Green Reflectance Research Articles

Clinical application of multicolor imaging in Leber hereditary optic neuropathy.

To characterize features of retinal never fiber in Leber Hereditary Optic Neuropathy (LHON) using multicolor (MC) imaging and color fundus photography (CFP). Ninety-two eyes of patients with LHON underwent MC imaging, optic disc spectral domain optical coherence tomography (SD-OCT), and CFP. Two independent observers graded RNFL visibility scores and two other experts determined never fiber bundle defects from four-quadrant readings. CFP, standard MC, infrared reflectance (IR), green reflectance (GR), blue reflectance (BR), and green-blue-enhanced (BG) imaging were compared. Agreement on never fiber bundle defects was substantial for CFP, standard MC, GR, BR, and BG images relative to IR. It was shown that BR (2.71 ± 0.55) had the best mean RNFL visibility score, BG (2.69 ± 0.52), GR (2.69 ± 0.56), standard MC (2.04 ± 0.79), CFP (1.80 ± 0.82), and IR (0.45 ± 0.59) followed. Agreement on temporal area defects was relatively improved. Youden's indices for CFP (78.21%), standard MC (84.48%), GR (90.92%), BR (89.64%), and BG (90.99%) indicated good detection of defects in the papillomacular bundle (PMB)/ high suspicion of patients with LHON, particularly for BG and GR. According to the proportion of never fiber bundle defects, standard MC, GR, BR, and BG can roughly determine the LHON clinical stage, especially in subacute and chronic stages, and standard MC is superior for patients with LHON of all stages. The stage judged by MC was consistent with the course inferred by pRNFL thickness. As an adjunct to SD-OCT, the MC image, particularly the GR and BG can delineate RNFL more effectively than CFP. The MC image may be a useful adjunct to OCT for detecting or monitoring never fiber bundle defects, providing inexpensive and rapid methods that can quickly identify patients with high suspicion of LHON.

Merits of multicolor imaging for tractional retinal detachment.

Purpose:To compare multicolor imaging (MCI) with Optos color fundus photography (OCFP) for the evaluation of morphology and extent of preretinal membranes in diabetic tractional retinal detachments (TRD).Methods:In this retrospective study, 30 eyes with diabetic TRDs were imaged using the MCI feature of the Heidelberg Spectralis Spectral-domain optical coherence tomography (SD-OCT) and color photo using the Optos Daytona ultra-widefield fundus camera. Two investigators independently graded and determined the agreeability between the two modalities with respect to the extent of the TRD and preretinal membranes on the SD-OCT B-scan images.Results:The MCI provided better visualization of the attachments and traction points of the posterior hyaloid face and preretinal membranes and is comparable to the SD-OCT B-scan images. The inter-rater agreeability rates for OCFP had a Kappa (κ) value of 0.37, while the MCI had a κ value of 0.46. When comparing between images of different wavelengths, grading using infrared reflectance (IR) had a poor agreement (−0.04 ± 0.04) while green reflectance (GR) (0.46 ± 0.32) and blue reflectance (BR) (0.53 ± 0.19) had a moderate agreement. The composite MCI and GR images also had comparatively higher intraclass coefficient when compared to the OCFP (0.25 [−0.09–0.55]) and IR (−0.03 [−0.39–0.34]) images.Conclusion:MCI is more sensitive for determining the extent of TRDs and for the detection of secondary membranes when compared to OCFP, thus, aiding in better surgical planning.

Relevance of Multicolor Imaging in Type 2 Macular Telangiectasia.

Purpose:To report the imaging characteristics of various clinical features in idiopathic macular telangiectasia (MacTel 2) on multicolor imaging (MCI) and compare its accuracy vis-à-vis color fundus photograph (CFP) and fluorescein angiography (FA).Methods:In this retrospective observational study, 54 eyes of 27 patients with MacTel 2 were included after institutional review board approval. Multimodal imaging with CFP, optical coherence tomography (OCT), MCI, and FA was done. Images were analyzed to identify and describe the clinical findings in MacTel 2. Sensitivity, specificity, and positive and negative predictive values were computed for the various imaging modalities in MacTel 2.Results:In this study, the MCI identified all the different clinical features of MacTel 2 in 100% of cases. The confocal blue reflectance (BR) image was more sensitive than CFP (100% vs. 96.3%) in identifying the loss of retinal transparency in MacTel 2. For other clinical features such as right-angled vessels, superficial retinal crystals, and retinal pigment epithelial hyperplasia/plaques, the sensitivity of BR, and green reflectance (GR) image, was comparable to that of CFP. Confocal infrared reflectance (IR) images showed poor sensitivity in identifying the non-proliferative features in MacTel 2 (P < 0.001). Loss of retinal transparency was not picked up on IR image. Other features such as right-angled vessels, superficial retinal crystals, and pigment plaques were seen in 20%, 4.6%, and 26.3% of cases, respectively. However, confocal IR images were superior to FA (100% vs. 47%) and CFP (100% vs. 15%) in identifying the extent and location of subretinal neovascular membrane. The confocal BR and GR images were unable to identify the choroidal neovascular membrane (P < 0.001).Conclusion:MCI is a useful and non-invasive imaging modality to identify the clinical features in MacTel 2. MCI can be used as a complementary imaging tool to CFP, FA, and OCT.

