Peripheral autofluorescence and clinical findings in neovascular and non-neovascular age-related macular degeneration

Comparison of Standard 7-Field, Clarus, and Optos Ultrawidefield Imaging Systems for Diabetic Retinopathy (COCO Study)

Purpose

The purpose of this study was to compare diabetic retinopathy (DR) severity levels assessed from 7 standard-field stereoscopic color photographs on a 35° fundus camera to both Clarus and Optos ultrawidefield color images.

Design

Cross-sectional, comparative imaging study.

Participants

Participants with DR imaged at a single-center retina practice.

Methods

Participants were imaged on 3 cameras at a single visit with the Topcon 35° fundus camera, Clarus, and Optos. The DR Severity Scale (DRSS) level was determined within the 7-field (7F) area of each image set using the ETDRS scale. An additional global DRSS was assigned for both Clarus and Optos images using the entire visible retina. Weighted kappa (wκ) measured the agreement between cameras.

Main Outcome Measures

The primary outcome was a 3-way comparison of DRSS level within the 7F area imaged on the 3 cameras. Secondary outcomes included a comparison of the DRSS obtained with standard 7F imaging to the global DRSS of Clarus and Optos and a comparison of the global DRSS between Clarus and Optos only.

Results

Ninety-seven eyes (50 participants) were evaluated. Agreement within 1-step of ETDRS levels between standard 7F imaging and Clarus 7F was 90.1% (wκ = 0.65), and with Optos 7F in 85.9%, (wκ = 0.58). Agreement within 1-step between standard 7F imaging and Clarus global was 88.9% of eyes (wκ = 0.63), and Optos global was 85.7%, (wκ = 0.54). Agreement between Clarus and Optos global DR level within 1-step was 89.1% (wκ = 0.68). Intergrader agreement for the 7F ETDRS level was 96% for standard 7F imaging, 98% for Clarus, and 95.5% for Optos.

Conclusions

These findings suggest that when evaluating the 7F area on Clarus and Optos, DR severity grades are comparable to standard 7F imaging. However, it is important to understand the unique attributes and differences of each fundus camera when changing the type of system used in a clinical setting due to upgrading equipment. Additionally, if the facility has access to > 1 device, there should not be an exchange between cameras for the same patient.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparison of Blue-Light Autofluorescence and Ultrawidefield Green-Light Autofluorescence for Assessing Geographic Atrophy

PURPOSE

The goal of this study was to evaluate and compare the intermodality and interreader agreement of manual and semiautomated geographic atrophy (GA) area measurements in eyes with GA due to age-related macular degeneration (AMD) using conventional blue-light fundus autofluorescence (FAF) and ultrawidefield (UWF) green-light FAF systems.

DESIGN

Prospective Cohort Study.

SUBJECTS

Seventy-two eyes of 50 patients with a diagnosis of advanced nonneovascular AMD with GA.

METHODS

Fundus autofluorescence images of eyes with GA were obtained during a single visit using both the Spectralis HRA + OCT2 device and the Optos California device. The area of the GA lesion(s) was segmented and quantified (mm2) with a fully manual approach where the lesions were outlined using Optos Advance and Heidelberg Eye Explorer (HEYEX) software. In addition, for the Heidelberg blue FAF images, GA lesions were also measured using the instrument's semiautomated software (Region Finder 2.6.4). For comparison between modalities/grading method, the mean values of the 2 graders were used. Intraclass correlation coefficients were computed to judge the agreement between graders.

RESULTS

Seventy-two eyes of 50 patients were included in this study. There was nearly perfect agreement between graders for the measurement of GA area for all 3 modalities (intraclass correlation coefficient: 0.996 for manual Optos Advance, 0.996 for manual Heidelberg HEYEX, and 0.995 for Heidelberg Region Finder). The measurement of GA area was strongly correlated between modalities, with Spearman correlation coefficients of 0.985 (P < 0.001) between manual Heidelberg and manual Optos, 0.991 (P < 0.001) for Region Finder versus manual Heidelberg, and 0.985 (P < 0.001) for Region Finder versus manual Optos. The absolute mean area differences between the Heidelberg manual versus Region Finder, manual Optos versus Region Finder, and manual Optos versus manual Heidelberg were 1.61 mm2 (P < 0.001), 0.90 mm2 (P < 0.006), and 0.71 mm2 (P < 0.001), respectively.

CONCLUSIONS

We observed excellent interreader agreement for measurement of GA using either 30-degree blue-light FAF or UWF green-light FAF, establishing the reliability of UWF imaging for macular GA assessment. Although the absolute measurements between devices were strongly correlated, they differed significantly, highlighting the importance of using the same device for a given patient for the duration of a study.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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

PURPOSE

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

STUDY DESIGN

Population-based longitudinal cohort study.

METHODS

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

RESULTS

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

CONCLUSIONS

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

Panretinal Optical Coherence Tomography

We introduce a new concept of panoramic retinal (panretinal) optical coherence tomography (OCT) imaging system with a 140° field of view (FOV). To achieve this unprecedented FOV, a contact imaging approach was used which enabled faster, more efficient, and quantitative retinal imaging with measurement of axial eye length. The utilization of the handheld panretinal OCT imaging system could allow earlier recognition of peripheral retinal disease and prevent permanent vision loss. In addition, adequate visualization of the peripheral retina has a great potential for better understanding disease mechanisms regarding the periphery. To the best of our knowledge, the panretinal OCT imaging system presented in this manuscript has the widest FOV among all the retina OCT imaging systems and offers significant values in both clinical ophthalmology and basic vision science.

Recent Advances in Clinical Applications of Imaging in Retinal Diseases

Many diseases that cause visual impairment, as well as systemic conditions, manifest in the posterior segment of the eye. With the advent of high-speed, high-resolution, reliable, and noninvasive imaging techniques, ophthalmologists are becoming more dependent on ocular imaging for disease diagnosis, classification, and management in clinical practice. There are rapid advances on the indications of multimodal retinal imaging techniques, including the application of ultra-widefield fundus angiography, fundus autofluorescence, optical coherence tomography, as well as optical coherence tomography angiography. This review summarizes and highlights the clinical applications, latest indications, and interpretations of multimodal imaging in age-related macular degeneration, polypoidal choroidal vasculopathy, diabetic macular edema, central serous chorioretinopathy, diabetic retinopathy, retinal vein occlusion, and uveitis.

