Clinical model assisting with the collaborative care of glaucoma patients and suspects

Exploring the relationship between 24-2 visual field and widefield optical coherence tomography data across healthy, glaucoma suspect and glaucoma eyes

PURPOSE

To utilise ganglion cell-inner plexiform layer (GCIPL) measurements acquired using widefield optical coherence tomography (OCT) scans spanning 55° × 45° to explore the link between co-localised structural parameters and clinical visual field (VF) data.

METHODS

Widefield OCT scans acquired from 311 healthy, 268 glaucoma suspect and 269 glaucoma eyes were segmented to generate GCIPL thickness measurements. Estimated ganglion cell (GC) counts, calculated from GCIPL measurements, were plotted against 24-2 SITA Faster visual field (VF) thresholds, and regression models were computed with data categorised by diagnosis and VF status. Classification of locations as VF defective or non-defective using GCIPL parameters computed across eccentricity- and hemifield-dependent clusters was assessed by analysing areas under receiver operating characteristic curves (AUROCCs). Sensitivities and specificities were calculated per diagnostic category.

RESULTS

Segmented linear regression models between GC counts and VF thresholds demonstrated higher variability in VF defective locations relative to non-defective locations (mean absolute error 6.10-9.93 dB and 1.43-1.91 dB, respectively). AUROCCs from cluster-wide GCIPL parameters were similar across methods centrally (p = 0.06-0.84) but significantly greater peripherally, especially when considering classification of more central locations (p < 0.0001). Across diagnoses, cluster-wide GCIPL parameters demonstrated variable sensitivities and specificities (0.36-0.93 and 0.65-0.98, respectively), with the highest specificities observed across healthy eyes (0.73-0.98).

CONCLUSIONS

Quantitative prediction of VF thresholds from widefield OCT is affected by high variability at VF defective locations. Prediction of VF status based on cluster-wide GCIPL parameters from widefield OCT could become useful to aid clinical decision-making in appropriately targeting VF assessments.

Systematic review and appraisal of quality, definitions and treatment recommendations of clinical guidelines for glaucoma suspects

BACKGROUND

To appraise the quality of clinical practice guidelines for glaucoma suspects, and to assess their consistency for how a 'glaucoma suspect' is defined and their recommendations for treatment initiation for such individuals.

METHODS

This study included all documents that self-identified as a 'guideline' and provided recommendation(s) for the clinical care of glaucoma suspects. The quality of eligible guidelines was assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument.

RESULTS

From 1196 records retrieved from comprehensive searches and two records manually included, 20 clinical practice guidelines were deemed eligible. Based on an appraisal using the AGREE II instrument, 16 (80%) guidelines had ≤2 domains with scores >66%. Overall, the lowest scoring domains were for applicability, editorial independence and stakeholder involvement. There was relatively poor agreement across the guidelines for what defines a 'glaucoma suspect' or 'primary open angle glaucoma [POAG] suspect', as well as the recommendations and criteria for treatment initiation in these populations. There was better agreement for the definition and recommendations for treatment initiation for 'primary angle closure suspects'.

CONCLUSIONS

There is substantial room to improve the methodological quality of most current international clinical guidelines for glaucoma suspects. Clinicians should consider this finding when using such guidelines to inform their care of glaucoma suspects. Substantial variation in the definition of a POAG suspect and recommendations for treatment initiation underscores important gaps in the current evidence for the accurate prediction of glaucoma development and treatment effectiveness in these individuals.

Characterisation of the normal human ganglion cell-inner plexiform layer using widefield optical coherence tomography

PURPOSE

To describe variations in ganglion cell-inner plexiform layer (GCIPL) thickness in a healthy cohort from widefield optical coherence tomography (OCT) scans.

METHODS

Widefield OCT scans spanning 55° × 45° were acquired from 470 healthy eyes. The GCIPL was automatically segmented using deep learning methods. Thickness measurements were extracted after correction for warpage and retinal tilt. Multiple linear regression analysis was applied to discern trends between global GCIPL thickness and age, axial length and sex. To further characterise age-related change, hierarchical and two-step cluster algorithms were applied to identify locations sharing similar ageing properties, and rates of change were quantified using regression analyses with data pooled by cluster analysis outcomes.

RESULTS

Declines in widefield GCIPL thickness with age, increasing axial length and female sex were observed (parameter estimates -0.053, -0.436 and -0.464, p-values <0.001, <0.001 and 0.02, respectively). Cluster analyses revealed concentric, slightly nasally displaced, horseshoe patterns of age-related change in the GCIPL, with up to four statistically distinct clusters outside the macula. Linear regression analyses revealed significant ageing decline in GCIPL thickness across all clusters, with faster rates of change observed at central locations when expressed as absolute (slope = -0.19 centrally vs. -0.04 to -0.12 peripherally) and percentage rates of change (slope = -0.001 centrally vs. -0.0005 peripherally).

CONCLUSIONS

Normative variations in GCIPL thickness from widefield OCT with age, axial length and sex were noted, highlighting factors worth considering in further developments. Widefield OCT has promising potential to facilitate quantitative detection of abnormal GCIPL outside standard fields of view.

Retinal vessel diameters in intermediate age-related macular degeneration using en face optical coherence tomography

CLINICAL RELEVANCE

Clinical assessment of age-related macular degeneration (AMD) relies on biomarkers that do not necessarily reflect the contributions of vascular dysfunction. Validation of clinically accessible methods of measuring retinal vascular integrity could provide a more holistic understanding of AMD-related changes to facilitate appropriate care.

BACKGROUND

There is conflicting evidence if retinal vessel calibre is significantly altered in the early stages of AMD. This study examined the outer and inner diameters of first order retinal vessels in intermediate AMD eyes using en face optical coherence tomography (OCT).

METHODS

Retinal en face (6 × 6 mm) OCT images were examined in a single eye of participants with intermediate AMD (n = 46) versus normal macula (n = 43) for arterioles (all identifiable) and venules (40/46 and 39/43 identifiable). All participants were aged ≥50 years without diabetes mellitus, hypertension, or other systemic vascular disease.

RESULTS

Intra- and inter-grader agreement was good-to-excellent for all en face OCT measurements of arteriole and venule diameters (intraclass correlation coefficient = 0.87 to 0.99). Arteriolar outer diameters (82.3 ± 19.8 µm vs 73.8 ± 16.1 µm; p < 0.05) and inner diameters (35.1 ± 8.4 µm vs 31.5 ± 8.1 µm; p < 0.05) were significantly greater in AMD eyes compared to normal eyes. Venular inner diameter was significantly greater (43.1 ± 9.5 µm vs 39.2 ± 10.1 µm; p < 0.05), but outer diameter remained unchanged (p = 0.17) in AMD eyes compared to normal eyes.

CONCLUSION

Arteriolar dilation and altered venular inner diameter were observed in intermediate AMD eyes. These results support further investigation of vascular contributions to AMD in the early stages of disease, possibly using the en face OCT imaging modality.

Building and maintaining interprofessional collaborative practice in eyecare: Learnings from the Queensland Paediatric Optometry Alignment Program

PURPOSE

The Queensland Children's Hospital Paediatric Optometry Alignment Program commenced with a pilot phase to assess its feasibility, effectiveness and acceptability. This study identified the barriers that hinder effective interprofessional collaboration and the facilitators that contribute to its success, and assessed changes in optometrists' satisfaction since the pilot phase of the collaborative care programme.

METHODS

Qualitative deductive and inductive content analysis was applied to open-ended free-text survey responses collected in 2018 from the optometrists involved in the Program's pilot phase. The responses were coded using the Theoretical Domains Framework (TDF) to categorise barriers and facilitators into key themes. Key behavioural determinants were mapped to the COM-B (Capability, Opportunity, Motivation-Behaviour) elements of the Behaviour Change Wheel model to identify intervention strategies. Intervention recommendations were derived from behaviour change mapping and compared with programme quality improvement initiatives. A cross-sectional explanatory survey informed by the TDF was conducted within the current 2023 cohort, and a longitudinal comparative analysis was carried out using data from the 2018 survey.

RESULTS

Among the 97 surveys distributed in 2018, 44 respondents participated; from this group, 38 individuals contributed a total of 200 free-text responses. Facilitators (240 comments) outnumbered barriers (65 comments). Key facilitators were accessible and timely care, professional development, confidence and positive outcome beliefs. Barriers included communication, information handover, credibility, relationships and skill gaps. Optometrists actively engaged in the programme in 2023 reported heightened satisfaction with their involvement, increased confidence and greater engagement in paediatric eyecare delivery. However, challenges in clinical information transfer persist.

