The burden of acute eye conditions on different healthcare providers: a retrospective population-based study.

BACKGROUND: The demand for acute eyecare exponentially outstrips capacity. The public lacks awareness of community eyecare services. AIM: To quantify the burden of acute eyecare on different healthcare service providers in a national population through prescribing and medicines provision by GPs, optometrists, and pharmacists, and provision of care by accident and emergency (A&E) services. A secondary aim was to characterise some of the drivers of this burden. DESIGN AND SETTING: A retrospective data-linkage study set in Wales, UK. METHOD: Analysis of datasets was undertaken from the Secure Anonymised Information Linkage Databank (GP and A&E), the Eye Health Examination Wales service (optometry), and the Common Ailments Scheme (pharmacy) during 2017-2018. RESULTS: A total of 173 999 acute eyecare episodes delivered by GPs (168 877 episodes) and A&E services (5122) were identified during the study. This resulted in 65.4 episodes of care per 1000 people per year. GPs prescribed a total of 87 973 653 prescriptions within the general population. Of these, 820 693 were related to acute eyecare, resulting in a prescribing rate of 0.9%. A total of 5122 eye-related and 905 224 general A&E attendances were identified, respectively, resulting in an A&E attendance rate of 0.6%. Optometrists and pharmacists managed 51.8% (116 868) and 0.6% (2635) of all episodes, respectively. Older females and infants of both sexes were more likely to use GP prescribing services, while adolescent and middle-aged males were more likely to visit A&E. GP prescribing burden was driven partially by economic deprivation, access to services, and health score. Season, day of the week, and time of day were predictors of burden in GP and A&E. CONCLUSION: Acute eyecare continues to place considerable burden on GP and A&E services in Wales, particularly in urban areas with greater economic deprivation and lower overall health. This is likely to increase with a rapidly ageing population. With ongoing pathway development to better utilise optometry and pharmacy, and improved public awareness, there may be scope to change this trajectory.

Reliability of gaze-contingent perimetry.

Standard automated perimetry, a psychophysical task performed routinely in eyecare clinics, requires observers to maintain fixation for several minutes at a time in order to measure visual field sensitivity. Detection of visual field damage is confounded by eye movements, making the technique unreliable in poorly attentive individuals and those with pathologically unstable fixation, such as nystagmus. Microperimetry, which utilizes 'partial gaze-contingency' (PGC), aims to counteract eye movements but only corrects for gaze position errors prior to each stimulus onset. Here, we present a novel method of visual field examination in which stimulus position is updated during presentation, which we refer to as 'continuous gaze-contingency' (CGC). In the first part of this study, we present three case examples that demonstrate the ability of CGC to measure the edges of the physiological blind spot in infantile nystagmus with greater accuracy than PGC and standard 'no gaze-contingency' (NoGC), as initial proof-of-concept for the utility of the paradigm in measurements of absolute scotomas in these individuals. The second part of this study focused on healthy observers, in which we demonstrate that CGC has the lowest stimulus positional error (gaze-contingent precision: CGC = ± 0.29°, PGC = ± 0.54°, NoGC = ± 0.81°). CGC test-retest variability was shown to be at least as good as both PGC and NoGC. Overall, CGC is supported as a reliable method of visual field examination in healthy observers. Preliminary findings demonstrate the spatially accurate estimation of visual field thresholds related to retinal structure using CGC in individuals with infantile nystagmus.

Pain related to intravitreal injections for age-related macular degeneration: a qualitative study of the perspectives of patients and practitioners.

