Diabetic Eye Disease

Wu M, Yu Z, Matar DY, Karvar M, Chen Z, Ng B, Aoki S, Haug V, Orgill DP, Panayi AC. Human Amniotic Membrane Promotes Angiogenesis in an Oxidative Stress Chronic Diabetic Murine Wound Model. Adv Wound Care (New Rochelle) 2022;Abstract
Objective: The development of animal models, which adequately replicate the pathophysiology of chronic wounds, has been challenging. In this study, we utilized an oxidative stress (OS) murine model, which was previously developed by our group, to study the effect of a human amniotic membrane (AM) on chronic wound healing. Approach: Forty-five diabetic (genetically obese leptin receptor-deficient mice [db/db]) mice were separated into three groups. Thirty mice received an OS regimen and a 1 - × 1 cm2 full-thickness excisional dorsal wound. The wounds were either covered with AM and occlusive dressing (db/dbOS-AM) or occlusive dressing only (db/dbOS). Fifteen mice did not receive the OS regimen, and were covered with AM and occlusive dressing (db/db-AM). The wounds were photographed, and tissue was harvested at various time points. Results: Vascular density was higher in the AM-treated groups (db/dbOS-AM: 34 ± 12; db/db-AM: 37 ± 14; vs. db/dbOS: 19 ± 9 cluster of differentiation 31 [CD31+]/high power field [HPF] photograph; p = 0.04 and p = 0.003). Vessel maturity was lowest in the db/dbOS group (21% ± 4%; vs. db/dbOS-AM: 38% ± 10%, p = 0.004; db/db-AM: 40% ± 11%, p = 0.0005). Leukocyte infiltration was higher in the AM groups (db/dbOS-AM: 15 ± 4; db/db-AM: 16 ± 4 vs. db/dbOS: 8 ± 3 lymphocyte common antigen [CD45+]/HPF; p = 0.005 and p = 0.06). AM upregulated various proangiogenic factors, including vascular endothelial growth factor (VEGF), and downregulated genes involved in chronicity, such as osteopontin, as visualized through proteome analysis and western blotting. Cell death was lower in the AM groups (db/dbOS-AM: 28 ± 10, db/db-AM: 7 ± 5 vs. db/dbOS: 17% ± 9% Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling [TUNEL+]; p = 0.03 and p < 0.0001). Innovation: This study offers new insight on the mechanisms of action of human AM in chronic wound healing. Conclusion: AM treatment promoted healing in mice with complex chronic wounds. The AM stimulated angiogenesis through upregulation of proangiogenic factors, improving the wound milieu by increasing leukocyte and growth factor delivery and decreasing cell death.
Ofuji Y, Katada Y, Tomita Y, Nagai N, Sonobe H, Watanabe K, Shinoda H, Ozawa Y, Negishi K, Tsubota K, Kurihara T. Non-Perfusion Area Index for Prognostic Prediction in Diabetic Retinopathy. Life (Basel) 2022;12(4)Abstract
Fundus fluorescent angiography is a standard examination in Japan that can directly visualize the circulatory failure in diabetic retinopathy but is not used in Western countries. In this study, we examine the relationship between the non-perfusion area in fundus fluorescent angiography and the progression of diabetic retinopathy. We evaluated 22 eyes between 22 patients who had their first fundus fluorescent angiography during a clinical episode at Keio University Hospital from January 2012 to May 2015, were diagnosed as having preproliferative diabetic retinopathy, and could be followed for at least three years. The non-perfusion area index (%) in nine segmented fundi in the initial fundus fluorescent angiography was calculated, and the progression to proliferative diabetic retinopathy over three years was evaluated. Three out of the 22 eyes (13.6%) developed proliferative diabetic retinopathy over three years. The non-perfusion area index for the initial fundus fluorescent angiography was significantly associated with progression to proliferative diabetic retinopathy. The non-perfusion area index in the posterior pole was most strongly correlated with the progression to proliferative diabetic retinopathy. Thus, the non-perfusion area index in the posterior pole among those with preproliferative diabetic retinopathy may predict the progression to proliferative diabetic retinopathy in the subsequent three years.
