Efficacy and Safety outcomes of a novel model to assess new medical retina referrals in a high-volume medical retina virtual clinic

BACKGROUND

Ophthalmology outpatient attendances have significantly increased recently with rising pressure from backlogs arising from the pandemic. Medical retina digital surveillance clinics for stable follow-up appointments are well established. We present a model for assessing new referrals and evaluating clinical outcomes and long-term sustainability in a complex high-volume medical retina service.

METHODS

Suitable routine new patient referrals were identified from electronic referrals and referred to this new pathway. Structured history, visual acuities, and intraocular pressures were recorded, and widefield colour fundus and optical coherence tomography imaging were performed at a imaging hub for asynchronous consultant-led review.

RESULTS

1458 patients were invited to attend over four months, with a 13.2% did-not-attend (DNA) rate. Common diagnoses included stable diabetic retinopathy (19.9%), early age-related macular degeneration (6.7%), central serous retinopathy (8.8%), and retinal vein occlusion (6.3%). 7 patients (0.05%) required urgent same-day review. 61 (5.0%) required urgent face-to-face (F2F) assessment within two weeks. A total of 727 (59.0%) were either discharged or remained in the virtual pathway following their first visit.

CONCLUSION

This study encourages the use of a digital model that efficiently assesses suitable newly referred medical retina patients in both complex and local eye unit settings. This decreased the need for F2F clinics and resources. Further patient satisfaction surveys for digital services are currently being evaluated to guide long-term sustainability of this model.

Impaired vision in children prenatally exposed to methadone: an observational cohort study

BACKGROUND/OBJECTIVES

To examine prevalence of failed visual assessment at 8-10 years in children born to methadone-maintained opioid dependent (MMOD) mothers and relate this to known in utero substance exposure.

SUBJECTS/METHODS

Follow up of observational cohort study of methadone-exposed and comparison children matched for birthweight, gestation and postcode of residence at birth. Participants were 144 children (98 exposed, 46 comparison). Prenatal drug exposure was previously established via comprehensive maternal and neonatal toxicology. Children were invited to attend for visual assessment and casenotes were reviewed. Presence of acuity poorer than 0.2 logMAR, strabismus, nystagmus and/or impaired stereovision constituted a 'fail'. Fail rates were compared between methadone-exposed and comparison children after adjusting for known confounding variables.

RESULTS

33 children attended in person: data were also derived from casenote review for all children. After controlling for maternal reported tobacco use, methadone-exposed children were more likely to have a visual 'fail' outcome, adjusted odds ratio 2.6, 95% CI 1.1-6.2; adjusted relative risk 1.8 (95% CI 1.1-3.4). Visual 'fail' outcome rates did not differ between methadone-exposed children who had (n = 47) or had not (n = 51) received pharmacological treatment for neonatal abstinence/opioid withdrawal syndrome (NAS/NOWS); fail rate 62% vs 53% (95% CI of difference-11-27%).

CONCLUSIONS

Children born to MMOD mothers are almost twice as likely as unexposed peers to have significant visual abnormalities at primary school age. Prenatal methadone exposure should be considered in the differential diagnosis of nystagmus. Findings support visual assessment prior to school entry for children with any history of prenatal opioid exposure.

TRIAL REGISTRATION

The study was prospectively registered on ClinicalTrials.gov (NCT03603301), https://clinicaltrials.gov/ct2/show/NCT03603301 .