The Optos 200Tx Scanning Laser Ophthalmoscope Application in Retinoblastoma Patients' Follow-Up

Methods

A total of 1134 examinations with Optomap 200Tx were performed for 318 children who were clinically diagnosed with RB in the Ophthalmology Department of Tianjin Medical University Eye Hospital, China, between July 2015 and July 2017, and achieved stable disease lasting for more than 6 months after combined treatment. The children received examinations every 1-12 months (mean 4 months), initially at 31 months to 15 years of age (mean 51 months), and were given a full eye examination under anesthesia (EUA) immediately if recurrent tumor, recurrent vitreous seeding (VS), or recurrent subretinal seeding (SRS) was detected, or in the next follow-up visit if no abnormality was detected, and early treatment was performed when the lesion was confirmed.

Results

Recurrence was detected in 4 children in the examination with Optomap 200Tx, including 2 cases of recurrent vitreous seeding (VS) and 2 cases of recurrent subretinal seeding (SRS), which were confirmed by EUA and well controlled after early treatment.

Conclusion

The use of Optomap 200Tx in the long-term following up of patients with RB reduces the number of eye examinations under general anesthesia (EUA), increases the time between EUAs, and protects children from exposure to the adverse effects of general anesthetics. Optomap 200Tx can detect recurrent tumor and recurrent seeding, allowing for early treatment which produces better outcomes.

Peripheral Manifestations in Age Related Macular Degeneration: A Review of Imaging and Findings

Purpose: To review novel findings in research with ultra-widefield imaging for analysis of peripheral manifestations in macular degeneration (AMD). We introduce the evolving widefield imaging modalities while summarizing the analytical techniques used in data collection of peripheral retinal findings thus far. Our review provides a summary of advancements to date and a commentary on future direction for AMD research. Methods: This is a literature review of all significant publications focused on the relationship between AMD and the retinal periphery conducted within the last two decades. Results and Conclusion: Promising research has been undertaken to elucidate peripheral retinal manifestations in macular degeneration using novel methodology. Advancements in ultra-widefield imaging and fundus autofluorescence have allowed us to elucidate peripheral retinal pigmentary changes, drusen deposition, and much more. Novel grid overlay techniques have been introduced to aid in analyzing these changes for pattern recognition and grouping of findings. This review discusses these findings in detail, providing evidence for the pan-retinal manifestations of AMD. Inter-study discordance in analytical approach highlights a need for more systematic future study.

Evaluation of Peripheral Retinal Changes on Ultra-Widefield Fundus Autofluorescence Images of Patients with Age-Related Macular Degeneration

Objectives:

Age-related macular degeneration (AMD) is the most common cause of central vision loss in individuals aged 65 years and older in developed countries. Earlier imaging systems did not enable visualization of the peripheral retina in diseases affecting the macula. With the introduction of new-generation devices, the peripheral retina is easily visualized. In our study, we aimed to evaluate the incidence of peripheral retinal changes in the color and autofluorescence fundus images of patients with AMD.

Materials and Methods:

In the study group, 550 eyes of 277 patients who were diagnosed with AMD and 90 eyes of 45 healthy patients in the control group were evaluated. An ultra-wide-angle imaging device was used to record standard 200° color and autofluorescence fovea-centered fundus images followed by superior and inferior fundus images obtained using the device’s fixation light. The fundus images were examined in 3 sections: zone 1, zone 2, and zone 3.

Results:

Evaluation of color fundus images revealed peripheral retinal changes in 67.8% of the 550 AMD eyes and 47.8% of the healthy eyes. Drusen was the most common peripheral retinal change. Evaluation of autofluorescence images revealed peripheral autofluorescence changes in 39.6% of the AMD eyes and 28.9% of the healthy eyes. Hypoautofluorescence was the most common autofluorescence change.

Conclusion:

Peripheral retinal changes were more common in AMD patients than the control group, indicating that AMD is not only a macular disease, but can affect the entire retina. Future prospective studies will elucidate the relationship between these peripheral retinal changes and patients’ genetic features and their importance in prognosis, diagnosis, and treatment.

DETECTION OF NEUROSENSORY RETINAL DETACHMENT COMPLICATING DEGENERATIVE RETINOSCHISIS BY ULTRA-WIDEFIELD FUNDUS AUTOFLUORESCENCE IMAGING

PURPOSE

To determine whether neurosensory retinal detachment complicating degenerative retinoschisis (RS) can be reliably detected with ultra-widefield fundus autofluorescence evaluation.

METHODS

Consecutive patients diagnosed with RS who had ultra-widefield fundus autofluorescence imaging were included in this retrospective case series. According to the fundus autofluorescence patterns, we divided the eyes into two groups: 1) eyes with RS and a hyperautofluorescent leading edge and 2) eyes with RS and without hyperautofluorescence. Peripheral spectral domain optical coherence tomography images at the level of RS were obtained.

RESULTS

Thirty-eight eyes that met eligibility criteria were identified. Review of ultra-widefield fundus autofluorescence demonstrated 21/39 (55%) eyes with distinctive hyperautofluorescence over the area of RS (Group A) and 17/38 (45%) eyes without any form of hyperautofluorescence (Group B). Spectral domain optical coherence tomography images confirmed the presence of full-thickness neurosensory retina separation from the underlying retinal pigment epithelium in the areas of hyperautofluorescence in 10/10 eyes (100%) from Group A. None (0/11; 0%) of the eyes from Group B showed full-thickness neurosensory retina separation on the spectral domain optical coherence tomography imaging of the retina-RS interface.

CONCLUSION

Hyperautofluorescent findings suggest the presence of a neurosensory retinal detachment. Retinal detachment associated with RS can be reliably detected on ultra-widefield fundus autofluorescence and may be a useful diagnostic imaging modality.

Clinical Characteristics, Differential Diagnosis and Genetic Analysis of Concentric Retinitis Pigmentosa

Concentric retinitis pigmentosa (RP), in which retinal degeneration is limited in the periphery, is rare and little information exists to date on the subject. Herein, we describe the clinical and genetic characteristics of this atypical form of RP. We retrospectively reviewed our database and identified 14 patients with concentric RP. Additionally, 14 patients with age-matched typical RP were also included. Patients with concentric RP had better visual acuity (logarithm of minimum angle of resolution −0.04 vs. 0.32, p = 0.047) and preserved ellipsoid zones (7630 µm vs. 2646 µm, p < 0.001) compared to typical RP. The electroretinogram showed subnormal but recordable responses in patients with concentric RP. Genetic testing was done in nine patients with concentric RP and revealed causative mutations in the EYS gene in one patient and the RP9 gene in one patient. Two patients had myotonic dystrophy and the diagnosis was revised as myotonic dystrophy-associated retinopathy. Concentric RP is a rare, atypical form of RP with better visual function. There is some overlap in the causative genes in concentric and typical RP. Myotonic dystrophy-associated retinopathy is an important differential diagnosis.

