Macular thickness and visual acuity are characterized by a quadratic nonlinear relation in previously treated neovascular AMD eyes.

PURPOSE: To assess the associations between visual acuity (VA) and retinal thickness in age-related macular degeneration (AMD) eyes treated with anti-vascular endothelial growth factor (VEGF) therapy. METHODS: Sixty-eight patients with neovascular AMD (68 eyes) undergoing anti-VEGF therapy with two years of follow-up imaging data after the initiation of treatment were retrospectively included. Linear and nonlinear regression analyses with curve fitting estimation were performed to explore the relationship between visual acuity and OCT-based parameters at the 3-month and 24-month follow-up visits. Regression analyses were also performed between visual acuity and the retinal thickness deviation which was calculated as the absolute value of the difference between measured and normative retinal thickness values. RESULTS: The VA was not associated with either foveal (R2 = 0.011 and p = .401 at 3 months; R2 = 0.032 and p = .142 at 24 months) or parafoveal (R2 = 0.045 and p = .081 at 3 months; R2 = 0.050 and p = .055 at 24 months) retinal thicknesses. Compared with the linear models, a quadratic function yielded a relative increase in the R2 coefficients. Conversely, the VA was linearly associated with foveal retinal thickness deviation (R2 = 0.041 and p = .037 at 24 months) and parafoveal retinal thickness deviation (R2 = 0.062 and p = .040 at 3 months; R2 = 0.088 and p = .014 at 24 months) values. CONCLUSIONS: Although there was no linear relationship between retinal thickness and VA, a weak but statistically significant linear relationship could be observed when a retinal thickness deviation was considered. This suggests that deviation-based parameters may be beneficial for structure-function correlations in the context of anti-VEGF therapy for neovascular AMD.

Spectral-domain OCT characteristics of intraretinal hyper-reflective foci associated with age-related macular degeneration and diabetic retinopathy.

OBJECTIVE: The purpose of this study was to quantitatively analyze and compare OCT characteristics of intraretinal hyper-reflective foci (IHRF) in eyes with diabetic retinopathy (DR) versus age-related macular degeneration (AMD). DESIGN: a retrospective observational study. PARTICIPANTS: 54 treatment-naïve eyes (27 DR and 27 AMD). METHODS: The IHRF lesions in OCT B-scan were semi-automatically segmented. Mean reflectivity (MR), maximum diameter, circularity index (Cir), area, and the angle between the greatest linear dimension (GLD) and the horizontal were computed for each IHRF lesion. The presence and absence of a posterior shadow and the axial location were assessed. The MR was normalized using the vitreous and nerve fiber layer reflectance as dark and bright reference standards, respectively. RESULTS: A total of 1149 IHRF (1051 in DR and 98 in the AMD group) were identified, with a mean of 39 ± 36 lesions in DR eyes compared to only 4 ± 4 in AMD eyes (p < 0.001). The mean area of individual IHRF lesions was greater in DR eyes (1305 ± 1647 µm² vs 1031 ± 750 µm²; p = 0.016), but IHRF in AMD eyes had higher reflectivity (1.17 ± 0.14 vs 1.03 ± 0.17; p < 0.001). The angle of the GLD relative to the horizontal was greater in AMD eyes, indicating that IHRF in AMD eyes were more horizontally oriented. In AMD eyes, 88.8% of IHRF were located beneath the inner border of the outer nuclear layer (ONL), while in DR eyes, 56.9% were located there (p < 0.001). CONCLUSIONS: IHRF lesions in eyes with DR and AMD demonstrate significant differences, with IHRF in DR eyes tending to be larger and less hyper-reflective compared to AMD eyes.

Sub retinal pigment epithelium hyporeflective spaces preceding large drusen collapse.