CONCLUSION

The interprofessional collaborative model of paediatric eyecare has contributed efficiencies within the health system by building paediatric care capacity in the community, fostering professional credibility and promoting interdisciplinary trust. Insights gained should prove valuable for other paediatric eyecare services exploring hospital-to-community care models.

Visualising structural and functional characteristics distinguishing between newly diagnosed high-tension and low-tension glaucoma patients

PURPOSE

To determine whether there are quantifiable structural or functional differences that can distinguish between high-tension glaucoma (HTG; intraocular pressure [IOP] > 21 mm Hg) and low-tension glaucoma (LTG; IOP ≤ 21 mm Hg) at diagnosis.

METHOD

This was a retrospective, cross-sectional study. Clinical results of one eye from 90 newly diagnosed HTG and 319 newly diagnosed LTG patients (117 with very-low-tension glaucoma [vLTG; ≤15 mm Hg] and 202 with middling LTG [mLTG; >15 mm Hg, ≤21 mm Hg]) were extracted, which included relevant demographic covariates of glaucoma, quantitative optical coherence tomography (including the optic nerve head, retinal nerve fibre layer and ganglion cell-inner plexiform layer) measurements and standard automated perimetry global metrics. We used binary logistic regression analysis to identify statistically significant clinical parameters distinguishing between phenotypic groups for inclusion in principal component (PC) (factor) analysis (PCA). The separability between each centroid for each cohort was calculated using the Euclidean distance (d(x,y)).

RESULTS

The binary logistic regression comparing HTG and all LTG identified eight statistically significant clinical parameters. Subsequent PCA results included three PCs with an eigenvalue >1. PCs 1 and 2 accounted for 21.2% and 20.2% of the model, respectively, with a d(x,y) = 0.468, indicating low separability between HTG and LTG. The analysis comparing vLTG, mLTG and HTG identified 15 significant clinical parameters, which were subsequently grouped into five PCs. PCs 1 and 2 accounted for 24.1% and 17.8%, respectively. The largest separation was observed between vLTG and HTG (d(x,y) = 0.581), followed by vLTG and mLTG (d(x,y) = 0.435) and lastly mLTG and HTG (d(x,y) = 0.210).

CONCLUSION

Conventional quantitative structural or functional parameters could not distinguish between pressure-defined glaucoma phenotypes at the point of diagnosis and are therefore not contributory to separating cohorts. The overlap in findings highlights the heterogeneity of the primary open-angle glaucoma clinical presentations among pressure-defined groups at the cohort level.

Drusen-aware model for age-related macular degeneration recognition

INTRODUCTION

The purpose of this study was to build an automated age-related macular degeneration (AMD) colour fundus photography (CFP) recognition method that incorporates confounders (other ocular diseases) and normal age-related changes by using drusen masks for spatial feature supervision.

METHODS

A range of clinical sources were used to acquire 7588 CFPs. Contrast limited adaptive histogram equalisation was used for pre-processing. ResNet50 was used as the backbone network, and a spatial attention block was added to integrate prior knowledge of drusen features into the backbone. The evaluation metrics used were sensitivity, specificity and F1 score, which is the harmonic mean of precision and recall (sensitivity) and area under the receiver-operating characteristic (AUC). Fivefold cross-validation was performed, and the results compared with four other methods.

RESULTS

Excellent discrimination results were obtained with the algorithm. On the public dataset (n = 6565), the proposed method achieved a mean (SD) sensitivity of 0.54 (0.09), specificity of 0.99 (0.00), F1 score of 0.62 (0.06) and AUC of 0.92 (0.02). On the private dataset (n = 1023), the proposed method achieved a sensitivity of 0.92 (0.02), specificity of 0.98 (0.01), F1 score of 0.92 (0.01) and AUC of 0.98 (0.01).

CONCLUSION

The proposed drusen-aware model outperformed baseline and other vessel feature-based methods in F1 and AUC on the AMD/normal CFP classification task and achieved comparable results on datasets that included other diseases that often confound classification. The method also improved results when a five-category grading protocol was used, thereby reflecting discriminative ability of the algorithm within a real-life clinical setting.

The paediatric optometry alignment program - a model of interprofessional collaborative eyecare

CLINICAL RELEVANCE

Collaboration  between hospital-based ophthalmology and community-based optometry could pave the way to improve access to paediatric eyecare services.

BACKGROUND

The Paediatric Optometry Alignment Program (POAP) began in 2016 as a proof-of-concept pilot project that aimed to improve access to specialist paediatric ophthalmology services. If found to be effective at improving patient access, and the quality of care acceptable to patients and professionals then the strategic intent was to upscale the programme to  serve as a model for paediatric eye care in the community.

METHODS

Temporal observational trend analysis was used to review ophthalmology clinic appointment waitlists prior and post POAP pilot project commencement. Family satisfaction with post-discharge care was surveyed in a purposive sample of 30 patients.  Aligned optometrists in the program pilot (n = 97) were invited to complete an online survey (response rate 46%; n = 45).

RESULTS

The percentage of children waiting longer than clinically recommended fell from 72% to 36%. Sixty-seven percent  of surveyed families had attended a community optometrist as recommended, and all rated the optometry experience from good to excellent.  Participating optometrists reported high levels of satisfaction with involvement in the program, and increased confidence and involvement in paediatric eye care delivery. The need to improve formal transfer  of clinical information was identified.

CONCLUSION

Facilitated integrated care between community-based optometrists and a hospital-based ophthalmology department can improve access for tertiary care services, with high satisfaction for families and participating community-based optometrists.

Topical Review: Optometry in Nepal-Clinical Practice, Research Advances, and Challenges

SIGNIFICANCE

This article reviews educational standard, clinical practice, research advances, and challenges associated with optometry in Nepal and provides critical considerations for contemporary and new optometry programs in countries with similar socioeconomic status and health care systems.Optometry education started in Nepal in 1998 with the primary objective of addressing the unmet needs of eye health and vision care in the country. Over the last two decades, this program has made significant contributions to facilitating and improving the delivery of quality eye care and establishing the nation's eye health system as an exemplary model in South Asia. Despite the positive impact in a short time, optometry education and the profession continue to face several challenges, including a shortage of training resources and facilities, poor quality control and regulation of practice standards, lack of professional recognition, limited pathways for entry to governmental jobs via the national public service commission, and limited clinical and academic opportunities in existing eye care programs. This article reviews current education and clinical practice standards, highlights research advances, and discusses present and future challenges in sustaining and improving the quality of education and advancing the scope of practice of optometry in Nepal. Given the limited access to primary eye care services in Nepal, appropriate professional recognition and integration into the national health system, and initiatives targeted at improving the delivery of optometry education in alignment with successful international models may provide a long-sought solution to making eye care services accessible to all and lowering the burden of visual impairment in the country.

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.

Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners

Ischaemic stroke is a major disease burden as well as a leading cause of death. Early signs of ischaemic stroke can manifest in the eye, placing primary eyecare practitioners in an important position to identify patients at risk of ischaemic stroke and initiate suitable referral pathways. The vascular supply to the brain is reviewed with reference to vision including the various retinal signs and ocular symptoms associated with transient ischaemic attacks and ischaemic stroke. Using a range of clinical cases, the diverse clinical presentations of retinal embolic events, as well as other forms of vascular occlusion, are highlighted and the underlying pathophysiology is discussed. A succinct scheme for the assessment and management of ischaemic events for primary eye care practitioners is provided.

Deployment of the Water Drinking Test and iCare HOME Phasing for Intraocular Pressure Profiling in Glaucoma Evaluation

SIGNIFICANCE

Intraocular pressure (IOP) profiling is an important component of the glaucoma examination. Two techniques for profiling are the water drinking test (WDT) and iCare HOME phasing, but the correlations between techniques and their ease of deployment have not been studied. These questions are important in determining suitability for clinical deployment.

PURPOSE

This study aimed to compare the IOP results of the WDT and iCare HOME phasing in patients with suspected or newly diagnosed glaucoma.

METHODS

Ninety-eight consecutive patients attending a glaucoma clinic underwent IOP profiling using both techniques. For the WDT, patients ingested 10 mL/kg body weight of water after a baseline applanation IOP measurement and then underwent serial IOP measurements approximately every 15 minutes, ceasing after 30 minutes of consecutive measurements within 3 mmHg of baseline. Patients successfully certified for self-administration of the iCare HOME were loaned the instrument for 1 week and instructed to take four measurements per day.