5 Tear proteins in premature babies at risk of retinopathy of prematurity

This feasibility study aimed to investigate the feasibility of collecting and analysing tear proteins from preterm infants at risk of retinopathy of prematurity (ROP). Additionally, we sought to identify any tear proteins which might be implicated in the pathophysiology of ROP.Eligible infants were those undergoing ROP screening without other ocular pathology. Tear samples were obtained by Schirmer's test strips coincident with routine ROP screening. Mass spectrometry was used for proteomic analysis. All participants' parents gave written, informed consent.Samples were collected from 12 infants, including two sets of twins. Gestation ranged from 25+6 to 31+1 weeks. Median postnatal age at sampling was 30.5 days (range 19 to 66). One infant developed self-limiting ROP. An adequate sample for protein analysis was obtained from each infant. 701 proteins were identified; 261 proteins identified in the majority of tear samples, including several common tear proteins, were used for analyses.Increased risk of ROP as determined by G-ROP prediction criteria was associated with an increase in lactate dehydrogenase B (LDH-B) chain protein in tears. Older, more mature infants demonstrated increased concentration of immunoglobulin complexes within their tear samples and two sets of twins in the cohort showed exceptionally similar proteomes, supporting validity of the analysis.Tear sampling by Schirmer test strips and subsequent proteomic analysis in preterm infants is feasible. A larger study is required to investigate the potential use of tear proteomics in early identification of ROP.

6 Restricted diet causing irreversible visual impairment in children with autistic spectrum disorder: case series and review

Though micronutrient deficiency is recognized to cause visual system dysfunction, avoidant/restrictive food intake disorder (ARFID) has been poorly described in relation to this.Review of 18 previously published similar cases highlights the importance of identifying other micronutrient deficiencies, even when vitamin A deficiency accounts for the presenting features. We present four patients with permanent visual loss as a result of highly restricted diets due to avoidant/restrictive food intake disorder (ARFID), and with autistic spectrum disorder (ASD).The four cases reported here make a total of 22 reported cases of visual impairment due to ARFID-like restricted diets in boys with ASD. The severity of ASD varied widely across the 22 cases, but all had extremely restricted diets, in some cases tolerating only one or two food items. The most avoided food groups in children with ASD and food selectivity have been reported from the USA as vegetables, fruit, dairy and protein, with the most preferred food items being bread, chicken, cereal and yoghurt. In the 22 cases reviewed or reported here, tolerated foods tended to be predominately carbohydrate based, with dry or crunchy textures and beige or pale colouring, i.e. French fries, potato waffles, potato chips (crisps), rice, white bread, bagels, biscuits or cookies.This case series and review highlights the need for heightened vigilance for visual problems in individuals with ASD-related ARFID and early and complete assessment of micronutrient deficiency.

CD193 ( CCR3 ) expression by B cells correlates with reduced IgE production in paediatric schistosomiasis

We demonstrate that CD193, the eotaxin receptor, is highly expressed on circulating B cells in paediatric schistosomiasis mansoni. CD193 plays a role in directing granulocytes into sites of allergic-like inflammation in the mucosa, but little is known about its functional significance on human B cells. We sought to characterize CD193 expression and its relationship with S. mansoni infection. We found that CD193+ B cells increased with the intensity of schistosome infection. In addition, a significant negative association was observed between CD193 expression by B cells and IgE production. Decreased IgE levels are generally associated with susceptibility to re-infection. B cell stimulation with eotaxin-1 increased CD193 levels whereas IL-4 led to a reduction. This was supported by plasma levels of eotaxin-1 correlating with CD193 levels on B cells and other cells. In contrast, CD193 expression was induced on naive B cells with a combination of IL-10 and schistosome antigens. Whereas T cells had a modest increase in CD193 expression, only B cell CD193 appeared functionally chemotactic to eotaxin-1. Thus, CD193+ B cells, which co-express CXCR5, may be enroute to sites with allergic-like inflammation, such as gastrointestinal follicles, or even to Th2 granulomas, which develop around parasite eggs. Overall, our results suggest that schistosome infection may promote CD193 expression and suppress IgE via IL-10 and other undefined mechanisms related to B cell trafficking. This study adds to our understanding of why young children may have poor immunity. Nonetheless, praziquantel treatment was shown to reduce percentages of circulating CD193+ B cells lending hope for future vaccine efforts.

