IDENTIFYING FEATURES OF EARLY AND LATE AGE-RELATED MACULAR DEGENERATION: A Comparison of Multicolor Versus Traditional Color Fundus Photography

Agreement Between Color, Fluorescein Angiography, and Spectral Domain Optical Coherence Tomography in the Detection of Macular Fibrosis in Neovascular Age-Related Macular Degeneration

PURPOSE

To evaluate the agreement between fibrosis on color imaging-, fluorescein angiography (FA)-, and spectral domain optical coherence tomography (SD-OCT)-detected hyperreflective material (HRM) and assess their clinical relevance.

DESIGN

Clinical cohort and diagnostic accuracy study.

METHODS

Multimodal fundus images (color, FA, and SD-OCT) of 130 eyes with neovascular age-related macular degeneration, collected 18 months after the initiation of anti-vascular endothelial growth factor treatment (anti-VEGF) as part of the Early Detection of Neovascular AMD (EDNA) study, were regraded for fibrosis and HRM. HRM location was assigned as subretinal (SR) and/or subretinal pigment epithelial (SPE). Agreement between detection methods was assessed with the kappa statistic, and regression analysis with best corrected visual acuity (BCVA) as outcome variable was used to evaluate clinical relevance.

RESULTS

Kappa was 0.56 for FA and 0.40 for HRM on SD-OCT, using color as the reference. Regression against BCVA showed low R² values for all tests (R² < 0.09). In the HRM-OCT model, with no HRM as the reference and location and dimensions as covariates, the R² increased to 0.301. Letter loss was 21.1 (P < .0001) for SR and 8.1 (P = .045) for SPE. When HRM on SD-OCT was the reference, the sensitivity for color and FA combination was 87.5% but was lower at 33.3% for SPE only.

CONCLUSIONS

Well-defined HRM detected by SD-OCT during the maintenance phase of anti-VEGF therapy explains BCVA variance, positioning OCT as a superior standard for detecting fibrosis.

Exploring retinal conditions through blue light reflectance imaging

Blue light reflectance (BLR) imaging offers a non-invasive, cost-effective method for evaluating retinal structures by analyzing the reflectance and absorption characteristics of the inner retinal layers. By leveraging blue light's interaction with retinal tissues, BLR enhances visualization beyond the retinal nerve fiber layer, improving detection of structures such as the outer plexiform layer and macular pigment. Its diagnostic utility has been demonstrated in distinct retinal conditions, including hyperreflectance in early macular telangiectasia, hyporeflectance in non-perfused areas indicative of ischemia, identification of pseudodrusen patterns (notably the ribbon type), and detection of peripheral retinal tears and degenerative retinoschisis in eyes with reduced retinal pigment epithelial pigmentation. Best practices for image acquisition and interpretation are discussed, emphasizing standardization to minimize variability. Common artifacts and mitigation strategies are also addressed, ensuring image reliability. BLR's clinical utility, limitations, and future research directions are highlighted, particularly its potential in automated image analysis and quantitative assessment. Different BLR acquisition methods, such as fundus photography, confocal scanning laser ophthalmoscopy, and broad line fundus imaging, are evaluated for their respective advantages and limitations. As research advances, BLR's integration into multimodal workflows is expected to improve early detection and precise monitoring of retinal diseases.

A high-fat plus high-sucrose diet induces age-related macular degeneration in an experimental rabbit model

Age-related macular degeneration (AMD) is a leading cause of blindness. Metabolic disorders and diets are risk factors. We compared lipid profiles and retinal phenotypes with long-term feeding of four diets in male Chinchilla rabbits. Animals were fed a normal diet (ND), high-fat diet (HFD), high-sucrose diet (HSD) or a high-fat plus high-sucrose diet (HFSD) for 6 months. Eyes were examined using multimodal imaging modalities and electroretinograms. Retinal sections were analyzed using H&E staining, Toluidine Blue staining, immunostaining and transmission electron microscopy. Lipids and complement C3 protein (C3) in serum or aqueous humor were measured. RNA sequencing was performed to evaluate the retinal transcriptomes. HFD and HSD had minor effects on lipid profiles but, when fed concomitantly, synergistically induced severe dyslipidemia. None of the four diets caused obesity. HFSD induced retinal lesions, such as reticular pseudodrusen (RPDs) and other pigmentary abnormalities. RPD-like lesions were mainly lipid droplets around cells of the retinal pigment epithelium. HFSD also induced elevated levels of ocular C3 and reduced the density of retinal vessels. In conclusion, HFD and HSD can - when combined - induce normal-weight dyslipidemia and RPD-like retinal lesions. HFSD-fed male Chinchilla rabbits are a good model of early AMD.

Multicolor imaging: Current clinical applications

Multicolor (MC) imaging is an innovative pseudocolor fundus imaging modality based on confocal scanning laser ophthalmoscopy. It effectively scans the retina at different depths to create a composite image. The green reflectance image depicts the middle retinal while blue reflectance image provides images of the retinal surface. The infrared reflectance image depicts retinal structures at the level of outer retina and choroid. We systematically analyze published case reports, case series, and original articles on MC imaging where it has helped in discovering additional clinical features of retinal diseases not readily apparent on conventional color fundus photography and played a role in monitoring the response to treatment.

Clinical application of multicolor scanning laser ophthalmology in diagnosis and grading of central retinal artery occlusion

Purpose

To characterize features of central retinal artery occlusion (CRAO) using multicolor (MC) imaging and to assess the differences in CRAO grading between color fundus photography (CFP) and MC image qualitatively and quantitatively.

Methods

We conducted a prospective, cross-sectional study in the Department of Ophthalmology of Renmin Hospital of Wuhan University. In total, 86 acute CRAO patients were included. Spectral-domain optical coherence tomography (SD-OCT), CFP, and MC examinations were taken at baseline. Based on the findings of these three examinations, CRAO was divided into three grades (incomplete, subtotal, and total). Based on OCT grading criteria, we qualitatively compared the ability of grading CRAO by CFP and MC. CRAO patient's visual acuity (VA) was obtained from the initial visit. The retinal thickness was measured by SD-OCT. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained from optical coherence tomography angiography (OCTA) examinations. Quantitative data were compared across the three acute CRAO subgroups and against three examination findings.

Results

MC image had significantly higher power of acute CRAO detection than CFP (P = 0.03). In the same group of CRAO patients, there was no significant difference in VA when comparing OCT with the MC grading system or with the CFP grading system (all P > 0.05). Significant differences in VA were found between the three CRAO subgroups only under MC grading (P = 0.016). In incomplete CRAO patients, significant differences were found in central fovea thickness (CFT) when comparing OCT with the CFP grading system (P = 0.019). In the same group of CRAO patients, there was no significant difference in retinal thickness when comparing OCT with the MC grading system (All P > 0.05). Significance differences in CFT (P < 0.001), innermost retinal layer (IMRL; P < 0.01), middle retinal layer (MRL; P < 0.001), and outer retinal layer (ORL; P = 0.021) were found between the three CRAO subgroups by MC grading. Vessel density of SCP showed a statistically increased as the severity of three CRAO subgroups (P = 0.03), whereas DCP did not have significant differences (P = 0.745). Comparisons were made between the OCT grading method and the MC and CFP grading methods; there is no significant difference in vessel density of SCP and DCP (All P > 0.05).