Full-field electroretinography in age-related macular degeneration: an overall retinal response

PURPOSE

Age-related macular degeneration (AMD) is generally considered a disease of the macula. However, recent studies show peripheral retinal lesions are prevalent in patients with AMD, indicative of a disease process that is more widespread. Full-field electroretinography (ffERG) measures an electrical response, not only from the macula, but from the entire retina. We wanted to study the ffERG response in eyes with AMD.

METHODS

We performed full-field electroretinography (RETI-port/scan 21, Roland, Berlin) in 13 patients with early AMD, 25 patients with late AMD and 24 individuals without vitreoretinal disease as a control group. Dawson-Trick-Litzkow fibre electrodes were used. Statistical analysis was performed and a p-value <0.05 was considered significant.

RESULTS

After adjusting for multiple comparisons, both the light-adapted 3.0 a-wave implicit time (p < 0.001) and 30-Hertz flicker peak time (p = 0.012) showed significant difference between patients with late AMD and individuals without vitreoretinal disease. There was a significant difference in the light-adapted 3.0 a-wave implicit time (p = 0.011) between patients with early AMD and the control group, but the difference in 30 Hz flicker peak time was not significant (p = 0.256).

CONCLUSION

The difference in cone function measured by light-adapted 3.0 a-wave implicit time and 30-Hertz flicker peak time in early and late AMD when compared to healthy controls suggests a more diminished overall response when AMD has reached later stages.

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.

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.

Genetic and environmental risk factors for extramacular drusen

PURPOSE

To analyze risk factors for extramacular drusen (EMD) in patients with age-related macular degeneration (AMD) and healthy control individuals.

METHODS

This case-control study included 1,520 patients from the prospective multicenter European Genetic Database (EUGENDA). Color fundus photographs and optical coherence tomography scans were evaluated for the presence of AMD and EMD. EMD was considered present if ten or fewer drusen including at least one intermediate-sized drusen were detected outside the macula. Association of EMD was evaluated with various genetic and non-genetic risk factors (31 single nucleotide polymorphisms, systemic complement activation, smoking, cardiovascular factors, and sunlight exposure) using logistic regression models adjusted for age, gender, and AMD.

RESULTS

EMD was found in 608 subjects (40%) and AMD in 763 (50%) of 1,520 participants. EMD was strongly associated with AMD (p = 2.83 × 10-63, odds ratio [OR] 7.63). After adjustment for AMD, age (p = 0.06, OR 1.02), female gender (p = 3.34 × 10-24, OR 4.44), history of sunlight exposure ≥ 8 h /day (p = 0.0004, OR 1.99), serum complement activation (p = 0.004, OR 1.61), and polymorphisms in ARMS2 (p = 0.00016, OR 1.43) and CFI (p = 0.043, OR 1.20) were identified as risk factors for EMD. The final prediction model including these variants showed an area under the curve of 0.820.

CONCLUSIONS

The comprehensive analysis of various risk factors revealed a common genetic and pathological pathway of EMD with AMD. Future longitudinal studies are needed to evaluate the role of EMD in otherwise healthy subjects as an expanded phenotype of AMD.

Recent advances in imaging technologies for assessment of retinal diseases

INTRODUCTION

Retinal imaging is a key investigation in ophthalmology. New devices continue to be created to keep up with the demand for better imaging modalities in this field. This review looks to highlight current trends and the future of retinal imaging.

AREAS COVERED

This review looks at the advances in topographical imaging, photoacoustic microscopy, optical coherence tomography and molecular imaging. There is future scoping on further advances in retinal imaging.

EXPERT OPINION

Retinal imaging continues to develop at a rapid pace to improve diagnosis and management of patients. We will see the development of big data to gain powerful insights and new technologies such as teleophthalmology mature in the future.

Three-dimensional analysis of choroidal vessels in eyes with Vogt-Koyanagi-Harada disease before and after treatment

OBJECTIVE

To investigate a 3-dimensional analysis of choroidal vessels using binarization of ultrawide-field indocyanine green angiography (UWFICGA) images and swept-source optical coherence tomography (SS-OCT) images before and after treatment in eyes with Vogt-Koyanagi-Harada (VKH) disease.

METHODS

Seven eyes of 7 patients (2 men and 5 women; mean age, 48.3 years) with VKH disease and 8 control eyes of 8 patients (4 men and 4 women; mean age, 47.6 years) who visited from August 1, 2015, through July 31, 2017, were enrolled. UWF fluorescein angiography images were subtracted from UWFICGA images in all patients to evaluate the choroidal vessel densities. A vertical analysis of the choroid also was performed in the same way with SS-OCT images.

RESULTS

At the acute stage of VKH disease, the mean choroidal vascular densities in both posterior and mid-peripheral areas were significantly (p < 0.01) lower than in control eyes, and recovered after the treatment. In addition, the choroidal stroma significantly (p < 0.01) decreased after the treatment and the choroidal lumina significantly (p < 0.01) increased.

CONCLUSIONS

Current results suggest that diffuse cellular infiltration into the choroidal stroma might compress choroidal vessels and the change would resolve after treatment.

Fundus autofluorescence imaging

Fundus autofluorescence (FAF) imaging is an in vivo imaging method that allows for topographic mapping of naturally or pathologically occurring intrinsic fluorophores of the ocular fundus. The dominant sources are fluorophores accumulating as lipofuscin in lysosomal storage bodies in postmitotic retinal pigment epithelium cells as well as other fluorophores that may occur with disease in the outer retina and subretinal space. Photopigments of the photoreceptor outer segments as well as macular pigment and melanin at the fovea and parafovea may act as filters of the excitation light. FAF imaging has been shown to be useful with regard to understanding of pathophysiological mechanisms, diagnostics, phenotype-genotype correlation, identification of prognostic markers for disease progression, and novel outcome parameters to assess efficacy of interventional strategies in chorio-retinal diseases. More recently, the spectrum of FAF imaging has been expanded with increasing use of green in addition to blue FAF, introduction of spectrally-resolved FAF, near-infrared FAF, quantitative FAF imaging and fluorescence life time imaging (FLIO). This article gives an overview of basic principles, FAF findings in various retinal diseases and an update on recent developments.

