MultiColor imaging in the evaluation of geographic atrophy due to age-related macular degeneration

Exploring laser-induced acute and chronic retinal vein occlusion mouse models: Development, temporal in vivo imaging, and application perspectives

Photodynamic venous occlusion is a commonly accepted method for establishing mouse models of retinal vein occlusion (RVO). However, existing model parameters do not distinguish between acute and chronic RVO subtypes. Large variations in laser energy seem to correlate with fluctuating retinopathy severity and high rates of venous recanalization during the acute phase, along with the variable levels of retinal perfusion during the chronic phase. After optimizing the modeling procedure and defining success and exclusion criteria, laser energy groups of 80mW, 100mW, and 120mW were established. Multimodal imaging confirmed that higher energy levels increased the incidence of retinal cystoid edema and intraretinal hemorrhage, exacerbated the severity of exudative retinal detachment, and reduced the venous recanalization rate. For the acute model, 100mW was considered an appropriate parameter for balancing moderate retinopathy and venous recanalization. Continuous imaging follow-up revealed that day 1 after RVO was the optimal observation point for peaking of retinal thickness and intensive occurrence of retinal cystic edema and intraretinal hemorrhage. After excluding the influence of venous recanalization on retinal thickness, acute retinal edema demonstrated a positive response to standard anti-vascular endothelial growth factor therapy, validating the clinical relevance of the acute RVO model for further study in pathogenic mechanisms and therapeutic efficacy. For the chronic model, the 120mW parameter with the lowest venous recanalization rate was applied, accompanied by an increase in both photocoagulation shots and range to ensure sustained vein occlusion. Imaging follow-up clarified non-ischemic retinopathy characterized by tortuosity and dilation of the distal end, branches, and adjacent veins of the occluded vein. These morphological changes are quantifiable and could be combined with electrophysiological functional assessment for treatment effectiveness evaluation. Moreover, the stable state of venous occlusion may facilitate investigations into response and compensation mechanisms under conditions of chronic retinal hypoperfusion.

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.

Relevance of multicolor imaging, its component channels, and fundus autofluorescence in describing macular telangiectasia type-2 (MacTel) lesion characteristics

PURPOSE

The aim of the study was to describe imaging characteristics and detection rates of phenotypic features in macular telangiectasia type-2 (MacTel) on multicolor (MC), blue reflectance (BR), green reflectance (GR), infrared reflectance (IR), and fundus autofluorescence (FAF) and to evaluate sensitivity, specificity, and predictive values across modalities.

METHODS

In this monocentric observational study, 282 eyes of 148 patients with MacTel underwent color fundus photograph, MC, BR, GR, IR, FAF, spectral-domain optical coherence tomography (SD-OCT), OCT-angiography (OCT-A), and fundus fluorescein angiography (FFA). Grading was done by two graders qualitatively and quantitatively for the presence of the following prespecified MacTel findings [crystals, right-angle vessels (RAVs), plaques, subretinal neovascularization (SRNV), and MacTel area]. Across each imaging modality, the detection rate of RAVs and SRNV was compared with reference standard OCT-A (RAVs and SRNV) and FFA (SRNV), whereas that of plaques was compared with reference standard SD-OCT.

RESULTS

MC identified overall MacTel characteristics in 92.7% of eyes. Regarding the presence, number, and quadrants of RAVs and the presence and number of crystals, MC and GR had superior detection rates as well as the highest sensitivity and negative predictive value. Retinal plaques were better detected using FAF (97%), followed by MC (88%). In proliferative MacTel, SRNV was identified in 86% and 79% of eyes on MC and IR, respectively. While BR clearly delineated MacTel area in 100% eyes, FAF was able to ascertain a larger area of involvement in proliferative MacTel.

CONCLUSION

The findings demonstrate the ability of MC, its component channels, and FAF to describe MacTel characteristics qualitatively and quantitatively.

Recent Advances in Imaging Macular Atrophy for Late-Stage Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. In late-stage AMD, geographic atrophy (GA) of dry AMD or choroidal neovascularization (CNV) of neovascular AMD eventually results in macular atrophy (MA), leading to significant visual loss. Despite the development of innovative therapies, there are currently no established effective treatments for MA. As a result, early detection of MA is critical in identifying later central macular involvement throughout time. Accurate and early diagnosis is achieved through a combination of clinical examination and imaging techniques. Our review of the literature depicts advances in retinal imaging to identify biomarkers of progression and risk factors for late AMD. Imaging methods like fundus photography; dye-based angiography; fundus autofluorescence (FAF); near-infrared reflectance (NIR); optical coherence tomography (OCT); and optical coherence tomography angiography (OCTA) can be used to detect and monitor the progression of retinal atrophy. These evolving diverse imaging modalities optimize detection of pathologic anatomy and measurement of visual function; they may also contribute to the understanding of underlying mechanistic pathways, particularly the underlying MA changes in late AMD.

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.

Comparison of multicolor scanning laser ophthalmoscopy and optical coherence tomography angiography for detection of microaneurysms in diabetic retinopathy

This study aimed to evaluate the usefulness of multicolor (MC) scanning laser ophthalmoscopy (MC-SLO) in detecting microaneurysm (MA) in eyes with diabetic retinopathy (DR). This was a retrospective cross-sectional study. Eyes with DR underwent fluorescein angiography (FA), MC-SLO, optical coherence tomography angiography (OCTA), and color fundus photography (CFP) were analyzed. The foveal region was cut in an 6 × 6 mm image and the number of MA in each image was counted by retina specialists to determine the sensitivity and positive predictive value. FA results were used as the ground standard. MAs were classified as those with early, late, or no dye leakage based on FA images. Fifty-four eyes of 35 patients with an average age of 64.5 ± 1.24 years were included. The sensitivity of MA detection was 37.3%, 15.3%, and 4.12% in MC-SLO, OCTA, and CFP, respectively (P < 0.01 in each pair).The positive predictive value was 66.4%, 46.4%, and 27.6% in MC, OCTA, and CFP, respectively (P < 0.01 in each pair). Sensitivity for MAs with early leakage was 36.4% in MC-SLO, which was significantly higher than 4.02% in OCTA. MC-SLO was more useful in detecting MA in eyes with DR than OCTA.