Conclusion

The images obtained by MC are superior to those obtained by CFP in CRAO grading, retinal thickness, and vessel density measurement. MC imaging may be more capable of CRAO grading than OCT. We recommend MC imaging to determine CRAO severity to guide disease treatment and predict visual prognosis.

Non-Neovascular Age-Related Macular Degeneration Assessment: Focus on Optical Coherence Tomography Biomarkers

The imagistic evaluation of non-neovascular age-related macular degeneration (AMD) is crucial for diagnosis, monitoring progression, and guiding management of the disease. Dry AMD, characterized primarily by the presence of drusen and retinal pigment epithelium atrophy, requires detailed visualization of the retinal structure to assess its severity and progression. Several imaging modalities are pivotal in the evaluation of non-neovascular AMD, including optical coherence tomography, fundus autofluorescence, or color fundus photography. In the context of emerging therapies for geographic atrophy, like pegcetacoplan, it is critical to establish the baseline status of the disease, monitor the development and expansion of geographic atrophy, and to evaluate the retina's response to potential treatments in clinical trials. The present review, while initially providing a comprehensive description of the pathophysiology involved in AMD, aims to offer an overview of the imaging modalities employed in the evaluation of non-neovascular AMD. Special emphasis is placed on the assessment of progression biomarkers as discerned through optical coherence tomography. As the landscape of AMD treatment continues to evolve, advanced imaging techniques will remain at the forefront, enabling clinicians to offer the most effective and tailored treatments to their patients.

Relative yield of retinal imaging versus clinical exam in following neovascular exudative age related macular degeneration

PURPOSE

To compare therapeutic decisions between 3 diagnostic protocols and to assess the need for in-person physical doctor-patient encounter in follow up and treatment of neovascular exudative age-related macular degeneration (AMD).

METHODS

Analysis of 88 eyes of 88 unique patients with neovascular AMD who were routinely followed at our medical retina clinic. A retinal specialist reviewed all images in advance and wrote his decisions. He later attended an in-person encounters with all patients and documented his decisions. Masking was done by not exposing any identifying information to the specialist and by randomizing patient's images order before the in-person encounter. Therapeutic decisions regarding intravitreal injections intervals and agent selection were made based on three protocols: (1) optic coherence tomography (OCT); (2) OCT/Ultra-widefield (UWF) color image; (3) OCT/UWF/full clinical exam. Visual acuity (VA) was incorporated into all protocols.

RESULTS

We found an agreement of 93% between those protocols regarding the intervals of injections, and of 100% regarding injection agent selection. When comparing OCT, OCT/UWF and OCT/UWF/clinical exam guided decision making, there were no discrepancies between OCT and OCT/UWF. There were 6 out of 88 discrepancies (7%) between OCT/UWF and OCT/UWF/clinical exam. Of those 6 discrepancies, all were regarding intervals (Bland-Altman bias = - 0.2386). All discrepancies between OCT/UWF and OCT/UWF/Clinical exam were due to patients' preferences, socioeconomic issues and fellow eye considerations, addressed during the face-to-face encounter with patients. Physical examination itself did not affect decision making.

CONCLUSIONS

Neovascular exudative AMD follow up and treatment decisions can be guided by VA and OCT, with UWF adding important information regarding macula and peripheral retina, but rarely affecting decision making. However, decision making may also be driven by patients' preferences and other considerations that are being made only during the face-to-face visit and discussion. Thus, every approach supporting imaging only decision making, must take these factors into account.

Structure-Function Correlation of Retinal Fibrosis in Eyes with Neovascular Age-Related Macular Degeneration

Purpose: To assess retinal function in areas of presumed fibrosis due to neovascular age-related macular degeneration (nAMD), using multimodal imaging and structure-function correlation. Design: Cross-sectional observational study. Methods: 30 eyes of 30 consecutive patients with nAMD with a minimum history of one year of anti-vascular endothelial growth factor therapy were included. Each patient underwent microperimetry (MP), color fundus photography (CFP), standard spectral-domain-based OCT (SD-OCT), and polarization sensitive-OCT (PS-OCT) imaging. PS-OCT technology can depict retinal fibrosis based on its birefringence. CFP, SD-OCT, and PS-OCT were evaluated independently for the presence of fibrosis at the corresponding MP stimuli locations. MP results and morphologic findings in CFP, SD-OCT, and PS-OCT were co-registered and analyzed using mixed linear models. Results: In total, 1350 MP locations were evaluated to assess the functional impact of fibrosis according to a standardized protocol. The estimated means of retinal areas with signs of fibrosis were 12.60 db (95% confidence interval: 10.44-14.76) in CFP, 11.60 db (95% COI: 8.84-14.36) in OCT, and 11.02 db (95% COI 8.10-13.94) in PS-OCT. Areas evaluated as subretinal fibrosis in three (7.2 db) or two (10.1 db) modalities were significantly correlated with a lower retinal sensitivity than a subretinal fibrosis observed in only one (15.3 db) or none (23.3 db) modality (p < 0.001). Conclusions: CFP, SD-OCT and PS-OCT are all suited to detect areas of reduced retinal sensitivity related to fibrosis, however, a multimodal imaging approach provides higher accuracy in the identification of areas with low sensitivity in MP (i.e., impaired retinal function), and thereby improves the detection rate of subretinal fibrosis in nAMD.

Prevalence and risk factors for age-related macular degeneration in a population-based cohort study of older adults in Northern Ireland using multimodal imaging: NICOLA Study

PURPOSE

To report prevalence and risk factor associations for age-related macular degeneration (AMD) and AMD features from multimodal retinal grading in a multidisciplinary longitudinal population-based study of aging in Northern Ireland.

STUDY DESIGN

Population-based longitudinal cohort study.

METHODS

Retinal imaging at the Norther Ireland Cohort for the Longitudinal Aging Study health assessment included stereo Colour Fundus Photography (CFP) (Canon CX-1, Tokyo, Japan) and Spectral-Domain Optical Coherence Tomography (SD-OCT) ((Heidelberg Retinal Angopgraph (HRA)+OCT; Heidelberg Engineering, Heidelberg, Germany). Medical history and demographic information was obtained during a home interview. Descriptive statistics were used to describe the prevalence of AMD and individual AMD features. Multiple imputation followed by multiple regression modelling was used to explore risk factor associations including relationships with AMD genetic risk score.

RESULTS

Retinal images from 3386 participants were available for analysis. Mean age of the sample was 63.4 (SD 9.01, range: 36-99). Population weighted prevalence of AMD using colour grading in those over 55 years was: no drusen: 6 0.4%; drusen <63 μm: 15.9%; drusen 63-125 µm: 13.7%; drusen >125 µm or pigmentary changes: 8.3%; late AMD: 1.6%. Prevalence of AMD features in those over 55 years was: OCT drusen 27.5%, complete outer retinal pigment epithelium and outer retinal atrophy (cRORA) on OCT was 4.3%, reticular drusen 3.2% and subretinal drusenoid deposits 25.7%. The genetic risk score was significantly associated with drusen and cRORA but less so for SDD alone and non-significant for hyperpigmentation or vitelliform lesions.