RESULTS

Twenty-seven patients (28%) successfully obtained four measurements per day using iCare HOME, and 96 patients (98%) were able to complete the WDT. Intraocular pressure profiles showed no difference between the time for peak IOP and across nearly all IOP parameters obtained from profiling except for the standard deviation of IOP measurements obtained using the iCare HOME (P = .005). There were moderate correlations between peak IOPs obtained using each technique (r = 0.67, P = .001, right eye; r = 0.66, P = .002, left eye) but no correlation between the daily range (iCare HOME) or peak-trough difference (WDT; r = 0.21, P = .28, right eye; r = 0.27, P = .02, left eye). Bland-Altman analysis returned similar results for peak and range.

CONCLUSIONS

Intraocular pressure profiling using both techniques can reveal the peak IOP, and these measurements are strongly correlated. Most patients were unable to complete the iCare HOME according to the manufacturer's recommendations. Clinicians should select the most appropriate technique for each patient.

Intra-session repeatability of anterior chamber depth across the chamber width using Pentacam Scheimpflug imaging in healthy subjects

PURPOSE

Despite the importance of anterior chamber depth (ACD) measurements in disease and ageing, the repeatability and their threshold for change is not known. Our purpose was to determine the intra-session repeatability of Pentacam Scheimpflug photography for measuring the ACD across the chamber width in healthy subjects and thus inform expected limits of normality.

METHODS

Pentacam Scheimpflug photography was used to obtain ACD measurements at 57 points across the central 8mm of the chamber width from one randomly selected eye of 130 healthy (normal vision and no ocular diseases, except age-normal cataracts) subjects (median age 58.0 years, interquartile range 46.3-63.0 years; 48 males, 82 females). Intra-session ACD measurements were compared. Univariate and multivariate linear regression was performed to identify categorical and continuous variables demonstrating a significant relationship with ACD and its repeatability.

RESULTS

Bland-Altman analyses showed no directional or depth-dependent bias in the difference between the first and second tests (mean bias -0.003 mm, 95% limits of agreement -0.115 to +0.109 mm). Multivariate analysis found gender to be a significant factor (p < 0.0001), but not age (p = 0.69) nor ethnicity (p = 0.65), although the model fit was poor (R²  = 0.004). There were no regional differences in repeatability measures found in males, but six locations in the superior aspect in females were found to be significantly different in their repeatability characteristics. Tolerance limits used to calculate the number of step sizes between <20 and >60-year-old age groups found 8.1-11.5 steps for females, and 7.5-9.2 steps for males.

CONCLUSIONS

Scheimpflug imaging using the Pentacam has excellent intra-session repeatability. Only gender appeared to affect repeatability characteristics, manifesting with a greater number of meaningful steps of change between two extremes of age range in females compared to males, which provides guidance for identifying clinically significant and measurable change between tests.

Patient and technician perspectives following the introduction of frontloaded visual field testing in glaucoma assessment

CLINICAL RELEVANCE

Frontloaded visual field testing (twice per eye per session) is well-tolerated by patients and technicians, representing a viable strategy that can be implemented in routine clinical practice to capture enough clinical perimetry data for effective disease diagnosis, surveillance and management.

BACKGROUND

To determine the experiences of patients and technicians following the implementation of frontloaded visual field testing (multiple tests per eye within the same session) in a glaucoma service.

METHODS

This was a retrospective, cross-sectional study. A written questionnaire was administered to patients (three questions) attending the glaucoma service at the Centre for Eye Health for glaucoma assessment and to their administering perimetry technicians (two questions). The questionnaire was administered after static automated perimetry (24-2 SITA-Faster on the Humphrey Field Analyzer) was performed twice for each eye (frontloaded) within the same session. Respondents were asked to provide a 1-5 Likert scale response to questions that targeted operational issues for frontloaded visual field testing. Responses were correlated against to demographic (age, gender, ethnicity) and clinical (diagnosis, refractive error, visual field indices, test duration) parameters.

RESULTS

Approximately 90% of patient respondents agreed that frontloaded visual field testing was clearly explained to them, that they were comfortable during the test, and would prefer completing the tests at a single visit rather than returning to repeat the test. Most technician respondents were also able to keep their patients comfortable. 13% of technician respondents felt they ran late during the session, but on average, the total test duration for four visual field tests was 13 minutes, including breaks. There was no correlation found between demographic and clinical factors, and the responses.

CONCLUSIONS

Frontloaded visual field testing was well-tolerated by patients and technicians. Strategies that may be helpful for other clinics to adopt this new paradigm are described.

Quality of referrals for glaucoma assessment: a cross-sectional survey of clinical data and outcomes

PURPOSE

This study assessed the completeness of clinical information provided by ophthalmological and optometric referrals to glaucoma specialists consulting for open-angle glaucoma (OAG).

METHODS

A retrospective, cross-sectional study of 72 internal referrals for evaluation of OAG in a multispecialty group practice was performed. The quality of the referral was assessed based on: (1) the completeness of the clinical triad of intraocular pressure measurement, visual field (VF), and cup-to-disk ratio for each eye; (2) the availability of the data necessary to calculate an ocular hypertension treatment study (OHTS) score; and (3) the presence of retinal nerve fiber layer (RNFL) imaging by mean of optical coherence tomography.

RESULTS

The clinical triad was available in 57% of referrals, whereas an OHTS score was calculable in 24% of referrals (p < 0.001); RNLF imaging was available in 51% of referrals (p = 0.859). The completeness of clinical information was similar for ophthalmological and optometric referrals. From the date of referral to the time of the consultation, there was a significant increase in the availability of the clinical triad (57-65%; p = 0.013) and the OHTS score (24-5%; p = 0.004) but not for RNFL imaging (51-56%; p = 0.618). The most common missing clinical information was VF testing, which was absent in 42% of referrals.

CONCLUSIONS

Key clinical data necessary for effective diagnosis and staging of OAG was lacking for many patients referred to glaucoma specialists.

Detection of glaucoma using retinal fundus images: A comprehensive review

Content-based image analysis and computer vision techniques are used in various health-care systems to detect the diseases. The abnormalities in a human eye are detected through fundus images captured through a fundus camera. Among eye diseases, glaucoma is considered as the second leading case that can result in neurodegeneration illness. The inappropriate intraocular pressure within the human eye is reported as the main cause of this disease. There are no symptoms of glaucoma at earlier stages and if the disease remains unrectified then it can lead to complete blindness. The early diagnosis of glaucoma can prevent permanent loss of vision. Manual examination of human eye is a possible solution however it is dependant on human efforts. The automatic detection of glaucoma by using a combination of image processing, artificial intelligence and computer vision can help to prevent and detect this disease. In this review article, we aim to present a comprehensive review about the various types of glaucoma, causes of glaucoma, the details about the possible treatment, details about the publicly available image benchmarks, performance metrics, and various approaches based on digital image processing, computer vision, and deep learning. The review article presents a detailed study of various published research models that aim to detect glaucoma from low-level feature extraction to recent trends based on deep learning. The pros and cons of each approach are discussed in detail and tabular representations are used to summarize the results of each category. We report our findings and provide possible future research directions to detect glaucoma in conclusion.

Clinical outcomes of the Centre for Eye Health: an intra-professional optometry-led collaborative eye care clinic in Australia

Clinical relevance: This novel clinical model is the first of its kind in Australia and was designed to help reduce unnecessary referrals into overburdened public systems by utilising pre-existing community-based resources.Background: The Centre for Eye Health (CFEH) is an intra-professional optometry-led care clinic offering an alternative pathway to traditional ophthalmology-based pathways (public hospital clinics or private practices) for 'at-risk' patients requiring ocular imaging, diagnostic and management services. This study evaluates the CFEH integrated eye-care model in the identification of chronic eye diseases within the community.Methods: A retrospective random clinical audit of over 750 medical records of patients referred to the CFEH between July 2016 and June 2019 was conducted. Demographics of patients, referral type, final diagnosis and recommended management plans were extracted from this subset. Clinic key performance indicators (referral turnaround time, and net cost per patient appointment) were also extracted.Results: Of the 755 referrals associated with the audited records, 77.4% resulted in the identification of patients with or at-risk of developing eye diseases with 73.5% of this cohort requiring ongoing monitoring at CFEH or referral to ophthalmology. Although the CFEH model is not designed to diagnose or manage acute conditions, 1.5% of patients in this pathway required same day ophthalmological or medical intervention. The cost per patient was equivalent to hospital eye departments costs.Conclusion: This integrated care pathway has the potential to reduce unnecessary referrals from optometrists to hospital ophthalmological service by offering a safe and effective alternate pathway. The majority of patients seen within this pathway were able to be monitored within optometry-led services. This is a unique clinical model utilising inter-professional referrals within optometry which has the potential to reduce preventable blindness within the community through the early detection of eye diseases.