PURPOSE: To describe and study hyporeflective sub retinal pigment epithelium (RPE) spaces in large drusen and drusenoid pigment epithelial detachment prior to collapse. METHOD: Retrospective longitudinal study which enrolled patients with large and very large drusen due to intermediate age-related macular degeneration (AMD). The following optical coherence tomography (OCT) parameters were assessed: Drusen size (maximum width and height), OCT biomarkers of RPE atrophy, presence of intraretinal and subretinal fluid (IRF, SRF), acquired vitelliform lesion and sub RPE regions of hyporeflectivity within the PED compartment. RESULTS: Of the 50 eyes from 41 patients (mean age of 77.1 ± 9 years, 78% women) with large and very large drusen, 16 eyes progressed to collapse. Eyes with sub RPE hyporeflective spaces (n=8 eyes, 50%) were associated with greater drusen width and height than eyes without sub RPE hyporeflective spaces. At the collapse visit, eyes with sub RPE hyporeflective spaces displayed poorer visual acuity and greater iRORA (incomplete RPE outer retinal atrophy) and cRORA (complete RORA) length than eyes without sub RPE hyporeflective spaces (p=0.004 and p=0.04, respectively). CONCLUSION: Sub RPE hyporeflective spaces are a novel OCT finding of large and very large drusen that collapse to atrophy. Progressive RPE dysfunction and failure may lead to reduced drusenoid material formation and progressive degenerative hydration of the large drusen prior to collapse, but this awaits confirmation with histopathological analysis.

Prediction of Long-Term Treatment Outcomes for Diabetic Macular Edema Using a Generative Adversarial Network.

Purpose: The purpose of this study was to analyze optical coherence tomography (OCT) images of generative adversarial networks (GANs) for the prediction of diabetic macular edema after long-term treatment. Methods: Diabetic macular edema (DME) eyes (n = 327) underwent anti-vascular endothelial growth factor (VEGF) treatments every 4 weeks for 52 weeks from a randomized controlled trial (CRTH258B2305, KINGFISHER) were included. OCT B-scan images through the foveal center at weeks 0, 4, 12, and 52, fundus photography, and retinal thickness (RT) maps were collected. GAN models were trained to generate probable OCT images after treatment. Input for each model were comprised of either the baseline B-scan alone or combined with additional OCT, thickness map, or fundus images. Generated OCT B-scan images were compared with real week 52 images. Results: For 30 test images, 28, 29, 15, and 30 gradable OCT images were generated by CycleGAN, UNIT, Pix2PixHD, and RegGAN, respectively. In comparison with the real week 52, these GAN models showed positive predictive value (PPV), sensitivity, specificity, and kappa for residual fluid ranging from 0.500 to 0.889, 0.455 to 1.000, 0.357 to 0.857, and 0.537 to 0.929, respectively. For hard exudate (HE), they were ranging from 0.500 to 1.000, 0.545 to 0.900, 0.600 to 1.000, and 0.642 to 0.894, respectively. Models trained with week 4 and 12 B-scans as additional inputs to the baseline B-scan showed improved performance. Conclusions: GAN models could predict residual fluid and HE after long-term anti-VEGF treatment of DME. Translational Relevance: The implementation of this tool may help identify potential nonresponders after long-term treatment, thereby facilitating management planning for these eyes.

Efficacy of dexamethasone implant in the management of chronic central serous chorioretinopathy without choroidal neovascularization.

PURPOSE: To demonstrate the treatment efficacy of intravitreal dexamethasone (DEX) implant in chronic recurrent/persistent central serous chorioretinopathy (CSC). DESIGN: Prospective, non-randomized, open-label study. METHODS: In this study, subjects with chronic CSC without signs of choroidal neovascularization (CNV) received intravitreal DEX implant therapy. The primary outcome measure was the change in visual acuity. Changes in central macular thickness (CMT) and change in subfoveal choroidal thickness (SFCT) on optical coherence tomography (OCT), incidence of recurrent fluid, and safety of DEX implant were secondary outcome measures. Subjects were followed up for a minimum of 3 months after DEX implantation. RESULTS: In total, 20 eyes of 20 subjects (mean age: 47 ± 9 years) with a median disease duration of 23.5 months were enrolled. With a single injection of DEX implant, a reduction in CMT was noted in 90% of eyes. Complete resolution of subretinal and intraretinal fluid was noted in 55% of eyes within 3 months of injection. A significant improvement in vision (mean Log MAR visual acuity 0.66 ± 0.49 vs. 0.54 ± 0.45; P = 0.020), mean CMT (338 ± 110 microns to 238 ± 73 microns; P < 0.001) and SFCT (514 ± 95 microns to 445 ± 111 microns; P < 0.001) was noted over 3 months. Recurrent fluid was noted in 50% of eyes after a mean follow-up duration of 7 ± 4 months. Elevated intraocular pressure, managed by topical therapy, was noted in six eyes. CONCLUSION: The consistent improvement in visual acuity, fluid resolution, and reduction in choroidal thickness suggests a possible role for DEX implants in managing chronic CSC. A larger randomized trial is warranted.