Evaluation of Hydroxychloroquine Retinopathy Using Ultra-Widefield Fundus Autofluorescence: Peripheral Findings in the Retinopathy

OBJECTIVES

To investigate the application of ultra-widefield fundus autofluorescence (UWF-FAF) imaging in evaluating hydroxychloroquine (HCQ) retinopathy and to report peripheral autofluorescence findings in Asian patients with this condition.

DESIGN

Retrospective case series.

METHODS

Setting: institutional.

PATIENT POPULATION

58 eyes of 29 patients with HCQ retinopathy.

OBSERVATION PROCEDURES

UWF-FAF imaging was performed, and the images were compared to conventional FAF images obtained using a confocal digital ophthalmoscope. The sensitivities of detecting retinopathy using the 2 modalities were compared. Peripheral autofluorescence findings in the eyes with HCQ retinopathy were assessed, and their association with the Humphrey visual field test results obtained using the 30-2 and full-field 120 (FF-120) protocols was analyzed. Main outcome measurements were abnormal FAF findings.

RESULTS

In 41 of 58 eyes (70.7%) with HCQ retinopathy, abnormal FAF findings were noted in the retinal periphery outside the field of view of conventional FAF as hypoautofluorescent (23 eyes, 39.7%) and hyperautofluorescent (38 eyes, 65.5%) lesions. In 5 eyes (8.6%), differences were revealed between conventional FAF and UWF-FAF in detecting retinopathy. Most of the eyes with severe retinopathy showed the most extensive hypoautofluorescence in the nasal peripheral retina. The areas with abnormal FAF findings were significantly correlated with the number of unseen spots on FF-120 results and mean deviation and pattern standard deviation of the 30-2 test results (all P < .001).

CONCLUSIONS

Peripheral autofluorescence findings varied in eyes with HCQ retinopathy according to the severity of the retinopathy. The retinal findings with UWF-FAF were functionally correlated to visual field results. UWF-FAF may be useful for evaluating HCQ retinopathy, particularly in Asian patients.

Wide-field angiography in retinal vein occlusions

BACKGROUND

Retinal vein occlusion (RVO) is the second most common retinal vascular disease after diabetic retinopathy. It can result in significant visual loss from complications like macula edema, retinal and iris neovascularization, and vitreous hemorrhage. Recently, ultra-widefield imaging (UWF) has been developed for posterior pole visualization and has shown to be useful in the evaluation and treatment of RVO.

MAIN TEXT

Ultra-widefield imaging (UWF) imaging allows for visualization of the retina up to an angle of 200°. This is especially important in detecting peripheral retinal pathologies, especially in retinal conditions such as RVO, where the disease process affects the peripheral as well as central retina. In particular, retinal non-perfusion in RVO is a risk factor for neovascularization. Various techniques, such as ischemic index and stereographic projection, have been described to assess areas of ischemia on UWF images. Retinal non-perfusion has an impact on disease complications, such as macular edema, and retinal and iris neovascularization. Retinal non-perfusion also has implications on disease response, including visual acuity, reduction in retinal edema and treatment burden.

CONCLUSION

Ultra-widefield imaging (UWF) imaging plays an important role in the assessment and management of RVO, especially in measuring retinal non-perfusion in the peripheries.

Comparisons of Effective Fields of Two Ultra-Widefield Ophthalmoscopes, Optos 200Tx and Clarus 500

Purpose

To compare the effective fields of the Optos 200Tx® and Clarus 500™, two ultra-widefield ophthalmoscopes, based on their ability to image branches of retinal vessel in the four retinal quadrants.

Methods

Ninety retinal images from 90 patients with various eye diseases were studied. All patients had undergone 200° retinal imaging to obtain a single image of Optos (O) and the montage of two images of the Clarus (C). The highest number of traceable vessel branches in the four retinal quadrants was determined by two masked raters. An image was classified as “O > C” when the number of identifiable branch was greater in the Optos than the Clarus, as “O = C” when the number was equal and as “O < C” when the number was fewer in the Optos than the Clarus.

Results

The appearance probability of “O > C” was significantly higher at the upper temporal quadrant than “O < C” (p < 0.01 for both raters). In contrast, the appearance probability of “O < C” was significantly higher at the lower nasal quadrant than “O > C” (p < 0.01 for both raters). There were no significant differences in the appearance probability between “O > C” and “O < C” at the other two retinal quadrants (p > 0.50 for both raters).

Conclusions

These results demonstrate that the effective field of views was different between the two devices at different retina quadrants. Further studies are needed to clarify possible factors such as artifacts by the eyelashes, differences in the depth of focus, motion of the device, and different locations of the images on the effective field of views.

Quantitative comparisons of ultra-widefield images of model eye obtained with Optos® 200Tx and Optos® California

Background

To compare the quality of the ultra-widefield images acquired by Optos® 200Tx to those acquired by Optos® California.

Methods

Images of the posterior surface of a Gullstrand’s model eye obtained by Optos® 200Tx were compared to those obtained by Optos® California in terms of the angular field of view and the symmetry of the image, i.e., vertical and horizontal aspect ratios at the center (0°) and at the periphery (40° and 80°) in each direction. In addition, we compared the enlargement of the image on the posterior surface as the square ratio, and the differences in the contrasts.

Results

No significant differences were detected in the angular field of view between the two instruments. The aspect ratios showed that the Optos® California had more symmetrical images than the Optos® 200Tx at the center (0.98 vs 0.89, P < 0.01) and at the 40° periphery (0.93–1.04, △0.11 vs 0.79–1.01, △0.22) and 80° periphery (0.81–1.25, △0.44 vs 0.42–1.12, △0.70) in each direction. The amplitude of the square ratio of the Optos® California was smaller at 40° periphery (1.16–1.28, △0.12 vs 1.06–1.37, △0.31) and 80° periphery (2.12–2.46, △0.34 vs 1.14–3.29, △2.15). The contrast of the Optos® California images was significantly higher in the posterior pole (0.09 vs 0.12, P < 0.01), upper (0.07 vs 0.03, P < 0.01), and right (0.12 vs 0.07, P < 0.01) peripheries.

Conclusion

Optos® California can record equal angular widefield images to Optos® 200Tx and more symmetrical images with higher contrast in the posterior pole, upper and right peripheries.

