Diagnostic Accuracy of Online Visual Acuity Testing of Paediatric Patients.

Background/Objectives: Remote assessment of children's visual acuity became necessary during the COVID-19 pandemic. This study aimed to assess the extent of agreement between hospital-based clinical testing and clinician-led home-based testing. Subjects/Methods: 50 children aged 2-16 (median 8) years attending hospital eye services at two UK hospitals had routine hospital-based acuities compared with subsequent online, orthoptist-supervised home visual acuities. Agreement was assessed using intra-class correlation and Bland-Altman plots, as was test-retest (TRT) agreement of two, repeated home acuity tests. Results: Monocular acuities tested at hospital and at home were obtained from all 50 children; 33 also had binocular acuities in both settings and 35 had acuities retested immediately at home. Most children were tested at home using a computer or tablet; two were tested with a smartphone. No mean test differences were found for hospital vs home testing (-0.004 (95% CI -0.06-0.05) and -0.008 (95% CI -0.04-0.03) for binocular and monocular testing, respectively). Limits of agreement (LOAs) were ±0.32 and ±0.35 logMAR for binocular and monocular testing, respectively. LOAs for inter-ocular acuity differences (hospital vs home) were -0.15-0.25 logMAR. TRT monocular acuity agreement was excellent, with an LOA of ±0.14 logMAR. Conclusions: We found good (binocular) and excellent (monocular) agreement between hospital and home acuity testing. LOAs were in keeping with multiple changes between measures (test; setting; time; tester) and a cohort including patients as young as two years old. Even smartphone testing proved feasible. Inability of the supervising orthoptist to check test distance or device calibration/orientation was a limitation, likely contributing to the breadth of LOAs. Home vision testing is feasible and accurate, but its precision, acceptability, health economic impact and carbon impact require more attention.

Live teleophthalmology avoids escalation of referrals to secondary care during COVID-19 lockdown.

CLINICAL RELEVANCE: Following the COVID-19 lockdown, uptake of slitlamp-enabled live teleophthalmology increased. Its use contributed to a reduction of referrals escalated to secondary care during-lockdown (avoided: 64% pre-lockdown vs 86% during-lockdown). BACKGROUND: Live teleophthalmology using video conferencing allows real-time, three-way consultation between secondary care, community providers and patients, improving interpretation of slit lamp findings and potentially reducing referrals to secondary care. NHS Forth Valley implemented live teleophthalmology in March 2019. In March 2020, the COVID-19 pandemic created urgency to deliver ophthalmic care while minimising the risk of contracting or spreading the disease. We aim to compare the uptake and two outcomes (number of avoided secondary care referrals; pattern of presenting conditions) of live teleophthalmology consultations in NHS Forth Valley before and during the COVID-19 national lockdown. METHODS: An NHS secure video conferencing platform connected the video slit lamps of optometrists, or an iPad mounted on a slit lamp and viewing through the eyepieces, to a secondary care ophthalmologist via a virtual live clinic/waiting area. Data about avoiding a secondary care referral were extracted from a post-consultation ophthalmologist survey for 14 months of data. Pre- and during-lockdown intervals were before/after 23 March 2020, when routine eyecare appointments were suspended. Numbers of avoided referrals to secondary care and patterns of presenting conditions were compared for pre- and during-lockdown periods. RESULTS: The COVID-19 pandemic markedly increased use of live teleophthalmology in NHS Forth Valley. Surveys were completed for 164 of 250 (66%) teleophthalmology consultations over the study period. Data from 154 surveys were analysed, 78 and 76 for the pre- and during-lockdown periods, respectively. Significantly more during-lockdown (86%) than pre-lockdown (64%; difference 21%, 95% CI 8-34%, p = 0.001) surveys indicated that referrals to secondary care were avoided. CONCLUSION: Survey data from ophthalmologists suggest significantly fewer escalations to secondary care due to teleophthalmology use.