OBJECTIVES: Ocular pain is a commonly reported finding in the intravitreal injection procedure, but post-injection experiences and patient adherence to treatment remain underexplored. We therefore aimed to identify key variations in the intravitreal injection procedure that may influence pain, and to gain insights into the post-injection experience and treatment adherence from the perspective of patients and practitioners. DESIGN: Qualitative semistructured interview study using reflexive thematic analysis of transcripts. SETTING: Hospital Eye Clinic in Wales, UK. Interviews were conducted between May and September 2019. PARTICIPANTS: Purposive sample of patients aged ≥50 years with neovascular age-related macular degeneration and no other retinal pathology who had received at least six intravitreal injections, and practitioners including ophthalmologists, registered nurses and optometrists who performed intravitreal injections at the research site. RESULTS: Data saturation was reached with 21 interviews: 14 patients and 7 practitioners. Three main themes were identified from the analysis: fear of losing eyesight and treatment anxiety influence patient adherence to treatment, variability in pain experience during treatment, and post-injection experience and impact on patient recovery. To reassure patients feeling apprehensive about the injections, practitioners promoted safety and trust, and used techniques to manage anxiety. Key variations that may influence pain identified were application of antiseptic or anaesthetic, injecting methods and communication. During injection, patients reported a dull-aching and sharp pain, contrary to practitioners' perspective of feeling a 'pressure'. Patients described prolonged soreness and irritation of up to 36 hours post-injection affecting their sleep and recovery. CONCLUSION: Establishing rapport supported patients to recognise the necessity of ongoing treatment to prevent sight loss; however, inadequate pain management led to undesirable outcomes. Practitioners should use pain assessment tools during and immediately after injection and provide ongoing consistent information to help patients manage pain at home.

An operations research approach to automated patient scheduling for eye care using a multi-criteria decision support tool.

Inefficient management of resources and waiting lists for high-risk ophthalmology patients can contribute to sight loss. The aim was to develop a decision support tool which determines an optimal patient schedule for ophthalmology patients. Our approach considers available booking slots as well as patient-specific factors. Using standard software (Microsoft Excel and OpenSolver), an operations research approach was used to formulate a mathematical model. Given a set of patients and clinic capacities, the model objective was to schedule patients efficiently depending on eyecare measure risk factors, referral-to-treatment times and targets, patient locations and slot availabilities over a pre-defined planning horizon. Our decision support tool can feedback whether or not a patient is scheduled. If a patient is scheduled, the tool determines the optimal date and location to book the patients' appointments, with a score provided to show the associated value of the decisions made. Our dataset from 519 patients showed optimal prioritization based on location, risk of serious vision loss/damage and the referral-to-treatment time. Given the constraints of available slots, managers can input hospital-specific parameters such as demand and capacity into our model. The model can be applied and implemented immediately, without the need for additional software, to generate an optimized patient schedule.

Factors influencing the prescribing behaviour of independent prescriber optometrists: a qualitative study using the Theoretical Domains Framework.

PURPOSE: Whilst the number of independent prescriber (IP) optometrists in the United Kingdom is increasing, there is limited evidence describing the experiences of these individuals. The Theoretical Domains Framework (TDF) provides an evidence-based approach to understand determinants of behaviour. This conceptual framework can enable mapping to the COM-B behaviour change model and the wider Behaviour Change Wheel to develop interventions to optimise behaviour-change and healthcare processes more systematically. The study aimed to use the TDF to identify the factors that influence independent prescribing behaviour, and to map these findings to the COM-B system to elucidate the relevant intervention functions, in order to identify the support required by optometrist prescribers. METHODS: Using a qualitative design, semi-structured interviews based on the TDF were undertaken with independent prescriber optometrists. Thematic analysis was used to identify themes inductively, which were then deductively mapped to the TDF and linked to the COM-B. RESULTS: Sixteen participants (9 male, 7 female; median age 45 years, range 28-65 years), based in community (n = 10) and hospital (n = 6) settings, were interviewed. Eleven of the TDF domains were found to influence prescribing behaviour. Findings highlighted the need for good communication with patients (TDF domain: Skills, COM-B: Capability); confidence (TDF domain: Beliefs about capabilities, COM-B: Motivation); good networks and relationships with other healthcare professionals, e.g., general practitioners (TDF domain: Social influences, COM-B: Opportunity; TDF domain: Social/professional role and identity, COM-B: Motivation); the need for appropriate structure for remuneration (TDF domain: Reinforcement, COM-B: Motivation; TDF domain: Social/professional role and identity, COM-B: Motivation) and the provision of professional guidelines (TDF domain: Knowledge, COM-B: Capability; TDF domain: Environmental context and resources, COM-B Opportunity). CONCLUSIONS: Having identified theory-derived influencers on prescribing decisions by optometrists, the findings can be used to develop a structured intervention, such as a support package to help optimise prescribing by optometrists, with the ultimate goal of eye care quality improvement.