Peripheral Retinal Lesions in Eyes with Age-Related Macular Degeneration Using Ultra-Widefield Imaging: A Systematic Review with Meta-analyses

TOPIC

Age-related macular degeneration (AMD) is highly prevalent among the elderly. We systematically reviewed the literature to provide an overview of ultra-widefield imaging (UWFI) of peripheral retinal lesions in AMD.

CLINICAL RELEVANCE

Information regarding retinal characteristics and prevalence of AMD is based mainly on studies using color photography of the central retina, where early and potentially severe manifestations of the disease are found. However, this approach has the effect of neglecting the periphery. Studies using UWFI provide new evidence to show that clinical features associated with AMD are not exclusive to the area of the macula.

METHODS

Eligible studies had to detect lesions of the peripheral retina (based on the original definition of a standard macular grid, with the addition of 2 zones classed as peripheral) using UWFI in eyes with AMD. Ultra-widefield imaging included pseudocolor photography, fundus autofluorescence, fluorescein angiography, and indocyanine green angiography. Eligibility was restricted to human participants and studies written in English. We searched the bibliographic databases PubMed, the Cochrane Library, EMBASE, and the Web of Science on March 27, 2018. We calculated the prevalence of peripheral findings in eyes with AMD and performed similar meta-analyses on the healthy control group. A random-effects model was used because of possible study heterogeneity.

RESULTS

Twelve studies were eligible for the review, which included 3261 or more eyes. Studies were clinic based, apart from 1 study that was a random population sample of individuals 62 years of age or older. Studies were cross-sectional in nature, apart from 1 case-control study. The peripheral lesions most commonly observed were drusen, atrophy, and changes to the retinal pigment epithelium. In eyes with AMD, peripheral lesions were found in 82.7% of eyes (confidence interval, 78.4%-86.7%) compared with 33.3% of healthy eyes (confidence interval, 28.3%-38.5%).

CONCLUSIONS

Peripheral changes were found to be highly prevalent in eyes with AMD, supporting the claim that the disease is panretinal and not macula only. The clinical significance of peripheral lesions in AMD remains incompletely understood, and therefore, further UWFI studies are recommended.

Peripheral retinal findings in populations with macular disease are similar to healthy eyes

PURPOSE

Recent evidence suggests several macular diseases are associated with peripheral retinal changes. This study investigated the number, type and management consequences of peripheral retinal findings detected in patients attending a referral only, eye-care clinic, the Centre for Eye Health(CFEH) with macular disease.

METHODS

Records of 537 patients attending CFEH for a macular assessment were included in the study. Subjects were classified as having age-related macular degeneration (AMD), epiretinal membrane (ERM), central serous chorioretinopathy (CSCR), inherited macular dystrophy or no macular disease. Data extracted included reason for referral, macular findings, peripheral findings (based on examination by ultra-widefield scanning laser ophthalmoscopy), diagnosis and management.

RESULTS

After age-matching, the number of peripheral findings in subjects with AMD, ERM or CSCR was not significant different to normal subjects. The most common finding for all cohorts were non-specific, degenerative changes such as drusen or pigmentation (61-72%) except inherited macular dystrophy subjects who had mostly vascular findings (30%; p < 0.05). Subjects with AMD and ERM with peripheral findings were significantly more likely to be reviewed or referred to an ophthalmologist than discharged back to their community eye care provider compared to subjects without findings. However only 8% of subjects had altered management based specifically on peripheral findings suggesting the macular findings in most subjects dictated their management. For those with a change, it was significant (upgrade to referral to an ophthalmologist). Peripheral findings also flagged 5% of subjects with vascular findings for referral to their general practitioner (GP).

CONCLUSIONS

Overall, the percentage and distribution of peripheral retinal findings in some macular diseases was similar to normal subjects. However, subjects with peripheral findings appeared to have significant differences in management. Considering some common findings, such as peripheral drusen may be relevant to AMD pathogenesis and therefore affect management of this disease, assessment of the peripheral retina should not be overlooked when the clinical focus is on the posterior pole.

Effect of phase-plate adjustment on retinal image sharpness and visible retinal area on ultrawide field imaging

BACKGROUND

To evaluate changes in image sharpness across ultrawide field (UWF) images and the effect of phase-plate adjustment on image contrast and extent of visible retinal area (VRA).

METHODS

This was a single site evaluation of 200° UWF images acquired with phase-plate adjustment (California, Optos, plc) and without (200TX, Optos, plc). Images were acquired using standardized protocol. VRA was manually outlined on each image and quantified using customized software. Mean image sharpness was evaluated using an automated method within the full VRA of each image and within the peripheral region of the VRA. The VRA and image sharpness were evaluated and compared between the two devices.

RESULTS

Twenty eyes of 10 healthy volunteers were evaluated. Devices with and without phase-plate adjustment produced a similar extent of VRA. Eye steering increased VRA in devices with and without phase-plate adjustment by 39.3% and 34.3%, respectively. Regardless of gaze direction, mean sharpness of the full VRA was reduced in peripheral area with or without phase-plate adjustment. Compared to images without phase-plate adjustment, use of phase-plate adjustment reduced the loss of peripheral image sharpness in all fields (-4.2 to -26.0%; p < 0.001 all fields). The sharpness of the peripheral area for on-axis images was 61.5% higher with phase-plate adjustment.

CONCLUSIONS

The use of phase-plate adjustment does not alter the extent of VRA. However, for on-axis images the loss of sharpness in the periphery is 4.5-fold less with phase-plate adjustment, potentially reducing the need to steer images and improving lesion detection in these areas.

The clinical relevance of visualising the peripheral retina

Recent developments in imaging technologies now allow the documentation, qualitative and quantitative evaluation of peripheral retinal lesions. As wide field retinal imaging, capturing both the central and peripheral retina up to 200° eccentricity, is becoming readily available the question is: what is it that we gain by imaging the periphery? Based on accumulating evidence it is clear that findings in the periphery do not always associate to those observed in the posterior pole. However, the newly acquired information may provide useful clues to previously unrecognised disease features and may facilitate more accurate disease prognostication. In this review, we explore the anatomy and physiology of the peripheral retina, focusing on how it differs from the posterior pole, recount the history of peripheral retinal imaging, describe various peripheral retinal lesions and evaluate the overall relevance of peripheral retinal findings to different 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.

Peripheral Changes Associated With Delayed Dark Adaptation in Age-related Macular Degeneration

PURPOSE

To study the association between peripheral changes in age-related macular degeneration (AMD) and dark adaptation (DA).