Teleophthalmology-Enabled Direct Vitreoretinal Surgery Listing from Community Optometric Practice: Enhanced Efficiency During Coronavirus Disease 2019, and Beyond?

Purpose: To share a method of appropriately connecting patients directly to tertiary ophthalmology centers where subspecialist vitreoretinal (VR) surgical management is required during coronavirus disease 2019 (COVID-19). Methodology: We present our experience of a live teleophthalmology link directly connecting an optometrist to tertiary center VR team at the point of retinal detachment presentation within the community. Results: After the COVID-19 lockdown in National Health Service Forth Valley, Emergency Eye Care Treatment Centers have been set up where optometrists are the first point of contact for patients in the community. Live teleophthalmology link has enabled the optometrist in the community to connect directly with local ophthalmologists. From March 23 to June 15, 2020, five referrals were taken for a suspected retinal detachment, and one for submacular hemorrhage. From the receiving ophthalmologists' viewpoint, satisfaction for the quality of sound, video, and connection was 5/5 in all cases on a 5-point Likert grading; from the referring optometrists' viewpoint mean 4.6/5 for sound and video satisfaction, and 5/5 rating in all cases for connection reliability. On 5/6 occasions (83%) the receiving ophthalmologist connected directly with a VR surgeon in a tertiary center. Four-way communication between the patient, optometrist, receiving ophthalmologist, and VR surgeon enabled all five patients to be listed directly for VR surgery from the community, avoiding local ophthalmology department contact during the COVID-19 pandemic. Conclusion: Overall satisfaction and recommendation to others was rated 5/5 in all instances on a 5-point Likert grading, from the patient, optometrist, and ophthalmologist viewpoint.

Extending the Reach and Task-Shifting Ophthalmology Diagnostics Through Remote Visualisation.

Driven by the global increase in the size and median age of the world population, sight loss is becoming a major public health challenge. Furthermore, the increased survival of premature neonates in low- and middle-income countries is causing an increase in developmental paediatric ophthalmic disease. Finally, there is an ongoing change in health-seeking behaviour worldwide, with consequent demand for increased access to healthcare, including ophthalmology. There is therefore the need to maximise the reach of resource-limited ophthalmology expertise in the context of increasing demand. Yet, ophthalmic diagnostics critically relies on visualisation, through optical imaging, of the front and of the back of the eye, and teleophthalmology, the remote visualisation of diagnostic images, shows promise to offer a viable solution.In this chapter, we first explore the strategies at the core of teleophthalmology and, in particular, real-time vs store-and-forward remote visualisation techniques, including considerations on suitability for different tasks and environments. We then introduce the key technologies suitable for teleophthalmology: anterior segment imaging, posterior segment imaging (retinal imaging) and, briefly, radiographic/tomographic techniques. We highlight enabling factors, such as high-resolution handheld imaging, high data rate mobile transmission, cloud storage and computing, 3D printing and other rapid fabrication technologies and patient and healthcare system acceptance of remote consultations. We then briefly discuss four canonical implementation settings, namely, national service provision integration, field and community screening, optometric decision support and virtual clinics, giving representative examples. We conclude with considerations on the outlook of the field, in particular, on artificial intelligence and on robotic actuation of the patient end point as a complement to televisualisation.

Too Many Shades of Grey: Photometrically and Spectrally Mismatched Targets and Backgrounds in Printed Acuity Tests for Infants and Young Children.