MORE EFFECTIVE SCREENING FOR EPIRETINAL MEMBRANES WITH MULTICOLOR SCANNING LASER OPHTHALMOSCOPE THAN WITH COLOR FUNDUS PHOTOGRAPHS

PURPOSE

To assess the ability of the multicolor scanning laser ophthalmoscope (MC-SLO) to screen for epiretinal membranes (ERMs).

METHODS

A retrospective cross-sectional study of 35 eyes of 32 patients with an ERM detected by optical coherence tomography and 46 eyes of 23 healthy volunteers. The detection of the ERM was graded into three visibility scores-1, not visible, 2, barely visible, and 3, clearly visible-by retina specialists or by ophthalmology residents. The sensitivity and specificity of the detection with the merged image of the MC-SLO or color fundus photographs (CFPs) were calculated.

RESULTS

The sensitivity for ERM detection in the MC-SLO and CFP were 91.4% and 65.7% by specialists and 97.1% and 60.0% by residents. The specificity for both devices was 100% by specialists and residents. The visibility score for the MC-SLO images were significantly higher than that for the CFP by both specialists and residents. In addition, the visibility score for the MC-SLO determined by residents was significantly higher than that for the CFP by specialists.

CONCLUSION

The detection of an ERM is better with the MC-SLO images than with CFP. Furthermore, the ERM detection in the MC-SLO images by residents was comparable to that by specialists.

CLINICAL APPLICATION OF MULTICOLOR IMAGING IN CENTRAL SEROUS CHORIORETINOPATHY

PURPOSE

To characterize features of central serous chorioretinopathy (CSC) using multicolor (MC) imaging and to compare the efficacy of using MC imaging and traditional color fundus photography (CFP) for detecting features of CSC.

METHODS

A retrospective review of 75 eyes of 69 participants with CSC from the Eye Center of the Renmin Hospital of Wuhan University. The patients underwent same-day CFP, fundus fluorescein angiography (FFA), spectral domain optical coherence tomography (SD-OCT), and MC imaging (including infrared reflectance (IR), green reflectance (GR), blue reflectance (BR), combined standard MC image, and green-blue-enhanced image). Positive CSC lesions were evaluated using FFA and SD-OCT. Features in images of CFP, standard MC, green-blue-enhanced, IR, GR, and BR were analyzed and calculated.

RESULTS

Among the 75 eyes of 69 patients, 75 eyes with subretinal fluid (SRF) and retinal pigment epithelial (RPE) leakage point, and 43 eyes with RPE damage were observed by FFA and SD-OCT. The detection rate of SRF was significantly higher with the standard MC image (92.0%), green-blue-enhanced image (92.0%), IR (88.0%), and GR (88.0%) than that with CFP (66.7%) (P < 0.05). Blue reflectance (45.3%) was associated with lower rate of SRF detection compared to CFP (P < 0.05). The standard MC image (84.0%), green-blue-enhanced image (84.0%), IR (78.7%), and GR (80%) delineated the boundaries of SRF more effectively than CFP (44%). The abnormal areas corresponding to RPE leakage points on FFA were observed with the standard MC image, green-blue-enhanced image, and IR at detection rates of 90.7, 82.7, and 90.7%, respectively, which were significantly higher than with CFP (29.3%) (P < 0.05). However, the detection rates of the abnormalities corresponding to leakage on FFA were lower with GR (5.3%) and BR (1.3%) than those with CFP (P < 0.05). Areas of RPE damage on FFA were observed at the same locations with the standard MC image, green-blue-enhanced image, and IR at detection rates of 97.7, 93.0, and 95.3%, respectively, which were significantly higher than with CFP (41.9%) (P < 0.05). Compared with CFP, the detectable rates of RPE damage on GR (14.0%) and BR (9.3%) were lower (P < 0.05).

CONCLUSION

As an adjunct to SD-OCT, the MC image can delineate the extent or boundaries of SRF more effectively than CFP. As an adjunct to FFA, the MC image can identify foci of leakage more effectively than CFP. The MC image, particularly the IR channel, can identify areas of RPE damage more effectively than CFP. Therefore, the MC image may be a useful adjunct to FFA and OCT for detecting or monitoring CSC.

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.

Ocular Imaging for Enhancing the Understanding, Assessment, and Management of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a progressive neuro-retinal disease and the leading cause of central vision loss among elderly individuals in the developed countries. Modern ocular imaging technologies constitute an essential component of the evaluation of these patients and have contributed extensively to our understanding of the disease. A challenge with any review of ocular imaging technologies is the rapid pace of progress and evolution of these instruments. Nonetheless, for proper and optimal use of these technologies, it is essential for the user to understand the technical principles underlying the imaging modality and their role in assessing the disease in various settings. Indeed, AMD, like many other retinal diseases, benefits from a multimodal imaging approach to optimally characterize the disease. In this chapter, we will review the various imaging technologies currently used in the assessment and management of AMD.

Multicolor Scanning Laser Ophthalmoscopy Strengthens Surgeons' Preoperative Decision-Making and Intraoperative Performance on Epiretinal Membrane

Purpose

To determine whether multicolor scanning laser ophthalmoscopy (MC-SLO) was better than color fundus photography (CFP) to enhance residents and specialists’ preoperative decision-making and intraoperative performance on the epiretinal membrane (ERM).

Methods

Consecutive patients with idiopathic ERM were recruited prospectively. All the patients underwent MC-SLO and CFP imagings and were randomized into MC-SLO (n = 20) and CFP (n = 20) groups. Preoperatively, residents and specialists were required to have ERM delineation and select an optimal location for initial ERM peeling independently, based on the MC-SLO (MC-SLO group) or CFP (CFP group) images. Intraoperative optical coherence tomography (iOCT) was introduced to evaluate the accuracy.

Results

Preoperatively, residents and specialists acted more effectively in ERM delineation and selection of initial grasping location in the MC-SLO group (both P < 0.001). In the MC-SLO group, higher resident–specialist agreements were achieved in ERM delineation (P = 0.002) and selection of initial grasping location (P = 0.035). The iOCT revealed greater interobserver (iOCT–resident and iOCT–specialist) agreements of ERM delineation in MC-SLO group (P < 0.001 and = 0.027, respectively). Surgeons acted more effectively on completely peeling the ERM in the MC-SLO group (P < 0.001).

Conclusions

MC-SLO provided a better visual reference for residents and specialists in ERM delineation and the selection of an initial grasping location for the surgery, compared with CFP.

Translational Relevance

MC-SLO is able to help surgeons achieve better intraoperative performance and shorten the learning process for residents.