Training results in increased practitioner confidence and identification of depression in people with low vision: a mixed methods study.

PURPOSE: The prevalence of depression in people with low vision is high and often goes undiagnosed. There is the potential for those who provide low vision services to perform concurrent depression screening. However, prior training in depression identification and suitable referral pathways is required. The aims of this study were: (1) to assess the impact of a training programme on practitioners' confidence and behaviour in addressing depression in patients with low vision, and (2) to review the training programme and identify areas for further development. METHODS: A convergent mixed methods approach was used. Questionnaires were completed by practitioners pre-, immediately post- and 6 months post- training (n = 40) to assess practitioner confidence in approaching depression in patients with low vision. Qualitative interviews were performed with a subset of practitioners 6 months post-training (n = 9). Additionally, routine data from the Low Vision Service Wales (LVSW) database was used to determine the change in the number of practitioners identifying depression in patients, and the change in the number of patients identified at risk of depression 6 months post-training. RESULTS: Of the 148 practitioners who completed low vision assessments pre- and post-training, 28 (18.9%) documented risk of depression in their patients pre-training, which increased substantially to 65 (43.9%) post-training (p < 0.0001). Mixed methods analysis confirmed increased documentation of depressive symptoms by practitioners. Practitioner confidence increased following training, with 92.3% feeling more confident to approach emotional issues with patients and 92.2% intending to use the recommended screening tool to identify depression. Interviews provided insight into areas where confidence was still lacking. Quantitative questionnaires revealed that training content was considered appropriate by 91% of participants. Interviews confirmed these findings while expanding upon possibilities for programme improvement. CONCLUSIONS: Training for depression screening was found to be time-efficient and acceptable for LVSW practitioners and shown to increase practitioner confidence in the identification of depression. Additionally, the programme changed behaviour, resulting in an increase in the identification of depression in patients with low vision. However, this is a complex topic and ongoing development is required to embed depression screening as an integral part of low vision services.

Agreement between ophthalmologists and optometrists in the certification of vision impairment.

BACKGROUND/OBJECTIVES: The certification process to register patients as sight impaired or severely sight impaired is undertaken by consultant ophthalmologists, in the UK. We sought to assess the agreement between optometrists and a consensus panel, in identifying patient eligibility for certification, relative to the agreement between ophthalmologists and the consensus panel. METHODS: The consensus panel (4 consultant ophthalmologists and 3 optometrists with a formal accreditation in low vision), 30 consultant ophthalmologists and 99 low vision optometrists reviewed 40 randomly selected abridged cases. The eligibility outcomes from the ophthalmologists and the optometrists were compared with the consensus panel outcomes. RESULTS: For ophthalmologists and optometrists, the median (IQR) number of cases in which there was agreement with the consensus panel was 33.0 (31.0, 33.0) and 36.0 (34.0, 36.5), respectively. In severely sight impaired cases, the probabilities of agreeing on eligibility for certification were 76.0% (95% CIs 71.4%, 80.1%) for ophthalmologists and 61.8% (59.0%, 64.6%) for optometrists. In sight impaired cases, the corresponding values were 51.6% (46.7%, 56.4%) for ophthalmologists and 72.2% (69.8%, 74.5%) for optometrists. In cases of bilateral atrophic age-related macular degeneration (AMD), both groups were more likely to agree with the consensus panel and the differences between optometrists and ophthalmologists were less marked. CONCLUSIONS: Optometrists demonstrated a comparable agreement relative to ophthalmologists, with the consensus panel on the eligibility of randomly selected, abridged cases for certification. The findings support the clinical decision-making ability of low vision optometrists in the certification of patients with vision impairment and provide evidence in support of policy change to allow low vision optometrists to certify individuals with atrophic AMD.