Purpose: Acuity tests for infants and young children use preferential looking methods that require a perceptual match of brightness and color between grey background and target spatial average. As a first step in exploring this matching, this article measures photometric and colorimetric matches in these acuity tests. Methods: The luminance, uniformity, contrast, and color spectra of Teller Acuity Cards, Keeler Acuity Cards for Infants, and Lea Paddles under ambient, warm, and cold lighting, and of grey-emulating patterns on four digital displays, were measured. Five normal adults' acuities were tested at 10 m observationally. Results: Luminance and spectral mismatches between target and background were found for the printed tests (Weber contrasts of 0.3% [Teller Acuity Cards], -1.7% [Keeler Acuity Cards for Infants], and -26% [Lea Paddles]). Lighting condition had little effect on contrast, and all printed tests and digital displays met established adult test luminance and uniformity standards. Digital display grey backgrounds had very similar luminance and color whether generated by a checkerboard, vertical grating, or horizontal grating. Improbably good psychophysical acuities (better than -0.300 logMAR: (logarithm of the minimum angle of resolution)) were recorded from adults using the printed tests at 10 m, but not using the digital test Peekaboo Vision. Conclusions: Perceptible contrast between target and background could lead to an incorrectly measured, excessively good acuity. It is not clear whether the luminance and spectral contrasts described here have clinically meaningful consequences for the target patient group, but they may be avoidable using digital tests. Translational Relevance: Current clinical infant acuity tests present photometric mismatches that may return inaccurate testing results.

Low-Cost Eye Phantom for Stereophotogrammetry-Based Optic Nerve Head Topographical 3D Imaging.

Glaucoma is the second leading cause of blindness globally. Stereophotogrammetry-based optic nerve head topographical imaging systems could potentially allow for objective glaucoma assessment in settings where technologies such as optical coherence tomography and the Heidelberg Retinal Tomograph are prohibitively expensive. In the development of such systems, eye phantoms are invaluable tools for both system calibration and performance evaluation. Eye phantoms developed for this purpose need to replicate the optical configuration of the eye, the related causes of measurement artefacts, and give the possibility to present to the imaging system the targets required for system calibration. The phantoms in the literature that show promise of meeting these requirements rely on custom lenses to be fabricated, making them very costly. Here, we propose a low-cost eye phantom comprising a vacuum formed cornea and commercially available stock bi-convex lens, that is optically similar to a gold-standard reference wide-angle schematic eye model and meets all the compliance and configurability requirements for use with stereo-photogrammetry-based ONH topographical imaging systems. Moreover, its modular design, being fabricated largely from 3D-printed components, lends itself to modification for other applications. The use of the phantom is successfully demonstrated in an ONH imager.

Screen and Virtual Reality-Based Testing of Contrast Sensitivity.

Contrast sensitivity is a key visual ability for everyday tasks, as well as a potential indicator of important optical and neurological diseases. Current clinical standards, based on visual discrimination performance on printed charts, present problems that could be bypassed using electronic devices. This work describes the development of new tests for contrast sensitivity, based on the detection of a moving target on a computer screen and in virtual reality headset. It presents preliminary evaluation of these innovations by comparison of their performance, using healthy adults with normal vision and by artificially altering their contrast sensitivity. The results demonstrate consistent correlation between all test modalities explored.

Testing Pediatric Acuity With an iPad: Validation of "Peekaboo Vision" in Malawi and the UK.

PURPOSE: To evaluate two builds of the digital grating acuity test, "Peekaboo Vision" (PV), in young (6-60 months) populations in two hospital settings (Malawi and United Kingdom). METHODS: Study 1 evaluated PV in Blantyre, Malawi (N = 58, mean age 33 months); study 2 evaluated an updated build in Glasgow, United Kingdom (N = 60, mean age 44 months). Acuities were tested-retested with PV and Keeler Acuity Cards for Infants (KACI). Bland-Altman techniques were used to compare results and repeatability. Child engagement was compared between groups. Study 2 included test-time comparison. RESULTS: Study 1 (Malawi): The mean difference between PV and KACI was 0.02 logMAR with 95% limits of agreement (LoA) of 0.33 to 0.37 LogMAR. On test-retest, PV demonstrated 95% LoA of -0.283 to 0.198 logMAR with coefficient of repeatability (CR) 0.27. KACI demonstrated 95% LoA of -0.427 to 0.323 logMAR, and larger CR was 0.37. PV evidenced higher engagement scores than KACI (P = 0.0005). Study 2 (UK): The mean difference between PV and KACI was 0.01 logMAR; 95% LoA was -0.413 to 0.437 logMAR. Again, on test-retest, PV had narrower LoA (-0.344 to 0.320 logMAR) and lower CR (0.32) versus KACI, with LoA -0.432 to 0.407 logMAR, CR 0.42. The two tests did not differ in engagement score (P = 0.5). Test time was ∼1 minute shorter for PV (185 vs. 251 s, P = 0.0021). CONCLUSIONS: PV gives comparable results to KACI in two pediatric populations in two settings, with benefits in repeatability indices and test duration. TRANSLATIONAL RELEVANCE: Leveraging tablet technology extends reliable infant acuity testing to bedside, home, and rural settings, including areas where traditional equipment cannot be financed.

