Novel artificial intelligence for diabetic retinopathy and diabetic macular edema: what is new in 2024?

PURPOSE OF REVIEW: Given the increasing global burden of diabetic retinopathy and the rapid advancements in artificial intelligence, this review aims to summarize the current state of artificial intelligence technology in diabetic retinopathy detection and management, assessing its potential to improve care and visual outcomes in real-world settings. RECENT FINDINGS: Most recent studies focused on the integration of artificial intelligence in the field of diabetic retinopathy screening, focusing on real-world efficacy and clinical implementation of such artificial intelligence models. Additionally, artificial intelligence holds the potential to predict diabetic retinopathy progression, enhance personalized treatment strategies, and identify systemic disease biomarkers from ocular images through 'oculomics', moving towards a more precise, efficient, and accessible care. The emergence of foundation model architectures and generative artificial intelligence, which more clearly reflect the clinical care process, may enable rapid advances in diabetic retinopathy care, research and medical education. SUMMARY: This review explores the emerging technology of artificial intelligence to assess the potential to improve patient outcomes and optimize personalized management in healthcare delivery and medical research. While artificial intelligence is expected to play an increasingly important role in diabetic retinopathy care, ongoing research and clinical trials are essential to address implementation issues and focus on long-term patient outcomes for successful real-world adoption of artificial intelligence in diabetic retinopathy.

Retinal microvascular complexity as a putative biomarker of biological age: a pilot study.

Physiological changes associated with aging increase the risk for the development of age-related diseases. This increase is non-specific to the type of age-related disease, although each disease develops through a unique pathophysiologic mechanism. People who age at a faster rate develop age-related diseases earlier in their life. They have an older "biological age" compared to their "chronological age". Early detection of individuals with accelerated aging would allow timely intervention to postpone the onset of age-related diseases. This would increase their life expectancy and their length of good quality life. The goal of this study was to investigate whether retinal microvascular complexity could be used as a biomarker of biological age. Retinal images of 68 participants ages ranging from 19 to 82 years were collected in an observational cross-sectional study. Twenty of the old participants had age-related diseases such as hypertension, type 2 diabetes, and/or Alzheimer's dementia. The rest of the participants were healthy. Retinal images were captured by a hand-held, non-mydriatic fundus camera and quantification of the microvascular complexity was performed by using Sholl's, box-counting fractal, and lacunarity analysis. In the healthy subjects, increasing chronological age was associated with lower retinal microvascular complexity measured by Sholl's analysis. Decreased box-counting fractal dimension was present in old patients, and this decrease was 2.1 times faster in participants who had age-related diseases (p = 0.047). Retinal microvascular complexity could be a promising new biomarker of biological age. The data from this study is the first of this kind collected in Montenegro. It is freely available for use.

LONGITUDINAL MICROVASCULAR AND NEURONAL RETINAL EVALUATION IN PATIENTS WITH DIABETES MELLITUS TYPES 1 AND 2 AND GOOD GLYCEMIC CONTROL.

PURPOSE: To evaluate microvascular and neuronal changes over 3 years in patients with Type 1/2 diabetes mellitus (DM1/DM2), good metabolic control, and no signs of diabetic retinopathy. METHODS: In this prospective, longitudinal study, 20 DM1, 48 DM2, and 24 controls underwent macular optical coherence tomography and optical coherence tomography angiography at baseline and after 3 years. Following parameters were considered: thickness of the central macula, retinal nerve fiber layer, ganglion cell (GCL+/GCL++) complex; perfusion and vessel density and fractal dimension at the superficial and deep capillary plexuses; choriocapillaris flow deficits; and foveal avascular zone metrics. MATLAB and ImageJ were used for optical coherence tomography angiography scans analyses. RESULTS: The mean HbA1c was 7.4 ± 0.8% in DM1 and 7.2 ± 0.8% in DM2 at baseline, with no change at 3 years. No eye developed diabetic retinopathy. In longitudinal analyses, perfusion density at superficial capillary plexuses ( P = 0.03) and foveal avascular zone area and perimeter ( P < 0.0001) significantly increased in DM2 compared with other groups. No longitudinal changes occurred in optical coherence tomography parameters. In comparisons within groups, DM2 had a significant thinning of GCL++ in the outer ring, decreased perfusion density at deep capillary plexuses and choriocapillaris flow deficits, and increase in foveal avascular zone perimeter and area in deep capillary plexuses; DM1 had an increase in foveal avascular zone perimeter in deep capillary plexuses ( P < 0.001 for all comparisons). CONCLUSION: Longitudinal data showed significant microvascular retinal changes in DM2. No changes were detected in neuronal parameters and in DM1. Longer and larger studies are needed to confirm these preliminary data.