Barriers to integrating routine depression screening into community low vision rehabilitation services: a mixed methods study.

BACKGROUND: Undetected depression is common in people with low vision and depression screening has been recommended. However, depression screening is a complex procedure for which low vision practitioners need training. This study examined the integration of routine depression screening, using two questions, and referral pathways into a national low vision service in Wales at 6 months following practitioner training, and identified key barriers to implementation. METHODS: This pre-post single group study employed a convergent mixed methods design to collect quantitative questionnaire and qualitative interview data on low vision practitioners' clinical practice and perceived barriers to implementing depression screening. Forty practitioners completed questionnaires pre-, immediately post- and 6 months post-training and nine engaged in interviews 6 months post-training. Ordinal questionnaire scores were Rasch-transformed into interval-level data before linear regression analyses were performed to determine the change in scores over time and the association between perceived barriers and clinical practice. Thematic Analysis was applied to the interviews and the narrative results merged with the questionnaire findings. RESULTS: Before training, only one third of practitioners (n = 15) identified depression in low vision patients, increasing to over 90% (n = 37) at 6 months post-training, with a corresponding increase in those using validated depression screening questions from 10% (n = 4) to 80% (n = 32). Six months post-training, practitioners reported taking significantly more action in response to suspected depression (difference in means = 2.77, 95% CI 1.93 to 3.61, p < 0.001) and perceived less barriers to addressing depression (difference in means = - 0.95, 95% CI - 1.32 to - 0.59, p < 0.001). However, the screening questions were not used consistently. Some barriers to implementation remained, including perceived patient reluctance to discuss depression, time constraints and lack of confidence in addressing depression. CONCLUSIONS: The introduction of depression screening service guidelines and training successfully increased the number of low vision practitioners identifying and addressing depression. However, standardized screening of all low vision attendees has not yet been achieved and several barriers remain. Healthcare services need to address these barriers when considering mental health screening, and further research could focus on the process from the patients' perspective, to determine the desire for and acceptability of screening.

Microperimetry in Age-Related Macular Degeneration: An Evidence-Base for Pattern Deviation Probability Analysis in Microperimetry.

PURPOSE: The "traffic light" color designation of differential light sensitivity used in a number of microperimeters does not encompass the conventional Total and Pattern Deviation probability analyses adopted by standard automated perimetry. We determined whether the color designation is indicative of abnormality as represented by the "gold standard" Pattern Deviation probability analysis. METHODS: Total and Pattern Deviation probability levels, using two different methods, were derived at each of 40 stimulus locations, within 7° eccentricity, from 66 ocular healthy individuals (66 eyes) who had undergone microperimetry with the Macular Integrity Assessment microperimeter. The probability levels were applied to the corresponding fields from each of 45 individuals (45 eyes) with age-related macular degeneration (AMD) and evaluated in relation to the color designation. RESULTS: Sensitivities designated in orange encompassed the entire range of Pattern Deviation probability levels (from normal to P ≤ 1%). Those designated in green were mostly normal; those in red/black generally corresponded to the ≤1% probability level. CONCLUSIONS: The green and the red/black designations are generally indicative of normal and abnormal probability values, respectively. The orange designation encompassed all probability outcomes and should not be relied upon for visual field interpretation. The evidence base indicates replacement of the color designation of sensitivity in AMD by Total Deviation and Pattern Deviation analyses. TRANSLATIONAL RELEVANCE: The use of Total and Pattern Deviation probability analyses is not universal in all microperimeters, and the derivation of these values indicates that color coding will lead to errors in evaluating visual field loss.

How do community-based eye care practitioners approach depression in patients with low vision? A mixed methods study.