CONCLUSIONS

Multimodal imaging-based classification has provided evidence of some divergence of genetic risk associations between classical drusen and SDD. Our findings support an urgent review of current AMD severity classification systems.

Fibrosis in neovascular age-related macular degeneration: A review of definitions based on clinical imaging

Despite the success of antiangiogenic therapy in controlling exudation in neovascular age-related macular degeneration (nAMD), the involvement of the outer retina in fibrosis results in gradual vision loss over time. The development of drugs that prevent or ameliorate fibrosis in nAMD requires that it is accurately detected and quantified with reliable endpoints and identification of robust biomarkers. Achievement of such an aim is currently challenging due to the lack of a consensus definition of fibrosis in nAMD. As a first step towards the establishment of a clear definition of fibrosis, we provide an extensive overview of the imaging modalities and criteria used to characterize fibrosis in nAMD. We observed variety in the selection of individual and combinations of imaging modalities, and criteria for detection. We also observed heterogeneity in classification systems and severity scales for fibrosis. The most commonly used imaging modalities were color fundus photography, fluorescein angiography and optical coherence tomography (OCT). A multimodal approach was frequently utilized. Our review suggests that OCT offers a more detailed, objective and sensitive characterization than color fundus photography/fluorescein angiography. Thus, we recommend it as a primary modality for fibrosis evaluation. This review provides a basis for future discussions to reach a consensus definition using standardized terms based on a detailed characterization of fibrosis, its presence and evolution, and taking into consideration impact on visual function. Achieving this goal is of paramount importance for the development of antifibrotic therapies.

Comparison of Color Fundus Photography and Multicolor Fundus Imaging for Detection of Lesions in Diabetic Retinopathy and Retinal Vein Occlusion

Purpose

To evaluate the agreement between conventional fundus photography (CFP) and multicolor fundus imaging (MFI) for the detection of lesions of diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods

Cross-sectional analysis of eyes with DR or RVO who underwent CFP and MFI. All images were independently analyzed by two observers (O1 and O2), and the evaluated lesions were classified as "present" or "absent". Then, a paired comparison between both exams of the same eye was performed, to assess which made it easier to detect the lesions.

Results

Considering DR, the agreement was substantial for cotton wool spots and photocoagulation scars for both observers (O1: κ=0.75 and κ=0.67; O2: κ=0.71 and κ=0.64, respectively) and for hard exudates for O1 (κ=0.80). These lesions were detected more frequently on MFI. Regarding RVO, the agreement was considered substantial for venous sheathing by O1 (κ=0.64) and moderate for optociliary shunts by O2 (κ=0.60). Optociliary shunts were detected more frequently in CPF by both observers and venous sheathing on MFI by O1. For microaneurysms, retinal hemorrhages, retinal neovascularization, and proliferative membranes, in DR, and retinal hemorrhages, venous engorgement, and retinal neovascularization in RVO, the agreement was almost perfect (κ>0.82). In the paired analysis, both observers considered that, in DR, microaneurysms and retinal hemorrhages were easier to detect on CFP and that retinal neovascularization, cotton wool spots, and photocoagulation scars were easier to identify on MFI. Regarding RVO, optocilliary shunts were easier to identify on CFP and venous engorgement on MFI.

Conclusion

The agreement of MFI and CFP was substantial to almost perfect for most lesions. MFI seems better to detect cotton wool spots and photocoagulations scars in DR and venous sheathing in RVO. Optocilliary shunts seem easier to detect on CFP.

Review of Retinal Imaging Modalities for Hydroxychloroquine Retinopathy

This review provides an overview of conventional and novel retinal imaging modalities for hydroxychloroquine (HCQ) retinopathy. HCQ retinopathy is a form of toxic retinopathy resulting from HCQ use for a variety of autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Each imaging modality detects a different aspect of HCQ retinopathy and shows a unique complement of structural changes. Conventionally, spectral-domain optical coherence tomography (SD-OCT), which shows loss or attenuation of the outer retina and/or retinal pigment epithelium-Bruch's membrane complex, and fundus autofluorescence (FAF), which shows parafoveal or pericentral abnormalities, are used to assess HCQ retinopathy. Additionally, several variations of OCT (retinal and choroidal thickness measurements, choroidal vascularity index, widefield OCT, en face imaging, minimum intensity analysis, and artificial intelligence techniques) and FAF techniques (quantitative FAF, near-infrared FAF, fluorescence lifetime imaging ophthalmoscopy, and widefield FAF) have been applied to assess HCQ retinopathy. Other novel retinal imaging techniques that are being studied for early detection of HCQ retinopathy include OCT angiography, multicolour imaging, adaptive optics, and retromode imaging, although further testing is required for validation.

Comparison of Multicolor Scanning Laser Imaging and Color Fundus Photography in Evaluating Vessel Whitening in Branch Retinal Vein Occlusion

INTRODUCTION

Few studies have explored MultiColor™ imaging (MCI) in evaluating retinal vascular diseases, particularly branch retinal vein occlusion (BRVO). This study aimed to compare the identification of retinal vessel whitening in BRVO using MCI by scanning confocal laser versus conventional white-flash color fundus photography (CFP).

METHODS

Paired images of consecutive patients diagnosed with BRVO who underwent same-day MCI and CFP were reviewed. Visualization of vessel whitening on MCI and CFP was graded and scored using a scale by two masked graders. A longitudinal analysis of the vessel grading score was performed to evaluate the vessel whitening detection by MCI. A correlation analysis was conducted between vessel whitening on MCI and the measured area of retinal ischemia on fluorescein angiography to evaluate the MCI performance.

RESULTS

Forty-four eyes of 41 patients (mean age 69 ± 14 years; 61% female) were analyzed. MCI demonstrated superior vessel whitening visibility score than CFP (p < 0.001). Longitudinal analysis showed no significant changes in vessel whitening visibility scores over a mean follow-up time of 430 ± 648 days (p = 0.655). There was a significantly positive correlation between the grading score of vessels whitening by MCI and the area of ischemia by fluorescein angiography (r2 = 0.15; p = 0.036).

CONCLUSION

MCI appears to provide a superior detection of whitening BRVO compared to CFP, serving as a rapid and non-invasive correlate of retinal ischemia.

Application of multicolour reflectance imaging for the characterisation of inherited retinal disorders

AIM

To describe the role of multicolour reflectance images (MCI) in the phenotypic diagnosis of inherited retinal disorders (IRDs).

METHODS

A retrospective review of consecutive patients affected by IRDs examined with MCI techniques from January to December 2019 at a tertiary care referral centre. All patients had MCI, fundus autofluorescence and optical coherence tomography taken at the same time point. The ability of each modality to highlight clinical features was assessed. Lesions' size was also measured and compared among imaging modalities.

RESULTS

Thirty eyes of 15 patients were included in the study, 6 males and 9 females, with a mean age of 44 years (range: 19-57.5). The most frequent clinical diagnosis were: pattern dystrophies, and late-onset retinal degeneration. Next-generation or Sanger sequencing analysis was carried out in all patients. Blue and green reflectance were relevant in highlighting peripheral mottling in fundus albipunctatus, pseudoreticular drusen in late-onset retinal degeneration, parafoveal hyperreflective area in bull's eye maculopathy and crystals in Bietti's crystalline dystrophy. Likewise, it is to mention the ability of infrared reflectance to detect hyperreflective patches in posterior pole in neurofibromatosis type 1 and retinal changes in pattern dystrophies and cone dystrophies.

