Infrared reflectance imaging in age-related macular degeneration

Investigating the Utility of Near-Infrared Reflectance Imaging for Diabetic Retinopathy Screening

BACKGROUND AND OBJECTIVE

We investigated the reliability of near-infrared reflectance (NIR) imaging as a method of assessing severity of diabetic retinopathy (DR).

PATIENTS AND METHODS

One hundred ninety-five NIR images were reviewed by two graders for the number of hyporeflective foci, presence or absence of vascular abnormalities, and presumptive DR stage; these were correlated to fundus photography-defined DR stage. Interrater reliability was confirmed via one-way random effects model of intraclass correlation coefficients. Analysis of variance was used in subgroup analysis, receiver operating characteristic (ROC) curves were created to validate reliability of the model, and logistic regression was used to model foci and vascular abnormalities as predictors for moderate or worse disease.

RESULTS

A statistically significant difference in mean number of hyporeflective foci was found between no DR and moderate non-proliferative DR (NPDR; P < 0.0001), no DR and severe NPDR (P < 0.001), no DR and proliferative DR (PDR; P < 0.0001), mild and moderate NPDR (P = 0.008), mild and severe NPDR (P < 0.001), and mild NPDR and PDR (P < 0.001). The area under the ROC curve was 0.849 (CI: 0.792 to 0.905). The threshold for detection of moderate NPDR or worse was 4.75 foci, with a sensitivity of 79.0% and a false positive rate of 20.0%. Multivariate logistic regression model incorporating hyporeflective foci with vascular abnormalities (odds ratio [OR] = 1.592, 95% CI: 1.381 to 1.835; P < 0.001) was able to accurately predict moderate disease or worse, just moderate disease (OR = 1.045, 95% CI: 1.003 to 1.089; P = 0.035), severe disease (OR = 1.050, 95% CI: 1.006 to 1.096; P = 0.027), and proliferative disease (OR = 1.050, 95% CI: 1.008 to 1.095; P = 0.018).

CONCLUSIONS

NIR imaging may be an adjunct tool in screening for DR. [Ophthalmic Surg Lasers Imaging Retina 2024;55:318-325.].

Assessment of intraretinal hyperreflective foci using multimodal imaging in eyes with age-related macular degeneration

PURPOSE

This study aimed to investigate the correspondence between intraretinal hyperreflective foci (IHRF) identified on optical coherence tomography (OCT) B-scans with hyperpigmentation on colour fundus photography (CFP) or hyperreflectivity on infrared reflectance (IR) images in eyes with age-related macular degeneration (AMD).

METHODS

Flash CFP, IR images and OCT B-scans obtained at the same visit were evaluated. Individual IHRF identified on OCT B-scans were assessed for the qualitative presence or absence of a hypotransmission tail into the choroid. The corresponding IR image obtained at the time of OCT acquisition was analysed for the presence or absence of hyperreflectivity in this region. The IR images were manually registered to the CFP image, and CFP images were inspected for the presence or absence of hyperpigmentation at the location of IHRF.

RESULTS

From 122 eyes, a total of 494 IHRF were evaluated. For the primary analysis of qualitative presence or absence of hyperpigmentation on CFP and hyperreflectivity on IR at the locations corresponding to IHRF on OCT, 301 (61.0%) of the IHRFs demonstrated evidence of hyperpigmentation on CFP, while only 115 (23.3%) showed evidence of hyperreflectivity on IR. The qualitative determination of the presence or absence of an abnormality on CFP or IR were significantly different (p < 0.0001). 327 (66.2%) of the IHRF showed hypotransmission, and 80.4% of these IHRF showed hyperpigmentation on CFP, though only 23.9% (p < 0.0001) demonstrated hyperreflectivity on IR.

CONCLUSIONS

Less than two-thirds of IHRF evident on OCT manifest as hyperpigmentation on colour photos, though IHRF with posterior shadowing are more likely to be evident as pigment. IR imaging appears to be even more poorly sensitive for visualizing IHRF.

Characteristics of subretinal particles detected after pars plana vitrectomy for rhegmatogenous retinal detachment

BACKGROUND

To determine the incidence and characteristics of the multiple subretinal particles (SRPs) present after pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD).

METHODS

The medical records of 224 eyes of 224 patients that underwent PPV for RRD were reviewed. The presence of SRPs in the subretinal fluid blebs and the presence of subretinal deposits were determined by optical coherence tomography (OCT) and fundus autofluorescence (FAF). The characteristics of the FAF and infrared reflectance (IR) images of a scanning laser ophthalmoscope in eyes with SRPs (SRPs group) were compared to that of eyes without SRPs (control group).