Modelling normal age-related changes in individual retinal layers using location-specific OCT analysis

Current descriptions of retinal thickness across normal age cohorts are mostly limited to global analyses, thus overlooking spatial variation across the retina and limiting spatial analyses of retinal and optic nerve disease. This retrospective cross-sectional study uses location-specific cluster analysis of 8 × 8 macular average grid-wise thicknesses to quantify topographical patterns and rates of normal, age-related changes in all individual retinal layers of 253 eyes of 253 participants across various age cohorts (n = 23-69 eyes per decade). Most retinal layers had concentric spatial cluster patterns except the retinal nerve fibre layer (RNFL) which displayed a nasal, asymmetric radial pattern. Age-related thickness decline mostly occurred after the late 4th decade, described by quadratic regression models. The ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer nuclear layer + Henle's fibre layer (ONL_+HFL) were significantly associated with age (p < 0.0001 to < 0.05), demonstrating similar rates of thickness decline (mean pooled slope =  - 0.07 µm/year), while the IS/OS had lesser mean pooled thickness slopes for all clusters (- 0.04 µm/year). The RNFL, OPL, and RPE exhibited no significant age-related thickness change, and the RNFL were significantly associated with sex. Analysis using spatial clusters compared to the ETDRS sectors revealed more extensive spatial definition and less variability in the former method. These spatially defined, clustered normative data and age-correction functions provide an accessible method of retinal thickness analysis with more spatial detail and less variability than the ETDRS sectors, potentially aiding the diagnosis and monitoring of retinal and optic nerve disease.

Comprehensive Analysis to Uncover Determinants of Patient Appointment Compliance in Ophthalmology at the Kresge Eye Institute, USA

INTRODUCTION

Appointment compliance (AC) has a significant impact on patient care; however, determinants of AC in Ophthalmology and its subspecialties remains elusive.

METHODS

We performed a five-year retrospective analysis across Kresge Eye Institute (KEI) and its affiliated Michigan locations. A total of 597,364 appointments across >13 subspecialties were included. AC was the primary outcome of interest. Compliant (CO) and non-compliant (NC) groups were compared to the following variables: patient characteristics (gender, race, age, insurance), appointment rank (relative to patient history), scheduling location, month, and ophthalmic specialty, in regard to arrival and no-show.

RESULTS

Among all appointments, 59.77% were associated with a female patient and 79.16% of the total number of appointments depicted patient compliance. AC differed concerning specialty, with retina representing the highest compliance across all appointments. Among 200+ insurance providers, Medicare was most frequently used and represented the highest share of CO appointments. African Americans were the primary ethnicity served by KEI and had the highest number of NC appointments.

CONCLUSION

Our study demonstrates the impact of patient demographics, appointment characteristics, and ophthalmic subspecialty on AC. A better understanding of these determinants could allow for an increased CO for Ophthalmology practices.

Glaucoma Community Care: Does Ongoing Shared Care Work?

Purpose:

We assessed a novel, public, vertical integrated care model for glaucoma management in the community.

Methods:

This study was a retrospective, longitudinal study of 266 patients diagnosed or suspected of glaucoma. Patients were stratified to either ongoing ophthalmology-led (n = 81) or optometry-led shared care (n = 185). Demographics and clinical characteristics, including the re-referral rate and timeliness of follow up were analysed.

Results:

Just under half (565/1224, 46%) of all follow up consultations over the total study period of 45 months were seen in optometry-led care, with a re-referral rate to ophthalmology of 21%. Treated patients showed a median intraocular pressure reduction of 20% and a median time delay of just two days between the actual and recommended review period.

Conclusions:

Shared care provides an effective option for managing the ongoing care burden in chronic stable glaucoma cases at low risk of vision loss.

Normal aging changes in the choroidal angioarchitecture of the macula

The choroidal vascularity index (CVI) has been shown to be sensitive in detecting changes in choroidal angioarchitecture in a range of ocular diseases. However, changes in CVI in association with normal physiological aging and spatial distribution remains to be determined. This is significant as a range of ocular conditions with choroidal degeneration are associated with aging. In this study, we assessed CVI for 106 healthy eyes from 106 individuals (range 21–78 years old, ~ 20 individuals/decade) at 15 eccentricities across the macula (0, 230 µm, 460 µm, 690 µm, 1,150 µm, 1,380 µm and 2,760 µm from the fovea in the superior and inferior direction). Total choroidal area, luminal area and stromal area were all significantly decreased with age (p < 0.001 for all parameters). CVI was also significantly decreased with age (p < 0.01) and eccentricity. Fitting of quadratic regression curves to CVI as a function of age yielded a good fit for all eccentricities (r² = 0.55–0.80) and suggested a decrease in CVI from the ages of 33–43 years at a rate of 0.7–2.7% per decade. CVI was lower in the inferior versus superior retina at matching eccentricities and a significant difference in age-related decline of CVI with eccentricity only occurred in inferior locations. These findings suggest choroidal angioarchitecture declines from the 4th decade of life with potential eccentricity differences in the inferior and superior retina. Considering the number of age-related diseases with choroidal dysfunction, these results provide foundational knowledge to understand choroidal involvement in these diseases.

Macula Ganglion Cell Thickness Changes Display Location-Specific Variation Patterns in Intermediate Age-Related Macular Degeneration

Purpose

The purpose of this study was to examine changes in the ganglion cell layer (GCL) of individuals with intermediate age-related macular degeneration (AMD) using grid-wise analysis for macular optical coherence tomography (OCT) volume scans. We also aim to validate the use of age-correction functions for GCL thickness in diseased eyes.

Methods

OCT macular cube scans covering 30° × 25° were acquired using Spectralis spectral-domain OCT for 87 eyes with intermediate AMD, 77 age-matched normal eyes, and 254 non-age-matched normal eyes. The thickness of the ganglion cell layer (GCL) was defined after segmentation at 60 locations across an 8 × 8 grid centered on the fovea, where each grid location covered 0.74 mm² (approximately 3° × 3°) within the macula. Each GCL location of normal eyes (n = 77) were assigned to a specific iso-ganglion cell density cluster in the macula, based on patterns of age-related GCL thickness loss. Analyses were then performed comparing AMD GCL grid-wise data against corresponding spatial clusters, and significant AMD GCL thickness changes were denoted as values outside the 95% distribution limits.

Results

Analysis of GCL thickness changes revealed significant differences between spatial clusters, with thinning toward the fovea, and thickening toward the peripheral macula. The direction of GCL thickness changes in AMD were associated more so with thickening than thinning in all analyses. Results were corroborated by the application of GCL thickness age-correction functions.

Conclusions

GCL thickness changed significantly and nonuniformly within the macula of intermediate AMD eyes. Further characterization of these changes is critical to improve diagnoses and monitoring of GCL-altering pathologies.

Anterior Chamber Angle Evaluation Using Gonioscopy: Consistency and Agreement between Optometrists and Ophthalmologists

SIGNIFICANCE

In our intermediate-tier glaucoma care clinic, we demonstrate fair to moderate agreement in gonioscopy examination between optometrists and ophthalmologists, but excellent agreement when considering open versus closed angles. We highlight the need for increased consistency in the evaluation and recording of angle status using gonioscopy.

PURPOSE

The consistency of gonioscopy results obtained by different clinicians is not known but is important in moving toward practice modalities such as telemedicine and collaborative care clinics. The purpose of this study was to evaluate the description and concordance of gonioscopy results among different practitioners.

METHODS

The medical records of 101 patients seen within a collaborative care glaucoma clinic who had undergone gonioscopic assessment by two clinicians (one optometrist and either one general ophthalmologist [n = 50] or one glaucoma specialist [n = 51]) were reviewed. The gonioscopy records were evaluated for their descriptions of deepest structure seen, trabecular pigmentation, iris configuration, and other features. These were compared between clinicians (optometrist vs. ophthalmologist) and against the final diagnosis.