Clinical application of ultra-widefield fundus autofluorescence

PURPOSE

To review the basic principles of ultra-widefield fundus autofluorescence (UWF-FAF) and discuss its clinical application for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms "ultra-widefield," "autofluorescence," "retinal disease" and "choroidal disease."

RESULTS

UWF-FAF imaging is a recently developed noninvasive retinal imaging modality with a wide imaging range that can locate peripheral fundus lesions that traditional fundus autofluorescence cannot. Multiple commercially available ultra-widefield imaging systems, including Heidelberg Spectralis and Optomap Ultra-Widefield systems, are available to the clinician. Imaging by UWF-FAF is more comprehensive; it can reflect the content and distribution of the predominant ocular fluorophore in retinal pigment epithelial cells and evaluate the metabolic status of RPE of various retinal and choroidal disorders.

CONCLUSION

UWF-FAF can detect abnormalities that traditional fundus autofluorescence cannot; therefore, it can be used to better elucidate disease pathogenesis, analyze genotype-phenotype correlations, diagnose and monitor disease.

Multimodal Imaging for the Assessment of Geographic Atrophy in Patients with "Foveal" and "No-Foveal" Sparing

INTRODUCTION

The aim of the study was to evaluate the applicability of optical coherence tomography (OCT) angiography (OCTA) for measuring geographic atrophy (GA) areas in age-related macular degeneration (AMD) patients with "foveal" and "no-foveal" sparing disease and compare it to other imaging modalities.

METHODS

A multimodal imaging protocol was applied, using infrared (IR) imaging, fundus autofluorescence (FAF), OCTA, and en-face OCT in 35 eyes of 23 AMD patients with GA. Patients were classified into 2 groups, with and without foveal sparing disease. GA area measurements for all imaging modalities were compared for each group separately.

RESULTS

The measured GA area was estimated to be 6.68 ± 3.18 mm2 using IR; 6.99 ± 3.09 mm2 using FAF; 6.56 ± 3.11 mm2 using OCTA, and 6.65 ± 3.14 mm2 using en-face OCT. There was no statistically significant difference in the GA area between different modalities (p = 0.977). When separate analysis was conducted for patients with "foveal" and "no-foveal" sparing disease, although GA measurements in FAF imaging displayed higher numerical values than the other modalities, especially in patients with foveal sparing, no statistically significant difference in the GA area was found between the different imaging modalities in either group (p = 0.816 for foveal sparing; p = 0.992 for no-foveal sparing group).

CONCLUSIONS

OCTA can be reliably used in the assessment of GA in AMD patients with and without foveal sparing disease. For both groups, measurements are comparable to IR, en-face OCT, and FAF, despite the fact that the latter recorded larger area of GA, mainly in the foveal sparing cases.

Artificial Intelligence Algorithms for Analysis of Geographic Atrophy: A Review and Evaluation

Purpose

The purpose of this study was to summarize and evaluate artificial intelligence (AI) algorithms used in geographic atrophy (GA) diagnostic processes (e.g. isolating lesions or disease progression).

Methods

The search strategy and selection of publications were both conducted in accordance with the Preferred of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed and Web of Science were used to extract literary data. The algorithms were summarized by objective, performance, and scope of coverage of GA diagnosis (e.g. lesion automation and GA progression).

Results

Twenty-seven studies were identified for this review. A total of 18 publications focused on lesion segmentation only, 2 were designed to detect and classify GA, 2 were designed to predict future overall GA progression, 3 focused on prediction of future spatial GA progression, and 2 focused on prediction of visual function in GA. GA-related algorithms reported sensitivities from 0.47 to 0.98, specificities from 0.73 to 0.99, accuracies from 0.42 to 0.995, and Dice coefficients from 0.66 to 0.89.

Conclusions

Current GA-AI publications have a predominant focus on lesion segmentation and a minor focus on classification and progression analysis. AI could be applied to other facets of GA diagnoses, such as understanding the role of hyperfluorescent areas in GA. Using AI for GA has several advantages, including improved diagnostic accuracy and faster processing speeds.

Translational Relevance

AI can be used to quantify GA lesions and therefore allows one to impute visual function and quality-of-life. However, there is a need for the development of reliable and objective models and software to predict the rate of GA progression and to quantify improvements due to interventions.

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.

Multicolor imaging in macular telangiectasia-a comparison with fundus autofluorescence

PURPOSE

To describe various clinical features of idiopathic juxtafoveal retinal telangiectasis group 2A or idiopathic macular telangiectasia type 2 (MacTel) on multicolor imaging (MCI) and compare imaging findings of MacTel on MCI with fundus autofluorescence (FAF).

METHODS

Patients with a clinical diagnosis of MacTel based on Gass and Blodi's classification were included. FAF and MCI images were graded qualitatively for stage of disease, margins of involvement, hyperautofluorescence on FAF (corresponding retinal atrophy on MCI), and detection of crystals. FAF and MCI were graded quantitatively for the area and number of quadrants involved, hypoautofluorescene on FAF (corresponding intraretinal pigment hyperplasia or retinal pigment epithelium [RPE] atrophy on MCI), and foci of right-angled venules.

RESULTS

Seventy-eight eyes of forty five patients were included with both imaging modalities showing no difference with respect to staging of non-proliferative MacTel. Retinal crystals were recognized on MCI but not on FAF. Neurosensory retinal atrophy and  subretinal neovascular membranes were detected using MCI with 92.3 and 83.3% sensitivity, respectively. Intraretinal pigmented hyperplasia was more accurately detected (70.1 vs 58.4%) compared with RPE atrophy on MCI. MCI showed larger area of involvement, higher number of quadrants involved (p < 0.001), and better delineation of margins (p = 0.002) compared with FAF. A higher mean number of vessel dipping foci was noted on MCI in comparison with FAF (3.34 vs 3.1).

CONCLUSION

Various parameters were more easily defined using MCI compared with FAF which qualifies MCI as an enface depth-resolved imaging adjunct to conventional multimodal imaging in MacTel. The ability to detect enface as well as cross-sectional imaging features makes MCI a valuable tool in MacTel.

IDENTIFICATION OF POSTERIOR SEGMENT PATHOLOGY WITH EN FACE RETINAL IMAGING USING MULTICOLOR CONFOCAL SCANNING LASER OPHTHALMOSCOPY

PURPOSE

To assess posterior segment findings on multicolor confocal scanning laser ophthalmoscopy by correlation with spectral domain optical coherence tomography (SD-OCT) and to quantify agreement between these imaging modalities.