RESULTS

SRPs were observed in 27 eyes (12%), and they were completely resolved in 20 eyes (74%) after 6 months. The incidence of macula-off RRD (85%) and preoperative precipitates (41%) were significantly higher in the SRPs group than that in the control group (64%, P = 0.046; 12%, P = 0.002). The axial length was significantly shorter in the SRPs group than that in the control group (25.04 ± 1.54 mm, 26.00 ± 1.78 mm, P = 0.012). The preoperative and postoperative best-corrected visual acuity were not significantly different between the two groups (P = 0.702, P = 0.337). The subretinal fluid bleb determined by OCT were hyperfluorescent in the FAF images in 24 eyes (89%), and the subretinal deposits were hypofluorescent with solid appearance by OCT other than fluid in 3 eyes (11%). The hypofluorescent subretinal deposits in the FAF images were bright in the IR images in 2 eyes.

CONCLUSIONS

The SRPs consist of lipofuscin-related hyperfluorescent subretinal fluid and the subretinal deposits containing bright IR melanin particles of proliferating retinal pigment epithelial cells.

Characterising the diagnosis of genetic maculopathies in a real-world private tertiary retinal practice in Australia: protocol for a retrospective clinical audit

PURPOSE

Accurate diagnosis of macular atrophy is paramount to enable appropriate treatment when novel treatments for geographic atrophy and macular dystrophies become available. Genetic testing is useful in distinguishing between the two conditions but is not feasible for the majority of patients in real-world clinical practice. Therefore, we aimed to investigate the potential misdiagnosis of inherited macular dystrophy as age-related macular degeneration (AMD) in real-world ophthalmic practice to assist in the development of guidelines to improve diagnostic accuracy while minimizing genetic testing for targeted patients.

METHODS

Retrospective review of the medical records of patients diagnosed with AMD, which included imaging, between 1995 and 2023 from a large multidisciplinary private ophthalmic practice in Australia. We will use a stepwise method to screen for probable cases of macular dystrophy, followed by a consensus review by an expert panel. The outcomes are (1) to determine the potential misdiagnosis rate of macular dystrophy as atrophic AMD by retinal specialists and general ophthalmologists; (2) to identify clinical imaging modalities that are most useful for differentiating macular dystrophy from atrophic AMD; and (3) to establish preliminary guidance for clinicians to improve the diagnosis of macular atrophy from AMD in practice, and thereby target cost-efficient genetic testing.

DISCUSSION

Improving the diagnostic accuracy of both AMD and macular dystrophy, while ensuring cost-efficient genetic testing, will improve the targeted treatment of macular diseases when emerging treatments become available.

Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives

When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.

The role of near-infrared reflectance imaging in retinal disease: A systematic review

Near-infrared reflectance (NIR) retinal imaging aids in a better visualization of structures at the level of outer retina, retinal pigment epithelium, and choroid. It has multiple advantages, including easy acquisition in association with structural spectral domain optical coherence tomography, more comfort for patients, and enhanced contrast and spatial resolution. It helps in the diagnosis of chorioretinal diseases that present with minimal funduscopic findings and can be used to follow up many chorioretinal conditions. We describe the chorioretinal NIR imaging appearance and the clinical role of NIR imaging in ocular inflammatory disease, vascular and acquired disease, degenerative disease, tumors, associated systemic condition, toxic and traumatic disease, optic nerve head conditions, and physiological findings.

Macular Atrophy Incidence, Progression, and Visual Acuity Effects in 5-Year Treatment of Neovascular Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE

Macular atrophy (MA) contributes to declining vision during prolonged anti-vascular endothelial growth factor (VEGF) treatment in neovascular age-related macular degeneration (nAMD) so greater understanding of its incidence, evolution, and impact on visual acuity is merited.

MATERIALS AND METHODS

This is a retrospective review of nAMD patients receiving anti-VEGF therapy for ≥ 5 years. Near-infrared reflectance images and vision data were extracted every 6 months. MA lesion areas were measured using ImageJ.

RESULTS

Vision showed a mean decline of -1.2 letters/year. Eyes with MA showed a greater decrease of -1.6 letters/year compared to eyes without MA (-0.7 letters/year). Cumulative incidence of MA was 38% at 5 years. MA was significantly associated with declining vision, showing a -0.7 letter decrease for every 1 mm² increase in lesion size.

CONCLUSION

Over a 5-year course of nAMD treatment, MA affected most eyes, and MA progression was significantly associated with vision decline. [Ophthalmic Surg Lasers Imaging Retina 2022;53:546-552.].