RESULTS

Overall, 51.9 and 59.8% of angles were graded identically in terms of deepest visible structure when comparing between optometrist versus general ophthalmologist and optometrist versus glaucoma specialist, respectively. The concordance increased when considering ±1 of the grade (67.4 and 78.5%, respectively), and agreement with the final diagnosis was high (>90%). Variations in angle grading other than naming structures were observed (2.0, 30, and 3.9% for optometrist, general ophthalmologist, and glaucoma specialist, respectively). Most of the time, trabecular pigmentation or iris configuration was not described.

CONCLUSIONS

Fair to moderate concordance in gonioscopy was achieved between optometrists and ophthalmologists in a collaborative care clinic in which there is consistent feedback and clinical review. To move toward unified medical records and a telemedicine model, improved consistency of record keeping and angle description is required.

Glaucoma referrals from primary care and subsequent hospital management in an urban Australian hospital

BACKGROUND

Public hospital ophthalmology services are in high demand and patients requiring medical or surgical intervention for glaucoma may worsen while awaiting care. In Australia, tertiary hospital care requires a referral from primary care providers. This study investigates the quality of glaucoma referrals received at a tertiary public hospital in Australia, and describes the types of glaucoma cases referred for hospital management.

METHODS

An investigation of 200 sequential glaucoma referrals received at a major Australian public hospital from 2013-2016, and the subsequent hospital management. A clinical file audit was made of patient medical records, including referral letters to extract the referral content, and the hospital glaucoma diagnostic outcomes and patient management.

RESULTS

Most referrals came from optometrists (72 per cent) and general practitioners (22 per cent) with the remainder from other specialists. The majority of the referrals contained less than 50 per cent of the key clinical and demographic parameters. Referrals from optometrists provided more ophthalmic information (visual acuity, visual field, intraocular pressure, ocular history). Referrals from general practitioners contained more medical information (systemic co-morbidities medication and allergies). The median wait-time from referral to hospital appointment was 400 days. Of patients attending a hospital appointment, 59 per cent required surgical or medical management, and 16 per cent did not have glaucoma. Overall 18 per cent were discharged, with no differences noted by referral content or referring practitioner.

CONCLUSION

Most referrals did not include useful diagnostic information on ocular, medical and social risks for glaucoma. There is an opportunity to improve targeting of primary care referrals for glaucoma, since patients who were discharged immediately after their hospital appointment are exacerbating the long hospital wait-time. Better information transfer may help to identify patients requiring more urgent intervention. A standardised referral template and guidelines would support collaborative care and streamline access to hospital services.

Impact of referral refinement on management of glaucoma suspects in Australia

BACKGROUND

In ageing populations, the prevalence of chronic diseases such as glaucoma is projected to increase, placing additional demands on limited health-care resources. In the UK, the demand for secondary care in hospital eye clinics was inflated by high rates of false positive glaucoma referrals. Collaborative care models incorporating referral refinement, whereby glaucoma suspect referrals are triaged by suitably trained optometrists through further testing, can potentially reduce false positive referrals. This study examined the impact of a referral refinement model on the accuracy of glaucoma referrals in Australia.

METHODS

Optometrist-initiated glaucoma suspect referrals to the Glaucoma Management Clinic (Sydney, Australia) were prospectively recruited. Glaucoma suspect referrals arising from two pathways were eligible for inclusion, either directly from a community optometrist (standard care) or following comprehensive assessment at the Centre for Eye Health (referral refinement). Main outcome measures were the positive predictive value and false positive rate of referrals. The impact of referral letter content on management outcomes was also investigated.

RESULTS

Of 464 referrals received between March 2015 and June 2018, 252 were for treatment of naïve glaucoma suspects and eligible for inclusion. Following ophthalmological assessment, 45.6 per cent (n = 115/252) were prescribed treatment for open angle glaucoma or ocular hypertension. Positive predictive value of community optometry referrals was 33.8 per cent (n = 25/74) and 50.6 per cent (n = 90/178) following referral refinement. The first visit discharge (false positive) rate was 26 per cent (n = 19/74) for community referrals compared to four per cent (n = 8/178) with referral refinement. Positive predictive value increased with the number of abnormal clinical examination findings associated with referral (χ² test, p < 0.0001). The number of abnormal findings reported in referrals was significantly higher with referral refinement compared to without (n = 1.9 versus 1.5, t-test, p < 0.0001).

CONCLUSION

Referral refinement can improve the diagnostic accuracy of optometry-initiated referrals for glaucoma suspects in Australia, thereby decreasing unnecessary referrals to hospital and other secondary clinics.

Multimodal imaging characteristics of congenital grouped hyper- and hypo-pigmented fundus lesions

BACKGROUND

The imaging characteristics of congenital grouped pigmentation of the retinal pigment epithelium (CGP-RPE) and its non-pigmented variant - grouped congenital albinotic retinal pigment epithelial spots (GCARPES) are poorly defined in the literature. Our case series reports their multimodal imaging characteristics across a spectrum of presentations.

METHODS

A retrospective review of patient records was conducted on patients seen at the Centre for Eye Health between January and December 2016. The multimodal imaging findings across four cases is described using optical coherence tomography (OCT), infrared imaging, ultra-widefield imaging, fundus photography and fundus autofluorescence (FAF).

RESULTS

Case 1 is a 55-year-old female with a bilateral presentation of CGP-RPE showing typical features. Case 2 is a 28-year-old male with a classical presentation of GCARPES in the left eye. Case 3 is a 33-year-old female with unilateral CGP-RPE and an atypical solitary congenital hypertrophy of the retinal pigment epithelium (CHRPE) in the same eye. Case 4 is a unilateral presentation in an 11-year-old female with unusual characteristics. Ocular imaging characteristics of CGP-RPE lesions varied between patients: OCT showed visible RPE changes in cases 3 and 4 but not case 1. The pattern of FAF and infrared imaging also varied with most lesions displaying a pattern of hypo-autofluorescence, but some central lesions in case 3 exhibited hyper-autofluorescence. All lesions were visible with fundus photography.

CONCLUSION

FAF can be helpful in alerting clinicians to the presence of lesions that may be difficult to visualise funduscopically and OCT can be helpful in differentiating between CGP-RPE and its variants from more sinister ocular conditions. All in all, these findings highlight the variable manifestation of CGP-RPE and its variants on multimodal imaging; the diagnosis of CGP-RPE and its variants should remain based on its characteristic funduscopic appearance.

Improving Patient Access and Reducing Costs for Glaucoma with Integrated Hospital and Community Care: A Case Study from Australia

Introduction:

Glaucoma, a chronic eye disease requires regular monitoring and treatment to prevent vision-loss. In Australia, most public ophthalmology departments are overburdened. Community Eye Care is a ‘collaborative’ care model, involving community-based optometrist assessment and ‘virtual review’ by ophthalmologists to manage low-risk patients. C-EYE-C was implemented at one Australian hospital. This study aims to determine whether C-EYE-C improves access to care and better utilises resources, compared to hospital-based care.

Methods:

A clinical and financial audit was conducted to compare access to care and health system costs for hospital care and C-EYE-C. Attendance, wait-time, patient outcomes, and the average cost per encounter were calculated. A weighted kappa assessed agreement between the optometrist and ophthalmologist decisions.

Results:

There were 503 low-risk referrals, hospital (n = 182) and C-EYE-C (n = 321). C-EYE-C had higher attendance (81.6% vs 68.7%, p = 0.001); and shorter appointment wait-time (89 vs 386 days, p < 0.001). Following C-EYE-C, 57% of patients avoided hospital; with 39% requiring glaucoma management. C-EYE-C costs were 22% less than hospital care. There was substantial agreement between optometrists and ophthalmologist for diagnosis (k = 0.69, CI 0.61–0.76) and management (k = 0.66, CI 0.57–0.74).

Discussion:

C-EYE-C showed higher attendance, and reduced wait-times and health system costs.

Conclusions:

Upscale of the C-EYE-C model should be considered to further improve capacity of public eye services in Australia.

Retinal Thickness Changes throughout the Natural History of Drusen in Age-related Macular Degeneration

SIGNIFICANCE

Drusen are associated with retinal thinning in age-related macular degeneration (AMD). These changes, however, have mostly been examined at single time points, ignoring the evolution of drusen from emergence to regression. Understanding the full breadth of retinal changes associated with drusen will improve understanding of disease pathogenesis.

PURPOSE

The purpose of this study was to assess how the natural history of drusen affects retinal thickness, focusing on the photoreceptor and retinal pigment epithelium (RPE) layers.