AB0309 MEASURING THE DIFFERENCE: COMPARISON OF MEASUREMENT OF FREE INFLIXIMAB ANTI-DRUG ANTIBODIES

Background:

Infliximab (IFX) was one of the first TNF alpha inhibitors to be licenced in inflammatory arthritis and is still commonly used today. Studies have shown that approximately 50% of primary IFX responders will suffer from secondary loss of response within the first 12 months of treatment (1). The development of Anti-Drug Antibodies (ADA’s) plays a significant role in this treatment failure (2).

Monitoring of ADA’s helps identify those patients who fail to respond to treatment due to low IFX trough levels. In this scenario the presence of ADA’s can aid decision-making regarding increasing IFX dosing or switching biologic therapy to optimise treatment. (3).

Objectives:

Despite their potential importance the detection of ADAs varies widely depending on the type of assays used. The aim of this study was to determine the qualitative concordance of three commercially available ELISA kits for measurement of free ADAs to IFX on the Grifols Triturus analyser.

Methods:

150 patient samples from patients with inflammatory conditions and low IFX trough drug levels (≤0.6µg/ml) were analysed for free ADAs using Promonitor, Lisa Tracker and IDKmonitor kits on the Grifols Triturus automated ELISA analyser.

Results:

Kappa coefficient (κ) analysis indicated a moderate agreement between the Promonitor and IDKmonitor assays (κ =0.484 (95% CI, 0.357 to 0.611)) and the IDKmonitor and Lisa Tracker assays (κ = 0.485 (95% CI, 0.348-0.621)) as well as substantial agreement between the Promonitor and Lisa Tracker assays (κ =0.768 (95% CI, 0.667-0.870)). Figure 1 shows the distribution of samples identified as free ADA positive by each kit.

Figure 1.

Distribution of samples identified as free ADA positive by Promonitor, Lisa Tracker, and IDKmonitor assays. Fifty samples were considered positive by all assays. Three samples were considered positive by Promonitor and Lisa Tracker, and eight samples were considered positive by Lisa Tracker and IDKmonitor. No samples were considered positive by Promonitor and IDKmonitor. One sample was considered positive by Promonitor only, seven samples were considered positive by Lisa Tracker only, and twenty-six samples were considered positive by IDKmonitor

Conclusion:

All kits appear amenable for utilisation in a high-throughput laboratory though a true quantitative comparison between these kits was precluded by the absence of any certified reference material for free ADAs to IFX.

Although broad qualitative agreement was found between the three kits, they should not be used interchangeably for patient management.

Further research is required to estimate the impact of free ADAs on efficiency of IFX treatment and patient management.

References:

[1]Quistrebert J, Hässler S, Bachelet D et al.Incidence and risk factors for adalimumab and infliximab anti-drug antibodies in rheumatoid arthritis: A European retrospective multicohort analysis. Seminars in Arthritis and Rheumatism Volume 48, Issue 6, June 2019, Pages 967-975 2.

[2]Moots RJ, Xavier RM, Mok CC, Rahman MU, Tsai W-C, Al-Maini MH, et al. (2017)The impact of anti-drug antibodies on drug concentrations and clinical outcomes in rheumatoid arthritis patients treated with adalimumab, etanercept, or infliximab: Results from a multinational, real-world clinical practice, non-interventional study. PLoS ONE 12(4): e0175207.https://doi.org/10.1371/journal.pone.0175207

[3]Smolen JS, Landewé R, Bijlsma J, et al.EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs:2016 update.Annals of the Rheumatic Diseases 2017;76:960-977.