CLINICAL APPLICATION OF MULTICOLOR IMAGING IN CENTRAL SEROUS CHORIORETINOPATHY.

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. 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. 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). 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.

Image characteristics and quantitative analysis of multicolor imaging in eyes with cystoid macular edema

Objective To observe the imaging features of cystoid macular edema (CME) in multicolor imaging (MC), and to evaluate the value of MC in the diagnosis of CME. Methods Descriptive case series study. From August 2017 to June 2018, 42 eyes of 37 patients with CME diagnosed in the people's Hospital of Wuhan University were included in the study. Among them, there were 24 males and 13 females, with an average age of 48.51±10.29 years. There were 14 eyes with diabetic retinopathy, 14 eyes with central retinal vein occlusion, 8 eyes with branch retinal vein occlusion, 4 eyes with uveitis, and 2 eyes with Eales disease. The macular color fundus photography (CFP) was performed with Visucam 200 non-mydriatic fundus camera of Zeiss company in Germany. MC, frequnce domainoptical OCT (SD-OCT) and FFA were examined by Spectralis HRA2 + OCT of Heidelberg company in Germany. According to the MC standard method, five images, including 488 nm blue reflection (BR), 515 nm green reflection (GR), 820 nm infrared reflection (IR) imaging and standard MC and blue-green enhancement (BG), were obtained at the same time. Compared with SD-OCT, CFP and MC images were scored. Friedman M test and Wilcoxon signed rank test were used for statistical analysis. Results The standard MC and BG images showed blue-green uplift area or petal-shaped appearance, surrounded by green reflection areas with clear boundaries. BR image can be seen in the low reflexes area. On the GR image, there were patches or cystic low reflection areas, surrounded by a slightly high reflection. On the IR image, patches or cystoid high reflexes can be seen, surrounded by low reflection dark areas with clear boundaries. The average scores of CFP, standard MC, GB, IR, GR and BR were 1.20±0.94, 3.05±0.99, 2.90±1.04, 2.55±1.27, 2.00±0.94, 0.51±0.85 respectively, and the differences were statistically significant (χ2= 151.61, P=0.000). The score of CFP were significantly lower than that of standard MC (Z=-5.421), BG (Z=-5.354), IR (Z=-4.714), GR (Z=-4.438) and higher than that of BR (Z=-3.435). The differences were statistically significant (P=0.000, 0.000, 0.000, 0.000, 0.001). Conclusions The quality of MC imaging is better than that of CFP. Combined with SD-OCT, it can be used as an assistant method to diagnose CME. Key words: Macular edema/diagnosis; Tomographyoptical coherence; Fluorescein angiography; Multicolor imaging

Multimodal imaging of combined harmatoma of the retina and retinal pigment epithelium

PurposeTo describe the use of multimodal imaging in defining the anatomical features of combined harmatoma of the retina and retinal pigment epithelium (CHRRPE) and assess its role in the diagnosis and management of CHRRPE.MethodsRetrospective case series of three patients with unilateral, juxta‐papillary CHRRPE, who underwent Spectralis Enhanced Depth Imaging Optical Coherence Tomography (EDI‐OCT), MultiColor (MC) and autofluorescence (AF) in addition to a complete ophthalmic examination.ResultsEDI‐OCT demonstrated thickening and disorganisation of retinal architecture, with intraretinal cysts disrupting the retinal layers and a loss of photoreceptors. An overlying epiretinal membrane was shown to be causing ‘mini‐peaks’ of the inner retinal surface in all cases and vitreoretinal traction in two cases. Details of the retinal pigment epithelium (RPE) were revealed, including RPE thickening and sectoral atrophy. MC revealed areas of red‐shifting, demonstrating partial pigmentation. On green reflectance (GR) the degree of inner retinal distortion and extent of macular involvement could be visualised. Near infra‐red (NIRR) reflectance displayed the lesions as areas of hyporeflectance and allowed delineation of the tumour borders. On AF, the lesions were represented by areas of hypo‐autofluorescence that obscured the normal blood vessel hypo‐autofluorescence.ConclusionsIn this case series, multimodal imaging enabled the anatomical characteristics of CHRRPE to be defined in greater detail. NIRR enabled better visualisation of tumour boundaries and the extent of macular involvement, which may be useful in assessing the impact on visual function. GR better defined the degree of inner retinal distortion, which may be useful in surgical management decisions. We believe that multimodal imaging is a valuable adjunct in correctly diagnosing and managing CHRRPE.