METHODS

Spectral domain optical coherence tomography of subjects with intermediate AMD (n = 50) who attended the Centre for Eye Health, Sydney, Australia, for two separate visits (476 ± 16 days between visits) was extracted. Scans were automatically segmented with manufacturer software then assessed for drusen that had emerged, grown, or regressed between visits. For each identified lesion, the thickness of each retinal layer at the drusen peak and at adjacent drusen-free areas (150 μm nasal and temporal to the druse) was compared between visits.

RESULTS

Before drusen emergence, the RPE was significantly thicker at the drusen site (14.2 ± 2.6%) compared with neighboring drusen-free areas. There was a 71% sensitivity of RPE thickening predicting drusen emergence. Once drusen emerged, significant thinning of all outer retinal layers was observed, consistent with previous studies. Drusen growth was significantly correlated with thinning of the outer retina (r = -0.38, P < .001). Drusen regression resulted in outer retinal layers returning to thicknesses not significantly different from baseline.

CONCLUSIONS

The natural history of drusen is associated with RPE thickening before drusen emergence, thinning of the outer nuclear layer as well as photoreceptor and RPE layers proportional to drusen growth, and return to baseline thickness after drusen regression. These findings have useful clinical applications, providing a potential marker for predicting drusen emergence for AMD prognostic and intervention studies and highlighting that areas of normal retinal thickness in AMD may be former sites of regressed drusen.

Remote Grading of the Anterior Chamber Angle Using Goniophotographs and Optical Coherence Tomography: Implications for Telemedicine or Virtual Clinics

PURPOSE

To evaluate the agreement and accuracy of grading goniophotographs and anterior segment optical coherence tomography (AS-OCT) results for assessment of the anterior chamber angle, and elicit factors driving concordance between perceived grade and ground truth.

METHODS

Three clinicians evaluated the goniophotographs and AS-OCT results of 75 patients. Graders' impressions of the angle grade, trabecular pigmentation, and iris contour were compared with the ground truth gonioscopic examination result when physically performed by a senior optometrist. Percentage agreement and kappa statistics were calculated. Binary logistic regression was used to elicit factors for accurate grading.

RESULTS

Exact angle matches and binary (open or closed) evaluations were above guessing rate for all graders. There was a systematic bias toward underestimating the angle structure across all graders, especially at the superior angle, by approximately 1 ordinal unit. Kappa statistics showed fair-moderate agreement for exact (0.387-0.520) and binary (0.347-0.520) angle evaluations. Agreement was unchanged when using a multimodal approach (0.373-0.523). Factors driving concordance were primarily related to the extremes of the anterior chamber angle configuration (shallow or deep structures, and iris contour). However, prediction models did not fully explain the levels of concordance with the ground truth (maximum R 2 amongst models 0.177).

CONCLUSIONS

Although moderate agreement between graders and ground truth could be obtained under binary evaluations, angle grades were generally underestimated. Factors affecting concordance were primarily the extremes of the ground truth angle and iris contour.

TRANSLATIONAL RELEVANCE

We highlight factors affecting accuracy of grading goniophotography and AS-OCT images of the anterior chamber angle.

Vascular Changes in Intermediate Age-Related Macular Degeneration Quantified Using Optical Coherence Tomography Angiography

Purpose

To examine changes in retinal vasculature and ganglion cell layer (GCL) thickness in intermediate age-related macular degeneration (AMD) using optical coherence tomography angiography (OCTA).

Methods

Zeiss Cirrus Angioplex OCTA 6 × 6 mm scans and a macula 512 × 128 cube scans of the central retina were taken of 63 eyes with intermediate AMD and 51 control eyes. For OCTA scans, the superficial and deep capillary plexus were automatically segmented and vascular density quantified as total number of pixels contributing to the blood flow signal detectable by OCTA. Images were then skeletonized and vessel length, diameter index, morphology, and branching complexity determined. Foveal avascular zone (FAZ) characteristics and GCL thickness were extracted from in-built Angioplex software.

Results

Vascular density was significantly reduced in the superficial capillary plexus of AMD eyes compared with normal eyes, particularly in the superior quadrant (42.4% ± 1.6% vs. 43.2% ± 1.4%; P < 0.05). A nonsignificant reduction was also seen in the deep capillary plexus (P = 0.06). Total vessel length and average vessel diameter were all significantly decreased in AMD eyes suggesting density changes were related to decreased vessel number and caliber. Vascular complexity and number of branch points was significantly decreased in the deep capillary plexus (P < 0.05) suggesting loss or significantly reduced flow of vessels. Average GCL thickness was also significantly reduced in the AMD eyes (P < 0.05). No significant changes in FAZ parameters were observed in AMD eyes.

Conclusions

This study suggests intermediate AMD affects both the quantity and morphology of inner retinal vasculature and may be associated with changes in inner retinal structure. This work builds upon the notion that AMD pathogenesis may extends beyond the outer retina.

Translational Relevance

Better understanding of retinal vascular changes in AMD can provide insights in the development of treatment and prevention protocols for these diseases.

A collaborative care pathway for patients with suspected angle closure glaucoma spectrum disease

BACKGROUND

Currently, no specific collaborative care pathway exists that distinguishes open angle glaucoma from narrow angle or angle closure disease. This study evaluates a newly developed referral and collaborative care pathway specifically for patients with angle closure spectrum disease.

METHODS

The medical records of consecutive patients referred to the Centre for Eye Health for glaucoma assessment were examined, six months before (Pre Suite) and after (Post Suite) the introduction of a novel referral pathway for anterior chamber angle assessment (Angle Suite). Patient demographic and clinical data, the referral letter and practitioner characteristics were extracted.

RESULTS

Angle Suite (n = 77) patients had an appointment much sooner compared to Pre (n = 383) and Post Suite (n = 425) patients (p < 0.0001). Following the introduction of Angle Suites, there was a reduction of incidental angle closure disease found in routine, non-angle closure glaucoma assessment. Onward referral was required by 36.4 per cent of patients referred for suspected angle closure disease, while the rest could be discharged back into the community (13.0 per cent) or reviewed at the Centre for Eye Health (50.6 per cent). Multinomial logistic regression found that the presence of an angle description in the referral letter improved the true positive rate for angle closure disease (p < 0.0001).

CONCLUSIONS

The clinical pathway may reduce the number of incidental angle closure patients and improved the timeliness of appropriate clinical care delivered to a subset of patients who may benefit from prompt medical attention. This pathway provides an opportunity for appropriately staffed and equipped collaborative care clinics to reduce the burden on tertiary level ophthalmic facilities.

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.

An evidence-based approach to the routine use of optical coherence tomography

Optical coherence tomography is an imaging technology that has revolutionised the detection, assessment and management of ocular disease. It is now a mainstream technology in clinical practice and is performed by non-specialised personnel in some settings. This article provides a clinical perspective on the implications of that movement and describes best practice using multimodal imaging and an evidence-based approach. Practical, illustrative guides on the interpretation of optical coherence tomography are provided for three major diseases of the ocular fundus, in which optical coherence tomography is often crucial to management: age-related macular degeneration, diabetic retinopathy and glaucoma. Topics discussed include: cross-sectional and longitudinal signs in ocular disease, so-called 'red-green' disease whereby clinicians rely on machine/statistical comparisons for diagnosis in managing treatment-naïve patients, and the utility of optical coherence tomography angiography and machine learning.

Application of Pattern Recognition Analysis to Optimize Hemifield Asymmetry Patterns for Early Detection of Glaucoma

Purpose

To assess the diagnostic utility of a new hemifield asymmetry analysis derived using pattern recognition contrast sensitivity isocontours (CSIs) within the Humphrey Field Analyzer (HFA) 24-2 visual field (VF) test grid. The performance of an optimal CSI-derived map was compared against a commercially available clustering method (Glaucoma Hemifield Test, GHT).

Methods

Five hundred VF results of 116 healthy subjects were used to determine normative distribution limits for comparisons. Pattern recognition analysis was applied to HFA 24-2 sensitivity data to determine CSI theme maps delineating clusters for hemifield comparisons. Then, 1019 VF results from 228 glaucoma patients were assessed using different clustering methods to determine the true-positive rate. We also assessed additional 354 VF results of 145 healthy subjects to determine the false-positive rate.

Results

The optimum clustering method was the CSI-derived seven-theme class map, which identified more glaucomatous VFs compared with the GHT map. The seven-class theme map also identified more cases compared with the five-, six-, and eight-class maps, suggesting no effect of number of clusters. Integrating information regarding the location of glaucomatous defects to the CSI clusters did not improve detection rate.