Recent Advances in Age-Related Macular Degeneration Therapies

Age-related macular degeneration (AMD) was described for the first time in the 1840s and is currently the leading cause of blindness for patients over 65 years in Western Countries. This disease impacts the eye’s posterior segment and damages the macula, a retina section with high levels of photoreceptor cells and responsible for the central vision. Advanced AMD stages are divided into the atrophic (dry) form and the exudative (wet) form. Atrophic AMD consists in the progressive atrophy of the retinal pigment epithelium (RPE) and the outer retinal layers, while the exudative form results in the anarchic invasion by choroidal neo-vessels of RPE and the retina. This invasion is responsible for fluid accumulation in the intra/sub-retinal spaces and for a progressive dysfunction of the photoreceptor cells. To date, the few existing anti-AMD therapies may only delay or suspend its progression, without providing cure to patients. However, in the last decade, an outstanding number of research programs targeting its different aspects have been initiated by academics and industrials. This review aims to bring together the most recent advances and insights into the mechanisms underlying AMD pathogenicity and disease evolution, and to highlight the current hypotheses towards the development of new treatments, i.e., symptomatic vs. curative. The therapeutic options and drugs proposed to tackle these mechanisms are analyzed and critically compared. A particular emphasis has been given to the therapeutic agents currently tested in clinical trials, whose results have been carefully collected and discussed whenever possible.

Multimodal Imaging, OCT B-Scan Localization, and En Face OCT Detection of Macular Hyperpigmentation in Eyes with Intermediate Age-Related Macular Degeneration

Purpose

Multimodal imaging was used to identify and characterize the cause of hyperpigmentation seen on color fundus images (CFIs) of eyes with intermediate age-related macular degeneration (iAMD).

Design

Retrospective review of a prospective study.

Participants

Patients with iAMD.

Methods

Color fundus images with macular hyperpigmentation were compared with same-day images obtained using fundus autofluorescence (FAF), near infrared reflectance (NIR), and swept-source (SS) OCT imaging. Two SS OCT en face slabs were generated: a retinal slab to identify hyperreflective foci within the retina and a slab from beneath the retinal pigment epithelium (RPE; the sub-RPE slab) that was used to detect regions that cause decreased light transmission into the choroid, also known as hypotransmission defects. All images were registered to allow for qualitative comparisons by 2 independent graders.

Main Outcome Measures

Comparison between foci of macular hyperpigmentation seen on CFIs with the detection of these regions on FAF, NIR, and SS OCT en face images.

Results

Compared with CFIs, FAF imaging seemed to be the least sensitive method for the detection of hyperpigmentation, whereas NIR and SS OCT imaging reliably detected these hyperpigmented areas. Although NIR imaging detected most of the hyperpigmentation seen in CFIs, SS OCT imaging detected all the areas of hyperpigmentation and anatomically localized these areas by using both en face and B-scan images. En face OCT slabs of the retina and sub-RPE region were registered to the CFIs, and areas of hyperpigmentation were shown to correspond to hyperreflective foci in the retina and regions of thickened RPE seen on OCT B-scans. Although both hyperpigmentation and early atrophic lesions appeared bright on NIR imaging, en face SS OCT imaging was able to distinguish these lesions because hyperpigmentary changes appeared dark and early atrophic lesions appeared bright on the sub-RPE slab.

Conclusions

En face OCT imaging in conjunction with OCT B-scans were able to identify and localize the hyperpigmentation seen in CFIs reliably. This hyperpigmentation was not only associated with intraretinal hyperreflective foci, but also corresponded to areas with a thickened RPE.

Multispectral pattern recognition measures change in drusen area in age-related macular degeneration with high congruency to expert graders

Drusen are a hallmark lesion of age-related macular degeneration (AMD) and changes in their area and/or volume are strongly associated with disease progression. Assessment of longitudinal change in drusen size in clinical practice however is limited to a single commercial tool or manual inspection by clinicians. In this study we analysed change in drusen area in 33 eyes with intermediate AMD across two separate visits using a novel technique known as multispectral pattern recognition for en face retinal images from various imaging modalities (infrared (815 nm), fundus autofluorescence (488 nm) and green (532 nm) scanning laser ophthalmoscopy). We found 91% (30/33 eyes) agreement in the direction of drusen change for multispectral pattern recognition relative to expert graders who graded eyes as having drusen progression, regression or being stable. Multispectral pattern recognition showed 100% sensitivity (22/22 eyes) and 73% specificity (8/11 eyes). In comparison, we found only 70% (23/33 eyes) agreement in the direction of drusen change with a commercially available change analysis software, the Cirrus Advanced RPE Analysis relative to expert graders, with a sensitivity 64% (14/22 eyes) and specificity of 82% (9/11 eyes). Total drusen area or amount of change between visits had no significant effect on agreement. This suggests multispectral pattern recognition can quantify longitudinal change in drusen area from multimodal imaging with greater congruency to expert graders than a commercially available platform based on a single imaging modality. Considering the association of drusen area and disease progression, this method could aid clinical assessment and monitoring of AMD.