DESIGN

Prospective, cross-sectional study.

METHODS

We recruited patients with AMD and a control group (>50 years) without any vitreoretinal disease. Ultra-widefield (UWF) pseudocolor and fundus autofluorescence (FAF) were obtained, and were assessed by 2 graders for the presence of several peripheral changes in perimacular, midperipheral, and far-peripheral zones. All participants were also imaged with 7-field color fundus photographs used for AMD staging (Age-Related Eye Disease Study classification system). Both eyes of study participants were tested with a dark adaptation (DA) extended protocol (20 minutes). Multilevel mixed-effect models (accounting for correlated outcomes between 2 eyes) were used for analyses.

RESULTS

We included 128 eyes (n = 72 patients), 75% with AMD and the remainder controls. The presence of reticular pigmentary changes in the midperipheral (ß = 4.3, P = .012) and far-peripheral zones (ß = 8.4, P < .001) was associated with delayed rod-intercept times (RITs), even after adjusting for confounding factors. The presence, number, and extent of peripheral classic drusen did not show a similar association (P ≥ .148). The presence of a mottled decreased FAF pattern in the midperipheral zone was also associated with prolonged RITs (β = 4.4, P = .031).

CONCLUSION

Our results suggest an association between DA and the presence of peripheral reticular pigmentary changes, as well as the presence of a peripheral mottled decreased FAF pattern. This provides new insights on the clinical significance of peripheral changes in AMD, and their contribution to impairments on DA.

The application of wide-field laser ophthalmoscopy in fundus examination before myopic refractive surgery

BACKGROUND

To evaluate wide-field laser ophthalmoscopy (Optomap 200Tx) for screening retinal lesions before myopic refractive surgery.

METHODS

Seventy-eight eyes of 78 consecutive refractive surgery candidates were included in this study. All subjects underwent Optomap 200Tx, mydriatic slit-lamp lens examination and the Goldmann three-mirror contact lens examination, which was considered as the reference method for determining retinal lesions.

RESULTS

Forty of 78 eyes had retinal lesions (51.28%) and three eyes had retinal breaks (3.85%), which were diagnosed by the Goldmann three-mirror contact lens examination. Compared to the Goldmann three-mirror contact lens examination, the detection rate with the Optomap 200Tx was 91.73%% for retinal lesions, while the detection rate of mydriatic slit-lamp lens exams was 81.20%. There were no statistically significant differences among the three methods used for the diagnoses of myopic conus, tessellation and retinal breaks(all p > 0.05). For peripheral retinal lesions, the detection rate of the Optomap 200Tx examinations were similar to the Goldmann three-mirror contact lens exams (all p > 0.05), but were higher than the results of slit-lamp lens examinations (all p < 0.05). Regarding the vitreoretinal adhesions, the Goldmann three-mirror contact lens examinations had higher detection rates than did the Optomap 200Tx examinations (p = 0.031).

CONCLUSIONS

The Optomap 200Tx examinations is a convenient and feasible method to determine fundus pathological changes in myopic patients, especially for patients who can not endure pupil dilation. In order to avoid misdiagnosis of peripheral retinal lesions, Goldmann three-mirror contact lens examination is needed.

Novel grid combined with peripheral distortion correction for ultra-widefield image grading of age-related macular degeneration

Purpose

Eyes with age-related macular degeneration (AMD) often harbor pathological changes in the retinal periphery and perimacular region. These extramacular changes have not been well classified, but may be phenotypically and functionally relevant. The purpose of this study was to demonstrate a novel grid to systematically study peripheral retinal abnormalities in AMD using geometric distortion-corrected ultra-widefield (UWF) imaging.

Methods

This is a cross-sectional observational case series. Consecutive patients with AMD without any other coexisting vitreoretinal disease and control patients over age 50 without AMD or any other vitreoretinal disease were imaged using Optos 200 Tx. Captured 200° UWF images were corrected for peripheral geometric distortion using Optos transformation software. A newly developed grid to study perimacular and peripheral abnormalities in AMD was then projected onto the images.

Results

Peripheral and perimacular changes such as drusen, retinal pigment epithelium changes and atrophy were found in patients with AMD. The presented grid in conjunction with geometric distortion-corrected UWF images allowed for systematic study of these peripheral changes in AMD.

Conclusion

We present a novel grid to study peripheral and posterior pole changes in AMD. The grid is unique in that it adds a perimacular zone, which may be important in characterizing certain phenotypes in AMD. Our UWF images were corrected for geometric peripheral distortion to accurately reflect the anatomical dimensions of the retina. This grid offers a reliable and reproducible foundation for the exploration of peripheral retinal pathology associated with AMD.

Cuticular Drusen: Clinical Phenotypes and Natural History Defined Using Multimodal Imaging

PURPOSE

To define the range and life cycles of cuticular drusen phenotypes using multimodal imaging and to review the histologic characteristics of cuticular drusen.

DESIGN

Retrospective, observational cohort study and experimental laboratory study.

PARTICIPANTS

Two hundred forty eyes of 120 clinic patients with a cuticular drusen phenotype and 4 human donor eyes with cuticular drusen (n = 2), soft drusen (n = 1), and hard drusen (n = 1).

METHODS

We performed a retrospective review of clinical and multimodal imaging data of patients with a cuticular drusen phenotype. Patients had undergone imaging with various combinations of color photography, fluorescein angiography, indocyanine green angiography, near-infrared reflectance, fundus autofluorescence, high-resolution OCT, and ultrawide-field imaging. Human donor eyes underwent processing for high-resolution light and electron microscopy.

MAIN OUTCOME MEASURES

Appearance of cuticular drusen in multimodal imaging and the topography of a cuticular drusen distribution; age-dependent variations in cuticular drusen phenotypes, including the occurrence of retinal pigment epithelium (RPE) abnormalities, choroidal neovascularization, acquired vitelliform lesions (AVLs), and geographic atrophy (GA); and ultrastructural and staining characteristics of druse subtypes.