Multimodal Retinal Imaging in Patients with Diabetes Mellitus and Association with Cerebrovascular Disease.

INTRODUCTION: This study aimed to evaluate the association between macular optical coherence tomography angiography (OCT-A) metrics, characteristics of ultrawide field (UWF) imaging, and cerebrovascular disease in patients with diabetes mellitus (DM) with different stages of diabetic retinopathy (DR). METHODS: 516 eyes of 258 DM patients were enrolled in two centers (Milan and Belfast). UWF color fundus photos (CFPs) were obtained with Optos California (Optos, PLC) and graded for both DR severity and predominantly peripheral lesions presence (>50% of CFP lesions) by two independent graders. OCT-A (3 × 3 mm), available in 252 eyes of 136 patients, was used to determine perimeter, area, and circularity index of the foveal avascular zone and vessel density (VD); perfusion density (PD); fractal dimension on superficial, intermediate (ICP), and deep capillary plexuses; flow voids (FVs) in the choriocapillaris. RESULTS: Out of 516 eyes, 108 eyes (20.9%) had no DR, and 6 eyes were not gradable. The remaining 402 eyes were as follows: 10.3% (53) had mild nonproliferative DR (NPDR), 38.2% (197) had moderate NPDR, 11.8% (61) had severe NPDR, and 17.6% (91) had proliferative DR. A worse DR stage was associated with a history of stroke (p = 0.044). Logistic regression analysis after taking into account sex, type of DM, age, DM duration, and OCT-A variables found that PD and VD on ICP were significantly associated with presence of stroke and DR severity. CONCLUSION: OCT-A metrics show an association with the presence of cerebrovascular complications, providing potentially useful parameters to estimate vascular risk in patients with DM.

Twenty-four-month real-life treatment outcomes of polypoidal choroidal vasculopathy versus type 1 macular neovascularization in Caucasians.

BACKGROUND: To compare 24-month real-world outcomes of Vascular Endothelial Growth Factor (VEGF) inhibitors for Polypoidal Choroidal Vasculopathy (PCV) and type 1 Macular Neovascularization (MNV) in a Caucasian population. METHODS: Retrospective analysis from a prospectively designed observational database. Data from Italian centres participating in the Fight Retinal Blindness! (FRB!) project were collected. Treatment-naïve PCV or type 1 MNV commencing treatment after January 2009 were included. The primary outcome was 24-month visual acuity (VA) change; other outcomes included baseline characteristics, number of anti-VEGF injections, time to lesion inactivation and proportion of active visits. RESULTS: A total of 322 eyes (114 PCVs) from 291 patients were included. Median [Q1, Q3] VA at baseline was comparable (70 [55, 75.8] vs. 70 [58.8, 75] letters, p = 0.95). Adjusted VA change at 2 years was higher in PCV (mean [95% CI], +1.2 [-1.6, 4.1] vs. -3.6 [-6, -1.2] letters, p = 0.005). PCV received fewer anti-VEGF injections over the first 24 months of treatment than type 1 MNV (median [Q1, Q3], 8 [5, 10] vs. 9 [7, 12.2] injections, p = 0.001), inactivated earlier (median [Q1, Q3], 235 [184, 308] vs. 252 [169, 343] days, p = 0.04) and was less frequently graded 'active' (62% vs. 68% of visits, p = 0.001). CONCLUSIONS: PCV had slightly better VA outcomes over 24 months of treatment than type 1 MNV after receiving less anti-VEGF injections. These results suggest a possible overlap of the two clinical entities with similar visual prognosis in Caucasians.

Retinal vascular occlusion and SARS-CoV-2 vaccination.