Long-Term Effects of Intravitreal Ranibizumab Compared With Panretinal Photocoagulation on Optical Coherence Tomography Measured Choroidal Thickness and Vascularity.

Purpose: Compare choroidal changes in ranibizumab versus panretinal photocoagulation (PRP)-treated eyes with proliferative diabetic retinopathy (PDR). Methods: DRCR Retina Network Protocol S post hoc analysis evaluated optical coherence tomography change in choroidal thickness (subfoveal and 3mm superior and inferior to the fovea) through five years; choroidal vascularity index (CVI) was assessed at baseline and one year. Mixed linear models for choroidal change included adjustments for the baseline choroidal value and age. Results: This study included 328 eyes (158 ranibizumab and 170 PRP) from 256 participants (88 ranibizumab and 95 PRP eyes at five years). Mean change in choroidal thickness from baseline to five years at the fovea was -12 µm in ranibizumab versus -8 µm in PRP (difference [95% confidence interval]: -4 [-18 to 10], P = 0.57), superior was -14 µm versus -19 µm (difference: 5 [-8 to 17], P = 0.45) and inferior was -26 µm versus -32 µm [difference: 5 (-9 to 20), P = 0.45]; change at all three points within the ranibizumab group, and the superior and inferior points for PRP, were statistically significant (P < .05). Mean change in CVI at one year was -0.02% in ranibizumab versus -0.95% in PRP (difference: 0.93 [-0.35 to 2.21], P = 0.14). Conclusions: In patients with PDR, treatment with ranibizumab versus PRP did not result in statistically significant differences in five-year choroidal thickness or one-year CVI change. Both groups had significant decreases in choroidal thickness at five years. Translational Relevance: Ranibizumab treatment for PDR did not statistically significantly affect choroidal thickness or vascularity differently than PRP.

The Progression of Stargardt Disease as Determined by Spectral-Domain Optical Coherence Tomography over a 24-Month Period (ProgStar Report No. 18).

INTRODUCTION: The aim of this study was to evaluate the progression of atrophy as determined by spectral-domain optical coherence tomography (SD-OCT) in patients with molecularly confirmed ABCA4-associated Stargardt disease type 1 (STGD1) over a 24-month period in a multicenter prospective cohort study. METHODS: SD-OCT images from 428 eyes of 236 patients were analyzed. Change of mean thickness (MT) and intact area were estimated after semiautomated segmentation for the following individual layers in the central subfield (CS), inner ring (IR), and outer ring (OR) of the ETDRS grid: retinal pigment epithelium (RPE), outer segments (OSs), inner segments (IS), outer nuclear layer (ONL) inner retina (IR), and total retina. RESULTS: Statistically significant decreases of all outer retinal layers (RPE, OS, IS, and ONL) could be observed over a 24-month period both in decline of mean retinal thickness and intact area (p < 0.0001, respectively), whereas the IR showed an increase of retinal thickness in the CS and IR and remained unchanged in the OR. CONCLUSIONS: Significant loss could be detected in outer retinal layers by SD-OCT over a 24-month period in patients with STGD1. Loss of thickness and/or intact area of such layers may serve as potential endpoints for clinical trials that aim to slow down the disease progression of STGD1.

Managing a patient with uveitis in the era of artificial intelligence: Current approaches, emerging trends, and future perspectives.