CONCLUSION

Multicolour imaging technique enables the detection of clinical features that could be overlooked by other imaging modalities, allowing accurate phenotypic characterisation of IRDs and guiding genetic diagnose, and may become a meaningful monitoring tool for future treatments.

Predicting Age-related Macular Degeneration Progression with Longitudinal Fundus Images Using Deep Learning

Accurately predicting a patient's risk of progressing to late age-related macular degeneration (AMD) is difficult but crucial for personalized medicine. While existing risk prediction models for progression to late AMD are useful for triaging patients, none utilizes longitudinal color fundus photographs (CFPs) in a patient's history to estimate the risk of late AMD in a given subsequent time interval. In this work, we seek to evaluate how deep neural networks capture the sequential information in longitudinal CFPs and improve the prediction of 2-year and 5-year risk of progression to late AMD. Specifically, we proposed two deep learning models, CNN-LSTM and CNN-Transformer, which use a Long-Short Term Memory (LSTM) and a Transformer, respectively with convolutional neural networks (CNN), to capture the sequential information in longitudinal CFPs. We evaluated our models in comparison to baselines on the Age-Related Eye Disease Study, one of the largest longitudinal AMD cohorts with CFPs. The proposed models outperformed the baseline models that utilized only single-visit CFPs to predict the risk of late AMD (0.879 vs 0.868 in AUC for 2-year prediction, and 0.879 vs 0.862 for 5-year prediction). Further experiments showed that utilizing longitudinal CFPs over a longer time period was helpful for deep learning models to predict the risk of late AMD. We made the source code available at https://github.com/bionlplab/AMD_prognosis_mlmi2022 to catalyze future works that seek to develop deep learning models for late AMD prediction.

STRUCTURAL PATHOLOGY AFTER RETINAL DETACHMENT: Multicolor Confocal Scanning Laser Ophthalmoscopy Versus Color Fundus Photography

PURPOSE

To compare pathology detection using multicolor confocal scanning laser ophthalmoscopy with color fundus photography following macula-off rhegmatogenous retinal detachment.

METHODS

Postsurgery multicolor confocal scanning laser ophthalmoscopy and color fundus photography images from 30 rhegmatogenous retinal detachment patients were examined by 10 masked graders. Imaging was performed with the Heidelberg Spectralis HRA and the digital retinal camera Basler acA2500-14gc GigE. Swept-source optical coherence tomography was used as verification modality. Detection rates of ellipsoid zone disruption, foveal ellipsoid zone rosette, outer retinal folds, intraretinal cysts, subretinal fluid layer, subretinal fluid blebs, retinal striae, and retinal detachment line were compared. Intermodality and intergrader agreement were estimated.

RESULTS

Overall pathology detection was significantly higher for multicolor confocal scanning laser ophthalmoscopy multicolor confocal scanning laser ophthalmoscopy (adjusted odds ratio = 7.39; 95% confidence interval, 1.64-33.30; P = 0.009). The intermodality and intergrader agreement on overall pathology detection were moderate. The intermodality agreement was 0.49 (95% confidence interval, 0.48-0.51; P < 0.0001) (Gwet's AC1). Intergrader agreement was 0.53 (95% confidence interval, 0.52-0.54; P < 0.0001) for multicolor confocal scanning laser ophthalmoscopy and 0.58 (95% confidence interval, 0.57-0.59; P < 0.0001) (Fleiss kappa) for color fundus photography.

CONCLUSION

Multicolor confocal scanning laser ophthalmoscopy imaging is superior to color fundus photography in detecting and delineating structural retinal abnormalities following rhegmatogenous retinal detachment and can be a helpful tool in the visualization of retinal remodeling processes in patients recovering from rhegmatogenous retinal detachment surgery.

Relationship of Gensini score with retinal vessel diameter and arteriovenous ratio in senile CHD

Background

This study aimed to find the correlation of Gensini score with retinal vessel diameter and arteriovenous ratio in elderly patients with coronary heart disease (CHD).

Methods

This study included 120 senile CHD patients as the CHD group and 100 healthy individuals as the normal group (NG). Gensini score was used to evaluate the severity of coronary artery lesions. Central retinal artery equivalents (CRAE), central retinal venular equivalents (CRVE), and arteriovenous ratio (AVR) were measured.

Results

CHD group has lower CRAE and AVR than NG, while higher CRVE was observed in NG. CRAE and AVR in UAP (unstable angina pectoris) and AMI (acute myocardial infarction) groups showed reduction (stable angina pectoris); however, enhanced CRVE and Gensini scores in UA and AMI groups were observed as compared to the SAP group. CRAE and AVR in moderate and severe groups were reduced to a greater extent compared to the mild groups, while enhanced CRVE and Gensini scores were observed more often in the severe group than the mild group. CRAE and AVR were negatively correlated with the Gensini score; however, CRVE was positively correlated with the Gensini score.

Conclusion

AVR is expected to be a noninvasive index to diagnose and predict senile CHD, which has a certain evaluation value. Diabetes, smoking history, and TC are independent risk factors of senile CHD.

COMPARISON OF MULTICOLOR IMAGING AND COLOR FUNDUS PHOTOGRAPHY IN THE DETECTION OF PATHOLOGICAL FINDINGS IN EYES WITH POLYPOIDAL CHOROIDAL VASCULOPATHY

PURPOSE

To compare the appearance and frequency of detection of common features in eyes with polypoidal choroidal vasculopathy using multicolor imaging (MC) or color fundus photography (CFP).

METHODS

Thirty-eight eyes with indocyanine green angiography-proven polypoidal choroidal vasculopathy, imaged with both MC and CFP, were graded by three independent retinal specialists. The presence of five prespecified pathological features (blood, exudation, polypoidal lesions, pigment epithelial detachments, and atrophy) was graded on each modality independently. Multimodal imaging including optical coherence tomography, fluorescein, and indocyanine green angiography was used as the gold standard.

RESULTS

Overall, there was no statistically significant difference in the ability of MC imaging compared with CFP in detecting the pathological features. Polypoidal lesions appear as small, dark green, round lesions which have higher contrast on MC compared with a nodular orange appearance seen on CFP. Polypoidal lesions can be identified noninvasively using both MC and CFP in about half of the cases.

CONCLUSION

There are differences in the appearance of polypoidal choroidal vasculopathy-associated features on MC compared with CFP. Both modalities are comparable for the detection of pathological features in eyes with polypoidal choroidal vasculopathy. MC imaging may be considered as an alternative to CFP.

Diabetic maculopathy: multicolour and SD-OCT versus fundus photography

Objective

The English Diabetic Eye Screening (DES) programme recommends patients with M1 diabetic maculopathy to be referred to hospital eye services. DES uses flash fundus photography as the reference standard for maculopathy grading. We compared multicolour versus non-stereoscopic fundus photography at identifying M1 maculopathy, with spectral domain optical coherence tomography (SD-OCT) identifying macular thickening.