Infrared reflectance image-guided laser photocoagulation of telangiectatic capillaries in persistent diabetic macular edema

This study aimed to assess detection rate of telangiectatic capillaries (TelCaps) with infrared reflectance (IR) and optical coherence tomography (OCT) images and to evaluate the clinical efficacy of IR image-guided focal laser photocoagulation of TelCaps in persistent diabetic macular edema (DME). This retrospective case series included 28 eyes of 28 patients with TelCap and persistent DME refractory to intravitreal anti-vascular endothelial growth factor or corticosteroids. The presence of TelCaps was confirmed using IR and OCT images. All patients were followed up for more than 12 months after direct focal laser photocoagulation of the TelCaps. The TelCap closure rate, changes in best-corrected visual acuity, and central subfield thickness were analyzed. On IR imaging, TelCap appeared as a characteristic hyperreflectivity within a hyporeflective spherical lesion in 85.7% of the eyes. After focal laser photocoagulation, the TelCap closure rate was 57.1% at 3 months and 71.4% at 12 months. A significant improvement in visual acuity and reduction in central subfield thickness were observed at three and 12 months after focal laser photocoagulation (all p < 0.05). The characteristic hyperreflectivity within hyporeflective lesions on the IR image in conjunction with OCT helps identify the TelCap. Our results suggest that IR imaging and OCT-guided focal laser photocoagulation of TelCaps can improve functional and anatomical outcomes in persistent DME.

Pentosan polysulfate maculopathy

Pentosan polysulfate sodium (PPS), a semisynthetic sulfated polysaccharide, is the only FDA-approved oral therapy for interstitial cystitis. Recent studies have described a progressive, vision-threatening macular condition associated with long-term PPS use. We reviewed all publications concerning PPS maculopathy to consolidate known clinical features and to evaluate the strength of this association. Current literature supports a strong dose-dependent association between PPS exposure and a progressive maculopathy impacting the retinal pigment epithelium (RPE) and RPE-photoreceptor interface that may worsen even after drug cessation. Initial symptoms may include prolonged dark adaptation and difficulty reading with relative visual acuity preservation. Fundus examination often shows macular pigment clumps corresponding to lesions of focal RPE thickening. Fundus autofluorescence most clearly depicts the condition, with a distinctive pattern of hypo- and hyperautofluorescent spots in the posterior pole that sometimes extends to the retinal periphery. Many cases also show a characteristic peripapillary hypoautofluorescent halo. Near infrared reflectance may aid in early detection. RPE atrophy, cystoid macular edema, and macular neovascularization may also occur, potentially resulting in loss of central acuity. This newly described association implies significant public health risk. Ophthalmologists should screen PPS users with multimodal retinal imaging, and prescribers should minimize dose and duration of PPS use.

In vivo retinal imaging in translational regenerative research

Regenerative translational studies must include a longitudinal assessment of the changes in retinal structure and function that occur as part of the natural history of the disease and those that result from the studied intervention. Traditionally, retinal structural changes have been evaluated by histological analysis which necessitates sacrificing the animals. In this review, we describe key imaging approaches such as fundus imaging, optical coherence tomography (OCT), OCT-angiography, adaptive optics (AO), and confocal scanning laser ophthalmoscopy (cSLO) that enable noninvasive, non-contact, and fast in vivo imaging of the posterior segment. These imaging technologies substantially reduce the number of animals needed and enable progression analysis and longitudinal follow-up in individual animals for accurate assessment of disease natural history, effects of interventions and acute changes. We also describe the benefits and limitations of each technology, as well as outline possible future directions that can be taken in translational retinal imaging studies.

Artificial Intelligence for Automated Overlay of Fundus Camera and Scanning Laser Ophthalmoscope Images

Purpose

The purpose of this study was to evaluate the ability to align two types of retinal images taken on different platforms; color fundus (CF) photographs and infrared scanning laser ophthalmoscope (IR SLO) images using mathematical warping and artificial intelligence (AI).

Methods

We collected 109 matched pairs of CF and IR SLO images. An AI algorithm utilizing two separate networks was developed. A style transfer network (STN) was used to segment vessel structures. A registration network was used to align the segmented images to each. Neither network used a ground truth dataset. A conventional image warping algorithm was used as a control. Software displayed image pairs as a 5 × 5 checkerboard grid composed of alternating subimages. This technique permitted vessel alignment determination by human observers and 5 masked graders evaluated alignment by the AI and conventional warping in 25 fields for each image.

Results

Our new AI method was superior to conventional warping at generating vessel alignment as judged by masked human graders (P < 0.0001). The average number of good/excellent matches increased from 90.5% to 94.4% with AI method.

Conclusions

AI permitted a more accurate overlay of CF and IR SLO images than conventional mathematical warping. This is a first step toward developing an AI that could allow overlay of all types of fundus images by utilizing vascular landmarks.

Translational Relevance

The ability to align and overlay imaging data from multiple instruments and manufacturers will permit better analysis of this complex data helping understand disease and predict treatment.