The integration of artificial intelligence (AI) with healthcare has opened new avenues for diagnosing, treating, and managing medical conditions with remarkable precision. Uveitis, a diverse group of rare eye conditions characterized by inflammation of the uveal tract, exemplifies the complexities in ophthalmology due to its varied causes, clinical presentations, and responses to treatments. Uveitis, if not managed promptly and effectively, can lead to significant visual impairment. However, its management requires specialized knowledge, which is often lacking, particularly in regions with limited access to health services. AI's capabilities in pattern recognition, data analysis, and predictive modelling offer significant potential to revolutionize uveitis management. AI can classify disease etiologies, analyze multimodal imaging data, predict outcomes, and identify new therapeutic targets. However, transforming these AI models into clinical applications and meeting patient expectations involves overcoming challenges like acquiring extensive, annotated datasets, ensuring algorithmic transparency, and validating these models in real-world settings. This review delves into the complexities of uveitis and the current AI landscape, discussing the development, opportunities, and challenges of AI from theoretical models to bedside application. It also examines the epidemiology of uveitis, the global shortage of uveitis specialists, and the disease's socioeconomic impacts, underlining the critical need for AI-driven approaches. Furthermore, it explores the integration of AI in diagnostic imaging and future directions in ophthalmology, aiming to highlight emerging trends that could transform management of a patient with uveitis and suggesting collaborative efforts to enhance AI applications in clinical practice.

Peripheral retinal lesions in diabetic retinopathy on ultra-widefield imaging.

Peripheral retinal imaging plays a crucial role in the diagnosis, management, and prognosis of diabetic retinopathy (DR). Traditional fundus imaging techniques have limited coverage of the retina, resulting in missed peripheral lesions. The advent of ultra-widefield (UWF) imaging has revolutionized the assessment of the peripheral retina. UWF imaging modalities provide comprehensive visualization of the retina, enabling the detection of peripheral lesions without the need for mydriasis. Integration of UWF imaging with other modalities, including fluorescein angiography (FA), indocyanine green angiography, pseudocolor imaging, and fundus autofluorescence, further enhances our understanding of peripheral retinal lesions. UWF imaging has demonstrated improved detection of DR lesions and presumably more accurate management of DR compared to traditional fundus photography and dilated fundus examination. UWF-FA and UWF-optical coherence tomography angiography have emerged as valuable tools for assessing retinal and choroidal vascular abnormalities, nonperfusion areas, neovascularization, and microvascular abnormalities. The presence and increasing extent of predominantly peripheral lesions detected using UWF FA are associated with a higher risk of DR progression and proliferative DR. UWF imaging provides a comprehensive evaluation of DR severity, aiding in more accurate risk stratification and treatment decision-making. Overall, UWF imaging modalities have significantly advanced our understanding of peripheral retinal lesions in DR, facilitating early detection and targeted management for better visual outcomes.

VITELLIFORM LESIONS ASSOCIATED WITH LEPTOCHOROID AND PSEUDODRUSEN.

OBJECTIVE: To characterize clinical and prognostic implications of leptovitelliform maculopathy (LVM), a distinctive phenotype of vitelliform lesion characterized by the coexistence of subretinal drusenoid deposits (SDD) and leptochoroid. DESIGN: Retrospective, cohort study. SUBJECTS: The study compares patients affected by leptovitelliform maculopathy with cohorts displaying a similar phenotypic spectrum. This includes patients with acquired vitelliform lesions (AVL) and those with SDD alone. METHODS: A total of 60 eyes of 60 patients were included, of whom 20 eyes had LVM, 20 eyes had AVL, and the remaining had SDD. Patients older than 50 years with complete medical records and multimodal imaging for at least 6 months of follow-up, including color fundus photograph (CFP) or MultiColor, optical coherence tomography (OCT), fundus autofluorescence (FAF), and OCT angiography (OCTA) were included. MAIN OUTCOME MEASURES: Choroidal vascularity index (CVI); proportion of late-stage complications (macular neovascularization, atrophy). RESULTS: The AVL subgroup exhibited a significantly higher CVI compared to both LVM (p<0.001) and SDD subgroups (p<0.001). The proportion of late-stage complications significantly differed among subgroups (χ2=7.5, p=0.02). Eyes with LVM presented the greatest proportion of complications (55%) after a mean of 29.3 months, while the remaining eyes presented a similar proportion of complications, including 20% in AVL after 27.6 months and 20% in SDD after 36.9 months. Kaplan-Meier estimates of survival demonstrated a significant difference in atrophy development between groups (p<0.001), with a median survival of 3.9 years for LVM and 7.1 years for controls. The presence of LVM correlated with a fourfold increase in the likelihood of developing complications. CONCLUSIONS: Leptovitelliform maculopathy, characterized by the association of vitelliform lesions with SDD and leptochoroid, represents a distinct clinical phenotype in the broader spectrum of vitelliform lesions. The importance of a clinical distinction for these lesions is crucial due to a higher propensity for faster progression and an elevated rate of complications, particularly toward atrophic conversion.