Conclusions

A clustering map derived using CSIs improved detection of glaucomatous VFs compared with the currently available GHT. An optimized CSI-derived map may serve as an additional means to aid earlier detection of glaucoma.

Translational Relevance

Pattern recognition–derived theme maps provide a means for guiding test point selection for asymmetry analysis in glaucoma assessment.

Glaucoma referral refinement in Ireland: managing the sensitivity-specificity paradox in optometric practice

PURPOSE

Glaucoma referral refinement (GRR) has proven a successful demand management strategy for glaucoma suspect cases in the United Kingdom (UK). A GRR clinic was established in Dublin, Ireland to investigate the clinical viability of this pathway outside the UK's National Health Service (NHS) structures, and away from the influence of National Institute for Clinical Excellence (NICE) guidance.

METHODS

Glaucoma suspect patients were recruited into the scheme following referral from community optometrists in the greater Dublin area. The GRR exam protocol was designed in consultation with the participating ophthalmology department. The refinement scheme optometrist, trained through apprenticeship style experience at a hospital outpatient clinic, made a tentative management decision after carrying out the GRR exam. The final management decision was made in a 'virtual clinic' by a glaucoma specialist consultant ophthalmologist.

RESULTS

Two hundred and twenty-five glaucoma suspect patients were seen in the scheme. After their first GRR visit, 28% were discharged back to their own optometrist, 42% were monitored in the GRR clinic, and 30% were referred to ophthalmology. After this monitoring cohort were further assessed, a total of 38% of the patients seen within the scheme required referral to ophthalmology. Sixteen percent of the total participant group (n = 225) were lost to follow up. Cohen's κ was used to determine the level of agreement between the scheme optometrist and ophthalmologist. There was substantial agreement, with κ = 0.63 for the first visit management decisions (n = 225). Agreement increased for subsequent monitoring visits with κ = 0.85 for second visits (n = 65), and κ = 0.69 for all management decisions within the scheme (n = 301). We received management outcomes for 44 of the 86 patients referred to ophthalmology. Of these 44, 57% received medical treatment for glaucoma, 34% were monitored without treatment, 2% were discharged, and 7% had comorbidities that were assessed and managed.

CONCLUSION

Of the patients seen within the scheme, 62% did not require referral onward to ophthalmology, thus releasing the significant majority of hospital clinic slots that would previously have been required to examine such patients. The high level of inter-professional decision agreement likely reflects the benefits of pre-scheme apprenticeship style training and ongoing hospital clinic participation by the scheme optometrist. The rate of loss to follow up compares favourably with ophthalmology led, hospital based, glaucoma clinics. Nevertheless, the losses indicate that patient education remains a key priority for future planning.

Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs

SIGNIFICANCE

This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs.

PURPOSE

The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters.

METHODS

A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts.

RESULTS

A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P < .0001), and areas of rim or parapapillary elevation (P < .0001).

CONCLUSIONS

This study reports an RNFL protrusion associated with tilted optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

Diurnal Intraocular Pressure Fluctuations with Self-tonometry in Glaucoma Patients and Suspects: A Clinical Trial

SIGNIFICANCE

This article shows that self-tonometry can provide robust measures of diurnal intraocular pressure (IOP) and also detect changes to IOP in response to treatment within a short period of monitoring. These advances in IOP monitoring may contribute to improved management of glaucoma patients and suspects.

PURPOSE

The aim of this study was to prospectively investigate the utility of rebound self-tonometry performed over several weeks for detecting diurnal IOP fluctuations in glaucoma patients and suspects and also initial response to topical treatment in glaucoma patients.

METHODS

Forty patients were recruited following glaucoma-specific examination. Subsequent to successful training with the iCare HOME tonometer, patients were instructed to measure IOP, in a sitting position, four times a day over 4 to 6 weeks. Date, time, laterality, and IOP downloaded from the tonometer and clinical examination data, including applanation IOP and corneal thickness, were analyzed. A user satisfaction survey was also administered at study completion. t Test and analysis of variance were used to compare groups and IOP across days. Pearson correlation was used to compare measurements to Goldmann applanation tonometry and IOP measurements from the first day/s to the overall mean IOP.

RESULTS

Twenty-seven patients (18 suspects and 9 glaucoma patients) completed data collection. Patients self-measured IOP on 118 (±29) occasions for 40 (±7.4) days. Two dominant patterns of fluctuation were revealed: peak IOP upon awakening (n = 11) and at midday (n = 13). Diurnal IOP measured in the first 7 days showed strong correlation to diurnal IOP across the entire study period (r = 0.82, P < .0001). Within 24 hours of treatment commencement (latanoprost 0.005% ophthalmic solution), IOP reduced from 23.9 (±5.2) to 16.1 (±2.6) mmHg. Overall, patients rated the instrument as easy to use, although difficulties with correct alignment were expressed.

CONCLUSIONS

Rebound self-tonometry demonstrated utility for measuring diurnal IOP fluctuations in most patients, hence enhancing management of patient with or at risk of developing glaucoma.

The impact of optic nerve and related characteristics on disc area measurements derived from different imaging techniques

PURPOSE

Optic nerve head (ONH) assessment and its interpretation in healthy patients and those with glaucoma remains a pivotal topic specifically considering rapid advancements in imaging technologies. We undertook a large-scale, mixed cohort, comparative study to assess the correlation of optic disc measurements between different imaging modalities and investigated the impact of patient and disc associated parameters.

METHODS

ONH sizes were obtained from one randomly selected eye of each of 209 patients using stereophotography, confocal scanning laser ophthalmoscopy and two different optical coherence tomographers (OCT). Patient related data, glaucoma status and optic disc variables, specifically oblique insertion, torsion, presence of beta PPA and spherical equivalent were recorded. Measurements between imaging modalities were analysed using Pearson correlation, linear regression analysis and Blend-Altman plots. Individual variables were compared applying multivariate regression analysis, ANOVA and chi square statistics was used to determine correlations between patient and clinical characteristics.

RESULTS

Absolute measurements significantly differed between imaging modalities generally producing smaller measurements for OCT derived measurements of Bruch's membrane opening (BMO). Pairwise correlations between imaging modalities were between 0.83 and 0.93 for discs without myopia, oblique insertion, or beta PPA. These features impacted on measurements for individual modalities and consequently contributed to inconsistencies and variability.

CONCLUSION

In comparison to planimetry, OCT derived BMO measurements are more variable in the presence of oblique insertion, beta PPA or magnification errors due to myopia. Impact of these factors, however, differs between instruments and needs to be considered to accurately interpret optic disc features in particular within the context of glaucoma diagnosis.

The advantages of intermediate-tier, inter-optometric referral of low risk pigmented lesions

Purpose

Pigmented ocular lesions are commonly encountered by eye‐care professionals, and range from benign to sight or life‐threatening. After identifying a lesion, the primary care professional must establish the likely diagnosis and decide either to reassure, to monitor or to refer. The increasing use of ocular imaging technologies has contributed to an increase in the detection rate of pigmented lesions and a higher number of referrals, which may challenge existing pathways of health‐care delivery. Specialist services may be over‐burdened by referring all patients with pigmented lesions for an opinion, while inter‐optometric referrals are underutilised. The aim of this study was to describe the referral patterns of pigmented lesions to an optometry led intermediate‐tier collaborative care clinic.

Methods

We performed a retrospective review of patient records using the list of patients examined at Centre for Eye Health (CFEH) for an initial or follow up pigmented lesion assessment between the 1/7/2013 and the 30/6/2016. Analysis was performed on: patient demographic characteristics, the referrer's tentative diagnosis, CFEH diagnosis and recommended management plan.

Results

Across 182 patient records, the primary lesion prompting referral was usually located in the posterior segment: choroidal naevus (105/182, 58%), congenital hypertrophy of the retinal pigment epithelium (CHRPE; 11/182, 6%), chorioretinal scarring (10/182, 5%) or not specified (52/182, 29%). Referrals described a specific request for ocular imaging in 25 instances (14%). The number of cases with a non‐specific diagnosis was reduced after intermediate‐tier care assessment (from 29% to 10%), while the number of diagnoses with less common conditions rose (from 2% to 21%). There was a 2% false positive referral rate to intermediate‐tier care and a first visit discharge rate of 35%. A minority required on‐referral to an ophthalmologist (22/182, 12%), either for unrelated incidental ocular findings, or suspicious choroidal naevi. Conditions most amenable to optometric follow up included: 1) chorioretinal scarring, 2) choroidal naevus, and 3) CHRPE.