METHODS

Retrospective review of 159 eyes of 96 consecutive patients who underwent concurrent imaging with multicolor confocal scanning laser ophthalmoscopy and SD-OCT. Positive percent agreement and negative percent agreement were calculated for each finding identified on infrared, green, blue, and multicolor reflectance images using SD-OCT as a comparator.

RESULTS

Infrared reflectance best detected outer retinal and choroidal findings such as choroidal lesions, retinal pigment epithelium atrophy, peripapillary atrophy, and drusen (positive percent agreement 100, 92, 92, and 67%, respectively). Inner retinal changes including epiretinal membrane, lamellar macular hole, and inner retinal alterations were best detected on blue reflectance (positive percent agreement 94, 50, and 100%, respectively). Composite multicolor reflectance most effectively detected conditions with retinal elevation, including pigment epithelial detachment, intraretinal fluid, and subretinal fluid (positive percent agreement 65, 49, and 54%, respectively). Multicolor confocal scanning laser ophthalmoscopy detected intraretinal and subretinal hemorrhages, which were not detected on SD-OCT (negative percent agreement 87 and 97%, respectively).

CONCLUSION

Multicolor confocal scanning laser ophthalmoscopy is capable of identifying posterior segment pathology at various anatomical depths and may be a useful adjunct to SD-OCT for detecting or monitoring certain retinal conditions.

Quantifiable In Vivo Imaging Biomarkers of Retinal Regeneration by Photoreceptor Cell Transplantation

Purpose

Short-term improvements in retinal anatomy are known to occur in preclinical models of photoreceptor transplantation. However, correlative changes over the long term are poorly understood. We aimed to develop a quantifiable imaging biomarker grading scheme, using noninvasive multimodal confocal scanning laser ophthalmoscopy (cSLO) imaging, to enable serial evaluation of photoreceptor transplantation over the long term.

Methods

Photoreceptor cell suspensions or sheets from rhodopsin-green fluorescent protein mice were transplanted subretinally, into either NOD.CB17-Prkdc^scid/J or C3H/HeJ-Pde6b^rd1 mice. Multimodal cSLO imaging was performed serially for up to three months after transplantation. Imaging biomarkers were scored, and a grade was defined for each eye by integrating the scores. Image grades were correlated with immunohistochemistry (IHC) data.

Results

Multimodal imaging enabled the extraction of quantitative imaging biomarkers including graft size, GFP intensity, graft length, on-target graft placement, intra-graft lamination, hemorrhage, retinal atrophy, and periretinal proliferation. Migration of transplanted material was observed. Changes in biomarker scores and grades were detected in 14/16 and 7/16 eyes, respectively. A high correlation was found between image grades and IHC parameters.

Conclusions

Serial evaluation of multiple imaging biomarkers, when integrated into a per-eye grading scheme, enabled comprehensive tracking of longitudinal changes in photoreceptor cell grafts over time. The application of systematic multimodal in vivo imaging could be useful in increasing the efficiency of preclinical retinal cell transplantation studies in rodents and other animal models.

Translational Relevance

By allowing longitudinal evaluation of the same animal over time, and providing quantifiable biomarkers, non-invasive multimodal imaging improves the efficiency of retinal transplantation studies in animal models. Such assays will facilitate the development of cell therapy for retinal diseases.

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.

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.

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.

Multicolor Imaging Characteristics of Best's Vitelliform Macular Dystrophy

A 40-year-old woman presented with vitellieruptive stage of Best's vitelliform macular dystrophy (BVMD) in the right eye and pseudohypopyon stage in the left eye. She underwent comprehensive ophthalmic examination and fundus imaging using multicolor (MC) imaging technology of Spectralis (Heidelberg Engineering, Heidelberg, Germany) spectral-domain-optical coherence tomography system. Composite MC imaging revealed larger area of retinal pigment epithelium atrophy in vitellierruptive stage of the disease in the right eye compared to color fundus photograph. Retinal elevation in the pseudohypopyon stage was better delineated on composite MC and blue reflectance images in the left eye. Subretinal lipofuscin was best seen in green reflectance and short-wave autofluorescence images. The present case reports the MC imaging features of BVMD.

[Possibilities of multicolor confocal scanning laser ophthalmoscopy in complex diagnostics of severe proliferative diabetic retinopathy]

Multicolor scanning laser ophthalmoscopy (multicolor SLO) is a new informative method of eye fundus visualization. The method is based on synchronously obtaining three separate confocal images with monochromatic laser sources - blue (488 nm), green (515 nm) and infrared (820 nm), which are then combined into one in the Multicolor mode.

PURPOSE

To evaluate the informative value of multicolor SLO in a complex examination of patients with severe proliferative diabetic retinopathy (PDR).

MATERIAL AND METHODS

A total of 46 patients (62 eyes) aged 19 to 75 years with severe PDR was examined. All patients had massive growth of proliferative tissue on the eye fundus, which caused traction deformation and/or retinal detachment in the posterior pole. Optical mediums of the eyes were sufficiently transparent to obtain high quality images. All patients underwent color photo-registration of the fundus, fluorescein angiography (FA), optical coherence tomography (OCT) and multicolor SLO under drug-induced mydriasis.

RESULTS

Pseudo-volumetric images obtained with multicolor SLO allow visualization of of preretinal proliferative membranes and their structure, the degree of their vascularization, the anatomical features of their attachment to retina, and the occluded vessels on fundus periphery. Being an additional option on scanning laser ophthalmoscope, the technique does not require special equipment, which enables several separate examinations, including OCT and FA, to be performed on a single device.

CONCLUSION

Multicolor SLO is a promising new method of visualizing structures of the eye fundus and can be successfully used in complex diagnostics, monitoring and preoperative preparation of patients with severe PDR.

Comparison of MultiColor fundus imaging and colour fundus photography in the evaluation of epiretinal membrane

PURPOSE

To compare MultiColor fundus imaging (MC) and colour fundus photography (CFP) for the evaluation of epiretinal membrane (ERM).

METHODS

In this retrospective study, 192 eyes (181 patients) that underwent vitrectomy for ERM were imaged using Spectralis optical coherence tomography (for MC) and AFC-210 digital camera (for CFP) 1 week before vitrectomy. Two investigators independently determined the rate of delineability and ERM area for each modality.