PURPOSE: To assess the clinical and retinal imaging features of patients in whom retinal vascular occlusion (VO) had developed in temporal associations with COVID-19 vaccination. METHODS: In this retrospective case series, all consecutive adult patients with new onset VO within 6 weeks of vaccination against COVID-19 were included in the study between May 1 and October 31, 2021. All patients had a systemic medical health assessment, full ophthalmic evaluation, and complete fundus imaging. RESULTS: Fifteen eyes of VO (14 patients) after COVID-19 vaccinations were identified. The median time between vaccination and symptoms onset was 14 days (range 7-42 days). The mean best-corrected visual acuity (BCVA) was 20/55 with a range of 20/20 to 20/200. Eleven of 15 eyes (73.3%) had visual acuity improvement after intravitreal treatment at 60-90 days (range, 45-105 days) from the presentation. Four of 5 cases without systemic risk factors for VO had a mean BCVA > 20/32 at presentation and > 20/25 at the latest evaluation. Between May 1 and October 31, 2021, a temporal association was found between the 15 reported cases and COVID-19 vaccination out of a total of 29 VO (p = 0.05). The incidence of VO was higher in the considered period compared to the equivalent 6-month period in 2019 (1.17% vs 0.52%, respectively; p = 0.0134). CONCLUSIONS: Retinal vascular occlusion with different grades of severity are reported in temporal association with COVID-19 vaccination. The exact pathogenic mechanism needs to be further studied. No certain causal relationship can be established from this case series.

Standardization of Optical Coherence Tomography Angiography Imaging Biomarkers in Diabetic Retinal Disease.

Optical coherence tomography Angiography (OCT-A) represents a revolution in the noninvasive evaluation of retinal and choroidal circulation especially in detecting early clinical signs of diabetic retinal disease (DRD). With appropriate use, OCT-A characteristics and measurements have the potential to become new imaging biomarkers in managing and treating DRD. Major challenges include (a) provision of standardized outputs from different OCT-A instruments providing standardized terminology to correctly interpret data; (b) the presence of artifacts; (c) the absence of standardized grading or interpretation method in the evaluation of DRD, similar to that already established in fundus photography; and (d) establishing how OCT-A might be able to provide surrogate markers to demonstrate blood retinal barrier breakdown and vascular leakage, commonly associated with DRD. In fact, OCT-A guidelines for DRD are still evolving. The outputs of quantitative OCT-A data offer a unique opportunity to develop tools based on artificial intelligence to assist the clinicians in diagnosing, monitoring, and managing patients with diabetes. In addition, OCT-A has the potential to become a useful tool for the evaluation of cardiovascular diseases and different neurological diseases including cognitive impairment. This article written by the members of Diabetic Retinopathy expert committee of the European Vision Clinical Research network will review the available evidence on the use of OCT-A as an imaging biomarker in DRD and discuss the limits and the current application as well as future developments for its use in both clinical practice and research trials of DRD.

Aflibercept and Ranibizumab Modulate Retinal Pigment Epithelial Cells Function by Acting on Their Cross Talk with Vascular Endothelial Cells.

BACKGROUND/AIMS: We performed co-culture experiments between human RPE cells (ARPE-19) and human umbilical vascular endothelial cells (HUVEC) in order to evaluate how anti-VEGF drugs could affect NO release, mitochondrial function, the oxidative status, proliferation and migration of RPE cells through modulation of their cross talk with vascular endothelial cells. METHODS: The co-culture HUVEC/RPE, was exposed to Ranibizumab/Aflibercept in the absence/presence of the NO synthase (NOS) inhibitor, the phosphatidylinositol 3'-kinase (PI3K), the extracellular-signal-regulated kinases 1/2 (ERK1/2) and the p38 mitogen-activated protein kinase (p38 MAPK) blockers. Specific kits were used for cell viability, mitochondrial membrane potential, NO, ROS and GSH production. Western blot was performed for apoptosis markers, NOS isoforms, and others kinases detection. Cell migration was analyzed by scratch assay, whereas cell proliferation and cell cycle through xCELLigence and flow cytometry. RESULTS: In RPE cells co-cultured with HUVEC in physiological conditions, Aflibercept/Ranibizumab increased NO release in a dose and time-dependent way. Opposite results were obtained in peroxidative conditions. Both anti-VEGF agents were able to prevent the fall of cell viability and mitochondrial membrane potential, an effect which was reduced by various inhibitors, and increased cell migration. Aflibercept/Ranibizumab counteracted the changes of apoptosis markers, NOS expression/activation, PI3K and ERK1/2 activation caused by peroxidation. These results were confirmed by cell cycle analysis. CONCLUSION: This study has shown new mechanisms at the basis of protective effects elicited by Aflibercept/Ranibizumab in RPE cells. HUVEC stimulated with Aflibercept/Ranibizumab, could release some paracrine factors that can modulate the RPE cells response in both physiologic and peroxidative conditions.