3D Reconstruction of the Optic Nerve Head of a Phantom Eye from Images Obtained using a Slit Lamp Fitted with Low Cost Add-Ons.

Early detection and treatment are key in limiting vision loss from glaucoma, the second leading cause of blindness worldwide. Morphological alteration of the optic nerve head (ONH), detectable early in the condition, is a key clinical indicator. The mainstay for evaluation in clinics is the subjective assessment of stereoscopic ONH images. If quantitative diagnostic devices, which extract 3D information and use this to make an objective assessment, could be made affordable, it could mean greater diagnostic capability in primary/community care. A potentially cost-effective solution is to extract, using computer stereo vision, 3D information from stereo images obtained through a slit lamp, a mainstay of eye diagnostics, present in practically all ophthalmology and optometry practices. This work shows 3D ONH reconstruction in an eye phantom through a common slit lamp fitted with low cost cameras. Quantitative reconstructions, in close agreement with ground truths, were obtained.

Accuracy and Feasibility of an Android-Based Digital Assessment Tool for Post Stroke Visual Disorders-The StrokeVision App.

BACKGROUND: Visual impairment affects up to 70% of stroke survivors. We designed an app (StrokeVision) to facilitate screening for common post stroke visual issues (acuity, visual fields, and visual inattention). We sought to describe the test time, feasibility, acceptability, and accuracy of our app-based digital visual assessments against (a) current methods used for bedside screening and (b) gold standard measures. METHODS: Patients were prospectively recruited from acute stroke settings. Index tests were app-based assessments of fields and inattention performed by a trained researcher. We compared against usual clinical screening practice of visual fields to confrontation, including inattention assessment (simultaneous stimuli). We also compared app to gold standard assessments of formal kinetic perimetry (Goldman or Octopus Visual Field Assessment); and pencil and paper-based tests of inattention (Albert's, Star Cancelation, and Line Bisection). Results of inattention and field tests were adjudicated by a specialist Neuro-ophthalmologist. All assessors were masked to each other's results. Participants and assessors graded acceptability using a bespoke scale that ranged from 0 (completely unacceptable) to 10 (perfect acceptability). RESULTS: Of 48 stroke survivors recruited, the complete battery of index and reference tests for fields was successfully completed in 45. Similar acceptability scores were observed for app-based [assessor median score 10 (IQR: 9-10); patient 9 (IQR: 8-10)] and traditional bedside testing [assessor 10 (IQR: 9-10); patient 10 (IQR: 9-10)]. Median test time was longer for app-based testing [combined time to completion of all digital tests 420 s (IQR: 390-588)] when compared with conventional bedside testing [70 s, (IQR: 40-70)], but shorter than gold standard testing [1,260 s, (IQR: 1005-1,620)]. Compared with gold standard assessments, usual screening practice demonstrated 79% sensitivity and 82% specificity for detection of a stroke-related field defect. This compares with 79% sensitivity and 88% specificity for StrokeVision digital assessment. CONCLUSION: StrokeVision shows promise as a screening tool for visual complications in the acute phase of stroke. The app is at least as good as usual screening and offers other functionality that may make it attractive for use in acute stroke. CLINICAL TRIAL REGISTRATION: https://ClinicalTrials.gov/ct2/show/NCT02539381.