BACKGROUND: Clinically significant depressive symptoms are prevalent in people attending low vision clinics and often go undetected. The Low Vision Service Wales (LVSW) plans to introduce depression screening and management pathways. Prior to implementation there is an unmet need to understand how eye care practitioners providing the service currently address depression with patients, and the characteristics and beliefs that influence their practice. METHODS: A mixed methods convergent design was employed. Twelve low vision practitioners were purposively selected to engage in individual semi-structured interviews which were analysed using thematic analysis. A further 167 practitioners were invited to complete a questionnaire assessing professional background, current practice, confidence and perceived barriers in working with people with low vision and suspected depression. Multiple regression analyses were performed to determine the characteristics related to the Rasch-transformed questionnaire scores. RESULTS: Of the 122 practitioners that responded to the questionnaire, 33% aimed to identify depression in patients, and those who were more confident were more likely to do so. Those who scored higher on the perceived barriers scale and lower on confidence were less likely to report acting in response to suspected depression (all p < 0.05). Three qualitative themes were identified; depression is an understandable response to low vision, patients themselves are a barrier to addressing depression and practitioners lacked confidence in their knowledge and skills to address depression. The qualitative data largely expanded the quantitative findings. CONCLUSIONS: Practitioners viewed their own lack of knowledge and confidence as a barrier to the identification and management of depression and expressed a need for training prior to the implementation of service changes. The study findings will help to inform the development of a training programme to support low vision practitioners and those working with other chronic illness in Wales, and internationally, in the identification and management of people with depression.

Microperimetry and multimodal imaging in polypoidal choroidal vasculopathy.

Polypoidal choroidal vasculopathy (PCV) is a degenerative macular disease. The study determined the topographical concordance in the areal extent of PCV, defined by indocyanine green angiography (ICGA), and the corresponding outcomes from spectral-domain optical coherence tomography (SD-OCT) and microperimetry, in 25 individuals (25 eyes) who had undergone 3 months of anti-vascular endothelial growth factor treatment. The differential light sensitivity within 10° eccentricity was evaluated by Pattern Deviation probability analysis. The concordances and proportional areal extents of the abnormality for ICGA, SD-OCT and microperimetry were compared. The concordance in the areal extent between all three modalities was 59%. The median concordance between ICGA and microperimetry was 60%; between ICGA and SD-OCT, 70%; and between SD-OCT and microperimetry, 72%. SD-OCT and microperimetry each identified a greater areal extent (>20%) compared to ICGA in 13 and 19 eyes, respectively. A greater areal extent (>20%) was present in 9 eyes for microperimetry compared to SD-OCT and in 5 eyes for SD-OCT compared to microperimetry. SD-OCT and microperimetry each identified a greater area of abnormality than ICGA which supports the clinical utility of SD-OCT. Strong concordance was present between SD-OCT and microperimetry; however, microperimetry identified additional areas of functional abnormality.

The use of microperimetry in assessing visual function in age-related macular degeneration.

Microperimetry is a novel technique for assessing visual function that appears particularly suitable for age-related macular degeneration (AMD). Compared with standard automated perimetry, microperimetry offers several unique features. It simultaneously images the fundus, incorporates an eye-tracking system to correct the stimulus location for fixation loss, and identifies any preferred retinal loci. We identified 52 articles that met the inclusion criteria for a systematic review of microperimetry in the assessment of visual function in AMD. We discuss microperimetry and AMD in relation to disease severity, structural imaging outcomes, other measures of visual function, and evaluation of the efficacy of surgical and/or medical therapies in clinical trials. The evidence for the use of microperimetry in the functional assessment of AMD is encouraging. Disruptions of the ellipsoid zone band and retinal pigment epithelium are clearly associated with reduced differential light sensitivity despite the maintenance of good visual acuity. Reduced differential light sensitivity is also associated with outer segment thinning and retinal pigment epithelium thickening in early AMD and with both a thickening and a thinning of the whole retina in choroidal neovascularization. Microperimetry, however, lacks the robust diffuse and focal loss age-corrected probability analyses associated with standard automated perimetry, and the technique is currently limited by this omission.