RESULTS

The intergrader agreement rates for delineability were very high for both image modalities. The rate of delineability of ERM (%) was higher for MC than for CFP, for both investigators [70.8% versus 52.6% and 73.4% versus 53.6% (both p -)]. Epiretinal membrane (ERM) area measurement showed high agreement between investigators for MC (p = 0.466) but differed significantly between the investigators for CFP (p -). The ERM area determined on MC was significantly wider than that on CFP for both investigators (p - for investigator 1 and p - for investigator 2).

CONCLUSION

The ERM area is more clearly detectable and widely demarcated in MC than in CFP images. MultiColor imaging (MC) may be more sensitive and accurate for early detection of ERM and ERM area measurement.

Anatomical and functional changes in neovascular AMD in remission: comparison of fibrocellular and fibrovascular phenotypes

PURPOSE

To investigate the anatomical changes and the macular function in neovascular age-related macular degeneration (AMD) eyes, according to the recognition of either fibrocellular or fibrovascular phenotype.

METHODS

We enrolled eyes with previously treated neovascular AMD in remission (no subretinal haemorrhage, sign of fluid in or under the retina and no treatment for at least 6 months). Subjects underwent multimodal imaging assessment and were tested for macular sensitivity using microperimetry. The study cohort was divided according to the presence of fibrosis on multicolour (MC) images, yielding two distinct phenotypic subgroups: (1) fibrocellular group and (2) fibrovascular group.

RESULTS

Nineteen eyes were classified as fibrocellular on MC images, while 22 eyes as fibrovascular. Mean±SD age was 73.9±11.0 years in the fibrocellular group and 75.9±7.1 years in the fibrovascular group (p=0.221). Best-corrected visual acuity was 0.7±0.5 logarithm of the minimum angle of resolution (LogMAR) in the fibrocellular group and 0.3±0.2 LogMAR in the fibrovascular group (p=0.003). On the optical coherence tomography and fundus autofluorescence evaluation, 17/19 eyes with the fibrocellular phenotype and 8/22 eyes with the fibrovascular phenotype displayed the presence of retinal pigment epithelium (RPE) atrophy (p=0.001). The perfusion density within the neovascular lesion was 28.9%±9.9% in the fibrocellular group and 44.2%±5.9 % in the fibrovascular group (p<0.0001).

CONCLUSION

Neovascular AMD eyes in remission and with evidence of fibrocellular scar are characterised by RPE atrophy and reduced perfusion, which are associated with a higher degree of functional impairment. These findings suggest that maturation of vessels in fibrosis might be a better target in neovascular AMD treatments rather than their abolishment.

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.

Ability of MultiColor scanning laser ophthalmoscope to detect non-glaucomatous retinal nerve fiber layer defects in eyes with retinal diseases

PURPOSE

To compare the ability of ocular fundus images obtained by Spectralis MultiColor scanning laser ophthalmoscope (MC-SLO) to that obtained by conventional color fundus images (CF) in detecting non-glaucomatous nerve fiber layer defects (NFLDs).

METHODS

A cross-sectional, retrospective study. Patients with retinal diseases who had ocular examination with both the MC-SLO and CF instruments at the Kagoshima University from December 2016 to February 2017 were studied. Eyes that had NFLDs with non-glaucomatous optic discs were analyzed. The visibility of the NFLDs was classified into three grades: grade 0, not visible; grade 1, barely visible; and grade 2, clearly visible. The NFLD grade for blue, green, and red scanning lights of the MC-SLO, merged images with three wavelengths and the color and red-free images were determined by two ophthalmologists. These scores were compared by Steel-Dwass tests.

RESULTS

Thirty-one eyes of 26 patients with a mean age of 63.1 ± 11.2 years were studied. There were 14 eyes with diabetic retinopathy, 11 eyes with age-related macular degeneration, 3 eyes with a branch retinal vein occlusion, and 3 eyes with an epiretinal membrane/macular hole. Both the intra-rater (0.631-0.790) and inter-rater (0.637-0.733) agreements were good. NFLDs were detected by the blue wavelength in all cases and by green wavelength and merged wavelengths in 90.3% of the images. The mean NFLD grade was 1.58 ± 0.49 for blue light images, 1.13 ± 0.54 for green light images, 0.07 ± 0.24 for red light images, and 1.16 ± 0.56 for merged images. The NFLD score for blue wavelength was significantly higher than that for green and red wavelength images (P < 0.05 and P < 0.01) but not significantly higher than that for the merged images. NFLDs were detected in 12 eyes (38.7%) in the color images and 16 eyes (51.6%) in the red-free images. The NFLD score for the CF and the red-free image was 0.41 ± 0.55 and 0.70 ± 0.67 which is significantly lower than that of blue MC-SLO images.

CONCLUSION

The images obtained by MC-SLO are superior to that obtained by CF in detecting NFLDs in eyes with retinal diseases. We recommend MC-SLO imaging to screen for NFLDs in eyes with retinal diseases.

Multimodal Imaging of Nonneovascular Age-Related Macular Degeneration

Nonneovascular (dry) AMD is a retinal disease with potential for significant central visual impairment. The hallmarks of this disease are macular drusen, RPE alterations, and geographic atrophy (GA). Classification schemes for nonneovascular AMD have evolved over the years as major advances in retinal imaging have enabled a greater understanding of disease pathophysiology. The original classifications of nonneovascular AMD were based on color fundus photography (CFP), while more modern schemes rely on a multimodal imaging approach. Effective diagnosis and management of nonneovascular AMD requires a thorough understanding of its multimodal imaging features as detailed in this review. Future imaging modalities and imaging biomarkers that may aid in diagnosis and management are also discussed.

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

PURPOSE

To compare multicolor (MC) and traditional color fundus photography (CFP) in their ability to detect features of early and late age-related macular degeneration (AMD).

METHODS

Study design: Observational case series.

PARTICIPANTS

fundus images captured using standard CFP and MC imaging from 33 patients attending hospital clinics and 26 participants from the pilot phase of the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA). Systematic grading of early and late AMD features; (hard drusen, soft drusen, reticular pseudodrusen, pigment clumping, non-geographic atrophy hypopigmentation, atrophy, hemorrhage, and fibrosis) on CFP and MC.