Methods and analysis

This cross-sectional study included 345 patients with R1M1 referred from DES and reviewed in secondary care with fundus photographs, multicolour and SD-OCT. Maculopathy was graded based on DES exudate criteria on both multicolour and fundus photography in a blind fashion by two independent graders. Macular thickness was ascertained on SD-OCT.

Results

Intergrader agreement on grading maculopathy using fundus photography (Cohen's κ=0.91) and multicolour (Cohen's κ=0.82) was 'almost perfect'. Agreement between fundus photography and multicolour on grading maculopathy (Cohen's κ=0.76) was 'substantial'. Compared with fundus photography, multicolour had sensitivity of 87% (95% CI 81% to 93%) and specificity of 90% (95% CI 87% to 94%) in detecting M1 maculopathy. SD-OCT identified 84 eyes with macular thickening, 47 of which were graded as M0 by fundus photography. 5 eyes with exudates and severe macular oedema requiring urgent intervention were also missed on fundus photography but not on multicolour. Multicolour, when complemented by SD-OCT, did not miss any clinically significant macular oedema.

Conclusion

Multicolour integrates synergistically in a single platform with SD-OCT providing effective monitoring of M1 diabetic maculopathy. The need for fundus photography is eliminated by multicolour/SD-OCT in dedicated R1M1 virtual clinics not requiring parallel diabetic retinopathy grading.

Recent Advances and Clinical Application of Color Scanning Laser Ophthalmoscope

Scanning laser ophthalmoscopes (SLOs) have been available since the early 1990s, but they were not commonly used because their advantages were not enough to replace conventional color fundus photography. In recent years, color SLOs have improved significantly, and the colored SLO images are obtained by combining multiple SLO images taken by lasers of different wavelengths. A combination of these images of different lasers can create an image that is close to that of the real ocular fundus. One advantage of the advanced SLOs is that they can obtain images with a wider view of the ocular fundus while maintaining a high resolution even through non-dilated eyes. The current SLOs are superior to the conventional fundus photography in their ability to image abnormal alterations of the retina and choroid. Thus, the purpose of this review was to present the characteristics of the current color SLOs and to show how that can help in the diagnosis and the following of changes after treatments. To accomplish these goals, we will present our findings in patients with different types of retinochoroidal disorders.

Comparison of Polypoidal Choroidal Vasculopathy Lesion Sizes Measured on Multicolor Imaging and Indocyanine Green Angiography

Purpose

To evaluate the areas of lesion components of polypoidal choroidal vasculopathy (PCV) measured using multicolor imaging compared to indocyanine green angiography (ICGA).

Methods

In a prospective study of 50 consecutive treatment-naïve PCV patients, multicolor imaging and ICGA were performed. The images were independently graded by reading center-certified retinal specialists to confirm the diagnosis of PCV and identify lesion components. The areas of the respective lesion components were compared.

Results

The mean age of the participants was 67.8 years. PCV was diagnosed in 96% of eyes using multicolor imaging. The mean numbers of polypoidal lesions identified using ICGA and multicolor were 4.0 and 2.1, respectively (P < 0.001), with mean total polypoidal lesion areas of 0.32 mm² versus 0.30 mm² (P = 0.727). The area of the branching vascular network (BVN) on ICGA was 7.8 mm² compared to 5.7 mm² on multicolor imaging (P = 0.289). Patients with four or more polypoidal lesions on ICGA had larger differences in total lesion area between ICGA and multicolor imaging (4.07 vs. –0.70 mm², p = 0.039). Those with total lesion area ≥ 2.0 mm² on ICGA had larger differences in mean polypoidal lesion number compared to those with smaller areas (2.2 vs. 0.5; P = 0.026).

Conclusions

Multicolor imaging is a useful, noninvasive adjunct for detecting PCV lesion components, revealing lesion areas similar to but generally smaller than those seen on ICGA. This is important to consider when making treatment decisions with different imaging modalities

Translational Relevance

New features seen on multicolor imaging can aid in the diagnosis and treatment of PCV.

EN FACE IMAGING OF OUTER RETINAL PATHOLOGY AFTER RETINAL DETACHMENT

PURPOSE

To explore the potentials of multicolor (MC) confocal scanning laser ophthalmoscopy (cSLO) to detect structural retinal pathology after macula-off rhegmatogenous retinal detachment (RRD) and to describe their appearances.

METHODS

Thirty MC cSLO images of 30 eyes after RRD repair were prospectively studied for the presence of RRD-related pathology. All MC cSLO findings were verified using swept source optical coherence tomography. Positive percent agreements were calculated using swept source optical coherence tomography as reference.

RESULTS

Eight RRD-related structural pathologies were identified and characterized: ellipsoid zone (EZ) disruption, foveal EZ rosette, outer retinal fold, retinal detachment line, subretinal fluid blebs, subretinal fluid layer, retinal striae, and intraretinal cysts. Multicolor cSLO positive percent agreements were as follows: EZ disruption: 79%, foveal EZ rosette: 73%, outer retinal fold: 67%, retinal detachment line: 84%, subretinal fluid blebs: 0.70%, subretinal fluid layer: 50%, intraretinal cysts: 60%, and retinal striae: 100%.

CONCLUSION

En face MC cSLO imaging detected and delineated RRD-related structural pathology in high agreement with cross-sectional swept source optical coherence tomography and can supplement optical coherence tomography in the documentation and monitoring of outer retinal remodeling processes after macula-off RRD. Foveal EZ rosette is a new finding of the foveal EZ.

Multimodal imaging and electroretinography highlights the role of VEGF in the laser-induced subretinal fibrosis of monkey

Age-related macular degeneration (AMD) is a leading cause of blindness. Laser-induced nonhuman primate choroidal neovascularization (CNV) is a widely used animal model of neovascular AMD. Subretinal fibrosis (SFb) is the major limiting factor of effective anti-VEGF therapy for neovascular AMD, yet SFb has never been systematically analyzed in the primate CNV model and if VEGF directly affect SFb is unknown. We recruited a large cohort of rhesus macaques to study the occurrence, multimodal imaging and electroretinography (ERG) features, and related cytokines of SFb. Here we show that among 33 rhesus macaques, 88% CNV eyes developed SFb. Spectral domain optical coherence tomography (SD-OCT) identified four types of subretinal hyper-reflective material (SHRM) of SFb in primate. Multimodal imaging is reliable for monitoring SFb and matches the histological results well. Reduced amplitude of oscillatory potentials correlates with the thinning of inner retina layers and is a possible SFb indicator. Iba1⁺ microglia/macrophage cells infiltrated in the fibrotic lesions, and aqueous cytokine analysis identified four fibrosis-related factors (GM-CSF, IL-10, TGFβ2 and VEGF). Unexpectedly, we found sustained expression of VEGF may be an important inducer of SFb, and anti-VEGF therapy actually partially suppresses SFb. Taken together, our data suggest the laser-induced primate SFb model, coupled with multimodal imaging and ERG recording, is a useful system to dissect the pathogenesis and explore the rationale of treatment for SFb; and combined therapy with anti-VEGF and anti-fibrosis agents is necessary for AMD treatment.

Macular Functional and Morphological Changes in Intermediate Age-Related Maculopathy

Purpose

The purpose of this study was to evaluate macular preganglionic function and to verify its relationship with retinal and choroidal morphology in patients with intermediate age-related macular degeneration (iAMD) patients.