Characterisation of reticular pseudodrusen and their central target aspect in multi-spectral, confocal scanning laser ophthalmoscopy

To analyse reticular pseudodrusen (RPD) in patients with age-related macular degeneration (AMD) using multi-spectral (MS), confocal scanning laser ophthalmoscopy (cSLO). cSLO images (blue fundus autofluorescence [FAF; exc., λ = 488; em., λ = 500-700 nm], near-infrared reflectance [IR; λ = 820 nm], MS [blue reflectance (BR) λ = 488 nm, green reflectance (GR) λ = 515 nm, IR λ = 820 nm], as well as colour fundus photographs (CFP) were taken of 200 eyes from 100 AMD patients suspected to show RPD on the basis of funduscopy or previous fundus imaging. FAF and IR images were graded by two independent readers. If both readers concordantly confirmed the presence of RPD in both modalities, eyes were subsequently also graded for RPD in MS, BR, GR, green-blue enhanced mode (GBE), and CFP. Besides, FAF, IR, and MS images were evaluated for the presence of a target aspect, which represents a common feature of RPD lesions. The presence of RPD was confirmed using FAF and IR images by both readers in 130 eyes of 76 patients. In those eyes, both readers concordantly diagnosed RPD in MS images in 124 (95.4%) eyes (BR: 52 [40.0%], GR: 63 [48.5%], GBE: 101 [77.7%], CF: 27 [20.8%]). Cohen kappa statistics revealed excellent inter-observer agreement for MS (0.95) and GBE (0.85), substantial agreement for BR (0.75), GR (0.78), and moderate agreement for CFP (0.59). A target aspect within RPD lesions was detected in 45 of 130 (35.0%) included eyes using FAF and IR. The presence of a target aspect improved the recognition of RPD lesions in all modalities. If a target aspect was present, RPD were diagnosed in 45 eyes (100%) using MS (GBE: 42 eyes [93.3%], BR: 30 eyes [66.7%], GR: 37 eyes [82.2%], CFP: 17 eyes [37.8%]). Using MS cSLO, a target aspect could be identified in 75 of 130 (57.7%) included eyes. MS cSLO imaging is equivalent to FAF and IR in identifying RPD in AMD patients. Higher identification rates in BR and GR of those RPD lesions featuring a target aspect confirm the current hypothesis of RPD localisation and its progression further into the photoreceptor layers. MS seems to be more sensitive in identifying a central target aspect in RPD lesions compared to blue FAF and IR.

On‐Farm Evaluations to Calibrate Tools for Estimating Late‐Season Nitrogen Status of Corn

Properly calibrated diagnostic tools are needed to evaluate the performance of different N management practices for corn (Zea mays L.). Until now, mostly controlled studies were used for such calibrations. We utilizedon‐farm evaluation studies to verify current and identify new N status categories using the corn stalk nitrate test (CSNT) andlate‐season digital aerial imagery of the corn canopy. From 2007 through 2010, producers conducted 125 trials across Iowa. Each trial had treatments of a producer's normal N rate alternated with a rate that was about one‐third lower or higher. Categorical yield response (YR), expressed as profitable and unprofitable, was related to green reflectance (GR), relative green reflectance (RGR), or CSNT sampled within nine areas in each trial. Multilevel binary logistic regressions were used to estimate the probability of receiving profitable YR for a range of CSNT, RGR, and GR values. Among the three diagnostics, RGR performed slightly better but required applying at least two N rates within producers' fields. For CSNT, the identified optimal category was almost the same as that currently recommended in Iowa (700–2000 mg NO3–N kg−1), even when corn and N prices deviated from their long‐term averages by 30%. Due to the uncertainty in N availability, however, the critical CSNT value for fall manure treatments was about 3000 mg NO3–N kg−1 higher than that for fall anhydrous NH3, spring urea–NH4NO3, or sidedress N. On‐farm studies can be used to calibratelate‐season N diagnostic tools for evaluating management practices that differ in rates, forms, and timing of N applications.

Michael Green's Reflections on Personal and Institutional Development of Cultural Studies in Education at Birmingham (Part II)

Michael Green's Reflections on Personal and Institutional Development of Cultural Studies in Education at Birmingham (Part II)