Infrared retinal images for flashless detection of macular edema

This study evaluates the use of infrared (IR) images of the retina, obtained without flashes of light, for machine-based detection of macular oedema (ME). A total of 41 images of 21 subjects, here with 23 cases and 18 controls, were studied. Histogram and gray-level co-occurrence matrix (GLCM) parameters were extracted from the IR retinal images. The diagnostic performance of the histogram and GLCM parameters was calculated in hindsight based on the known labels of each image. The results from the one-way ANOVA indicated there was a significant difference between ME eyes and the controls when using GLCM features, with the correlation feature having the highest area under the curve (AUC) (A_Z) value. The performance of the proposed method was also evaluated using a support vector machine (SVM) classifier that gave sensitivity and specificity of 100%. This research shows that the texture of the IR images of the retina has a significant difference between ME eyes and the controls and that it can be considered for machine-based detection of ME without requiring flashes of light.

Near-Infrared Reflectance Imaging for Quantification of Atrophy Associated with Age-Related Macular Degeneration

PURPOSE

To compare measurements of area of geographic atrophy (GA) in dry age-related macular degeneration (AMD) obtained by fundus autofluorescence (FAF) to those obtained by near-infrared reflectance (NIR).

DESIGN

Interrater reliability analysis.

METHODS

Ninety-seven confocal NIR images (Heidelberg HRA + Spectralis) and FAF images from 97 patients/eyes with GA with dry AMD were collected retrospectively from existing anonymized Doheny Image Reading Center datasets. Two masked reading center graders (N.S., J.S.) independently and blindly performed manual segmentation of the GA lesions on each NIR and FAF image using GNU Image Manipulation Program software (version 2.8.22). GA on NIR/FAF images was defined in accordance to recently published Classification of Atrophy Meeting criteria as sharply demarcated hyperreflective regions ≥250 μm in diameter. The difference and point-to-point correspondence between gradings in GA area measurements between NIR and FAF were assessed by mean difference, overlap ratio, and Dice similarity coefficient.

RESULTS

Among the 97 eyes with dry AMD, the mean GA area was 7.62 ± 7.77 mm² from FAF images and 7.65 ± 7.83 mm² from NIR, with a mean nonsignificant difference of 0.31 ± 0.55 mm² (2-tailed t test, P = .65). The overlap ratio in the segmented GA lesion between modalities was 0.84 ± 0.28 with a Dice similarity coefficient of 0.87 ± 0.27. Intermodal reliability was high (intraclass correlation coefficient = 0.998, P < .01). Of note, in 5 cases (5.2%), the GA lesion could be identified on the FAF image but not on the NIR image, translating into a sensitivity of 94.8%.

CONCLUSIONS

GA lesions in dry AMD can be identified and quantified reliably using NIR images in many cases, though eyes with a thin choroid resulting in isoreflective GA lesions may be challenging. NIR imaging is comfortable for patients and is commonly obtained along with OCT, and therefore NIR-based GA assessment may be a useful surrogate in clinical settings.

Application of wide-field infrared reflectance imaging in retinoschisis, retinal detachments, and schisis detachments

Background

Retinoschisis and retinal detachment are distinguished based on features in clinical examination. Even to skilled examiners, some cases may be diagnostic challenges. Infrared and wide-angle infrared reflectance imaging are relatively new modalities that can provide additional diagnostic information. Non-contact infrared reflectance imaging (also described as near-infrared imaging) highlights sub-retinal features which may otherwise be obscured by standard retinal photography. It is non-invasive and uses the retina’s ability to absorb, reflect or scatter infrared light to produce high quality images.

Main body

The aim of this review is to describe the role of wide-field infrared imaging in screening, diagnosing, and monitoring structural peripheral retinal disorders including retinoschisis, retinal detachment or combined retinoschisis rhegmatogenous detachments. Infrared imaging can also be used to monitor anterior segment inflammation. Heidelberg Wide-Field Module lens and Heidelberg Spectralis^® HRA + OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to obtain noncontact, wide-field infrared images on each study eye. Pseudocolor photos were captured by Optos Optomap^® (Optos, Inc, Massachusetts, USA).

Conclusion

Wide angle infrared imaging offers a quick, noncontact, and noninvasive way to help specialists accurately diagnose, monitor for progression, and educate patients about retinal detachment, retinoschisis and even anterior segment inflammation.

Automatic Identification and Intuitive Map Representation of the Epiretinal Membrane Presence in 3D OCT Volumes

Optical Coherence Tomography (OCT) is a medical image modality providing high-resolution cross-sectional visualizations of the retinal tissues without any invasive procedure, commonly used in the analysis of retinal diseases such as diabetic retinopathy or retinal detachment. Early identification of the epiretinal membrane (ERM) facilitates ERM surgical removal operations. Moreover, presence of the ERM is linked to other retinal pathologies, such as macular edemas, being among the main causes of vision loss. In this work, we propose an automatic method for the characterization and visualization of the ERM's presence using 3D OCT volumes. A set of 452 features is refined using the Spatial Uniform ReliefF (SURF) selection strategy to identify the most relevant ones. Afterwards, a set of representative classifiers is trained, selecting the most proficient model, generating a 2D reconstruction of the ERM's presence. Finally, a post-processing stage using a set of morphological operators is performed to improve the quality of the generated maps. To verify the proposed methodology, we used 20 3D OCT volumes, both with and without the ERM's presence, totalling 2428 OCT images manually labeled by a specialist. The most optimal classifier in the training stage achieved a mean accuracy of 91 . 9 % . Regarding the post-processing stage, mean specificity values of 91 . 9 % and 99 . 0 % were obtained from volumes with and without the ERM's presence, respectively.