Choriocapillaris Impairment, Visual Function, and Distance to Fovea in Aging and Age-Related Macular Degeneration: ALSTAR2 Baseline.

Purpose: In aging and early-intermediate age-related macular degeneration (AMD), rod-mediated dark adaptation (RMDA) slows more at 5° superior than at 12°. Using optical coherence tomography angiography (OCTA), we asked whether choriocapillaris flow deficits are related to distance from the fovea. Methods: Persons ≥60 years stratified for AMD via the Age-Related Eye Disease Study's nine-step system underwent RMDA testing. Two adjacent 4.4° × 4.4° choriocapillaris OCTA slabs were centered on the fovea and 12° superior. Flow signal deficits (FD%) in concentric arcs (outer radii in mm, 0.5, 1.5, 2.2, 4.0, and 5.0 superior) were correlated with rod intercept time (RIT) and best-corrected visual acuity (BCVA). Results: In 366 eyes (170 normal, 111 early AMD, 85 intermediate AMD), FD% was significantly worse with greater AMD severity in all regions (overall P < 0.05) and poorest under the fovea (P < 0.0001). In pairwise comparisons, FD% worsened with greater AMD severity (P < 0.05) at distances <2.2 mm. At greater distances, eyes with intermediate, but not early AMD differed from normal eyes. Foveal FD% was more strongly associated with longer RIT at 5° (r = 0.52) than RIT at 12° (r = 0.39) and BCVA (r = 0.21; all P < 0.0001). Choroidal thickness was weakly associated with longer RIT at 5° and 12° (r = 0.10-0.20, P < 0.05) and not associated with AMD severity. Conclusions: Reduced transport across the choriocapillaris-Bruch's membrane-retinal pigment epithelium complex, which contributes to drusen formation under the macula lutea (and fovea), may also reduce retinoid resupply to rods encircling the high-risk area. FD% has potential as a functionally validated imaging biomarker for AMD emergence.

Effect of brolucizumab and aflibercept on the maximum thickness of pigment epithelial detachments and sub-RPE fluid in HAWK and HARRIER.

OBJECTIVE: To compare the efficacy of brolucizumab and aflibercept treatment in reducing maximum thickness of pigment epithelial detachments (PED) and sub-retinal pigment epithelium (sub-RPE) fluid in patients with neovascular age-related macular degeneration (nAMD) in the HAWK and HARRIER studies. DESIGN: HAWK and HARRIER were 96-week, prospective, randomized, double-masked, controlled, multicenter studies SUBJECTS, PARTICIPANTS, AND/OR CONTROLS: 1,775 patients across 11 countries were included in the HAWK study and 1,048 patients across 29 countries were included in the HARRIER study. METHOD AND INTERVENTIONS: After three monthly loading doses, brolucizumab-treated eyes received injections every 12 weeks (q12w) or q8w if disease activity (DA) was detected. Aflibercept-treated eyes received fixed q8w dosing. MAIN OUTCOMES MEASURES: Maximum thickness of PED and sub-RPE fluid across the macula were assessed at baseline through Week 96 in the brolucizumab- and aflibercept-treated patients, and in the patient subgroups with DA at Week 16 (matched in terms of injection number and treatment interval). RESULTS: At Week 96, there were greater mean percentage reductions from baseline in maximum thickness of both PED and sub-RPE fluid in brolucizumab-treated patients versus aflibercept-treated patients (PED: 19.7% [n=336] vs 11.9% [n=335] in HAWK; 29.5% [n=364] vs 18.3% [n=361] in HARRIER. Sub-RPE fluid: 75.4% vs 57.3% in HAWK; 86.0% vs 76.3% in HARRIER). A similar trend in mean percentage reductions was observed in patients with DA at Week 16. CONCLUSIONS: This analysis shows that brolucizumab achieved greater reductions in PED and sub-RPE fluid thickness than aflibercept in HAWK and HARRIER.