CHANGES OF AQUEOUS HUMOR MÜLLER CELLS' BIOMARKERS IN HUMAN PATIENTS AFFECTED BY DIABETIC MACULAR EDEMA AFTER SUBTHRESHOLD MICROPULSE LASER TREATMENT.

PURPOSE: To evaluate the changes in activity of biomarkers of Mu[Combining Diaeresis]ller cells (MC) in aqueous humor of patients with diabetic macular edema after subthreshold micropulse laser, over 1 year. METHODS: Patients with untreated diabetic macular edema and central retinal thickness ≤ 400 µm were enrolled. Best-corrected visual acuity, full ophthalmic examination, and optical coherence tomography were performed. Subthreshold micropulse laser was applied every 3 months. Glial fibrillary acidic protein and inwardly rectifying potassium channel (Kir 4.1), MC activity markers, and vascular endothelial growth factor were quantified in the aqueous humor collected at baseline and at 1, 3, and 12 months after laser. Changes in the macular thickness and inner nuclear layer thickness, where MC bodies are located, were measured. RESULTS: Ten eyes of 10 patients were included. Best-corrected visual acuity improved at 3 months (P = 0.047) and remained stable. Inner nuclear layer thickness significantly reduced at 12 months (P = 0.012). Glial fibrillary acidic protein, Kir 4.1, and vascular endothelial growth factor decreased at 1 and/or 3 and/or 12 months compared with baseline (P < 0.05). CONCLUSION: Subthreshold micropulse laser improves visual function in diabetic macular edema. Kir 4.1 and glial fibrillary acidic protein decrease and inner nuclear layer thickness reduction demonstrate that subthreshold micropulse laser may restore MC function. Subthreshold micropulse laser also reduces vascular endothelial growth factor concentration. The effect of subthreshold micropulse laser in diabetic macular edema may in part be due to changes of MC metabolic activity.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY CHANGES AFTER SUBTHRESHOLD MICROPULSE YELLOW LASER IN DIABETIC MACULAR EDEMA.

PURPOSE: To assess changes on optical coherence tomography (OCT) angiography in diabetic macular edema (DME) treated with subthreshold micropulse yellow laser (SMPL) over a period of 6 months. METHODS: Thirty-five eyes (35 consecutive patients) with treatment-naive DME prospectively underwent (at baseline, 3 and 6 months) best-corrected visual acuity, swept-source OCT angiography/OCT, and fundus autofluorescence. Following parameters were evaluated on OCT angiography in the superficial capillary plexus (SCP) and deep capillary plexus (DCP): the area of foveal avascular zone, number of microaneurysms (MA), area of cysts, and presence of capillary network alterations. Microaneurysm change was also evaluated in 15 fellow eyes, not needing treatment over 6 months. Vessel and perfusion densities were evaluated in the SCP, DCP, and choriocapillaris, with image J. Retina thickness, number of hyperreflective retinal spots, and external limiting membrane integrity were evaluated on OCT. All measurements were performed by two masked graders, independently. RESULTS: All patients had diabetes mellitus Type 2 (mean age, 69.4 ± 10.9 years; duration of diabetes mellitus, 15.7 ± 8.7 years; and HbA1c 7.7 ± 1.2%). Mean best-corrected visual acuity at baseline was 69.7 ± 12.0 letters ETDRS, 72.7 ± 10.7 at 3 months (gain 3.1 ± 4.3, P = 0.0049) and 74.3 ± 9.5 at 6 months (gain 4.6 ± 7.2, P < 0.0001). Foveal avascular zone area decreased in the DCP at 6 months (P = 0.01). Area of cysts decreased in the SCP at 3 months and 6 months (P = 0.038; P = 0.049), and in the DCP at 6 months (P = 0.0071). Number of MA decreased at 6 months in the SCP (P = 0.0007) and at 3 months and 6 months in the DCP (P = 0.048; P < 0.0001) in treated eyes. No significant change in number of MA was found in nontreated eyes. There was no statistically significant change in any other OCT angiography/OCT parameter. CONCLUSION: Subthreshold micropulse yellow laser induces more pronounced changes in the DCP than in the SCP in DME. These changes occurred as early as 3 months after treatment. The evaluation of specific parameters in the DCP may help in determining treatment response.