Methods

All included patients performed multifocal electroretinogram (mfERG) for investigating on macular function from the central 15° of foveal eccentricity, spectral domain optical coherence tomography (SD-OCT) for studying retinal structure, enhanced depth imaging OCT (EDI-OCT) for the measure of choroidal vascularity index (CVI), and OCT-angiography (OCTA) for the evaluation of vessel density (VD) in the superficial and deep capillary plexus, and choriocapillaris (CC) layer.

Results

Twenty-seven patients with iAMD and 20 age-matched control eyes were analyzed. Significantly (P < 0.01) delayed and reduced mfERG responses in the central 0 to 2.5°, paracentral 2.5 to 5°, and overall 0 to 5° areas, as well as increased CVI values in both foveal (1 mm centered to the fovea) and fovea + parafovea areas (3 mm centered to the fovea), increased foveal and parafoveal (annular area of 1-3 mm centered to the fovea) retinal pigment epithelium thickness, and volume and parafoveal outer retinal volume were found in iAMD eyes as compared to controls. Moreover, iAMD eyes showed significantly (P < 0.01) reduced foveal and parafoveal OCTA-VD values in the CC layer when compared to controls. In the iAMD group, not significant (P > 0.01) correlations were found between morphological and functional parameters.

Conclusions

Our findings support a dysfunction of photoreceptors and bipolar cells in both foveal and parafoveal areas in the presence of outer retina, CC, and choroidal structural changes, however, not significantly correlated. The observed enlargement of luminal choroidal area (measured by CVI) is possibly compensatory to CC vascular insufficiency.

Nonmydriatic widefield retinal imaging with an automatic white LED confocal imaging system compared with dilated ophthalmoscopy in screening for diabetic retinopathy

PURPOSE

To compare nonmydriatic montage widefield images with dilated fundus ophthalmoscopy for determining diabetic retinopathy (DR) severity.

MATERIALS AND METHODS

In this prospective, observational, cross-sectional study, patients with a previous diagnosis of diabetes and without history of diabetes-associated ocular disease were screened for DR. Montage widefield imaging was obtained with a system that combines confocal technology with white-light emitting diode (LED) illumination (DRSplus, Centervue, Padua, Italy). Dilated fundus examination was performed by a retina specialist.

RESULTS

Thirty-seven eyes (20 patients, 8 females) were finally included in the analysis. Mean age of the patients enrolled was 58.0 ± 11.6 years [range 31-80 years]. The level of DR identified on montage widefield images agreed exactly with indirect ophthalmoscopy in 97.3% (36) of eyes and was within 1 step in 100% (37) of eyes. Cohen's kappa coefficient (κ) was 0.96, this suggesting an almost perfect agreement between the two modalities in DR screening. Nonmydriatic montage widefield imaging acquisition time was significantly shorter than that of dilated clinical examination (p = 0.010).

CONCLUSION

Nonmydriatic montage widefield images were compared favorably with dilated fundus examination in defining DR severity; however, they are acquired more rapidly.

COMPARISON OF RETINAL PATHOLOGY VISUALIZATION IN MULTISPECTRAL SCANNING LASER IMAGING

PURPOSE

To compare retinal pathology visualization in multispectral scanning laser ophthalmoscope imaging between the Spectralis and Optos devices.

METHODS

This retrospective cross-sectional study included 42 eyes from 30 patients with age-related macular degeneration (19 eyes), diabetic retinopathy (10 eyes), and epiretinal membrane (13 eyes). All patients underwent retinal imaging with a color fundus camera (broad-spectrum white light), the Spectralis HRA-2 system (3-color monochromatic lasers), and the Optos P200 system (2-color monochromatic lasers). The Optos image was cropped to a similar size as the Spectralis image. Seven masked graders marked retinal pathologies in each image within a 5 × 5 grid that included the macula.

RESULTS

The average area with detected retinal pathology in all eyes was larger in the Spectralis images compared with Optos images (32.4% larger, P < 0.0001), mainly because of better visualization of epiretinal membrane and retinal hemorrhage. The average detection rate of age-related macular degeneration and diabetic retinopathy pathologies was similar across the three modalities, whereas epiretinal membrane detection rate was significantly higher in the Spectralis images.

CONCLUSION

Spectralis tricolor multispectral scanning laser ophthalmoscope imaging had higher rate of pathology detection primarily because of better epiretinal membrane and retinal hemorrhage visualization compared with Optos bicolor multispectral scanning laser ophthalmoscope imaging.

Validation of multicolor imaging signatures of central serous chorioretinopathy lesions vis-a-vis conventional color fundus photographs

Purpose

The current study compares the ability of multicolor imaging (MCI) to detect the lesions of central serous chorioretinopathy against conventional color fundus photographs (CFP).

Methods

It was a retrospective, observational case series of 93 eyes of 58 patients of central serous chorioretinopathy who underwent MCI and CFP. MCI and spectral-domain optical coherence tomography (SD-OCT) were performed using Spectralis SD-OCT system (HRA + OCT). CFP was obtained using FF 450 Plus fundus camera (Carl Zeiss Meditec, Jena, Germany). SD-OCT was considered gold standard for subretinal fluid (SRF) and retinal pigment epithelium detachment (PED). CFP was considered confirmatory investigation for fibrin and blue autofluorescence image (BAF) was considered gold standard to detect retinal pigment epithelium (RPE) atrophy.

Results

CFP could detect SRF in 41 (44.1%) eyes. MCI detected SRF in 43 (46.2%) eyes. The sensitivity and specificity of MCI to detect SRF were 70.7% and 94.3%, respectively. PED was detected by CFP in 21 (22.6%) eyes and MCI in 27 (29%) eyes. The sensitivity and specificity of MCI to detect PED were 70% and 97.7% respectively. CFP could pick RPE atrophy in 52 (55.9%) eyes whereas MCI was picked it in 78 (83.9%) of eyes.

Conclusion

Both MCI and CFP were inferior to a gold standard in identifying the SRF, PED, and RPE atrophy. However, MCI was better than CFP in comparison with gold standard for these clinical findings in CSC. Thus, MCI seems to be a more valuable imaging tool compared to CFP.

Latest Developments in Polypoidal Choroidal Vasculopathy: Epidemiology, Etiology, Diagnosis, and Treatment

Polypoidal choroidal vasculopathy (PCV) is a condition characterized by multiple, recurrent, serosanguineous pigment epithelial detachments, and neurosensory retinal detachments due to abnormal aneurysmal neovascular lesions. It is generally considered as a variant of neovascular age-related macular degeneration, but there are some differences between the clinical presentation, natural history, and treatment response between patients with PCV and typical neovascular age-related macular degeneration patients. Over the past decade, new research and technological advancements have greatly improved our understanding of the PCV disease process and the management of PCV. This review aims to summarize the recent research findings to highlight the epidemiology, pathogenesis, genetics, the application of various diagnostic tools for PCV, and the available treatment options for PCV.

Sensitivity and Specificity of Multimodal Imaging in Characterizing Drusen

PURPOSE

To calculate the measures of accuracy of different imaging modalities in patients with early/intermediate age-related macular degeneration (AMD).

DESIGN

Prospective, observational, cross-sectional study.

