loss in these individuals.

Elevated Retinol Binding Protein 3 Concentrations Are Associated With Decreased Vitreous Inflammatory Cytokines, VEGF, and Progression of Diabetic Retinopathy.

OBJECTIVE: To correlate inflammatory cytokines and vascular endothelial growth factor (VEGF) in vitreous and plasma with vitreous retinol binding protein 3 (RBP3), diabetic retinopathy (DR) severity, and DR worsening in a population with type 1 and type 2 diabetes. RESEARCH DESIGN AND METHODS: RBP3, VEGF, and inflammatory cytokines were measured in plasma and vitreous samples (n = 205) from subjects of the Joslin Medalist Study and Beetham Eye Institute. RESULTS: Higher vitreous RBP3 concentrations were associated with less severe DR (P < 0.0001) and a reduced risk of developing proliferative DR (PDR) (P < 0.0001). Higher RBP3 correlated with increased photoreceptor segment thickness and lower vitreous interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α), and TNF-ß (P < 0.05). PDR was associated with lower vitreous interferon-γ and IL-10 and higher VEGF, IL-6, and IL-15 (P < 0.05), but was not associated with their plasma concentrations. CONCLUSIONS: Higher vitreous RBP3 concentrations are associated with less severe DR and slower rates of progression to PDR, supporting its potential as a biomarker and therapeutic agent for preventing DR worsening, possibly by lowering retinal VEGF and inflammatory cytokines.

A Randomized Trial of Photobiomodulation Therapy for Center-Involved Diabetic Macular Edema with Good Visual Acuity (Protocol AE).

PURPOSE: To determine if treatment with a photobiomodulation (PBM) device results in greater improvement in central subfield thickness (CST) than placebo in eyes with center-involved diabetic macular edema (CI-DME) and good vision. DESIGN: Phase 2 randomized clinical trial. PARTICIPANTS: Participants had CI-DME and visual acuity (VA) 20/25 or better in the study eye and were recruited from 23 clinical sites in the United States. METHODS: One eye of each participant was randomly assigned 1:1 to a 670-nm light-emitting PBM eye patch or an identical device emitting broad-spectrum white light at low power. Treatment was applied for 90 seconds twice daily for 4 months. MAIN OUTCOME MEASURES: Change in CST on spectral-domain OCT at 4 months. RESULTS: From April 2019 to February 2020, 135 adults were randomly assigned to either PBM (n = 69) or placebo (n = 66); median age was 62 years, 37% were women, and 82% were White. The median device compliance was 92% with PBM and 95% with placebo. OCT CST increased from baseline to 4 months by a mean (SD) of 13 (53) µm in PBM eyes and 15 (57) µm in placebo eyes, with the mean difference (95% confidence interval [CI]) being -2 (-20 to 16) µm (P = 0.84). CI-DME, based on DRCR Retina Network sex- and machine-based thresholds, was present in 61 (90%) PBM eyes and 57 (86%) placebo eyes at 4 months (adjusted odds ratio [95% CI] = 1.30 (0.44-3.83); P = 0.63). VA decreased by a mean (SD) of -0.2 (5.5) letters and -0.6 (4.6) letters in the PBM and placebo groups, respectively (difference [95% CI] = 0.4 (-1.3 to 2.0) letters; P = 0.64). There were 8 adverse events possibly related to the PBM device and 2 adverse events possibly related to the placebo device. None were serious. CONCLUSIONS: PBM as given in this study, although safe and well-tolerated, was not found to be effective for the treatment of CI-DME in eyes with good vision.

Randomized trial evaluating short-term effects of intravitreal ranibizumab or triamcinolone acetonide on macular edema after focal/grid laser for diabetic macular edema in eyes also receiving panretinal photocoagulation.