Optometry Australia's chairside reference for the diagnosis and management of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in people over the age of 50 years in Australia. Optometry Australia has developed this AMD chairside reference in consultation with a member-based working group comprised of experienced practitioners. It provides an evidence-based approach to current best practice in the diagnosis and management of AMD. Optometrists should be competent in assessing patients with or at risk of developing AMD, so that they are able to provide evidence-based management including appropriate communication, diagnosis and referral when indicated. This AMD chairside reference covers risk factors for the development of AMD or progression to late-stage AMD; the current clinical classification of AMD; common signs and symptoms; optometric assessment including ocular imaging and biomarkers; differential diagnoses; and management of early, intermediate and late AMD. Optometry Australia's chairside reference is intended as a general guide for optometrists, and is not a formal management protocol.

Fast visible and extended near-infrared multispectral fundus camera

We present a multispectral fundus camera that performs fast imaging of the ocular posterior pole in the visible and near-infrared (400 to 1300 nm) wavelengths through 15 spectral bands, using a flashlight source made of light-emitting diodes, and CMOS and InGaAs cameras. We investigate the potential of this system for visualizing occult and overlapping structures of the retina in the unexplored wavelength range beyond 900 nm, in which radiation can penetrate deeper into the tissue. Reflectance values at each pixel are also retrieved from the acquired images in the analyzed spectral range. The available spectroscopic information and the visualization of retinal structures, specifically the choroidal vasculature and drusen-induced retinal pigment epithelium degeneration, which are hardly visible in conventional color fundus images, underline the clinical potential of this system as a new tool for ophthalmic diagnosis.

Repeatability of Meibomian Gland Contrast, a Potential Indicator of Meibomian Gland Function

PURPOSE

Meibomian gland contrast may be a potential indicator of gland health, especially among isotretinoin users. We aimed to develop a repeatable and reliable method for measuring Meibomian gland contrast from meibography images.

METHODS

Lower lid (LL) and upper lid (UL) meibography were captured with the OCULUS Keratograph 5M (OCULUS, Inc) at 2 visits under the following 4 conditions: face centered with room lights on (C), left-turned face (L), right-turned face (R), and face centered with room lights off (CLO). Contrast was measured with Fiji (v2.0.0-rc-59). Coefficient of repeatability and limits of agreement (LOA) were determined using Bland-Altman plots.

RESULTS

A total of 512 meibography images from 16 subjects (age ± SD = 24.8 ± 5.2 years; 13 female patients) were collected. Coefficient of repeatability between visits was 10.5 for UL and 14.9 for LL. Lower and upper LOA, respectively, for UL, compared with condition C, were -10.9 [95% confidence interval (CI), -13.5 to -8.3] and 6.2 (95% CI, 3.6-8.8) for L; -11.0 (95% CI, -13.8 to -8.1) and 7.0 (95% CI, 4.2-9.8) for R; and -9.0 (95% CI, -11.6 to -6.5) and 7.2 (95% CI, 4.7-9.8) for CLO. Lower and upper LOA, respectively, for LL, compared with condition C, were -18.1 (95% CI, -22.6 to -13.5) and 11.0 (95% CI, 6.5-15.5) for L; -15.3 (95% CI, -19.2 to -11.3) and 9.9 (95% CI, 6.0-13.9) for R; and -12.0 (95% CI, -15.1 to -8.8) and 8.2 (95% CI, 5.0-11.3) for CLO.

CONCLUSIONS

Meibomian gland contrast is a repeatable and reliable measure for changes in Meibomian gland contrast greater than 11 in the UL and 18 in the LL.

Confocal infrared imaging with optical coherence tomography provides superior detection of a number of common macular lesions compared to colour fundus photography

PURPOSE

To compare diagnostic accuracy of confocal infrared reflectance (IR), with and without optical coherence tomography (OCT), to colour fundus photography (CFP) in the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) Study.

METHODS

Cross-sectional observational study of participants in NICOLA. CFP, IR and IR/OCT of 640 eyes were graded for hard, soft and reticular pseudodrusen; geographic atrophy; choroidal neovascularisation; naevus; epiretinal membrane; and haemorrhages. Test characteristics (sensitivity and specificity) for each imaging modality with respect to each retinal feature were calculated.