PARTICIPANTS

Patients with early or intermediate AMD.

METHODS

All participants underwent a complete multimodal imaging assessment with a confocal scanning laser ophthalmoscope, including near-infrared reflectance (NIR), green fundus autofluorescence (G-FAF), confocal pseudocolor, and retromode deviated to right (DR) and left (DL). Drusen were topographically divided as small and medium (≤125 μ diameter) and large (>125 μ diameter), whereas subretinal drusenoid deposits (SDDs) were divided into dot and ribbon phenotypes. Multimodal imaging was considered the reference standard for detecting different subtypes of drusen and SDDs. Cohen's kappa (k) was used to test interobserver agreement for each imaging modality.

MAIN OUTCOME MEASURES

Capability to differentiate subtypes of drusen and SDDs with different imaging modalities.

RESULTS

A total of 100 eyes (62% were female participants) were evaluated. The inter-rate reliability between 2 readers for each imaging modality ranged between 0.76 and 0.95. Overall, large drusen were better identified with confocal pseudocolor imaging (96.6% sensitivity; 77.8% specificity). Smaller drusen were better detected with retromode modalities DR or DL (92% sensitivity; 58.3% specificity and 85.2% sensitivity; 83.3% specificity, respectively). Ribbon SDDs were better detected by color imaging (80.5% sensitivity; 98.3% specificity). Dot SDDs were well identified with NIR (83.1% sensitivity; 91.4% specificity) and G-FAF (84.6% sensitivity; 77.1% specificity).

CONCLUSIONS

Near-infrared reflectance and G-FAF should be considered for classification of dot SDDs, and confocal pseudocolor is optimal for characterizing ribbon SDDs. Among all imaging modalities, retromode technology DR and DL may be a potential supplementary modality to detect even smaller drusen.

REAL-COLOR VERSUS PSEUDO-COLOR IMAGING OF FIBROTIC SCARS IN EXUDATIVE AGE-RELATED MACULAR DEGENERATION

PURPOSE

To compare the morphological characteristics of subretinal fibrosis in late age-related macular degeneration using multicolor (MC) imaging, color fundus photography (CFP), and ultra-widefield CFP (UWFCFP).

METHODS

Thirty-two eyes of 31 patients diagnosed with subretinal fibrosis complicating exudative age-related macular degeneration were included. Included eyes were imaged by MC, CFP, and UWFCFP. The overall ability to visualize fibrosis, its margins, and dissimilarity with surrounding atrophy was graded using a score (0: not visible, 1: barely visible, 2: mostly visible, and 3: fully visible) by two readers. Area of fibrosis was calculated. Scaling, lesion colocalization on all three imaging techniques, and area measurements were performed using ImageJ.

RESULTS

Ninety-six images of 32 eyes were graded. The average area of fibrosis was 14.59 ± 8.94 mm for MC, 13.84 ± 8.56 mm for CFP, and 13.76 ± 8.79 mm for UWFCFP. Fibrosis was fully visible in 87.5% of cases using MC and 50% using CFP and UWFCFP. Fibrosis' margins were sharply defined in 40.6% of eyes with MC, 15.6% and 9.4% with CFP and UWFCFP, respectively. Multicolor imaging provided superior distinction between fibrosis and atrophy (100% for MC vs. 13.4% for CFP and 33.3% for UWFCFP). The inter- and intra-reader agreement was high for all measurements (P < 0.0001).

CONCLUSION

Multicolor technology allows for improved visualization and analysis of subretinal fibrosis when compared with CFP and UWFCFP, especially when surrounding atrophy is present.

Correlation of multicolor images and conventional color fundus photographs with foveal autofluorescence patterns in diabetic macular edema

Purpose:

The aim of this study is to assess the ability of multicolour imaging (MCI) to detect foveal cysts in diabetic macular edema (DME) and compare it with conventional color fundus photography (CFP) and foveal autofluorescence (FAF) pattern.

Methods:

It was a retrospective review of 112 eyes of 84 DME patients with central foveal thickness ≥250 μ who underwent MCI, CFP and shortwave autofluorescence imaging. MCI was performed with Sepctralis spectral domain optical coherence tomography (SDOCT) (Heidelberg Engineering, Germany).

Results:

97 (86.6%) eyes had cystoid increased autofluorescence (cystoid iFAF), 9 (8%) had spot iFAF and 6 (5.35%) had irregular decreased FAF (dFAF). Among eyes with cystoid iFAF, OCT detected DME cysts in 93 (95.6%) eyes, MCI in 75 (77.3%) and CFP in 5 (5.15%) eyes. In all these eyes, the location of cysts on OCT and MCI corresponded with the location of cystoid iFAF, whereas none of the eyes with cyst seen on CFP correlated with the location of cystoid iFAF.

Conclusion:

MCI was superior to CFP in detecting DME cysts at fovea. It also correlated with hyperautofluorescence pattern in these eyes. MCI may have a potential role in diabetic retinopathy screening by segregating eyes with DME which would require treatment. Our findings need to be further validated in a larger and prospective study design.

A comparison between a white LED confocal imaging system and a conventional flash fundus camera using chromaticity analysis

Background

Conventional flash fundus cameras capture color images that are oversaturated in the red channel and washed out in the green and blue channels, resulting in a retinal picture that often looks flat and reddish. A white LED confocal device was recently introduced to provide a high-quality retinal image with enhanced color fidelity. In this study, we aimed to evaluate the color rendering properties of the white LED confocal system and compare them to those of a conventional flash fundus camera through chromaticity analysis.

Methods

A white LED confocal device (Eidon, Centervue, Padova, Italy) and a traditional flash fundus camera (TRC-NW8, Topcon Corporation, Tokyo, Japan) were used to capture fundus images. Color images were evaluated with respect to chromaticity. Analysis was performed according to the image color signature. The color signature of an image was defined as the distribution of its pixels in the rgb chromaticity space. The descriptors used for the analysis are the average and variability of the barycenter positions, the average of the variability and the number of unique colors (NUC) of all signatures.

Results

Two hundred thirty-three color photographs were acquired with each retinal camera. The images acquired by the confocal white LED device demonstrated an average barycenter position (rgb = [0.448, 0.328, 0.224]) closer to the center of the chromaticity space, while the conventional fundus camera provides images with a clear shift toward red at the expense of the blue and green channels (rgb = [0.574, 0.278, 0.148] (p < 0.001). The variability of the barycenter positions was higher in the white LED confocal system than in the conventional fundus camera. The average variability of the distributions was higher (0.003 ± 0.007, p < 0.001) in the Eidon images compared to the Topcon camera, indicating a greater richness of color. The NUC percentage was higher for the white LED confocal device than for the conventional flash fundus camera (0.071% versus 0.025%, p < 0.001).

Conclusions

Eidon provides more-balanced color images, with a wider richness of color content, compared to a conventional flash fundus camera. The overall higher chromaticity of Eidon may provide benefits in terms of discriminative power and diagnostic accuracy.