Salongcay RP, Aquino LAC, Salva CMG, Saunar AV, Alog GP, Sun JK, Peto T, Silva PS. Comparison of Handheld Retinal Imaging with ETDRS 7-Standard Field Photography for Diabetic Retinopathy and Diabetic Macular Edema. Ophthalmol Retina 2022;6(7):548-556.Abstract
PURPOSE: To compare nonmydriatic (NM) and mydriatic (MD) handheld retinal imaging with standard ETDRS 7-field color fundus photography (ETDRS photographs) for the assessment of diabetic retinopathy (DR) and diabetic macular edema (DME). DESIGN: Prospective, comparative, instrument validation study. SUBJECTS: A total of 225 eyes from 116 patients with diabetes mellitus. METHODS: Following a standardized protocol, NM and MD images were acquired using handheld retinal cameras (NM images: Aurora, Smartscope, and RetinaVue-700; MD images: Aurora, Smartscope, RetinaVue-700, and iNview) and dilated ETDRS photographs. Grading was performed at a centralized reading center using the International Clinical Classification for DR and DME. Kappa statistics (simple [K], weighted [Kw]) assessed the level of agreement for DR and DME. Sensitivity and specificity were calculated for any DR, referable DR (refDR), and vision-threatening DR (vtDR). MAIN OUTCOME MEASURES: Agreement for DR and DME; sensitivity and specificity for any DR, refDR, and vtDR; ungradable rates. RESULTS: Severity by ETDRS photographs: no DR, 33.3%; mild nonproliferative DR, 20.4%; moderate DR, 14.2%; severe DR, 11.6%; proliferative DR, 20.4%; no DME, 68.0%; DME, 9.3%; non-center involving clinically significant DME, 4.9%; center-involving clinically significant DME, 12.4%; and ungradable, 5.3%. For NM handheld retinal imaging, Kw was 0.70 to 0.73 for DR and 0.76 to 0.83 for DME. For MD handheld retinal imaging, Kw was 0.68 to 0.75 for DR and 0.77 to 0.91 for DME. Thresholds for sensitivity (0.80) and specificity (0.95) were met by NM images acquired using Smartscope and MD images acquired using Aurora and RetinaVue-700 cameras for any DR and by MD images acquired using Aurora and RetinaVue-700 cameras for refDR. Thresholds for sensitivity and specificity were met by MD images acquired using Aurora and RetinaVue-700 for DME. Nonmydriatic and MD ungradable rates for DR were 15.1% to 38.3% and 0% to 33.8%, respectively. CONCLUSIONS: Following standardized protocols, NM and MD handheld retinal imaging devices have substantial agreement levels for DR and DME. With mydriasis, not all handheld retinal imaging devices meet standards for sensitivity and specificity in identifying any DR and refDR. None of the handheld devices met the established 95% specificity for vtDR, suggesting that lower referral thresholds should be used if handheld devices must be utilized. When using handheld devices, the ungradable rate is significantly reduced with mydriasis and DME sensitivity thresholds are only achieved following dilation.
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.
Yang L, Xiao A, Li Q-Y, Zhong H-F, Su T, Shi W-Q, Ying P, Liang R-B, Xu S-H, Shao Y, Zhou Q. Hyperintensities of middle frontal gyrus in patients with diabetic optic neuropathy: a dynamic amplitude of low-frequency fluctuation study. Aging (Albany NY) 2022;14(3):1336-1350.Abstract
Diabetic optic neuropathy (DON) is a diverse complication of diabetes and its pathogenesis has not been fully elucidated. The purpose of this study was to explore dynamic cerebral activity changes in DON patients using dynamic amplitude of low-frequency fluctuation (dALFF). In total, 22 DON patients and 22 healthy controls were enrolled. The dALFF approach was used in all participants to investigate dynamic intrinsic brain activity differences between the two groups. Compared with HCs, DON patients exhibited significantly increased dALFF variability in the right middle frontal gyrus (P < 0.01). Conversely, DON patients exhibited obviously decreased dALFF variability in the right precuneus (P < 0.01). We also found that there were significant negative correlations between HADS scores and dALFF values of the right middle frontal gyrus in the DON patients (r = -0.6404, P <0.01 for anxiety and r = -0.6346, P <0.01 for depression; HADS, Hospital Anxiety and Depression Scale). Abnormal variability of dALFF was observed in specific areas of the cerebrum in DON patients, which may contribute to distinguishing patients with DON from HCs and a better understanding of DON, hyperintensities of right middle frontal gyrus may be potential diagnostic marker for DON.