RESULTS

With CFP as the reference standard, sensitivity of IR by itself ranged from 75% for RPD to 93.5% for hard drusen and specificity was above 90% for all features except hard drusen (71.7%). For IR combined with OCT, sensitivity ranged from 80% for choroidal neovascularisation to 96.5% for hard drusen. When IR alone was the reference standard, CFP sensitivity was high for naevi (97.5%) but reduced markedly for epiretinal membrane (48.5%). When the combination of IR and OCT was the reference standard, sensitivity for CFP was least for epiretinal membrane (31.5%), low for geographic atrophy and reticular pseudodrusen (77.8% and 76.2% respectively) and high for all other lesion types.

CONCLUSION

Our findings support the use of confocal IR with OCT as a screening tool for a variety of features of macular disease in community optometric practice.

Developing prognostic biomarkers in intermediate age-related macular degeneration: their clinical use in predicting progression

Age-related macular degeneration is a common, complex and blinding eye disease. When early and intermediate levels of severity are detected in one or both eyes, there is a wide-ranging 0.4 to 53 per cent risk of progression to advanced disease in five years. In order to maximise visual outcomes for their patients, practising eye-care professionals must be able to stratify patients according to their risk of progression, intervene (for example by recommending smoking cessation or nutritional supplements and Amsler grid self-monitoring in intermediate disease) and monitor accordingly. With the aid of ocular imaging, a range of under-recognised yet meaningful risk factors have been identified. The purpose of this review is to assist the eye-care practitioner in stratifying the risk of progression in intermediate age-related macular degeneration using the range of established and emerging precursory signs that herald loss of vision.

Advanced imaging for the diagnosis of age-related macular degeneration: a case vignettes study

Background

The aim of this study is to evaluate the diagnosis, staging, imaging and management preferences, and the effect of advanced imaging among practising optometrists in age‐related macular degeneration (AMD).

Methods

Up to 20 case vignettes (computer‐based case simulations) were completed online in a computer laboratory in random order by 81 practising optometrists of Australia. Each case presented findings from a randomly selected patient seen previously at the Centre for Eye Health for a macular assessment in the following order: case history, preliminary tests and colour fundus photography. Participants were prompted to provide their diagnosis, management and imaging preference. One additional imaging result (either modified fundus photographs and infrared images, fundus autofluorescence, or optical coherence tomography [OCT]) was then provided and the questions repeated. Finally, all imaging results were provided and the questions repeated a third time.

Results

A total of 1,436 responses were analysed. The presence of macular pathology in AMD was accurately detected in 94 per cent of instances. The overall diagnostic accuracy of AMD was 61 per cent using colour fundus photography. This improved by one per cent using one additional imaging modality and a further four per cent using all imaging. Across all responses, a greater improvement in the diagnostic accuracy of AMD occurred following the presentation of OCT findings (versus other modalities). OCT was the most preferred imaging modality for AMD, while multimodal imaging was of greatest benefit in cases more often misdiagnosed using colour fundus photography alone. Overall, the cohort also displayed a tendency to underestimate disease severity.

Conclusion

Despite reports that imaging technologies improve the stratification of AMD, our findings suggest that this effect may be small when applied among practising optometrists without additional or specific training.

Intraretinal Correlates of Reticular Pseudodrusen Revealed by Autofluorescence and En Face OCT

Purpose

We sought to determine whether information revealed from the reflectance, autofluorescence, and absorption properties of RPE cells situated posterior to reticular pseudodrusen (RPD) could provide insight into the origins and structure of RPD.

Methods

RPD were studied qualitatively by near-infrared fundus autofluorescence (NIR-AF), short-wavelength fundus autofluorescence (SW-AF), and infrared reflectance (IR-R) images, and the presentation was compared to horizontal and en face spectral domain optical coherence tomographic (SD-OCT) images. Images were acquired from 23 patients (39 eyes) diagnosed with RPD (mean age 80.7 ± 7.1 [SD]; 16 female; 4 Hispanics, 19 non-Hispanic whites).

Results

In SW-AF, NIR-AF, and IR-R images, fundus RPD were recognized as interlacing networks of small scale variations in IR-R and fluorescence (SW-AF, NIR-AF) intensities. Darkened foci of RPD colocalized in SW-AF and NIR-AF images, and in SD-OCT images corresponded to disturbances of the interdigitation (IZ) and ellipsoid (EZ) zones and to more pronounced hyperreflective lesions traversing photoreceptor-attributable bands in SD-OCT images. Qualitative assessment of the outer nuclear layer (ONL) revealed thinning as RPD extended radially from the outer to inner retina. In en face OCT, hyperreflective areas in the EZ band correlated topographically with hyporeflective foci at the level of the RPE.

Conclusions

The hyperreflective lesions corresponding to RPD in SD-OCT scans are likely indicative of degenerating photoreceptor cells. The darkened foci at positions of RPD in NIR-AF and en face OCT images indicate changes in the RPE monolayer with the reduced NIR-AF and en face OCT signal suggesting a reduction in melanin that could be accounted for by RPE thinning.