PURPOSE: To evaluate 14-week effects of intravitreal ranibizumab or triamcinolone in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation. METHODS: Three hundred and forty-five eyes with a visual acuity of 20/320 or better, center-involved diabetic macular edema receiving focal/grid laser, and diabetic retinopathy receiving prompt panretinal photocoagulation were randomly assigned to sham (n = 123), 0.5-mg ranibizumab (n = 113) at baseline and 4 weeks, and 4-mg triamcinolone at baseline and sham at 4 weeks (n = 109). Treatment was at investigator discretion from 14 weeks to 56 weeks. RESULTS: Mean changes (±SD) in visual acuity letter score from baseline were significantly better in the ranibizumab (+1 ± 11; P < 0.001) and triamcinolone (+2 ± 11; P < 0.001) groups compared with those in the sham group (-4 ± 14) at the 14-week visit, mirroring retinal thickening results. These differences were not maintained when study participants were followed for 56 weeks for safety outcomes. One eye (0.9%; 95% confidence interval, 0.02%-4.7%) developed endophthalmitis after receiving ranibizumab. Cerebrovascular/cardiovascular events occurred in 4%, 7%, and 3% of the sham, ranibizumab, and triamcinolone groups, respectively. CONCLUSION: The addition of 1 intravitreal triamcinolone injection or 2 intravitreal ranibizumab injections in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation is associated with better visual acuity and decreased macular edema by 14 weeks. Whether continued long-term intravitreal treatment is beneficial cannot be determined from this study.

Association of Cognitive Function and Retinal Neural and Vascular Structure in Type 1 Diabetes.

CONTEXT: Cognitive dysfunction is a growing and understudied public health issue in the aging type 1 diabetic population and is difficult and time-consuming to diagnose. Studies in long duration type 1 diabetes have reported the presence of proliferative diabetic retinopathy was associated with cognitive dysfunction. OBJECTIVE: This study assessed whether structural and vascular abnormalities of the retina, representing an extension of the central nervous system, are associated with cognitive impairment and other complications of type 1 diabetes. METHODS: An observational cross-sectional study of individuals with 50 or more years of type 1 diabetes (Joslin Medalist Study) was conducted at a university hospital in the United States. The study included 129 participants with complete cognitive testing. Validated cognitive testing measures included psychomotor speed, and immediate, and delayed memory. Optical coherence tomography (OCT) and OCT angiography (OCTA) were performed to obtain neural retinal layer thicknesses and vascular density for superficial (SCP) and deep retinal capillary plexus (DCP). Multivariable modeling was adjusted for potential confounders associated with outcomes in unadjusted analyses. RESULTS: Decreased vessel density of the SCP and DCP was associated with worse delayed memory (DCP: P = .002) and dominant hand psychomotor speed (SCP: P = .01). Thinning of the retinal outer nuclear layer was associated with worse psychomotor speed both in nondominant and dominant hands (P = .01 and P = .05, respectively). Outer plexiform layer thickness was associated with delayed memory (P = .04). CONCLUSION: These findings suggest that noninvasive retinal imaging using OCT and OCTA may assist in estimating the risks for cognitive dysfunction in people with type 1 diabetes.

Associations of Microvascular Complications With the Risk of Cardiovascular Disease in Type 1 Diabetes.

OBJECTIVE: We examined whether the presence of microvascular complications was associated with increased subsequent risk of cardiovascular disease (CVD) among participants with type 1 diabetes in the Diabetes Control and Complications Trial and Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study followed for >35 years. RESEARCH DESIGN AND METHODS: Standardized longitudinal data collection included: 1) stereoscopic seven-field retinal fundus photography centrally graded for retinopathy stage and clinically significant macular edema; 2) urinary albumin excretion rate (AER) and estimated glomerular filtration rate (eGFR); 3) cardiovascular autonomic neuropathy (CAN) reflex testing; and 4) adjudicated CVD events, including death from CVD, nonfatal myocardial infarction, stroke, subclinical myocardial infarction on electrocardiogram, confirmed angina, or coronary artery revascularization. Cox proportional hazards models assessed the association of microvascular complications with subsequent risk of CVD. RESULTS: A total of 239 participants developed CVD, including 120 participants who suffered major adverse cardiovascular events (MACE) defined as nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. The presence of microvascular disease (diabetic retinopathy, kidney disease, or CAN) was associated with increased risk of subsequent CVD and MACE (hazard ratios 1.86 to 3.18 and 2.09 to 3.63, respectively), associations that remained significant after adjusting for age and HbA1c. After adjustment for traditional CVD risk factors, however, only sustained AER ≥30 mg/24 h occurring alone and/or with eGFR <60 mL/min/1.73 m2 and the presence of both retinal and kidney disease remained associated with CVD. CONCLUSIONS: Advanced microvascular disease, especially moderate to severe albuminuria or eGFR <60 mL/min/1.73 m2, conveyed an increased risk of subsequent cardiovascular disease in the DCCT/EDIC cohort.