EARLY MICROVASCULAR AND NEURAL CHANGES IN PATIENTS WITH TYPE 1 AND TYPE 2 DIABETES MELLITUS WITHOUT CLINICAL SIGNS OF DIABETIC RETINOPATHY.

PURPOSE: To assess and compare early modifications in inner retinal layer thickness and optical coherence tomography angiography parameters in patients with diabetes mellitus (DM) Types 1 and 2 without clinical signs of diabetic retinopathy. METHODS: Ninety eyes of 90 subjects (24 Type 1 DM, 36 Type 2 DM, and 30 healthy controls) were prospectively evaluated with spectral domain OCT, swept-source OCT angiography, and color fundus photography (on the same day). Retinal nerve fiber layer, ganglion cell layer (GCL+), and nerve fiber layer + GCL+ (GCL++) thickness were automatically determined by the instrument in the 1, 3, and 6 central mm. On OCT angiography, the following parameters were evaluated: area of foveal avascular zone, number of focally dilated endings of the capillaries (detected only on OCT angiography), presence of regular/irregular foveal avascular zone, capillary loss, and capillary network irregularities in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). RESULTS: Ganglion cell layer+ (P = 0.0099) and GCL++ (P = 0.0367) were significantly thicker in DM Type 1 versus DM Type 2 in 1 central mm, after adjustment for age and DM duration. The area of foveal avascular zone was significantly larger in DM Type 1 versus controls in both SCP and DCP and in DM Type 1 versus Type 2 only in DCP (P < 0.05 for all); the number of focally dilated endings of the capillaries was higher in DM Type 1 versus controls in both SCP and DCP (P < 0.01 for all); and in DM Type 2 versus controls only in DCP (P = 0.007). Perifoveal capillary loss in SCP and inner retinal layer thickness had the highest correlation in both DM types. CONCLUSION: There are specific neural and microvascular modifications even before clinical signs of diabetic retinopathy in DM Types 1 and 2. Perifoveal capillary loss in the SCP is highly correlated with inner retinal layer. These data may help in characterization of patients at the preclinical stage of diabetic retinopathy.

SCOTOMA CHARACTERISTICS IN MACULAR TELANGIECTASIA TYPE 2: MacTel Project Report No. 7-The MacTel Research Group.

PURPOSE: To characterize scotomas in macular telangiectasia Type 2 (MacTel). METHODS: Five of the 27 centers performed microperimetry as part of the MacTel Natural History Observation Study. Data were analyzed in the Moorfields Eye Hospital Reading Centre. The number of stimuli under a threshold of 12, 10, 8, and <0 dB were counted (thresholding) and compared with one another. RESULTS: A total of 565 examinations were gradable, received from 632 eyes of 322 participants (age 61.1 ± 9.1 years, 62% females). The authors found absolute scotomas in 243 eyes (43%), 98% of these affected the temporal quadrant, and 99.5% were unifocal. Growth of absolute scotomas was limited to an extent of approximately 40 deg. Although transition from functionally unimpaired retina to absolute scotomas is generally steeply sloped, the larger a scotoma, the steeper it is. CONCLUSION: Scotoma features were consistent throughout a large MacTel cohort. The temporal quadrant was confirmed as predominantly affected, which might result from vascular or metabolic asymmetry. Functional loss did not exceed an area of 5° × 8° however advanced the disorder. Different MacTel phenotypes seem likely and point toward different types of progression; identifying these would improve planning for clinical trials and might lead to better understanding patient outcome.