RESULTS

There were 105 eyes with gradable images for comparison. Using CFP as the gold standard, sensitivity values for MC ranged from 100% for atrophy, non-geographic atrophy hypopigmentation, and fibrosis to 69.7% for pigment clumping. Specificity values were high: >80% for all features. On using MC as the comparator, CFP had lower sensitivity for the detection of early AMD features (27.8% for reticular drusen to 77.8% for non-geographic atrophy hypopigmention). Analysis of OCT in discrepant cases showed better agreement with MC for all AMD lesions, except hemorrhage and non-geographic atrophy hypopigmentation. For pigment clumping, CFP and MC were in equal agreement with OCT.

CONCLUSION

Multicolor retinal imaging allowed for improved detection and definition of AMD features.

Tear film evaluation by scanning laser ophthalmoscopy during retinal imaging

Purpose:

Herein, we describe a novel finding which appears as a reticular pattern on multicolor confocal scanning laser ophthalmoscopy image during routine imaging of retina and we aim to show whether there is an association between this pattern and dry eye findings.

Materials and methods:

A total of 162 eyes of 81 patients that were scheduled for a routine retinal imaging by scanning laser ophthalmoscopy at a vitreoretinal practice underwent dry eye evaluation including corneal and conjunctival lissamine green staining, fluorescein staining, tear break-up time, and tear meniscus height measurement before acquiring any images. Then, multicolor images were taken and graded for the severity of reticular pattern.

Results:

Among 150 eyes of 81 patients with gradable multicolor imaging, 45 eyes (30%) had some reticular pattern on multicolor image. Severity of reticular pattern on multicolor imaging was significantly correlated with total lissamine score (rho = 0.378, p = 0.007) and tear meniscus height (rho = −0.408, p = 0.011). Furthermore, they were found to be the best set of predictors for the severity pattern on multicolor imaging (odds ratio = 1.30, 95% confidence interval = 1.01–1.37, p = 0.027 and odds ratio = 0.25, 95% confidence interval = 0.128–0.342, p < 0.001, respectively).

Conclusion:

Reticular pattern seen on multicolor image while acquiring retinal images using scanning laser ophthalmoscopy may be related to tear film instability. Further modulations of the scanning laser ophthalmoscopy instrument will likely improve this indicator of dry eye syndrome.

Optical coherence tomography angiography

Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole.

Clinical application of multicolour scanning laser imaging in diabetic retinopathy

To compare the visualization of the lesions of diabetic retinopathy (DR) using multicolour scanning laser imaging (MSLI) and conventional colour fundus photography (CFP). The paired images of diabetic patients who underwent same-day MSLI and CFP examinations were reviewed. Combined multicolour (MC) images were acquired simultaneously using three laser wavelengths: blue reflectance (BR, λ = 488 nm), green reflectance (GR, λ = 518 nm) and infrared reflectance (IR, λ = 820 nm). The number of positive DR lesions was calculated using fundus fluorescein angiography as the reference standard. The visibility of the microaneurysms (Mas) was graded using a scale, and the number of Mas for each method was counted by two masked readers. Eighty eyes of 42 diabetic patients were included. The average grading score for Mas visualization was significantly higher with MC (1.50 ± 0.71) and GR (1.55 ± 0.69) than with CFP (0.95 ± 0.81). The average number of Mas was also significantly higher with MC (11.41 ± 14.02) and GR (11.93 ± 13.43) than with CFP (6.43 ± 9.39). The number of positive Mas, diabetic macular edema (DME) and epiretinal membranes (ERM) were significantly higher with MC than CFP (P < 0.05), while the numbers of cotton wool spots, haemorrhages, hard exudates, venous beading and abnormal new vessels were not significantly different (P > 0.05). Mas and ERM were most effectively detected on GR images, and an elevated greenish shift was clearly visualized in patients with DME on the MC images. MSLI can effectively visualize Mas and other pathological lesions of DR compared with CFP. MSLI with superior resolution may be a useful complement for DME and ERM detection.

Comparison of conventional color fundus photography and multicolor imaging in choroidal or retinal lesions

PURPOSE

Our purpose was to compare the characteristics of the retinal and choroidal lesions including choroidal nevus, choroidal melanoma and congenital hypertrophy of the retina pigment epithelium using conventional color fundus photography (CFP) and multicolor imaging (MCI).

METHODS

The paired images of patients with retinal or choroidal lesions were assessed for the visibility of lesion's border, halo and drusen using a grading scale (0-2). The area of the lesion was measured on both imaging modalities. The same grading was also done on the individual color channels of MCI for a further evaluation.

RESULTS

Thirty-three eyes of 33 patients were included. There were no significant differences in the mean border, drusen and halo visibility scores between the two imaging modalities (p = 0.12, p = 0.70, p = 0.35). However, the mean area of the lesion was significantly smaller on MCI than that on CFP (14.9±3.3 versus 18.7±3.4 mm², p = 0.01).

CONCLUSION

The appearance of choroidal and/ or retinal lesions on MCI may be different than that on CFP. Though MCI can provide similar information with CFP for the features of retinal and/ or choroidal lesions including border, halo and drusen; the infrared light reflection on MCI underestimates the extent of the choroidal lesion by 33%.

VISUALIZATION OF MACULAR PUCKER BY MULTICOLOR SCANNING LASER IMAGING

PURPOSE

To compare the visualization of the epiretinal membrane (ERM) using multicolor imaging (MCI) (Heidelberg Engineering, Carlsbad, CA) and conventional white light flood color fundus photography (FP) (Topcon).

METHODS

The paired images of patients with ERM who underwent same-day MCI and FP examinations were reviewed. Visibility of the ERM was graded using a scale (0: not visible, 1: barely visible, and 2: clearly visible) by masked readers, and surface folds were counted to quantify the membrane visibility for each method. Images from individual color channels in MCI (green, blue, and infrared) were also graded using the same method to further investigate MCI images.

RESULTS

Forty-eight eyes of 42 patients were included. The average ERM visibility score was 1.8 ± 0.37 for MCI and 1.01 ± 0.63 for FP (P < 0.001). The number of the surface folds detected per quadrant was signifi8cantly higher in MCI than that in FP (6.79 ± 3.32 vs. 2.85 ± 2.81, P < 0.001). The ERM was graded with similar scores on the two modalities in 43.8% of the eyes; in 56.2%, the ERM was better visualized on MCI than that on FP. Conventional FP failed to detect ERM in 11.4% of eyes when the mean central retinal thickness was <413 microns. Analysis of laser color reflectance revealed that green reflectance provided better detection of surface folds (5.54 ± 2.12) compared to blue reflectance (4.2 ± 2.34) and infrared reflectance (1.2 ± 0.9).