Disclosure of Interests:

Rhona Hamilton: None declared, Stephanie Shields: None declared, Andrew McGucken: None declared, Jonathan MacDonald: None declared, Martin Perry Grant/research support from: Grifols, Abbvie, Sandoz unrestricted educational grant, Consultant of: Abbvie, Gilead, Celltrion Advisory Board, Speakers bureau: Sandoz, Allan Dunlop: None declared, Elaine Gribben: None declared, Peter Galloway: None declared

The Prostate Cancer Rehabilitation Clinic: a biopsychosocial clinic for sexual dysfunction after radical prostatectomy

Purpose

The most prevalent intervention for localized prostate cancer (pca) is radical prostatectomy (rp), which has a 10-year relative survival rate of more than 90%. The improved survival rate has led to a focus on reducing the burden of treatment-related morbidity and improving the patient and partner survivorship experience. Post-rp sexual dysfunction (sdf) has received significant attention, given its substantial effect on patient and partner health-related quality of life. Accordingly, there is a need for sdf treatment to be a fundamental component of pca survivorship programming.

Methods

Most research about the treatment of post-rp sdf involves biomedical interventions for erectile dysfunction (ed). Although findings support the effectiveness of pro-erectile agents and devices, most patients discontinue use of such aids within 1 year after their rp. Because side effects of pro-erectile treatment have proved to be inadequate in explaining the gap between efficacy and ongoing use, current research focuses on a biopsychosocial perspective of ed. Unfortunately, there is a dearth of literature describing the components of a biopsychosocial program designed for the post-rp population and their partners.

Results

In this paper, we detail the development of the Prostate Cancer Rehabilitation Clinic (pcrc), which emphasizes multidisciplinary intervention teams, active participation by the partner, and a broad-spectrum medical, psychological, and interpersonal approach.

Conclusions

The goal of the pcrc is to help patients and their partners achieve optimal sexual health and couple intimacy after rp, and to help design cost-effective and beneficial rehabilitation programs.

Dark-adapted red flash ERGs in healthy adults

Purpose

The x-wave of the dark-adapted (DA) ERG to a red flash reflects DA cone function. This exploratory study of healthy adults aimed to investigate changes in the DA red ERG with flash strength and during dark adaptation to optimise visualisation and therefore quantification of the x-wave.

Methods

The effect of altering red flash strength was investigated in four subjects by recording ERGs after 20 min dark adaptation to red flashes (0.2–2.0 cd s m⁻²) using skin electrodes and natural pupils. The effect of dark adaptation duration was investigated in 16 subjects during 20 min in the dark, by recording DA 1.5 red ERGs at 1, 2, 3, 4, 5, 10, 15 and 20 min.

Results

For a dark adaption period of 20 min, the x-wave was more clearly visualised to weaker (< 0.6 cd s m⁻²) red flash strengths: to stronger flashes it became obscured by the b-wave. For red flashes of 1.5 cd s m⁻², the x-wave was most prominent in ERGs recorded after 1–5 min of dark adaptation: with longer dark adaptation, it was subsumed into the b-wave’s rising edge.

Conclusions

This small study suggests that x-wave visibility in healthy subjects after 20 min dark adaptation is improved by using flashes weaker than around 0.6 cd s m⁻²; for flash strengths of 1.5 cd s m⁻², x-wave visibility is enhanced by recording after only around 5 min of dark adaptation. No evidence was found that interim red flash ERGs affect the dark-adapted state of the normal retina.

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1-2mA and during tACS at higher peak-to-peak intensities above 2mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity 'conventional' TES defined as <4mA, up to 60min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3-13A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6-7, 2016 and were refined thereafter by email correspondence.

Abstract P6-07-07: ESR1 amplification and 5'-3' exon imbalance in metastatic breast cancer

BACKGROUND: Growing evidence indicates that base pair mutations in ESR1 are relatively uncommon in newly diagnosed, treatment-naive breast cancer, but frequently acquired in hormone-resistant metastatic breast cancer (MBC). We and others have recently identified ESR1 gene fusion and amplification in MBC, with the ESR1 fusions generally encompassing AF1 and the DNA binding domain. The genomic break required for gene fusions often results in an imbalance in the DNA copy number of exons around the break. We examined ESR1 amplification and 5' and 3' exon copy number imbalance in MBC.