Clinical Validation of a Smartphone-Based Adapter for Optic Disc Imaging in Kenya.

IMPORTANCE: Visualization and interpretation of the optic nerve and retina are essential parts of most physical examinations. OBJECTIVE: To design and validate a smartphone-based retinal adapter enabling image capture and remote grading of the retina. DESIGN, SETTING, AND PARTICIPANTS: This validation study compared the grading of optic nerves from smartphone images with those of a digital retinal camera. Both image sets were independently graded at Moorfields Eye Hospital Reading Centre. Nested within the 6-year follow-up (January 7, 2013, to March 12, 2014) of the Nakuru Eye Disease Cohort in Kenya, 1460 adults (2920 eyes) 55 years and older were recruited consecutively from the study. A subset of 100 optic disc images from both methods were further used to validate a grading app for the optic nerves. Data analysis was performed April 7 to April 12, 2015. MAIN OUTCOMES AND MEASURES: Vertical cup-disc ratio for each test was compared in terms of agreement (Bland-Altman and weighted κ) and test-retest variability. RESULTS: A total of 2152 optic nerve images were available from both methods (also 371 from the reference camera but not the smartphone, 170 from the smartphone but not the reference camera, and 227 from neither the reference camera nor the smartphone). Bland-Altman analysis revealed a mean difference of 0.02 (95% CI, -0.21 to 0.17) and a weighted κ coefficient of 0.69 (excellent agreement). The grades of an experienced retinal photographer were compared with those of a lay photographer (no health care experience before the study), and no observable difference in image acquisition quality was found. CONCLUSIONS AND RELEVANCE: Nonclinical photographers using the low-cost smartphone adapter were able to acquire optic nerve images at a standard that enabled independent remote grading of the images comparable to those acquired using a desktop retinal camera operated by an ophthalmic assistant. The potential for task shifting and the detection of avoidable causes of blindness in the most at-risk communities makes this an attractive public health intervention.

Development and Validation of a Smartphone-Based Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork.

IMPORTANCE: Visual acuity is the most frequently performed measure of visual function in clinical practice and most people worldwide living with visual impairment are living in low- and middle-income countries. OBJECTIVE: To design and validate a smartphone-based visual acuity test that is not dependent on familiarity with symbols or letters commonly used in the English language. DESIGN, SETTING, AND PARTICIPANTS: Validation study conducted from December 11, 2013, to March 4, 2014, comparing results from smartphone-based Peek Acuity to Snellen acuity (clinical normal) charts and the Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart (reference standard). This study was nested within the 6-year follow-up of the Nakuru Eye Disease Cohort in central Kenya and included 300 adults aged 55 years and older recruited consecutively. MAIN OUTCOMES AND MEASURES: Outcome measures were monocular logMAR visual acuity scores for each test: ETDRS chart logMAR, Snellen acuity, and Peek Acuity. Peek Acuity was compared, in terms of test-retest variability and measurement time, with the Snellen acuity and ETDRS logMAR charts in participants' homes and temporary clinic settings in rural Kenya in 2013 and 2014. RESULTS: The 95% CI limits for test-retest variability of smartphone acuity data were ±0.033 logMAR. The mean differences between the smartphone-based test and the ETDRS chart and the smartphone-based test and Snellen acuity data were 0.07 (95% CI, 0.05-0.09) and 0.08 (95% CI, 0.06-0.10) logMAR, respectively, indicating that smartphone-based test acuities agreed well with those of the ETDRS and Snellen charts. The agreement of Peek Acuity and the ETDRS chart was greater than the Snellen chart with the ETDRS chart (95% CI, 0.05-0.10; P = .08). The local Kenyan community health care workers readily accepted the Peek Acuity smartphone test; it required minimal training and took no longer than the Snellen test (77 seconds vs 82 seconds; 95% CI, 71-84 seconds vs 73-91 seconds, respectively; P = .13). CONCLUSIONS AND RELEVANCE: The study demonstrated that the Peek Acuity smartphone test is capable of accurate and repeatable acuity measurements consistent with published data on the test-retest variability of acuities measured using 5-letter-per-line retroilluminated logMAR charts.