RESULTS

The mean age of patients at the first visit was 57.9±13.4 years. Drusen and RPE changes were seen in the peripheral retina, anterior to the vortex veins, in 21.8% of eyes. Of eyes with more than 5 years of follow-up, cuticular drusen disappeared from view in 58.3% of eyes, drusen coalescence was seen in 70.8% of eyes, and new RPE pigmentary changes developed in 56.2% of eyes. Retinal pigment epithelium abnormalities, AVLs, neovascularization, and GA occurred at a frequency of 47.5%, 24.2%, 12.5%, and 25%, respectively, and were significantly more common in patients older than 60 years of age (all P < 0.015). Occurrence of GA and neovascularization were important determinants of final visual acuity in eyes with the cuticular drusen phenotype (both P < 0.015). Small cuticular drusen typically demonstrated a homogenous ultrastructural appearance similar to hard drusen, whereas fragmentation of the central and basal contents was seen frequently in larger cuticular drusen.

CONCLUSIONS

Although the ultrastructural characteristics of cuticular drusen appear more similar to those of hard drusen, their lifecycle and macular complications are more comparable with those of soft drusen. Cuticular drusen phenotype may confer a unique risk for the development of GA and neovascularization.

Morphological and Angiographic Peripheral Retinal Changes in Patients with Age-Related Macular Degeneration

OBJECTIVE

To show morphologic and angiographic changes in the peripheral retina in patients with age-related macular degeneration (AMD) using wide-field fundus imaging, and to compare these findings with those from healthy controls.

DESIGN

Cross-sectional clinical study.

PARTICIPANTS

In total, 152 patients with clinical AMD and 150 healthy controls (without AMD in either macula) were studied. Subjects were ≥50 years of age. Exclusion criteria were diabetic retinopathy, previous retinal surgery, high myopia, or dense cataract, as well as any retinal inflammatory, degenerative, or occlusive disease.

METHODS

For both groups of patients, color fundus images were captured with the Optos P200 MA camera (Optos, Dunfermline, Scotland). Image analysis software was used to characterize each image. Angiography was performed on the AMD group only. Morphological and angiographic peripheral retinal changes were studied per the frequency of their occurrence, the affected peripheral retina (clock hours), and the localization of peripheral changes with regard to the eye equator. Statistical significance was defined at a level of P < 0.05.

MAIN OUTCOME MEASURES

Peripheral changes in both groups according to their type and frequency (percentage of eyes with detected retinal changes), the number of clock hours of affected peripheral retina, and their localization with regard to the equator of the eye.

RESULTS

Drusen, reticular pigmentary changes, and paving stone degeneration occurred more frequently in the AMD group than in controls (P < 0.001, P < 0.001, and P < 0.001 respectively), whereas white without pressure occurred more frequently in the control group (P = 0.027). In both groups, peripheral retinal changes were observed peripheral to the equator in more than 40% of analyzed eyes. In control Croatian subjects, peripheral drusen were seen in 38% of subjects compared with 68% of AMD subjects.

CONCLUSION

Drusen, reticular pigmentary change , and paving stone degeneration occur significantly more frequently in subjects with AMD compared with controls. White without pressure degeneration was present in a high percentage of control subjects.

Fundus Autofluorescence in Age-related Macular Degeneration

: Fundus autofluorescence (FAF) provides detailed insight into the health of the retinal pigment epithelium (RPE). This is highly valuable in age-related macular degeneration (AMD) as RPE damage is a hallmark of the disease. The purpose of this paper is to critically appraise current clinical descriptions regarding the appearance of AMD using FAF and to integrate these findings into a chair-side reference. A wide variety of FAF patterns have been described in AMD, which is consistent with the clinical heterogeneity of the disease. In particular, FAF imaging in early to intermediate AMD has the capacity to reveal RPE alterations in areas that appear normal on funduscopy, which aids in the stratification of cases and may have visually significant prognostic implications. It can assist in differential diagnoses and also represents a reliable, sensitive method for distinguishing reticular pseudodrusen. FAF is especially valuable in the detection, evaluation, and monitoring of geographic atrophy and has been used as an endpoint in clinical trials. In neovascular AMD, FAF reveals distinct patterns of classic choroidal neovascularization noninvasively and may be especially useful for determining which eyes are likely to benefit from therapeutic intervention. FAF represents a rapid, effective, noninvasive imaging method that has been underutilized, and incorporation into the routine assessment of AMD cases should be considered. However, the practicing clinician should also be aware of the limitations of the modality, such as in the detection of foveal involvement and in the distinction of phenotypes (hypo-autofluorescent drusen from small areas of geographic atrophy).

Ultra-widefield fundus autofluorescence in age-related macular degeneration

Background

Establish accuracy and reproducibility of subjective grading in ultra-widefield fundus autofluorescence (FAF) imaging in patients with age-related macular degeneration (AMD), and determine if an association exists between peripheral FAF abnormalities and AMD.

Methods

This was a prospective, single-blinded case-control study. Patients were consecutively recruited for the study. Patients were excluded if there was a history of prior or active ocular pathology other than AMD or image quality was insufficient for analysis as determined by two independent graders. Control patients were those without any evidence of AMD or other ophthalmic disease apart from cataract. Using the Optos 200Tx (Optos, Marlborough, MA, USA), a ResMax central macula and an ultra-widefield peripheral retina image was taken for each eye in both normal color and short wavelength FAF. Ultra-widefield photographs were modified to mask the macula. Each ResMax and ultra-widefield image was independently graded by two blinded investigators.

Results

There were 28 AMD patients and 11 controls. There was a significant difference in the average age between AMD patients and control groups (80 versus 64, respectively P<0.001). There was moderate, statistically significant agreement between observers regarding image interpretation (78.4%, K = 0.524, P<0.001), and 69.0% (K = 0.49, P<0.001) agreement between graders for FAF abnormality patterns. Patients with AMD were at greater risk for peripheral FAF abnormalities (OR: 3.43, P = 0.019) and patients with FAF abnormalities on central macular ResMax images were at greater risk of peripheral FAF findings (OR: 5.19, P = 0.017).

Conclusion

Subjective interpretation of FAF images has moderate reproducibility and validity in assessment of peripheral FAF abnormalities. Peripheral FAF abnormalities are seen in both AMD and control patients. Those with AMD, poor visual acuity, and macular FAF abnormalities are at greater risk.

Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

PURPOSE

We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF) in wet age-related macular degeneration (AMD) using wide-field imaging instrument.

PATIENTS AND METHODS

A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients), polypoidal choroidal vasculopathy (PCV) (22 eyes/20 patients), and retinal angiomatous proliferation (RAP) (seven eyes/four patients). Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments.

RESULTS

Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001). Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7%) showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively) than control eyes (18.8%). There were no significant differences (P=0.76) between the frequencies in untreated and treated eyes.

CONCLUSION

Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes.