MATERIALS and METHODS: We designed NanoString DNA hybridization probes against coding and non-coding exons (n=9) in ESR1 and 15 reference probes. We analyzed 128 samples consisting of 61 ER-positive and 44 ER-negative metastases, and 23 primary breast cancers. DNA copy number (CN) was determined using nSolver, with &gt;2.7CN as copy number gain, and &gt;10 as CN amplification. ESR1 CN was calculated by averaging the DNA copy number obtained from all coding exons. The 5'-3' copy number ratio was the average copy number of the 5' exons (3-6) divided by the 3' exons (7-10).

RESULTS: 8 (13%) ER positive metastatic breast cancers showed ESR1 amplification with 5 (8%) having &gt;2.7CN, and 3 (5%) with &gt;10CN. In contrast, in ER-negative metastases, we did not detect any samples with amplification &gt;10CN, and a gain (&gt;2.7 CN) in one case. Similarly, in ER+ primary cancers we did not detect any samples with &gt;10 CN amplifications and 2 samples with CN gain (&gt;2.7 CN). ESR1 showed 5'-3' CN imbalance in 1 primary (5%) and in 5 metastatic (5%) breast cancers. We are currently confirming and expanding these data in a larger dataset.

CONCLUSIONS: In addition to ESR1 mutations, ESR1 CN amplifications and 5'-3' imbalance are represent frequent occurrences in endocrine resistant breast cancer. Future studies are aimed at understanding whether the observed exon imbalances are associated with generation of fusion proteins, and whether and how ESR1 amplifications cause changes in endocrine treatment response.

Citation Format: Oesterreich S, Basudan A, Preideigkeit N, Hartmaier RJ, Bahreini A, Gyanchandani R, Leone JP, Lucas PC, Hamilton RL, Brufsky AM, Lee AV. ESR1 amplification and 5'-3' exon imbalance in metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-07.

Abstract PD1-05: Breast cancer brain metastases show limited intrinsic subtype switching, yet exhibit acquired ERBB2 amplifications and activating mutations

BACKGROUND: Metastasis is the major cause of mortality in breast cancer (BrCa) patients. Our understanding of brain metastasis (BrM) is limited, reflected by a lack of effective treatments. We aimed to (1) determine BrCa gene signature differences between primary tumors and matched BrM and (2) uncover BrM-specific alterations that may be clinically actionable.

MATERIALS and METHODS: NanoString expression profiling of 127 genes from 5 major prognostic tests (MammaPrint, EndoPredict, PAM50, OncotypeDX, MGI) was performed on 20 patient-matched primary (10 ER-neg, 10 ER-pos) and metastatic brain tumors. Subtype classification was performed using genefu. Protein changes in ER and HER2 (ERBB2) were confirmed by IHC. BrM-specific ERBB2 gains were corroborated in a publicly available dataset of 18 additional patient-matched cases (dbGAP phs000730.v1.p1). To test whether ERBB2 amplification and base pair mutation is metastasis-site specific, we further analyzed an expanded cohort of 7,884 breast tumors enriched for metastatic samples (52%) including liver (16.7%), lung (4.3%), bone (3.6%), and brain (2.0%) using comprehensive hybrid-capture sequencing of ERBB2.

RESULTS: 17/20 BrM retained the PAM50 subtype of the primary BrCa. Despite this concordance, 17/20 BrM harbored expression changes (&lt; or &gt; 2-fold) in clinically actionable genes including gains of FGFR4 (30%), FLT1 (20%), AURKA (10%) and loss of ESR1 expression (45%). The most recurrently upregulated gene was ERBB2, showing a &gt;2-fold expression increase in 35% of BrM. 3 of 13 (23.3%) cases originally HER2-negative, and thus HER2-therapy naive, in the primary BrCa were IHC-positive (3+) in the paired BrM with an observed metastasis-specific amplification of the ERBB2 locus. In an independent dataset, 2 of 9 (22.2%) HER2-negative BrCa switched to HER2-positive with one BrM acquiring ERBB2 amplification and the other showing metastastic enrichment of the activating V777L ERBB2 mutation. Analysis of a large cohort of breast tumors (n=7,884) showed that across all organs ERBB2 amplification and/or base pair mutation was similar (p=0.18) between primary (13%) and metastatic disease (12%), however, a strong and significant enrichment was seen for BrM (primary 13% vs BrM 24%, p&lt;0.0005).