Molecular Mechanisms of Complement System Proteins and Matrix Metalloproteinases in the Pathogenesis of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is an eye disorder affecting predominantly the older people above the age of 50 years in which the macular region of the retina deteriorates, resulting in the loss of central vision. The key factors associated with the pathogenesis of AMD are age, smoking, dietary, and genetic risk factors. There are few associated and plausible genes involved in AMD pathogenesis. Common genetic variants (with a minor allele frequency of >5% in the population) near the complement genes explain 40-60% of the heritability of AMD. The complement system is a group of proteins that work together to destroy foreign invaders, trigger inflammation, and remove debris from cells and tissues. Genetic changes in and around several complement system genes, including the CFH, contribute to the formation of drusen and progression of AMD. Similarly, Matrix metalloproteinases (MMPs) that are normally involved in tissue remodeling also play a critical role in the pathogenesis of AMD. MMPs are involved in the degradation of cell debris and lipid deposits beneath retina but with age their functions get affected and result in the drusen formation, succeeding to macular degeneration. In this review, AMD pathology, existing knowledge about the normal and pathological role of complement system proteins and MMPs in the eye is reviewed. The scattered data of complement system proteins, MMPs, drusenogenesis, and lipofusogenesis have been gathered and discussed in detail. This might add new dimensions to the understanding of molecular mechanisms of AMD pathophysiology and might help in finding new therapeutic options for AMD.

Multicolor imaging in central serous chorioretinopathy - a quantitative and qualitative comparison with fundus autofluorescence

Central serous chorioretinopathy (CSCR) is characterised by choroidal hyperpermeability which results in neurosensory detachments (NSD) along with numerous retinal pigment epithelium (RPE) alterations such as RPE atrophy. Fundus autofluorescence (FAF) demonstrates the functionality of the RPE while multicolor imaging(MCI), by means of its three incident wavelengths, provides insight into clinical changes at various levels of the retina and choroid in CSCR. This study compares various clinical findings in CSCR (NSD, subretinal deposits, RPE atrophy, pigment epithelial detachments (PED) and pachyvessels) on the above mentioned imaging modalities both qualitatively and quantitatively. MCI showed higher mean cumulative area of RPE atrophic patches (6.3 ± 6.02 vs 5.7 ± 5.7 mm2, p = 0.046), PED (1.3 ± 1.4 vs 1.1 ± 1.2 mm2, p = 0.068) and NSD (17.2 ± 11.4 vs 15.7 ± 10.7 mm2, p = 0.033). MCI demonstrated better defined lesions (NSD, PED, RPE atrophy) and more number of eyes with PED and pachyvessels in comparison to FAF.Both investigations had a 100% sensitivity in detecting NSD and 100% specificity for sub retinal deposits. This study demonstrates the ability of MCI to quantitatively and qualitatively define various clinical features in CSCR and the advantages it holds over FAF. MCI can hence be considered as a useful imaging modality in documenting and monitoring various structural changes in eyes with CSCR.

Validation of Multicolor Imaging of Diabetic Retinopathy Lesions Vis a Vis Conventional Color Fundus Photographs

BACKGROUND AND OBJECTIVE

To analyze the visibility of various diabetic retinopathy lesions in multicolor imaging (MCI) and compare them to corresponding color fundus photography (CFP).

PATIENTS AND METHODS

Retrospective review of 130 eyes of 65 consecutive patients with diabetic retinopathy who underwent multicolor confocal scanning laser ophthalmoscopy and CFP.

RESULTS

Hard exudates (Hex) were seen in 74 eyes (71.2%). In all 74 eyes, Hex were visible on both CFP and MCI. Among other color channels, Hex were picked up most in green reflectance (GR) images in 73 eyes (70.2%). Cotton-wool spots (CWS) were picked up in 29 eyes (27.9%) on MCI and in 27 eyes (26%) on CFP. In both GR and blue reflectance (BR) imaging, they were equally picked up in 29 eyes (27.9%). Retinal hemorrhages were picked up in 83 eyes (79.8%) on MCI and in 82 eyes (72.8%) on CFP. Among other channels, they were picked up most in GR images in 81 (77.9%) eyes. Hex, CWS, and hemorrhages were seen better on MCI and in GR images as compared to CFP, BR, and infrared imaging, respectively. With CFP as the comparator, the sensitivity and specificity of MCI to detect of these lesions were more than 90%.

CONCLUSIONS

The authors' pilot study validates the efficacy of MCI in picking up lesions of DR vis a vis CFP. MCI has potential to replace CFP in clinical and DR screening setting. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:8-15.].

Clinical application of multicolor optical coherence tomography in the diagnosis of retinal pathologies

Objective:

To assess the clinical application of multicolor optical coherence tomography (OCT) using confocal scanning laser ophthalmoscopy (cSLO) in different retinal pathologies.

Methods:

This observational study was conducted at the Layton Rahmatullah Benevolent Trust (LRBT), Free Base Eye Hospital, Karachi, from April 2018 to June 2018. It includes 36 patients suffering from different retinal pathologies including diabetic retinopathy, age related macular degeneration, and vitreomacular interface disorders using multicolor optical coherence tomography as a screening tool.

Results:

It was found that automated eye tracking system of this new version tool enables ophthalmologists to take high-resolution cSLO reflectance images. The light scatter can be avoided with the use of confocal optics. Appearances of pigment changes and hemorrhages were some of the differences found when compared to the conventional CFP. About 20% in AMD, 37.5% with diabetes and 100% patients with vitreomacular interface disorders could have be easily missed by CFP.

Conclusions:

Multicolor OCT can provide information and figures far more authoritatively than the conventional CFP, which is highly affected by media opacities. To interpret Multicolor OCT ophthalmologists should be watchful with plenty of understanding.

Multicolor imaging for retinal nerve fiber layer defect in glaucoma

Glaucoma is a progressive optic neuropathy associated with irreversible loss of retinal ganglion cells (RGC). This emblematic localized retinal nerve fiber layer defect (RNFLD) can be the earliest sign to detect the ongoing glaucomatous damage. Slitlamp biomicroscopy [90D & 78D], colour and redfree fundus photography, OCT & HRT are used conventionally for early detection of RNFLD. Multicolour Imaging (MCI) is a new non-invasive retinal imaging modality available in Spectralis platform which simultaneously acquires three reflectance images of the retina using three individual lasers producing a composite image thereby allowing analysis of changes at various levels within the retina. MCI provides sharper image, enables imaging through small pupil and hazy media. Current report describes 2 cases where in MCI proved superior to CFP and conventional redfree photograph in delineating area of RNFLD. This is the first report of MCI in RNFL imaging. The present report highlights the role of MCI in detection of RNFLD.

Multimodal imaging characteristics of hydroxychloroquine retinopathy

Hydroxychloroquine (HCQ) is known to cause retinal toxicity. Early detection of the toxicity is necessary to stop the drug in time. Multicolor imaging (MC) is a new noninvasive retinal imaging modality that simultaneously acquires three reflectance images of the retina using three individual lasers producing a composite image, thereby allowing analysis of changes at various levels within the retina. It is a new and promising addition to the retinal imaging armory. MC characteristics of HCQ toxicity are hitherto unreported. A 61-year-old female presented with history of HCQ intake (400 mg/day) for the last 6 years. She had retinopathy in both eyes. Multicolor composite image showed circumscribed perifoveal arcuate area of darkening, and infrared reflectance showed speckled hyperreflecetance in both eyes. MC imaging shows definite changes in HCQ toxicity, and it might emerge as a possible screening tool in future.