Quantitative Assessment of the Severity of Diabetic Retinopathy.

PURPOSE: To determine whether a quantitative approach to assessment of the severity of diabetic retinopathy (DR) lesions on ultrawide field (UWF) images can provide new parameters to predict progression to proliferative diabetic retinopathy (PDR). METHODS: One hundred forty six eyes from 73 participants with DR and 4 years of follow-up data were included in this post hoc analysis, which was based on a cohort of 100 diabetic patients enrolled in a previously published prospective, comparative study of UWF imaging at the Joslin Diabetes Center. Diabetic Retinopathy Severity Score level was determined at baseline and 4-year follow-up visits using mydriatic 7-standard field Early Treatment Diabetic Retinopathy Study (ETDRS) photographs. All individual DR lesions (hemorrhage [H], microaneurysm [ma], cotton wool spot [CWS], intraretinal microvascular abnormality [IRMA]) were manually segmented on stereographic projected UWF. For each lesion type, the frequency/number, surface area, and distances from the optic nerve head (ONH) were computed. These quantitative parameters were compared between eyes that progressed to PDR in 4 years and eyes that did not progress. Univariable and multivariable logistic regression analyses were performed to identify parameters that were associated with an increased risk for progression to PDR. RESULTS: A total of 146 eyes of 73 subjects were included in the final analysis. The mean age of the study cohort was 53.1 years, and 42 (56.8%) subjects were female. The number and surface area of H/ma's and CWSs were significantly (P ≤ .05) higher in eyes that progressed to PDR compared with eyes that did not progress by 4 years. Similarly, H/ma's and CWSs were located further away from the ONH (ie, more peripheral) in eyes that progressed (P < .05). DR lesion parameters that conferred a statistically significant increased risk for proliferative diabetic retinopathy in the multivariate model included hemorrhage area (odds ratio [OR], 2.63; 95% confidence interval [CI], 1.25-5.53), and greater distance of hemorrhages from the ONH (OR, 1.24; 95% CI, 0.97-1.59). CONCLUSIONS: Quantitative analysis of DR lesions on UWF images identifies new risk parameters for progression to PDR including the surface area of hemorrhages and the distance of hemorrhages from the ONH. Although these risk factors will need to be confirmed in larger, prospective studies, they highlight the potential for quantitative lesion analysis to inform the design of a more precise and complete staging system for diabetic retinopathy severity in the future. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Risk Factors for Retinopathy in Type 1 Diabetes: The DCCT/EDIC Study.

OBJECTIVE: The Diabetes Control and Complications Trial (DCCT) demonstrated that intensive therapy reduced the development and progression of retinopathy in type 1 diabetes (T1D) compared with conventional therapy. The Epidemiology of Diabetes Interventions and Complications (EDIC) study observational follow-up showed persistent benefits. In addition to glycemia, we now examine other potential retinopathy risk factors (modifiable and nonmodifiable) over more than 30 years of follow-up in DCCT/EDIC. RESEARCH DESIGN AND METHODS: The retinopathy outcomes were proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), and ocular surgery. The survival (event-free) probability was estimated using the Kaplan-Meier method. Cox proportional hazards models assessed the association between risk factors and subsequent risk of retinopathy. Both forward- and backward-selection approaches determined the multivariable models. RESULTS: Rate of ocular events per 1,000 person-years was 12 for PDR, 14.5 for CSME, and 7.6 for ocular surgeries. Approximately 65%, 60%, and 70% of participants remained free of PDR, CSME, and ocular surgery, respectively. The greatest risk factors for PDR in descending order were higher mean HbA1c, longer duration of T1D, elevated albumin excretion rate (AER), and higher mean diastolic blood pressure (DBP). For CSME, risk factors, in descending order, were higher mean HbA1c, longer duration of T1D, and greater age and DBP and, for ocular surgeries, were higher mean HbA1c, older age, and longer duration of T1D. CONCLUSIONS: Mean HbA1c was the strongest risk factor for the progression of retinopathy. Although glycemic control is important, elevated AER and DBP were other modifiable risk factors associated with the progression of retinopathy.