International Classification System for Ocular Complications of Anti-VEGF Agents in Clinical Trials.

PURPOSE: Complications associated with intravitreal anti-VEGF therapies are reported inconsistently in the literature, thus limiting an accurate evaluation and comparison of safety between studies. This study aimed to develop a standardized classification system for anti-VEGF ocular complications using the Delphi consensus process. DESIGN: Systematic review and Delphi consensus process. PARTICIPANTS: Twenty-five international retinal specialists participated in the Delphi consensus survey. METHODS: A systematic literature search was conducted to identify complications of intravitreal anti-VEGF agent administration based on randomized controlled trials (RCTs) of anti-VEGF therapy. A comprehensive list of complications was derived from these studies, and this list was subjected to iterative Delphi consensus surveys involving international retinal specialists who voted on inclusion, exclusion, rephrasing, and addition of complications. Furthermore, surveys determined specifiers for the selected complications. This iterative process helped to refine the final classification system. MAIN OUTCOME MEASURES: The proportion of retinal specialists who choose to include or exclude complications associated with anti-VEGF administration. RESULTS: After screening 18 229 articles, 130 complications were categorized from 145 included RCTs. Participant consensus via the Delphi method resulted in the inclusion of 91 complications (70%) after 3 rounds. After incorporating further modifications made based on participant suggestions, such as rewording certain phrases and combining similar terms, 24 redundant complications were removed, leaving a total of 67 complications (52%) in the final list. A total of 14 complications (11%) met exclusion thresholds and were eliminated by participants across both rounds. All other remaining complications not meeting inclusion or exclusion thresholds also were excluded from the final classification system after the Delphi process terminated. In addition, 47 of 75 proposed complication specifiers (63%) were included based on participant agreement. CONCLUSIONS: Using the Delphi consensus process, a comprehensive, standardized classification system consisting of 67 ocular complications and 47 unique specifiers was established for intravitreal anti-VEGF agents in clinical trials. The adoption of this system in future trials could improve consistency and quality of adverse event reporting, potentially facilitating more accurate risk-benefit analyses. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evaluating fingerprint-like patterns in the healthy Henle fiber layer using enface OCT imaging.

PURPOSE: Enface OCT may disclose a distinct "fingerprint-like' pattern within the HFL in various macular disorders. This study aims to investigate the frequency and characteristics of this pattern in healthy eyes and identify potential factors influencing its visibility. METHODS: Two, independent masked reading center graders evaluated for the presence and prominence of a fingerprint pattern in the Henle fiber layer (HFL) on enface OCT images from 33 healthy subjects (66 eyes). The prominence of the pattern was rated qualitatively using a 0-3 scale, with 3 indicating the strongest prominence. Tilt angles (relative to the normal/perpendicular at the center) of the retina were measured on horizontal and vertical B-scans, and the retinal curvature was assessed using ImageJ, in order to determine the impact of the incident light angle on the visibility and prominence of the fingerprint pattern. Inter-grader agreement using Cohen's kappa and the frequency and percentage of patterns in the entire enface image and in each quadrant were calculated and compared using the Friedman test with Dunn's post-test. A generalized estimating equation (GEE) was used to analyze the association between these metrics and fingerprint prominence. RESULTS: Substantial inter-grader agreement was observed (Cohen's kappa = 0.71) for assessing the prominence of the fingerprint pattern. Over 70% of eyes exhibited some evidence of the pattern (score ≥1). Significant difference in pattern prominence across quadrants was detected (p < 0.05), with lowest prominence in the temporal quadrant (p < 0.001 for pairwise comparisons against all other quadrants). The GEE analysis to account for the extent of the effect of scan tilt angle and RPE curvature was not able to predict the prominence of the fingerprint pattern, highlighting that angle of incidence (of the scanning laser light) alone could not explain the pattern. CONCLUSIONS: This study confirms that a fingerprint-like pattern within the HFL can also be observed in healthy eyes, challenging the notion that this finding is only manifest in the setting of disease. In addition, the lack of correlation with angle of incident light suggests that the pattern may be related to other intrinsic characteristics of the HFL.

Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management.

Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.

Probing Deposit-Driven Age-Related Macular Degeneration Via Thicknesses of Outer Retinal Bands and Choroid: ALSTAR2 Baseline.

Purpose: We aimed to identify structural differences in normal eyes, early age-related macular degeneration (AMD), and intermediate AMD eyes using optical coherence tomography (OCT) in a well-characterized, large cross-sectional cohort. Methods: Subjects ≥ 60 years with healthy normal eyes, as well as early or intermediate AMD were enrolled in the Alabama Study on Age-related Macular Degeneration 2 (ALSTAR2; NCT04112667). Using Spectralis HRA + OCT2, we obtained macular volumes for each participant. An auto-segmentation software was used to segment six layers and sublayers: photoreceptor inner and outer segments, subretinal drusenoid deposits (SDDs), retinal pigment epithelium + basal lamina (RPE + BL), drusen, and choroid. After manually refining the segmentations of all B-scans, mean thicknesses in whole, central, inner and outer rings of the ETDRS grid were calculated and compared among groups. Results: This study involved 502 patients, 252 were healthy, 147 had early AMD, and 103 had intermediate AMD eyes (per Age-Related Eye Disease Study [AREDS] 9-step). Intermediate AMD eyes exhibited thicker SDD and drusen, thinner photoreceptor inner segments, and RPE compared to healthy and early AMD eyes. They also had thicker photoreceptor outer segments than early AMD eyes. Early AMD eyes had thinner photoreceptor outer segments than normal eyes but a thicker choroid than intermediate AMD eyes. Using the Beckman scale, 42% of the eyes initially classified as early AMD shifted to intermediate AMD, making thickness differences for photoreceptor outer segments and choroid insignificant. Conclusions: With AMD stages, the most consistent structural differences involve appearance of drusen and SDD, followed by RPE + BL thickness, and then thickness of photoreceptor inner and outer segments. Structural changes in the transition from aging to intermediate AMD include alterations in the outer retinal bands, including the appearance of deposits on either side of the RPE.

Subretinal hyperreflective material in regions of atrophy and fibrosis in eyes with neovascular age-related macular degeneration.

BACKGROUND: Subretinal hyperreflective material (SHRM) is a significant biomarker for poor visual outcomes in neovascular age-related macular degeneration (nAMD); however, its relationship with fibrosis and atrophy is not well understood. This study aims to evaluate the relationship between SHRM, atrophy, and fibrosis in eyes receiving antivascular endothelial growth factor therapy for nAMD. METHODS: Post-hoc analysis of the 65 patients enrolled in the SEVEN-UP study, a multicenter cross-sectional study of patients originally enrolled in the ANCHOR and MARINA trials of ranibizumab. Color fundus photographs (CFP) were reviewed and manually segmented to define regions of atrophy and fibrosis. SHRM borders on OCT volume scans were manually delineated, and thickness measurements were computed and compared in corresponding regions of atrophy and fibrosis on the CFPs. RESULTS: Of the 65 subjects, 51 eyes showed atrophy and/or fibrosis on CFP and were included in the final analysis. Both atrophy and fibrosis regions exhibited SHRM on OCT. The mean SHRM thickness on OCT was significantly greater in CFP-fibrosis regions (44.19 ± 46.95 µm) compared with CFP-atrophy regions (14.28 ± 13.35 µm; p < 0.001). Additionally, the average maximum height of SHRM in fibrotic regions (268.04 ± 130.05 µm) was significantly thicker than in atrophic regions (121.95 ± 51.17 µm; p < 0.001). CONCLUSIONS: Although atrophy and fibrosis are thought to be different end-stage outcomes in eyes with nAMD, they both demonstrate SHRM on OCT; the main distinction being thickness. Given these similarities, these regions of nAMD-associated atrophy may be better-termed "atrosis" to distinguish these lesions from typical atrophy in the absence of neovascular disease.