Anti-Vascular Endothelial Growth Factors Protect Retinal Pigment Epithelium Cells Against Oxidation by Modulating Nitric Oxide Release and Autophagy.

BACKGROUND/AIMS: the anti-vascular endothelial growth factors (VEGF), Aflibercept and Ranibizumab, are used for the treatment of macular degeneration. Here we examined the involvement of nitric oxide (NO), mitochondria function and of apoptosis/autophagy in their antioxidant effects in human retinal pigment epithelium cells (RPE). METHODS: RPE were exposed to Ranibizumab/Aflibercept in the absence or presence of NO synthase (NOS) inhibitor and of autophagy activator/blocker, rapamicyn/3-methyladenine. Specific kits were used for cell viability, NO and reactive oxygen species detection and mitochondrial membrane potential measurement, whereas Western Blot was performed for apoptosis/ autophagy markers and other kinases detection. RESULTS: In RPE cultured in physiological conditions, Aflibercept/Ranibizumab increased NO release in a dose and time-dependent way. Opposite results were obtained in RPE pretreated with hydrogen peroxide. Moreover, both the anti-VEGF agents were able to prevent the fall of cell viability and of mitochondrial membrane potential. Those effects were reduced by the NOS inhibitor and 3-methyladenine and were potentiated by rapamycin. Finally, Aflibercept and Ranibizumab counteracted the changes of apoptosis/autophagy markers, NOS, Phosphatidylinositol-3-Kinase/Protein Kinase B and Extracellular signal-regulated kinases 1/2 caused by peroxidation. CONCLUSION: Aflibercept and Ranibizumab protect RPE against peroxidation through the modulation of NO release, apoptosis and autophagy.

Long-term longitudinal modifications in mesopic microperimetry in early and intermediate age-related macular degeneration.

PURPOSE: To evaluate functional changes (retinal sensitivity and fixation characteristics) determined by microperimetry in patients with early and intermediate AMD over 6 years. METHODS: Prospective, longitudinal follow-up (FU) study of 16 patients (29 eyes) with early and intermediate AMD (AREDS 2 and AREDS 3 classification). All eyes underwent: complete ophthalmic examination with best corrected visual acuity (BCVA) determination, color fundus photo (CFP), optical coherence tomography and microperimetry. All CFP were evaluated by two retinal specialists masked to functional data for changes in severity of clinical features over the course of FU. RESULTS: Of 17 eyes graded as AREDS 2 at baseline, 14 (82.35 %) remained stable, and 3 (18.75 %) progressed to AREDS 3. Of 12 eyes graded as AREDS 3 at baseline, 10 remained stable (83.33 %), and 2 (16.67 %) progressed to AREDS 4. Mean BCVA significantly deteriorated in both AREDS 2 (p = 0.006) and AREDS 3 (p = 0.016), with greater decrease in AREDS 3 (p = 0.01)6. Mean retinal sensitivity (RS) significantly decreased over time in both AREDS 2 (p < 0.0001) and AREDS 3 group (p = 0.002), with greater decrease in AREDS 3 (p = 0.006). The mean number of dense scotomas did not change in AREDS 2 (p = 0.3), but significantly increased in the AREDS 3 group (p = 0.035). Points with decreased RS were located in all but the central point (p < 0.0001 for all), without significant differences in number among rings. In the AREDS 2 group, fixation stability remained unchanged. In the AREDS 3 group, four eyes deteriorated from stable to unstable fixation at FU (p = 0.045). CONCLUSION: A significant deterioration in RS is reported in early and intermediate AMD eyes, whereas fixation stability changed only in intermediate AMD (AREDS 3) over long-term follow-up. Microperimetry examination can become a new functional biomarker in early and intermediate AMD patients.

HYPERREFLECTIVE RETINAL SPOTS IN NORMAL AND DIABETIC EYES: B-Scan and En Face Spectral Domain Optical Coherence Tomography Evaluation.