Advances in retinal imaging for diabetic retinopathy and diabetic macular edema

Diabetic retinopathy and diabetic macular edema (DME) are leading causes of blindness throughout the world, and cause significant visual morbidity. Ocular imaging has played a significant role in the management of diabetic eye disease, and the advent of advanced imaging modalities will be of great value as our understanding of diabetic eye diseases increase, and the management options become increasingly varied and complex. Color fundus photography has established roles in screening for diabetic eye disease, early detection of progression, and monitoring of treatment response. Fluorescein angiography (FA) detects areas of capillary nonperfusion, as well as leakage from both microaneurysms and neovascularization. Recent advances in retinal imaging modalities complement traditional fundus photography and provide invaluable new information for clinicians. Ultra-widefield imaging, which can be used to produce both color fundus photographs and FAs, now allows unprecedented views of the posterior pole. The pathologies that are detected in the periphery of the retina have the potential to change the grading of disease severity, and may be of prognostic significance to disease progression. Studies have shown that peripheral ischemia may be related to the presence and severity of DME. Optical coherence tomography (OCT) provides structural detail of the retina, and the quantitative and qualitative features are useful in the monitoring of diabetic eye disease. A relatively recent innovation, OCT angiography, produces images of the fine blood vessels at the macula and optic disc, without the need for contrast agents. This paper will review the roles of each of these imaging modalities for diabetic eye disease.

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.

The role of central reading centers--current practices and future directions

Central reading centers (CRCs) have several crucial roles in the conduct of clinical trials, providing key input during the study design, preparation of the operations manual, as well as site and photographer certification. They provide objective, standardized grading of images from study subjects, which determines study eligibility, and also evaluate lesion features at subsequent study visits. CRCs need to adhere strictly to Good Clinical Practice (GCP) guidelines, as well as the established standard operating procedures in order to ensure that images are graded properly. The role of CRCs will continue to evolve, and include the use of web-based image transmission and grading platforms.

ULTRA-WIDEFIELD FUNDUS IMAGING: A Review of Clinical Applications and Future Trends

PURPOSE

To review the basic principles of ultra-widefield fundus imaging and discuss its clinical utility for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms Optos, optomap, panoramic, ultra-widefield, wide-angle, and ellipsoid mirror. This yielded 158 publications of which 128 were selected based on content and relevance.

RESULTS

A total of 128 articles pertaining to ultra-widefield imaging were cited in this review.

CONCLUSION

Optos ultra-widefield imaging has become an essential tool for the identification of peripheral retinal and vascular pathology. The high resolution and multimodal capabilities of this device are also providing new insights into a variety of disorders, even those that primarily involve the posterior pole. Although the presence of artifact and the need for clinical validation are significant hurdles to more widespread use, ultra-widefield is evolving to become the standard-of-care imaging modality for many diseases and is finding new clinical and research applications such as for screening and telemedicine.

Densitometry of Choroidal Vessels in Eyes With and Without Central Serous Chorioretinopathy by Wide-Field Indocyanine Green Angiography

PURPOSE

To develop a new method to quantify the choroidal vessel density by binarizing ultra-wide-field indocyanine green angiography (ICGA) images and determine whether values are altered in diseased eyes.

DESIGN

Reliability and validity analysis.

METHODS

Ultra-wide-field fluorescein angiography (FA) and ICGA images were obtained using an ultra-wide-field imaging device (Optos California ultra-wide-field imaging device; Dunfermline, Scotland, UK) in 11 eyes of 11 patients without chorioretinal diseases. The angiographic signals of the choroidal vessels were determined by subtracting those of the retinal vasculature and optic disc on the FA images from the ICGA images, binarized by Niblack's method, and the choroidal vessel density calculated. Reproducibility of the method was assessed by calculating the coefficient of variance, coefficient of repeatability, and intraclass correlation coefficient. The relationships between age, spherical equivalent refractive error (SERE), and intraocular pressure and the vasculature density were assessed. To investigate possible impacts of chorioretinal diseases on the vasculature density, 10 eyes of 7 patients with central serous chorioretinopathy (CSC) were compared with the 11 control eyes.

RESULTS

Choroidal vessels were contrasted by binarizing ICGA images. The method to quantify the choroidal vessel density showed high reproducibility. The SERE was correlated significantly (r = 0.573, P < .05) with the vasculature density. In the 11 control eyes, the vasculature density was 34.26% ± 0.77% in the entire area, 31.37% ± 0.97% in the superior portion, 36.98% ± 0.88% in the inferior portion, 37.01% ± 1.44% in the posterior portion, and 34.17% ± 0.77% in the peripheral portion. In eyes with CSC, the density was significantly (P < .05) higher: 36.46% ± 0.49%, 34.02% ± 0.97%, 38.65% ± 0.27%, 41.04% ± 0.82%, and 36.36% ± 0.51%, respectively.

CONCLUSIONS

Binarization of ultra-wide-field ICGA images enabled quantification of the choroidal vessel density, which was altered in eyes with CSC. This method of measuring the choroidal vessel density may provide new insights into diagnosing and treating chorioretinal diseases.

Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography

Retinal thickness measurements obtained using optical coherence tomography (OCT) play an essential role both in multi-center clinical trials and in normal clinical practice. Different scanning protocols are available on most OCT devices, and it is important to ascertain whether the retinal thickness measurements obtained from these are comparable. This study aimed to compare retinal thickness measurements between raster and radial scanning protocols using spectral-domain OCT (SD-OCT). In a prospective study, 32 healthy subjects were scanned sequentially using raster and radial protocols from a SD-OCT device. For both the raster and radial OCT scans, retinal thicknesses were measured manually subfoveally and at 12 other points at 0.5 mm intervals temporally and nasally on the horizontal OCT B-scan passing through the fovea. The retinal thickness measurements were compared using intraclass correlation (ICC) and Bland-Altman plots. Subfoveal retinal thickness was 227.0 µm when measured on the raster scan and 229.2 µm on the radial scan, with a mean difference of 2.2 µm (P = 0.141).The ICC for agreement was 0.889 (95 % confidence interval 0.818-0.933). Similar results were observed for retinal thickness measurements at all other points, with mean differences ranging from -3.37 to 2.59 µm, and ICC values ranging from 0.837 to 0.972. The retinal thickness measurements obtained by the raster and radial scans of the same SD-OCT device are comparable, with differences of less than 4 µm. This is of relevance when measurements made using different OCT scan protocols are compared.