Jacoba CMP, Ashraf M, Cavallerano JD, Tolson AM, Tolls D, Pellegrini E, Fleming A, Sun JK, Aiello LP, Silva PS. Association of Maximizing Visible Retinal Area by Manual Eyelid Lifting With Grading of Diabetic Retinopathy Severity and Detection of Predominantly Peripheral Lesions When Using Ultra-Widefield Imaging. JAMA Ophthalmol 2022;140(4):421-425.Abstract
Importance: Methods that increase visible retinal area (VRA; measured in millimeters squared) may improve identification of diabetic retinopathy (DR) lesions. Objective: To evaluate the association of dilation and manual eyelid lifting (MLL) with VRA on ultra-widefield imaging (UWFI) and the association of VRA with grading of DR severity and detection of predominantly peripheral lesions (PPLs). Design, Setting, and Participants: Retrospective, comparative case-control study at the Joslin Diabetes Center, Boston, Massachusetts. Nonmydriatic UWFI with MLL was acquired from a DR teleophthalmology program (Joslin Vision Network [JVN]). A second cohort of mydriatic UWFI was acquired at an academic retina practice (Beetham Eye Institute [BEI]) from November 6, 2017, to November 6, 2018, and with MLL thereafter until November 6, 2019. Fully automated algorithms determined VRA and hemorrhage and/or microaneurysm (HMA) counts. Predominantly peripheral lesions and HMAs were defined as present when at least 1 field had greater HMA number in the peripheral retina than within the corresponding Early Treatment Diabetic Retinopathy Study field. Participants included 3014 consecutive patients (5919 eyes) undergoing retinal imaging at JVN and BEI. Exposures: Dilation and MLL performed at the time of UWFI. Main Outcomes and Measures: Visible retinal area, DR severity, and presence of PPLs. Results: Of the 3014 participants, mean (SD) age was 56.1 (14.5) years, 1302 (43.2%) were female, 2450 (81.3%) were White, and mean (SD) diabetes duration was 15.9 (11.4) years. All images from 5919 eyes with UWFI were analyzed. Mean (SD) VRA was 665.1 (167.6) mm2 for all eyes (theoretical maximal VRA, 923.9 mm2), 550.8 (240.7) mm2 for nonmydriatic JVN with MLL (1418 eyes [24.0%]), 688.1 (119.9) mm2 for mydriatic BEI images (3650 eyes [61.7%]), and 757.0 (69.7) mm2 for mydriatic and MLL BEI images (851 eyes [14.4%]). Dilation increased VRA by 25% (P < .001) and MLL increased VRA an additional 10% (P < .001). Nonmydriatic MLL increased VRA by 11.0%. With MLL, HMA counts in UWFI fields increased by 41.7% (from 4.8 to 6.8; P < .001). Visible retinal area was moderately associated with increasing PPL-HMA overall and in each cohort (all, r = 0.33; BEI, r = 0.29; JVN, r = 0.36; P < .001). In JVN images, increasing VRA was associated with more PPL-HMA (quartile 1 [Q1], 23.7%; Q2, 45.8%; Q3, 60.6%; and Q4, 69.2%; P < .001). Conclusions and Relevance: Using fully automated VRA and HMA detection algorithms, pupillary dilation and eyelid lifting were shown to substantially increase VRA and PLL-HMA detection. Given the importance of HMA and PPL for determining risk of DR progression, these findings emphasize the importance of maximizing VRA for optimal risk assessment in clinical trials and teleophthalmology programs.
Schreur V, Larsen MB, Sobrin L, Bhavsar AR, den Hollander AI, Klevering JB, Hoyng CB, de Jong EK, Grauslund J, Peto T. Imaging diabetic retinal disease: clinical imaging requirements. Acta Ophthalmol 2022;Abstract
Diabetic retinopathy (DR) is a sight-threatening complication of diabetes mellitus (DM) and it contributes substantially to the burden of disease globally. During the last decades, the development of multiple imaging modalities to evaluate DR, combined with emerging treatment possibilities, has led to the implementation of large-scale screening programmes resulting in improved prevention of vision loss. However, not all patients are able to participate in such programmes and not all are at equal risk of DR development and progression. In this review, we discuss the relevance of the currently available imaging modalities for the evaluation of DR: colour fundus photography (CFP), ultrawide-field photography (UWFP), fundus fluorescein angiography (FFA), optical coherence tomography (OCT), OCT angiography (OCTA) and functional testing. Furthermore, we suggest where a particular imaging technique of DR may aid the evaluation of the disease in different clinical settings. Combining information from various imaging modalities may enable the design of more personalized care including the initiation of treatment and understanding the progression of disease more adequately.