PURPOSE: To evaluate hyperreflective retinal spots (HRS), in normal subjects and diabetic patients without and with macular edema (diabetic macular edema, DME), on linear B-scans and corresponding en face image of spectral-domain optical coherence tomography. METHODS: Retrospective evaluation of images of 54 eyes/subjects (16 normal subjects, 19 diabetic patients without DME, and 19 with DME). On horizontal B-scan spectral-domain optical coherence tomography, passing through the center of the fovea, the following characteristics of HRS were evaluated: location (inner retina or outer retina), size (≤30 or >30 µm), reflectivity (similar to nerve fiber layer or to retinal pigment epithelium-Bruch complex), and presence or absence of back shadowing. On en face spectral-domain optical coherence tomography, the following patterns were evaluated: 1) isolated HRS (not corresponding to any visible lesion); 2) HRS corresponding to a segment of retinal capillary or microaneurysm wall; and 3) HRS corresponding to hard exudate. All gradings were performed twice by two graders in a masked fashion. RESULTS: Size ≤30 µm, reflectivity similar to nerve fiber layer, and absence of back shadowing were associated with absence of vessels or any other lesion on en face image (P = 0.0001 for all). Size >30 µm, reflectivity similar to retinal pigment epithelium-Bruch complex, presence of back shadowing, and location in the outer retina were all associated with presence of hard exudate on en face imaging (P < 0.0001 for all). Multiple logistic regression analysis showed that HRS present in the inner retina (P < 0.0001), size >30 µm (P = 0.0029), and presence of back shadowing (P < 0.0001) are directly associated with presence of microaneurysms on en face image. Intragrader and intergrader repeatability were excellent for all evaluations. CONCLUSION: Hyperreflective retinal spots ≤30 µm, reflectivity similar to nerve fiber layer, and absence of back shadowing may represent activated microglial cells; HRS >30 µm, reflectivity similar to retinal pigment epithelium-Bruch complex, presence of back shadowing, and location in the outer retina may represent hard exudate; HRS >30 µm, presence of back shadowing, and location in the inner retina may represent microaneurysms. These hypotheses may be tested in further studies.

HYPERREFLECTIVE RETINAL SPOTS AND VISUAL FUNCTION AFTER ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR TREATMENT IN CENTER-INVOLVING DIABETIC MACULAR EDEMA.

BACKGROUND: To assess and correlate early modifications in hyperreflective retinal spots (HRS), retinal sensitivity (RS), fixation stability, and best-corrected visual acuity (BCVA) after anti-vascular endothelial growth factor treatment in naive center-involving diabetic macular edema. METHODS: Cross-sectional comparative case-control series. Twenty diabetic patients underwent 3 consecutive intravitreal anti-vascular endothelial growth factor injections in the study eye (20 fellow eyes served as control), full ophthalmologic examination including spectral domain optical coherence tomography (Retinascan RS-3000; Nidek, Gamagori, Japan), and microperimetry (MP1; Nidek) at baseline (Visit-V1), 1 month after each injection (V2, V3, V4), and at 6 months (V5). Central retinal thickness, inner and outer retinal thickness, number of HRS, BCVA, RS, and bivariate contour ellipse area were evaluated by analysis of variance test with Bonferroni post hoc test. Correlation analyses were performed by Spearman correlation. RESULTS: In treated eyes, central retinal thickness and inner retinal thickness significantly decreased at V2, V3, V4 versus V1 (P < 0.03 at least for all); the mean number of HRS significantly decreased in both inner and outer retina at all follow-up visits versus V1 (P < 0.008 at least for all); mean RS and bivariate contour ellipse area remained statistically unchanged during the follow-up; BCVA significantly improved at V3, V4, and V5 versus V1 (P = 0.009 at least for all). In fellow eyes, central retinal thickness, HRS, RS, and BCVA did not change at any follow-up. The number of HRS correlated inversely with RS, directly with bivariate contour ellipse area, and not significantly with BCVA. CONCLUSION: A significant decrease in HRS in the retina after anti-vascular endothelial growth factor treatment is documented. A decrease in HRS correlates with functional parameters, specifically RS. New parameters may be used for treatment evaluation in center-involving diabetic macular edema.