CONCLUSION

Multicolor scanning laser imaging provides superior ERM detection and delineation of surface folds than conventional FP, primarily due to the green channel present in the combination-pseudocolor image in MCI.

Morphologic characteristics and clinical significance of the macular-sparing area in patients with retinitis pigmentosa as revealed by multicolor imaging

Retinitis pigmentosa (RP) is an inherited retinal disease caused by the degeneration of photoreceptors and retinal pigment epithelium cells within the eye. The present study aimed to evaluate the effectiveness of multicolor imaging as a novel technique for the depiction of morphological features in the macular area of patients with RP. Additionally, the correlation between the size of the macular-sparing area and the best corrected visual acuity (BCVA), central visual field function and subfoveal choroidal thickness (SFCT) was analyzed. A total of 25 individuals with RP (n=50 eyes) and 35 healthy individuals (n=70 eyes) were enrolled in the current study. Images of the macular area were captured using multicolor imaging and traditional fundus photography, and their ability to depict retinal features was compared. The size of the macular-sparing area in patients with RP was measured using built-in measurement software programs. The correlations between the macular-sparing area and the BCVA, visual field and SFCT were analyzed using a Spearman's rank correlation test. The results demonstrated that multicolor imaging revealed clinical features of the macular area in greater detail than traditional fundus photography irrespective of whether the patient also had complications, including cataracts and epiretinal membranes. Multicolor imaging clearly defined the borders of the macular-sparing area corresponding to the relatively intact outer retinal structures on optical coherence tomography images, particularly the status of the ellipsoid zone and external limiting membrane. There was a significant positive correlation between the macular-sparing area and BCVA (r=−0.631; P<0.001), and the visual field in terms of MD (r=0.402; P<0.05) and PSD (r=0.595; P<0.001), however, there was not a statistically significant correlation between the macular-sparing area and SFCT. The present study demonstrated that multicolor imaging is capable of detecting macular changes and complications in patients with RP. Multicolor imaging may be particularly useful in assessing the detailed characteristics of the macular-sparing area, as this appears to be associated with visual function.

Linking OCT, Angiographic, and Photographic Lesion Components in Neovascular Age-Related Macular Degeneration

PURPOSE

To develop methods to make precise comparisons of specific retinal features between and within spectral-domain (SD) OCT images, color fundus photography (CFP) images, and fluorescein angiography (FA) images in eyes treated with anti-vascular endothelial growth factor (VEGF) agents for neovascular age-related macular degeneration (nAMD).

DESIGN

Retrospective study.

PARTICIPANTS

Patients with good study-eye images at the 104-week visit in the Comparison of Age-Related Macular Degeneration Treatments Trials.

METHODS

Graders reviewed CFP and FA images and delineated areas of fibrotic or nonfibrotic scar and geographic atrophy (GA) or non-GA. Other graders reviewed SD-OCT images and delineated retinal and subretinal lesion characteristics. Using newly developed custom software and graphic user interfaces, the presence and thickness of each feature at each pixel on the en face view was determined.

MAIN OUTCOME MEASURES

Spectral-domain OCT findings versus CFP and FA lesion components from regional overlays.

RESULTS

Per-eye distribution and thickness of SD-OCT features within CFP- and FA-established areas of scar and atrophy can be determined precisely, can be displayed in multiple formats, and can be extracted into pixel-specific data sets. These methods enable statistical analysis of imaging results within eyes and across eyes of different patients. For example, photoreceptor loss, subretinal lesion material, and thicknesses of photoreceptor layer and subretinal material across those SD-OCT features can be related precisely to CFP and FA regions of scar or atrophy.

CONCLUSIONS

Methods to integrate qualitative and quantitative retinal and subretinal changes to coincide with photographic and angiographic designations of the nAMD lesion areas and sequelae are integral for accurate assessments of posttreatment retinal morphologic features. These may lead to better understanding of disease progression and improved treatment strategies.

The Progression of Geographic Atrophy Secondary to Age-Related Macular Degeneration

Geographic atrophy (GA) is an advanced form of age-related macular degeneration (AMD) that leads to progressive and irreversible loss of visual function. Geographic atrophy is defined by the presence of sharply demarcated atrophic lesions of the outer retina, resulting from loss of photoreceptors, retinal pigment epithelium (RPE), and underlying choriocapillaris. These lesions typically appear first in the perifoveal macula, initially sparing the foveal center, and over time often expand and coalesce to include the fovea. Although the kinetics of GA progression are highly variable among individual patients, a growing body of evidence suggests that specific characteristics may be important in predicting disease progression and outcomes. This review synthesizes current understanding of GA progression in AMD and the factors known or postulated to be relevant to GA lesion enlargement, including both affected and fellow eye characteristics. In addition, the roles of genetic, environmental, and demographic factors in GA lesion enlargement are discussed. Overall, GA progression rates reported in the literature for total study populations range from 0.53 to 2.6 mm²/year (median, ∼1.78 mm²/year), assessed primarily by color fundus photography or fundus autofluorescence (FAF) imaging. Several factors that could inform an individual's disease prognosis have been replicated in multiple cohorts: baseline lesion size, lesion location, multifocality, FAF patterns, and fellow eye status. Because best-corrected visual acuity does not correspond directly to GA lesion enlargement due to possible foveal sparing, alternative assessments are being explored to capture the relationship between anatomic progression and visual function decline, including microperimetry, low-luminance visual acuity, reading speed assessments, and patient-reported outcomes. Understanding GA progression and its individual variability is critical in the design of clinical studies, in the interpretation and application of clinical trial results, and for counseling patients on how disease progression may affect their individual prognosis.

Treatment-Naïve Quiescent Choroidal Neovascularization in Geographic Atrophy Secondary to Nonexudative Age-Related Macular Degeneration

PURPOSE

To describe the characteristics and natural history of quiescent choroidal neovascularization (CNV) in geographic atrophy (GA) secondary to nonexudative age-related macular degeneration (AMD) through multimodal imaging.

DESIGN

Retrospective observational case series.

METHODS

Patients diagnosed with quiescent CNV were analyzed in 2 high-volume referral centers. Imaging features obtained using fluorescein angiography (FA), indocyanine green angiography (ICGA), structural optical coherence tomography (OCT), and OCT angiography (OCT-A) were noted at first presentation and during the study period.