CONCLUSIONS: Taken together, these results demonstrate that the majority (85%) of patient-matched BrM retain the intrinsic subtype of the primary cancer. However, despite this transcriptional similarity, alterations in clinically actionable genes are common, with BrM acquiring ERBB2 amplifications and/or base pair mutations at a frequency of ∼20%, even in HER2-therapy naive tumors. In a large cohort of primary and metastatic breast cancers, there is also a unique enrichment for ERBB2 alterations in BrM. This study provides a strong rationale to molecularly profile metastatic lesions to both better understand biological mechanisms of metastases and to perhaps refine therapeutic decision-making in advanced cancers.

Citation Format: Priedigkeit N, Hartmaier RJ, Chen Y, Vareslija D, Basudan A, Thomas R, Leone JP, Lucas PC, Bhargava R, Hamilton RL, Chmielecki J, Davidson NE, Oesterreich S, Brufsky AM, Young L, Lee AV. Breast cancer brain metastases show limited intrinsic subtype switching, yet exhibit acquired ERBB2 amplifications and activating mutations [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD1-05.

Clinical Characteristics and Outcomes of Late Relapse in Stage I Testicular Seminoma

AIMS

To identify the characteristics and outcomes associated with late relapse in stage I seminoma.

MATERIALS AND METHODS

A retrospective review was carried out of all patients with stage I seminoma managed at our institution between 1981 and 2011. Data were obtained from a prospectively maintained database. Late relapse was defined as tumour recurrence > 2 years after orchiectomy.

RESULTS

Overall, 1060 stage I seminoma patients were managed with active surveillance (n=766) or adjuvant radiotherapy (n=294). At a median follow-up of 10.6 years (range 1.2-30), 142 patients relapsed at a median (range) of 14 (3-129) months; 128 on active surveillance and 14 after adjuvant radiotherapy. The late relapse rate for the active surveillance and adjuvant radiotherapy groups was 4% and 1%, respectively. There was no specific clinicopathological factor associated with late relapse. Isolated para-aortic node(s) was the most common relapse site in active surveillance patients either in late (88%) or early relapse (82%). Among the active surveillance group, no patients with late relapse subsequently developed a second relapse after either salvage radiotherapy (n=25) or chemotherapy (n=6), whereas in early relapse patients a second relapse was reported in seven (10%) of 72 patients treated with salvage radiotherapy and one (4%) of 23 patients who received chemotherapy; all second relapses were subsequently salvaged with chemotherapy. No patient in the adjuvant radiotherapy group developed a second relapse after salvage chemotherapy (n=10) or inguinal radiotherapy/surgery (n=4). Of seven deaths, only one was related to seminoma. Among active surveillance patients, the 10 year overall survival for late and early relapse groups were 100% and 96% (P = 0.2), whereas the 10 year cancer-specific survival rates were 100% and 99% (P = 0.3), respectively.

CONCLUSIONS

In stage I seminoma, the extent and pattern of late relapse is similar to that for early relapse. For active surveillance patients, selective use of salvage radiotherapy/chemotherapy for relapse results in excellent outcomes regardless of the timing of relapse, whereas salvage radiotherapy for late relapse seems to be associated with a minimal risk of second relapse.

Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices

Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer's recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out-performed ETDRS charts in terms of photometric compliance with high contrast acuity standards.