Optical coherence tomography measurements and analysis methods in optical coherence tomography studies of diabetic macular edema.

OBJECTIVE: To evaluate optical coherence tomography (OCT) measurements and methods of analysis of OCT data in studies of diabetic macular edema (DME). DESIGN: Associations of pairs of OCT variables and results of 3 analysis methods using data from 2 studies of DME. PARTICIPANTS: Two hundred sixty-three subjects from a study of modified Early Treatment of Diabetic Retinopathy Study (mETDRS) versus modified macular grid (MMG) photocoagulation for DME and 96 subjects from a study of diurnal variation of DME. METHODS: Correlations were calculated for pairs of OCT variables at baseline and for changes in the variables over time. Distribution of OCT measurement changes, predictive factors for OCT measurement changes, and treatment group outcomes were compared when 3 measures of change in macular thickness were analyzed: absolute change in retinal thickness, relative change in retinal thickness, and relative change in retinal thickening. MAIN OUTCOME MEASURES: Concordance of results using different OCT variables and analysis methods. RESULTS: Center point thickness correlated highly with central subfield mean thickness (CSMT) at baseline (0.98-0.99). The distributions of changes in CSMT were approximately normally distributed for absolute change in retinal thickness and relative change in retinal thickness, but not for relative change in retinal thickening. Macular thinning in the mETDRS group was significantly greater than in the MMG group when absolute change in retinal thickness was used, but not when relative change in thickness and relative change in thickening were used. Relative change in macular thickening provides unstable data in eyes with mild degrees of baseline thickening, unlike the situation with absolute or relative change in retinal thickness. CONCLUSIONS: Central subfield mean thickness is the preferred OCT measurement for the central macula because of its higher reproducibility and correlation with other measurements of the central macula. Total macular volume may be preferred when the central macula is less important. Absolute change in retinal thickness is the preferred analysis method in studies involving eyes with mild macular thickening. Relative change in thickening may be preferable when retinal thickening is more severe.

Estimation of Diabetic Retinal Microaneurysm Perfusion Parameters Based on Computational Fluid Dynamics Modeling of Adaptive Optics Scanning Laser Ophthalmoscopy.

Diabetic retinopathy (DR) is a leading cause of vision loss worldwide. Microaneurysms (MAs), which are abnormal outpouchings of the retinal vessels, are early and hallmark lesions of DR. The presence and severity of MAs are utilized to determine overall DR severity. In addition, MAs can directly contribute to retinal neural pathology by leaking fluid into the surrounding retina, causing abnormal central retinal thickening and thereby frequently leading to vision loss. Vascular perfusion parameters such as shear rate (SR) or wall shear stress (WSS) have been linked to blood clotting and endothelial cell dysfunction, respectively in non-retinal vasculature. However, despite the importance of MAs as a key aspect of diabetic retinal pathology, much remains unknown as to how structural characteristics of individual MAs are associated with these perfusion attributes. MA structural information obtained on high resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) was utilized to estimate perfusion parameters through Computational Fluid Dynamics (CFD) analysis of the AOSLO images. The HemeLB flow solver was used to simulate steady-state and time-dependent fluid flow using both commodity hospital-based and high performance computing resources, depending on the degree of detail required in the simulations. Our results indicate that WSS is lowest in MA regions furthest away from the feeding vessels. Furthermore, areas of low SR are associated with clot location in saccular MAs. These findings suggest that morphology and CFD estimation of perfusion parameters may be useful tools for determining the likelihood of clot presence in individual diabetic MAs.