Effect of a Home Visit-Based Low Vision Rehabilitation Intervention on Visual Function Outcomes: An Exploratory Randomized Controlled Trial.

Purpose: To examine the effect of a home visit-based visual rehabilitation intervention on: (1) self-reported visual function and (2) depression, wellbeing, loneliness, adjustment to visual loss, and generic health-related quality of life. Methods: In an exploratory, assessor-masked, individually randomized, single-center controlled trial, 67 participants (age: 75.22 ± 16.21 years) with low vision were allocated either to receive the home visit-based visual rehabilitation intervention (n = 35) or to a waiting list control arm (n = 32). Outcome measures were collected by telephone interview at baseline and 6 months later. The primary outcome measure was the 48-item Veterans Affairs Low Vision Visual Functioning Questionnaire (VA LV VFQ-48). Secondary outcome measures were: the Patient Health Questionnaire; the Warwick-Edinburgh Mental Well-being Scale, the Adjustment to Age-related Visual Loss Scale, the standardized health-related quality of life questionnaire, and the University of California, Los Angeles Loneliness Scale. Questionnaire scores at follow-up were analyzed using analysis of covariance, controlling for the baseline score and the variables, age, number of comorbidities, visual acuity, and baseline wellbeing score. Results: Visual function (VA LV VFQ-48) improved at follow-up in both groups, with a significantly greater improvement demonstrated by the intervention group (95% confidence interval, 0.33-0.68 logits, P = 0.031), with a moderate effect size (0.55). Secondary outcomes did not indicate any statistically significant differences between groups. Conclusions: The study provides preliminary evidence that a home visit-based visual rehabilitation intervention has a positive influence on vision-related functional outcomes. A larger trial with an expanded intervention to include a mental health component and cost-effectiveness analysis is needed. (ISRCTN.com number, 44807874.).

Automated Retinal Layer Segmentation Using Spectral Domain Optical Coherence Tomography: Evaluation of Inter-Session Repeatability and Agreement between Devices.

Retinal and intra-retinal layer thicknesses are routinely generated from optical coherence tomography (OCT) images, but on-board software capabilities and image scaling assumptions are not consistent across devices. This study evaluates the device-independent Iowa Reference Algorithms (Iowa Institute for Biomedical Imaging) for automated intra-retinal layer segmentation and image scaling for three OCT systems. Healthy participants (n = 25) underwent macular volume scans using a Cirrus HD-OCT (Zeiss), 3D-OCT 1000 (Topcon), and a non-commercial long-wavelength (1040nm) OCT on two occasions. Mean thickness of 10 intra-retinal layers was measured in three ETDRS subfields (fovea, inner ring and outer ring) using the Iowa Reference Algorithms. Where available, total retinal thicknesses were measured using on-board software. Measured axial eye length (AEL)-dependent scaling was used throughout, with a comparison made to the system-specific fixed-AEL scaling. Inter-session repeatability and agreement between OCT systems and segmentation methods was assessed. Inter-session coefficient of repeatability (CoR) for the foveal subfield total retinal thickness was 3.43µm, 4.76µm, and 5.98µm for the Zeiss, Topcon, and long-wavelength images respectively. For the commercial software, CoR was 4.63µm (Zeiss) and 7.63µm (Topcon). The Iowa Reference Algorithms demonstrated higher repeatability than the on-board software and, in addition, reliably segmented all 10 intra-retinal layers. With fixed-AEL scaling, the algorithm produced significantly different thickness values for the three OCT devices (P<0.05), with these discrepancies generally characterized by an overall offset (bias) and correlations with axial eye length for the foveal subfield and outer ring (P<0.05). This correlation was reduced to an insignificant level in all cases when AEL-dependent scaling was used. Overall, the Iowa Reference Algorithms are viable for clinical and research use in healthy eyes imaged with these devices, however ocular biometry is required for accurate quantification of OCT images.