HYPERREFLECTIVE INTRARETINAL SPOTS IN RADIATION MACULAR EDEMA ON SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To better pathophysiologically characterize macular edema secondary to eye irradiation, analyzing the presence of optical coherence tomography (OCT) hyperreflective spots. METHODS: Twenty-five consecutive eyes affected by radiation maculopathy, secondary to irradiation for a primary uveal melanoma, without macular involvement in the irradiation field, were consecutively enrolled. All subjects underwent full ophthalmologic examination, including fluorescein angiography, color fundus photography, and spectral domain OCT, even in en face modality. Optical coherence tomography central subfield thickness was stratified into the following 3 categories: <400 µm, 400 to 600 µm, and >600 µm. Spectral domain OCT images were analyzed to measure and localize hyperreflective spots by two independent masked graders. RESULTS: Hyperreflective spots were documented in all eyes (100%). Hyperreflective spots significantly increased in number according to OCT central subfield thickness (<400 µm, 400-600 µm, >600 µm, P < 0.05). The intergrader agreement was at least substantial for all measurements (intraclass correlation coefficient: 0.80). CONCLUSION: Spectral domain OCT documents discrete intraretinal reflectivity changes (hyperreflective spots) in all (studied) eyes affected by radiation maculopathy. Hyperreflective spots increase in number with increasing central subfield thickness and could be considered as a new clinical biomarker of intraretinal inflammation in patients affected by macular edema secondary to irradiation for uveal melanoma.

SUBTHRESHOLD MICROPULSE YELLOW LASER VERSUS SUBTHRESHOLD MICROPULSE INFRARED LASER IN CENTER-INVOLVING DIABETIC MACULAR EDEMA: Morphologic and Functional Safety.

BACKGROUND: To evaluate and compare in vivo retinal and choroidal morphologic changes and macular function in patients treated with yellow (Y-MPL) or infrared (IR-MPL) subthreshold micropulse laser in center-involving diabetic macular edema. METHODS: Prospective, randomized, single institution, comparative 6-month pilot study of 53 eyes (53 patients with diabetes). Inclusion criteria were previously untreated center-involving diabetic macular edema with central retinal thickness ≤400 µm (mild diabetic macular edema). Y-MPL or IR-MPL treatment was performed in a standardized pattern, using in both cases the lowest duty cycle (5%). Morphologic outcomes were the visibility of laser spots (on color fundus photographs [COL], fundus autofluorescence, fluorescein angiography, and spectral domain optical coherence tomography), retinal thickness and volume changes, foveal choroidal thickness changes, and integrity and reflectivity of the outer retinal layers. Visual function outcomes were variation in mean 4° and 12° retinal sensitivity and best-corrected visual acuity. RESULTS: Twenty-six eyes were treated with Y-MPL and 27 eyes with IR-MPL. No visible laser spots on the retina were found on COL, fundus autofluorescence, and fluorescein angiography in both treatment groups at 3 months and 6 months of follow-up. Central retinal thickness, macular volume, foveal choroidal thickness, and best-corrected visual acuity were not significantly different at any follow-up visit between the two treatment groups. There were no changes in the integrity of the external limiting membrane or inner segment/outer segment junction in both treatment groups. Mean central 4° retinal sensitivity increased in both treatment groups at 6 months (P = 0.01 and P = 0.04, respectively). Mean central 12° retinal sensitivity increased in the Y-MPL group only (P = 0.047). But, there was no significant difference in mean 4° and 12° retinal sensitivity between the 2 treatment groups at any follow-up visit. CONCLUSION: No clinically visible or invisible scars in the macula were found after Y-MPL or IR-MPL treatment. Both Y-MPL and IR-MPL with the lowest duty cycle (5%) and fixed power parameters seem to be safe from the morphologic and visual function points of view in mild center-involving diabetic macular edema.

Metamorphopsia: An Overlooked Visual Symptom.

Metamorphopsia is a common symptom in different macular disorders. Micropsia and macropsia are special types of metamorphopsia. Recent theories suggest that both retinal and cortical mechanisms are involved in the development and changes of metamorphopsia. Different functional tests have been proposed for the evaluation of metamorphopsia: from the Amsler grid to the hand-held mobile devices for home monitoring. This review addresses some new insights into the pathophysiology of metamorphopsia and different available tests for the evaluation of this symptom in most common macular disorders. The importance of quantification of metamorphopsia in macular diseases is confirmed by the most recent therapeutic approaches.