Levine RS, Sapieha P, Dutta S, Sun JK, Gardner TW. It is time for a moonshot to find "Cures" for diabetic retinal disease. Prog Retin Eye Res 2022;90:101051.Abstract
Diabetic retinal disease (DRD), the most common complication of diabetes and a leading cause of blindness in working age individuals, is now understood to be a form of sensory neuropathy or neurovascular degeneration. Current treatments are focused on advanced vision-threatening disease and a single molecular target, vascular endothelial growth factor, has an approved therapy. We trace the evolution of understanding of DRD pathogenesis, identify new approaches to clinical assessment, trials infrastructure and design, and target identification to accelerate selection and evaluation of new therapeutics that will speed development of potentially curative interventions. Critically, the "Restoring Vision Moonshot" framework will address gaps in knowledge to be filled to achieve the goal of restoring sight and preventing vision loss in persons with diabetes.
Wykoff CC, Abreu F, Adamis AP, Basu K, Eichenbaum DA, Haskova Z, Lin H, Loewenstein A, Mohan S, Pearce IA, Sakamoto T, Schlottmann PG, Silverman D, Sun JK, Wells JA, Willis JR, Tadayoni R, and Investigators YOSEMITERHINE. Efficacy, durability, and safety of intravitreal faricimab with extended dosing up to every 16 weeks in patients with diabetic macular oedema (YOSEMITE and RHINE): two randomised, double-masked, phase 3 trials. Lancet 2022;399(10326):741-755.Abstract
BACKGROUND: To reduce treatment burden and optimise patient outcomes in diabetic macular oedema, we present 1-year results from two phase 3 trials of faricimab, a novel angiopoietin-2 and vascular endothelial growth factor-A bispecific antibody. METHODS: YOSEMITE and RHINE were randomised, double-masked, non-inferiority trials across 353 sites worldwide. Adults with vision loss due to centre-involving diabetic macular oedema were randomly assigned (1:1:1) to intravitreal faricimab 6·0 mg every 8 weeks, faricimab 6·0 mg per personalised treatment interval (PTI), or aflibercept 2·0 mg every 8 weeks up to week 100. PTI dosing intervals were extended, maintained, or reduced (every 4 weeks up to every 16 weeks) based on disease activity at active dosing visits. The primary endpoint was mean change in best-corrected visual acuity at 1 year, averaged over weeks 48, 52, and 56. Efficacy analyses included the intention-to-treat population (non-inferiority margin 4 Early Treatment Diabetic Retinopathy Study [ETDRS] letters); safety analyses included patients with at least one dose of study treatment. These trials are registered with ClinicalTrials.gov (YOSEMITE NCT03622580 and RHINE NCT03622593). FINDINGS: 3247 patients were screened for eligibility in YOSEMITE (n=1532) and RHINE (n=1715). After exclusions, 940 patients were enrolled into YOSEMITE between Sept 5, 2018, and Sept 19, 2019, and 951 patients were enrolled into RHINE between Oct 9, 2018, and Sept 20, 2019. These 1891 patients were randomly assigned to faricimab every 8 weeks (YOSEMITE n=315, RHINE n=317), faricimab PTI (n=313, n=319), or aflibercept every 8 weeks (n=312, n=315). Non-inferiority for the primary endpoint was achieved with faricimab every 8 weeks (adjusted mean vs aflibercept every 8 weeks in YOSEMITE 10·7 ETDRS letters [97·52% CI 9·4 to 12·0] vs 10·9 ETDRS letters [9·6 to 12·2], difference -0·2 ETDRS letters [-2·0 to 1·6]; RHINE 11·8 ETDRS letters [10·6 to 13·0] vs 10·3 ETDRS letters [9·1 to 11·4] letters, difference 1·5 ETDRS letters [-0·1 to 3·2]) and faricimab PTI (YOSEMITE 11·6 ETDRS letters [10·3 to 12·9], difference 0·7 ETDRS letters [-1·1 to 2·5]; RHINE 10·8 ETDRS letters [9·6 to 11·9], difference 0·5 ETDRS letters [-1·1 to 2·1]). Incidence of ocular adverse events was comparable between faricimab every 8 weeks (YOSEMITE n=98 [31%], RHINE n=137 [43%]), faricimab PTI (n=106 [34%], n=119 [37%]), and aflibercept every 8 weeks (n=102 [33%], n=113 [36%]). INTERPRETATION: Robust vision gains and anatomical improvements with faricimab were achieved with adjustable dosing up to every 16 weeks, demonstrating the potential for faricimab to extend the durability of treatment for patients with diabetic macular oedema. FUNDING: F Hoffmann-La Roche.