Adipose-specific effect of rosiglitazone on vascular permeability and protein kinase C activation: novel mechanism for PPARgamma agonist's effects on edema and weight gain.

PPARgamma agonists, thiazolidinediones, cause fluid retention and edema due to unknown mechanisms. We characterized the effect of rosiglitazone (RSG), a thiazolidinedione, to induce vascular permeability, vascular endothelial growth factor (VEGF) expression, and protein kinase C (PKC) activation with edema and wt gain. In lean, fatty and diabetic Zucker rats, and endothelial insulin receptor knockout mice, RSG increased wt and vascular permeability, selectively in fat and retina, but not in heart or skeletal muscle. H2O content and wt of epididymal fat were increased by RSG and correlated to increases in capillary permeability in fat and body wt. RSG induced VEGF mRNA expression and PKC activation in fat and retina up to 2.5-fold. Ruboxistaurin, a PKCbeta isoform inhibitor, in the latter 2 wk of a 4-wk study, normalized vascular permeability in fat and decreased total wt gain, H2O content, and wt of fat vs. RSG alone but did not decrease VEGF expression, basal permeability, or food intake. Finally, RSG did not increase wt or vascular permeability in PKCbeta knockout vs. control mice. Thus, thiazolidinedione's effects on edema and wt are partially due to an adipose tissue-selective activation of PKC and vascular permeability that may be prevented by PKCbeta inhibition.

A phase II randomized double-masked trial of pegaptanib, an anti-vascular endothelial growth factor aptamer, for diabetic macular edema.

OBJECTIVE: To evaluate the safety and efficacy of pegaptanib sodium injection (pegaptanib) in the treatment of diabetic macular edema (DME). DESIGN: Randomized, double-masked, multicenter, dose-ranging, controlled trial. PARTICIPANTS: Individuals with a best-corrected visual acuity (VA) between 20/50 and 20/320 in the study eye and DME involving the center of the macula for whom the investigator judged photocoagulation could be safely withheld for 16 weeks. INTERVENTION: Intravitreous pegaptanib (0.3 mg, 1 mg, 3 mg) or sham injections at study entry, week 6, and week 12 with additional injections and/or focal photocoagulation as needed for another 18 weeks. Final assessments were conducted at week 36. MAIN OUTCOME MEASURES: Best-corrected VA, central retinal thickness at the center point of the central subfield as assessed by optical coherence tomography measurement, and additional therapy with photocoagulation between weeks 12 and 36. RESULTS: One hundred seventy-two patients appeared balanced for baseline demographic and ocular characteristics. Median VA was better at week 36 with 0.3 mg (20/50), as compared with sham (20/63) (P = 0.04). A larger proportion of those receiving 0.3 mg gained VAs of > or =10 letters (approximately 2 lines) (34% vs. 10%, P = 0.003) and > or =15 letters (18% vs. 7%, P = 0.12). Mean central retinal thickness decreased by 68 microm with 0.3 mg, versus an increase of 4 microm with sham (P = 0.02). Larger proportions of those receiving 0.3 mg had an absolute decrease of both > or =100 microm (42% vs. 16%, P = 0.02) and > or =75 microm (49% vs. 19%, P = 0.008). Photocoagulation was deemed necessary in fewer subjects in each pegaptanib arm (0.3 mg vs. sham, 25% vs. 48%; P = 0.04). All pegaptanib doses were well tolerated. Endophthalmitis occurred in 1 of 652 injections (0.15%/injection; i.e., 1/130 [0.8%] pegaptanib subjects) and was not associated with severe visual loss. CONCLUSIONS: In this phase II trial, subjects assigned to pegaptanib had better VA outcomes, were more likely to show reduction in central retinal thickness, and were deemed less likely to need additional therapy with photocoagulation at follow-up.