Collaborative care of non-urgent macular disease: a study of inter-optometric referrals

Purpose

Diseases involving the macula and posterior pole are leading causes of visual impairment and blindness worldwide and may require prompt ophthalmological care. However, access to eye‐care and timely patient management may be limited due to inefficient and inappropriate referrals between primary eye‐care providers and ophthalmology. Optometrists with a special interest in macular disease may be useful as a community aid to better stratify and recommend best‐practice management plans for suitable patients. This study assesses such a notion by appraising the optometric referral patterns of patients with suspected macular disease to an intermediate‐tier optometric imaging clinic.

Methods

We performed a retrospective review of patient records and referrals using patients examined at Centre for Eye Health (CFEH) for an initial or follow up macular assessment between the 1/7/2013 and 30/6/2014 (n = 291). The following data were analysed: patient demographic characteristics, primary reason for referral, diagnosed/suspected condition, CFEH diagnosis and recommended management plan.

Results

The number of referrals stipulating a diagnosis, confirmed after evaluation at CFEH was 121 of 291 (42%). After evaluation at CFEH, the number of cases without a specific diagnosis was approximately halved (reduced from 47% to 23%), while the number of cases with no apparent defect or normal aging changes rose from 1% to 15%. Overall diagnostic congruency for specified macular conditions was high (58–94%); cases were seldom (30/291, 10%) found to have a completely different macular condition. 244 of 291 (84%) patients seen at CFEH were recommended ongoing optometric care: either with the referring optometrist or through recall to CFEH. Referral to an ophthalmologist was recommended in 47 instances (16%).

Conclusions

More widespread adoption of intermediate‐tier optometric eye‐care referral pathways in macular disease (following opportunistic primary care screening) has the potential to reduce the number of cases with non‐specific diagnoses and to increase those with a diagnosis of normal aging changes or no apparent disease. The majority of cases seen under this intermediate‐tier model required ongoing optometric care only and did not require face‐to‐face consultation with an ophthalmologist.

Infrared reflectance imaging in age-related macular degeneration

PURPOSE

The purpose of this article is to describe the appearance of age-related macular degeneration (AMD) phenotypes using infrared (IR) reflectance imaging. IR reflectance imaging of the retina has the potential to highlight specific sub-retinal features and pathology. However, its role in macular disease, specifically AMD, is often underestimated and requires clarification.

RECENT FINDINGS

Recent advances in clinical methods, imaging and scientific knowledge may be integrated to improve the accuracy of disease stratification in AMD. In particular, IR imaging holds an underutilised sensitivity to detect reticular pseudodrusen, which have been repeatedly described as a high-risk sign for late AMD.

SUMMARY

This article provides clinically relevant descriptions of AMD phenotypes using IR reflectance imaging. The findings are integrated with images from cases seen at the Centre for Eye Health. As primary eye-care providers assume a critical role in the detection, diagnosis and management of AMD, we also provide a chair-side reference to assist clinicians in interpreting IR images in AMD.

Self-reported optometric practise patterns in age-related macular degeneration

BACKGROUND

The use of advanced imaging in clinical practice is emerging and the use of this technology by optometrists in assessing patients with age-related macular degeneration is of interest. Therefore, this study explored contemporary, self-reported patterns of practice regarding age-related macular degeneration diagnosis and management using a cross-sectional survey of optometrists in Australia and New Zealand.

METHODS

Practising optometrists were surveyed on four key areas, namely, demographics, clinical skills and experience, assessment and management of age-related macular degeneration. Questions pertaining to self-rated competency, knowledge and attitudes used a five-point Likert scale.

RESULTS

Completed responses were received from 127 and 87 practising optometrists in Australia and New Zealand, respectively. Advanced imaging showed greater variation in service delivery than traditional techniques (such as slitlamp funduscopy) and trended toward optical coherence tomography, which was routinely performed in age-related macular degeneration by 49 per cent of respondents. Optical coherence tomography was also associated with higher self-rated competency, knowledge and perceived relevance to practice than other modalities. Most respondents (93 per cent) indicated that they regularly applied patient symptoms, case history, visual function results and signs from traditional testing, when queried about their management of patients with age-related macular degeneration. Over half (63 per cent) also considered advanced imaging, while 31 per cent additionally considered all of these as well as the disease stage and clinical guidelines. Contrary to the evidence base, 68 and 34 per cent rated nutritional supplements as highly relevant or relevant in early age-related macular degeneration and normal aging changes, respectively.

CONCLUSIONS

These results highlight the emergence of multimodal and advanced imaging (especially optical coherence tomography) in the assessment of age-related macular degeneration by optometrists. Clinically significant variations in self-rated test competency and the understanding regarding nutritional supplements for different stages of age-related macular degeneration suggest that further work to up-skill optometrists may be required.