Li H, Deng Y, Sampani K, Cai S, Li Z, Sun JK, Karniadakis GE. Computational investigation of blood cell transport in retinal microaneurysms. PLoS Comput Biol 2022;18(1):e1009728.Abstract
Microaneurysms (MAs) are one of the earliest clinically visible signs of diabetic retinopathy (DR). MA leakage or rupture may precipitate local pathology in the surrounding neural retina that impacts visual function. Thrombosis in MAs may affect their turnover time, an indicator associated with visual and anatomic outcomes in the diabetic eyes. In this work, we perform computational modeling of blood flow in microchannels containing various MAs to investigate the pathologies of MAs in DR. The particle-based model employed in this study can explicitly represent red blood cells (RBCs) and platelets as well as their interaction in the blood flow, a process that is very difficult to observe in vivo. Our simulations illustrate that while the main blood flow from the parent vessels can perfuse the entire lumen of MAs with small body-to-neck ratio (BNR), it can only perfuse part of the lumen in MAs with large BNR, particularly at a low hematocrit level, leading to possible hypoxic conditions inside MAs. We also quantify the impacts of the size of MAs, blood flow velocity, hematocrit and RBC stiffness and adhesion on the likelihood of platelets entering MAs as well as their residence time inside, two factors that are thought to be associated with thrombus formation in MAs. Our results show that enlarged MA size, increased blood velocity and hematocrit in the parent vessel of MAs as well as the RBC-RBC adhesion promote the migration of platelets into MAs and also prolong their residence time, thereby increasing the propensity of thrombosis within MAs. Overall, our work suggests that computational simulations using particle-based models can help to understand the microvascular pathology pertaining to MAs in DR and provide insights to stimulate and steer new experimental and computational studies in this area.
Kim JE, Glassman AR, Josic K, Melia M, Aiello LP, Baker C, Eells JT, Jampol LM, Kern TS, Marcus D, Salehi-Had H, Shah SN, Martin DF, Stockdale CR, Sun JK, Sun JK. A Randomized Trial of Photobiomodulation Therapy for Center-Involved Diabetic Macular Edema with Good Visual Acuity (Protocol AE). Ophthalmol Retina 2022;6(4):298-307.Abstract
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.
Patel NA, Yannuzzi NA, Lin J, Smiddy WE. A Cost-Effectiveness Analysis of Intravitreal Aflibercept for the Prevention of Progressive Diabetic Retinopathy. Ophthalmol Retina 2022;6(3):213-218.Abstract
PURPOSE: To calculate costs required to prevent center-involved diabetic macular edema (CI-DME) or proliferative diabetic retinopathy (PDR), and to improve the diabetic retinopathy severity score (DRSS) with intravitreal anti-VEGF injections, as reported for aflibercept in 2 randomized control trials. DESIGN: Cost-effectiveness analysis modeling based on published data. SUBJECTS: None. METHODS: Results from PANORAMA and the Diabetic Retinopathy Clinical Research Network Protocol W were analyzed. Parameters collected included DRSS, risk reduction of PDR, risk reduction of CI-DME, and the number of treatments required. Costs were modeled based on 2020 Medicare reimbursement data practice settings of hospital-based facility and nonfacility. MAIN OUTCOME MEASURES: Cost to prevent cases of PDR and CI-DME and to improve DRSS stage. RESULTS: Over 2 years in Protocol W, the cost required to prevent 1 case of PDR was $83 000 ($72 400) in the facility (nonfacility) setting; in PANORAMA, the corresponding 2-year costs were $89 400 ($75 000) for the 2-mg aflibercept every 16 weeks (2Q16) arm, and $91 200 ($89 900) for the 2-mg aflibercept every 8 weeks as needed (2Q8PRN) arm. To prevent 1 case of CI-DME with vision loss in Protocol W, the cost was $154 000 ($133 000). For all CI-DME, with and without vision loss, in PANORAMA, the costs to prevent a case were $70 900 ($59 500) for the 2Q16 arm and $90 000 ($88 800) for the 2Q8PRN arm. In Protocol W, the overall accumulated total for cost/DRSS unit change at the 2-year point for facility (nonfacility) setting was $2700 ($2400)/DRSS. In the first year alone, it was $2100 ($1800)/DRSS and in the second year, it was $6100 ($5300)/DRSS. CONCLUSIONS: There is a considerable cost associated with the prevention of PDR and CI-DME with intravitreal aflibercept injections. A price per unit of change in DRSS is a new parameter that might serve as a benchmark in future utility analyses that could be used to bring the perspective to cost-utility considerations.