Conclusions

Intermediate‐tier optometric eye‐care in pigmented lesions (following opportunistic primary care screening) has the potential to reduce the number of cases with non‐specific diagnoses and to increase those with less common diagnoses. The majority of cases seen under this intermediate‐tier model required only ongoing optometric surveillance.

Pattern Recognition Analysis of Age-Related Retinal Ganglion Cell Signatures in the Human Eye

Purpose

To characterize macular ganglion cell layer (GCL) changes with age and provide a framework to assess changes in ocular disease. This study used data clustering to analyze macular GCL patterns from optical coherence tomography (OCT) in a large cohort of subjects without ocular disease.

Methods

Single eyes of 201 patients evaluated at the Centre for Eye Health (Sydney, Australia) were retrospectively enrolled (age range, 20–85); 8 × 8 grid locations obtained from Spectralis OCT macular scans were analyzed with unsupervised classification into statistically separable classes sharing common GCL thickness and change with age. The resulting classes and gridwise data were fitted with linear and segmented linear regression curves. Additionally, normalized data were analyzed to determine regression as a percentage. Accuracy of each model was examined through comparison of predicted 50-year-old equivalent macular GCL thickness for the entire cohort to a true 50-year-old reference cohort.

Results

Pattern recognition clustered GCL thickness across the macula into five to eight spatially concentric classes. F-test demonstrated segmented linear regression to be the most appropriate model for macular GCL change. The pattern recognition–derived and normalized model revealed less difference between the predicted macular GCL thickness and the reference cohort (average ± SD 0.19 ± 0.92 and −0.30 ± 0.61 μm) than a gridwise model (average ± SD 0.62 ± 1.43 μm).

Conclusions

Pattern recognition successfully identified statistically separable macular areas that undergo a segmented linear reduction with age. This regression model better predicted macular GCL thickness. The various unique spatial patterns revealed by pattern recognition combined with core GCL thickness data provide a framework to analyze GCL loss in ocular disease.

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.

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives

White‐on‐white standard automated perimetry (SAP) is widely used in clinical and research settings for assessment of contrast sensitivity using incremental light stimuli across the visual field. It is one of the main functional measures of the effect of disease upon the visual system. SAP has evolved over the last 40 years to become an indispensable tool for comprehensive assessment of visual function. In modern clinical practice, a range of objective measurements of ocular structure, such as optical coherence tomography, have also become invaluable additions to the arsenal of the ophthalmic examination. Although structure‐function correlation is a highly desirable determinant of an unambiguous clinical picture for a patient, in practice, clinicians are often faced with discordance of structural and functional results, which presents them with a challenge. The construction principles behind the development of SAP are used to discuss the interpretation of visual fields, as well as the problem of structure‐function discordance. Through illustrative clinical examples, we provide useful insights to assist clinicians in combining a range of clinical results obtained from SAP and from advanced imaging techniques into a coherent picture that can help direct clinical management.

Reconciling visual field defects and retinal nerve fibre layer asymmetric patterns in retrograde degeneration: an extended case series

BACKGROUND

Accurate diagnosis in patients presenting with lesions at various locations within the visual pathway is challenging. This study investigated functional and structural changes secondary to such lesions to identify patterns useful to guide early and effective management.

METHODS

Over 10,000 records from patients referred for optic nerve head assessment were reviewed and 31 patients with a final diagnosis of likely neuropathic lesions posterior to the eye were included in the current study. Fundus photographs, optic coherence tomography images and visual field tests were evaluated for changes with respect to retinal nerve fibre layer topography and prediction of structure-function paradigms. Emerging clinical patterns were examined for their consistency with the likely anatomical origin of the underlying insult in the presence of varying diagnoses.

RESULTS

Data from patients with lesions along the visual system allowed identification of retinal nerve fibre layer asymmetry correlated with visual field defects and ganglion cell analysis. Bilateral discordance in retinal nerve fibre loss easily discernible from an altered pattern of the temporal-superior-nasal-inferior-temporal curve was characteristic for post-chiasmal lesions. These sometimes-subtle changes supported diagnosis in cases with multiple aetiologies or with ambiguous visual field analysis and/or ganglion cell loss.

CONCLUSION

Intricate knowledge of the retinal architecture and projections allows coherent predictions of functional and structural deficits following various lesions affecting the visual pathway. The integration of adjunct imaging and retinal nerve fibre layer thinning will assist clinicians to guide clinical investigations toward a likely diagnosis in the light of significant individual variations. The case series presented in this study aids in differential diagnosis of retrograde optic neuropathies by using retinal nerve fibre layer asymmetric patterns as an important clinical marker.

A comparison of Goldmann III, V and spatially equated test stimuli in visual field testing: the importance of complete and partial spatial summation

PURPOSE

Goldmann size V (GV) test stimuli are less variable with a greater dynamic range and have been proposed for measuring contrast sensitivity instead of size III (GIII). Since GIII and GV operate within partial summation, we hypothesise that actual GV (aGV) thresholds could predict GIII (pGIII) thresholds, facilitating comparisons between actual GIII (aGIII) thresholds with pGIII thresholds derived from smaller GV variances. We test the suitability of GV for detecting visual field (VF) loss in patients with early glaucoma, and examine eccentricity-dependent effects of number and depth of defects. We also hypothesise that stimuli operating within complete spatial summation ('spatially equated stimuli') would detect more and deeper defects.

METHODS

Sixty normal subjects and 20 glaucoma patients underwent VF testing on the Humphrey Field Analyzer using GI-V sized stimuli on the 30-2 test grid in full threshold mode. Point-wise partial summation slope values were generated from GI-V thresholds, and we subsequently derived pGIII thresholds using aGV. Difference plots between actual GIII (aGIII) and pGIII thresholds were used to compare the amount of discordance. In glaucoma patients, the number of 'events' (points below the 95% lower limit of normal), defect depth and global indices were compared between stimuli.

RESULTS

90.5% of pGIII and aGIII points were within ±3 dB of each other in normal subjects. In the glaucoma cohort, there was less concordance (63.2% within ±3 dB), decreasing with increasing eccentricity. GIII found more defects compared to GV-derived thresholds, but only at outermost test locations. Greater defect depth was found using aGIII compared to aGV and pGIII, which increased with eccentricity. Global indices revealed more severe loss when using GIII compared to GV. Spatially equated stimuli detected the greatest number of 'events' and largest defect depth.

CONCLUSIONS

Whilst GV may be used to reliably predict GIII values in normal subjects, there was less concordance in glaucoma patients. Similarities in 'event' detection and defect depth in the central VF were consistent with the fact that GIII and GV operate within partial summation in this region. Eccentricity-dependent effects in 'events' and defect depth were congruent with changes in spatial summation across the VF and the increase in critical area with disease. The spatially equated test stimuli showed the greatest number of defective locations and larger sensitivity loss.

Equating spatial summation in visual field testing reveals greater loss in optic nerve disease

PURPOSE

To test the hypothesis that visual field assessment in ocular disease measured with target stimuli within or close to complete spatial summation results in larger threshold elevation compared to when measured with the standard Goldmann III target size. The hypothesis predicts a greater loss will be identified in ocular disease. Additionally, we sought to develop a theoretical framework that would allow comparisons of thresholds with disease progression when using different Goldmann targets.

METHODS

The Humphrey Field Analyser (HFA) 30-2 grid was used in 13 patients with early/established optic nerve disease using the current Goldmann III target size or a combination of the three smallest stimuli (target size I, II and III). We used data from control subjects at each of the visual field locations for the different target sizes to establish the number of failed points (events) for the patients with optic nerve disease, as well as global indices for mean deviation (MD) and pattern standard deviation (PSD).

RESULTS

The 30-2 visual field testing using alternate target size stimuli showed that all 13 patients displayed more defects (events) compared to the standard Goldmann III target size. The median increase for events was seven additional failed points: (range 1-26). The global indices also increased when the new testing approach was used (MD -3.47 to -6.25 dB and PSD 4.32 to 6.63 dB). Spatial summation mapping showed an increase in critical area (Ac) in disease and overall increase in thresholds when smaller target stimuli were used.

CONCLUSIONS

When compared to the current Goldmann III paradigm, the use of alternate sized targets within the 30-2 testing protocol revealed a greater loss in patients with optic nerve disease for both event analysis and global indices (MD and PSD). We therefore provide evidence in a clinical setting that target size is important in visual field testing.