Relationship between macular perfusion and lesion distribution in diabetic retinopathy.

BACKGROUND/OBJECTIVES: To assess the relationship between macular vessel density metrics and foveal avascular zone (FAZ) characteristics on optical coherence tomography angiography (OCTA) and lesion distribution in eyes with diabetic retinopathy (DR). SUBJECTS/METHODS: Patients with DR who underwent both Optos ultrawidefield (UWF) pseudocolor imaging and macular OCTA (Cirrus Angioplex, 6 × 6 mm) were included in this cross-sectional observational study. The distribution of DR lesions was assessed by comparing each of the peripheral ETDRS extended fields (3-7) against their corresponding ETDRS field, hence eyes were defined as either having predominantly peripheral lesions (PPL) or predominantly central lesions (PCL). En face OCTA images from the superficial and deep capillary plexuses (SCP and DCP) were then analysed using Image J software. Perfusion density (PD), vessel length density (VLD), and fractal dimensions (FD) were calculated following binarization and skeletonization of the images. RESULTS: Out of 344 eyes, 116 (33.72%) eyes had PPL and 228 (66.28%) eyes had PCL. For all DRSS levels, VLD, PD, and FD were not significantly different between eyes with PPL and PCL. The FAZ in eyes with PPL, however, was found to be more circular in shape compared to eyes with PCL (p = 0.037). CONCLUSION: Although the presence of PPL has been associated with a higher risk for diabetic retinopathy progression, the macular perfusion is similar in eyes with PPL and PCL. The FAZ is more circular in eyes with PPL, but the clinical relevance of this difference remains to be defined.

Alterations of the Ganglion Cell Complex in Age-Related Macular Degeneration: An Amish Eye Study Analysis.

PURPOSE: To compare the ganglion cell complex (GCC) thickness in eyes with age-related macular degeneration (AMD) vs healthy controls in an elderly Amish population. DESIGN: Prospective cross-sectional study. METHODS: This is a post hoc analysis of the family-based prospective study of Amish subjects. Study subjects underwent imaging with the Cirrus HD-OCT (Carl Zeiss Meditec Inc) using a macular cube protocol of 512 × 128 scans (128 horizontal B-scans, each comprising 512 A-scans) over a 6 mm × 6 mm region centered on the fovea. The ganglion cell analysis algorithm calculated the GCC thickness by segmenting the outer boundaries of the retinal nerve fiber layer (RNFL) and inner plexiform layer (IPL) in all B-scans of the volume, with the region between these boundaries representing the combined thickness of the ganglion cell layer (GCL) and the IPL. A number of parameters were used to evaluate the GCC thickness: the average GCC thickness, minimum (lowest GCC thickness at a single meridian crossing the elliptical annulus), and sectoral (within each of 6 sectoral areas: superior, superotemporal, superonasal, inferior, inferonasal, and inferotemporal). The stage of AMD was graded on color fundus photographs in accordance with the Beckman Initiative for Macular Research classification system. RESULTS: Of 1339 subjects enrolled in the Amish eye study, a total of 1294 eyes of 1294 subjects had all required imaging studies of sufficient quality and were included in the final analysis. Of these, 798 (62%) were female. Following age adjustment, the average GCC thickness was significantly (P < .001) thinner in AMD subjects (73.71 ± SD; 13.77 µm) compared to normals (77.97 ± 10.42 µm). An independent t test showed that the early AMD (75.03 ± 12.45 µm) and late AMD (61.64 ± 21.18 µm) groups (among which eyes with geographic atrophy [GA] had the lowest thickness, of 58.10 ± 20.27 µm) had a statistically significant lower GCC thickness compared to eyes without AMD. There was no significant differences in average GCC thickness between early AMD and intermediate AMD (76.36 ± 9.25 µm) eyes. CONCLUSIONS: The GCC thickness in AMD eyes is reduced compared to normal eyes; however, the relationship is complex, with the greatest reduction in late AMD eyes (particularly eyes with GA) but no difference between early and intermediate AMD eyes.