Effect of rehabilitation worker input on visual function outcomes in individuals with low vision: study protocol for a randomised controlled trial.

BACKGROUND: Visual Rehabilitation Officers help people with a visual impairment maintain their independence. This intervention adopts a flexible, goal-centred approach, which may include training in mobility, use of optical and non-optical aids, and performance of activities of daily living. Although Visual Rehabilitation Officers are an integral part of the low vision service in the United Kingdom, evidence that they are effective is lacking. The purpose of this exploratory trial is to estimate the impact of a Visual Rehabilitation Officer on self-reported visual function, psychosocial and quality-of-life outcomes in individuals with low vision. METHODS/DESIGN: In this exploratory, assessor-masked, parallel group, randomised controlled trial, participants will be allocated either to receive home visits from a Visual Rehabilitation Officer (n = 30) or to a waiting list control group (n = 30) in a 1:1 ratio. Adult volunteers with a visual impairment, who have been identified as needing rehabilitation officer input by a social worker, will take part. Those with an urgent need for a Visual Rehabilitation Officer or who have a cognitive impairment will be excluded. The primary outcome measure will be self-reported visual function (48-item Veterans Affairs Low Vision Visual Functioning Questionnaire). Secondary outcome measures will include psychological and quality-of-life metrics: the Patient Health Questionnaire (PHQ-9), the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), the Adjustment to Age-related Visual Loss Scale (AVL-12), the Standardised Health-related Quality of Life Questionnaire (EQ-5D) and the UCLA Loneliness Scale. The interviewer collecting the outcomes will be masked to the group allocations. The analysis will be undertaken on a complete case and intention-to-treat basis. Analysis of covariance (ANCOVA) will be applied to follow-up questionnaire scores, with the baseline score as a covariate. DISCUSSION: This trial is expected to provide robust effect size estimates of the intervention effect. The data will be used to design a large-scale randomised controlled trial to evaluate fully the Visual Rehabilitation Officer intervention. A rigorous evaluation of Rehabilitation Officer input is vital to direct a future low vision rehabilitation strategy and to help direct government resources. TRIAL REGISTRATION: The trial was registered with ( ISRCTN44807874 ) on 9 March 2015.

Fundus-driven perimetry (microperimetry) compared to conventional static automated perimetry: similarities, differences, and clinical applications.

Fundus-driven perimetry, commonly known as microperimetry, is a technique for measuring visual field sensitivity, whilst simultaneously viewing the fundus. In this article, we review the technique, focusing on the MP-1 microperimeter (Nidek Instruments, Inc, Padua, Italy); we compare it with conventional static automated perimetry, emphasizing the importance of understanding the effects of the different stimulus conditions and data analyses on the interpretation of microperimetry data. The clinical applications of the technique, in the evaluation of functional and structural changes that accompany retinal diseases, are illustrated by its use in patients with age-related macular degeneration, Stargardt disease, and retinitis pigmentosa. In addition, the advantages and limitations of the technique are summarized.

Evaluation of multimodal imaging in carriers of X-linked retinitis pigmentosa.