RESULTS

Nineteen eyes of 19 patients were included. Mean (+SD) follow-up was 45.7 ± 14.7 months. Quiescent CNV appeared as an ill-defined hyperfluorescent lesion without leakage or pooling of dye in the late phase of FA. On ICGA, quiescent CNV appeared as a distinct area of hyperfluorescence (vascular network) in early to intermediate frames and as a hyperfluorescent plaque in the late frame (late plaque). OCT-A revealed a flow signal beneath the small irregular elevation of the retinal pigment epithelium at the site of the quiescent CNV visualized by structural OCT. During the study period, 5 of the 19 CNV patients developed exudation. The remainder showed specific alterations in both structural OCT and OCT-A imaging. At last follow-up, 92% of the quiescent CNV seemed to cover the area spared from atrophy.

CONCLUSIONS

The characteristics of the quiescent CNVs were very similar to those already described for intermediate AMD, although they had several specific features in the context of GA.

Fundus autofluorescence imaging: systematic review of test accuracy for the diagnosis and monitoring of retinal conditions

We conducted a systematic review of the accuracy of fundus autofluorescence (FAF) imaging for diagnosing and monitoring retinal conditions. Searches in November 2014 identified English language references. Sources included MEDLINE, EMBASE, the Cochrane Library, Web of Science, and MEDION databases; reference lists of retrieved studies; and internet pages of relevant organisations, meetings, and trial registries. For inclusion, studies had to report FAF imaging accuracy quantitatively. Studies were critically appraised using QUADAS risk of bias criteria. Two reviewers conducted all review steps. From 2240 unique references identified, eight primary research studies met the inclusion criteria. These investigated diagnostic accuracy of FAF imaging for choroidal neovascularisation (one study), reticular pseudodrusen (three studies), cystoid macular oedema (two studies), and diabetic macular oedema (two studies). Diagnostic sensitivity of FAF imaging ranged from 32 to 100% and specificity from 34 to 100%. However, owing to methodological limitations, including high and/or unclear risks of bias, none of these studies provides conclusive evidence of the diagnostic accuracy of FAF imaging. Study heterogeneity precluded meta-analysis. In most studies, the patient spectrum was not reflective of those who would present in clinical practice and no studies adequately reported whether FAF images were interpreted consistently. No studies of monitoring accuracy were identified. An update in October 2016, based on MEDLINE and internet searches, identified four new studies but did not alter our conclusions. Robust quantitative evidence on the accuracy of FAF imaging and how FAF images are interpreted is lacking. We provide recommendations to address this.

Use of MultiColor imaging in the assessment of suspected papilledema in 20 consecutive children

PURPOSE

To investigate the use of MultiColor Scanning Laser Imaging as an adjunct to traditional imaging modalities in the assessment of children with suspected disk swelling.

METHODS

In this study of 20 consecutive children with suspected papilledema, MultiColor imaging was performed on all patients in addition to fundus examination, fundus autofluorescence, disk spectral domain optical coherence tomography (SD-OCT), and disk retinal nerve fiber layer thickness (RNFL) measurement. Diagnoses were determined in all 20 patients, and all images were evaluated by a medical retina specialist.

RESULTS

Of the 20 cases (average age 11 years [range, 5-16 years]; 10 males), papilledema was confirmed in 11 (55%) and pseudopapilledema diagnosed in 9 (45%). Of pseudopapilledema cases, there were 4 cases of optic disk drusen, 2 hypermetropic disks, 2 "crowded disks," and 1 anomalous disk. In patients with true papilledema, on the combined MultiColor image, a green shift in the form of an elevated green ring was seen consistently. This ring was also hyperreflective on the blue and green images and surrounded a central "shadow," which was seen best on near infrared reflectance (NIR). The disk margins and vasculature were obscured on the combined, green, blue, and NIR images. These changes were not present in the pseudopapilledema cases.

CONCLUSIONS

MultiColor imaging of disks with papilledema shows characteristic changes that may prove useful in differentiating true papilledema from pseudopapilledema. It is therefore a useful adjunct to traditional disk imaging modalities in assessing children with suspected disk swelling.

Hyperreflective Choroidal Vessels in Geographic Atrophy Secondary to Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE

To describe choroidal vessels in areas of geographic atrophy (GA) secondary to age-related macular degeneration that appear as hyperreflective choroidal vessels (HRCVs) on multicolor (MC) imaging.

PATIENTS AND METHODS

Retrospective case series of patients with GA. Multimodal imaging evaluation was performed.

RESULTS

HRCVs, which seem to be sclerotic on MC imaging, appeared as hyperautofluorescent on fundus autofluorescence, clearly distinguishable over the background of hypo-autofluorescence, and correlated with late-phase hypocyanescence areas on indocyanine green angiography. Average size of GA areas was significantly larger in eyes with (4.19 mm ± 0.83 mm) compared to eyes without (3.22 mm ± 1.05 mm) HRVCs (P = .0002). Similarly, mean choroidal thickness (CT) was significantly thinner in eyes with (78.5 µm ± 33.8 µm) compared to eyes without (155.4 µm ± 69.8 µm) HRVCs (P < .0001).

CONCLUSIONS

HRCVs are more clearly distinguishable than other choroidal vessels on MC imaging in GA. HRCV identification is more frequent in eyes with larger areas of atrophy and reduced CT, and thus possibly represent a maker of more advanced GA. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:1106-1114.].

Clinical Application of Multicolor Imaging Technology

PURPOSE

To assess the clinical application of multicolor imaging by confocal scanning laser ophthalmoscopy (cSLO).

METHODS

Retinal imaging was performed in 76 patients including cSLO multicolor imaging (SPECTRALIS SD-OCT, Heidelberg Engineering, Heidelberg, Germany) and color fundus photography (CFP).

RESULTS

The use of confocal optics, reduced light scatter and automated eye tracking enable high-resolution cSLO reflectance images. Compared to CFP, the appearance of pigment alterations and hemorrhages were some of the differences observed. Various artifacts including those derived from optical media alterations need to be considered when interpreting images. Specific pathological findings including epiretinal membranes, fibrovascular proliferations, and reticular pseudodrusen may be better visualized on multicolor images.

CONCLUSIONS

When using multicolor imaging, ophthalmologists need to be mindful about differences in the appearance of pathological changes and artifacts. Multicolor imaging may offer information over and above conventional CFP; it can be performed through undilated pupils and is less affected by media opacities.