The aim of this study was to investigate visualization of the tapetal-like reflex using current imaging modalities and evaluate SD-OCT changes in known carriers of X-linked retinitis pigmentosa (XLRP); the objective being the development of an optimal protocol for clinicians to identify carriers. Ten XLRP carriers (19 eyes) were examined using color fundus photography, 488 nm reflectance (488-R), near-infrared reflectance (NIR-R), autofluorescence (AF) and spectral domain optical coherence tomography (SD-OCT) imaging (Spectralis SLO-OCT, Heidelberg). Horizontal line scans through the fovea were acquired in all subjects and in a group of 10 age-similar controls. Peripheral SD-OCT scans (extending to 27.5° eccentricity) were also acquired in both eyes of 7 carriers. MP-1 microperimetery (10-2 pattern; Nidek) was performed in one eye of each carrier. For the XLRP carriers, a tapetal reflex was observed with all imaging modalities in 8 of 19 eyes. It had the same retinal location on color fundus, 488-R and NIR-R imaging but a different location on AF. The tapetal reflex was most easily detected in 488-R images. The horizontal foveal SD-OCT scans were qualitatively normal, but measurements showed significant outer retinal layer thinning in all eyes. Additionally, the 14 eyes with peripheral SD-OCTs demonstrated patchy loss of the inner segment ellipsoid band. Microperimetry exhibited patchy visual sensitivity loss in 9 eyes. Full field ERGs were variable, ranging from normal to severely abnormal rod and cone responses. Our findings suggest that an optimal protocol for identifying carriers of XLRP should include 488-R imaging in a multimodal approach. Peripheral SD-OCT imaging and central retinal layer quantification revealed significant structural abnormalities.

Relationship between retinal layer thickness and the visual field in early age-related macular degeneration.

PURPOSE: To quantify and compare the structural and functional changes in subjects with early age-related macular degeneration (AMD), using spectral-domain optical coherence tomography (SD-OCT) and microperimetry. METHODS: Twenty-one eyes of 21 subjects with early AMD were examined. MP-1 10-2 visual fields (VFs) and SD-OCT line and detail volume scans were acquired. The thicknesses of the outer segment (OS; distance between inner segment ellipsoid band and upper retinal pigment epithelium [RPE] border) and RPE layers and elevation of the RPE from Bruch's membrane were measured using a computer-aided manual segmentation technique. Thickness values were compared with those for 15 controls, and values at locations with VF total deviation defects were compared with values at nondefect locations at equivalent eccentricities. RESULTS: Sixteen of 21 eyes with AMD had VF defects. Compared with controls, line scans showed significant thinning of the OS layer (P = 0.006) and thickening and elevation of the RPE (P = 0.037, P = 0.002). The OS layer was significantly thinner in locations with VF defects compared with locations without defects (P = 0.003). There was a negligible difference between the retinal layer thickness values of the 5 eyes without VF defects and the values of normal controls. CONCLUSIONS: In early AMD, when VF defects were present, there was significant thinning of the OS layer and thickening and elevation of the RPE. OS layer thinning was significantly associated with decreased visual sensitivity, consistent with known photoreceptor loss in early AMD. For AMD subjects without VF defects, thickness values were normal. The results highlight the clinical utility of both SD-OCT retinal layer quantification and VF testing in early AMD.

Quantification of visual field loss in age-related macular degeneration.

BACKGROUND: An evaluation of standard automated perimetry (SAP) and short wavelength automated perimetry (SWAP) for the central 10-2 visual field test procedure in patients with age-related macular degeneration (AMD) is presented in order to determine methods of quantifying the central sensitivity loss in patients at various stages of AMD. METHODS: 10-2 SAP and SWAP Humphrey visual fields and stereoscopic fundus photographs were collected in 27 eyes of 27 patients with AMD and 22 eyes of 22 normal subjects. RESULTS: Mean Deviation and Pattern Standard Deviation (PSD) varied significantly with stage of disease in SAP (both p<0.001) and SWAP (both p<0.001), but post hoc analysis revealed overlap of functional values among stages. In SWAP, indices of focal loss were more sensitive to detecting differences in AMD from normal. SWAP defects were greater in depth and area than those in SAP. Central sensitivity (within 1°) changed by -3.9 and -4.9 dB per stage in SAP and SWAP, respectively. Based on defect maps, an AMD Severity Index was derived. CONCLUSIONS: Global indices of focal loss were more sensitive to detecting early stage AMD from normal. The SWAP sensitivity decline with advancing stage of AMD was greater than in SAP. A new AMD Severity Index quantifies visual field defects on a continuous scale. Although not all patients are suitable for SWAP examinations, it is of value as a tool in research studies of visual loss in AMD.