Treatment of corneal cystine crystal accumulation in patients with cystinosis.

Cystinosis is a rare autosomal recessive disorder characterized by the accumulation of cystine within the cells of different organs. Infantile nephropathic cystinosis is the most common and severe phenotype. With the success of renal transplantation, these patients are now living longer and thus more long-term complications within different organs are becoming apparent. Ophthalmic manifestations range from corneal deposits of cystine crystals to pigmentary retinopathy. With increasing age, more severe ocular complications have been reported. Photophobia is a prominent symptom for patients. With prolonged survival and increasing age, this symptom, along with corneal erosions and blepharospasm, can become debilitating. This review revisits the basic pathogenesis of cystinosis, the ocular manifestations of the disease, and the treatment of corneal crystals.

A smartphone based ophthalmoscope.

A low-cost alternative to the direct ophthalmoscope, a simple optical adapter for a smartphone, is described. It can overcome many of the technical challenges of fundoscopy, providing a high-resolution view of the retina through an un-dilated pupil. This can be used in locations with limited diagnostic resources to detect conditions such as glaucomatous optic neuropathy. Comparison of optic nerve images from commercial retinal screening cameras with the smartphone adapter demonstrates strong evidence for no difference in performance in glaucomatous disc grading (p=0.98, paired student t test, n=300).

Delayed dislocation of an injectable hydrophilic acrylic lens after Nd:YAG capsulotomy in anterior capsular contraction syndrome.

Posterior dislocation of IOLs has been reported following Nd:YAG laser for anterior capsule contraction in only 3 cases and these involved plate haptic silicone lenses; while the dislocation of IOLs into the vitreous cavity following posterior Nd:YAG laser capsulotomy have been reported in plate haptic silicone lenses and single piece hydrophilic acrylic (polymacon) lenses. We report a patient who suffered the delayed dislocation of an injectable hydrophilic acylic IOL (SlimFlex-m 123 IOL, PhysIOL, Liège, Belgium) following combined Nd:YAG laser anterior and posterior capsulotomy. We also explore the factors that may predispose to anterior capsular contraction syndrome and IOL dislocation.

Corneal perforation due to limbal involvement in Sézary syndrome.

BACKGROUND: The majority of lymphomas involving the eye and ocular adnexa are B-cell lymphomas. Ocular involvement by T-cell lymphoma is rare. We report a case of corneal perforation due to direct involvement of the corneal limbus by lymphoma in a patient with Sézary syndrome. METHODS: A 58-year-old male with cutaneous T-cell lymphoma presented with painful, left-sided corneal ulceration, a dense infiltrate, severe epitheliopathy, hypopyon and a diffuse confluent dermatitis involving the lids. He had a history of Sézary syndrome. Despite maximal treatment, this severe ulcerative keratitis progressed to central corneal perforation. The eye was subsequently enucleated and submitted for histopathological examination. RESULTS: Histopathological examination confirmed corneal ulceration with perforation. There was an infiltrate of large atypical cells at the limbus, with tropism for the overlying epithelium. Immunohistochemical staining of these cells was positive for CD2, CD3, CD5, CD4 and CD7. Staining for CD8, CD30 and CD56 was negative. The appearances were those of an epitheliotrophic T-cell lymphoma, and were considered to represent spread from the patient's underlying Sézary syndrome. The patient died 2 months later from bronchopneumonia. CONCLUSIONS: Ocular involvement by cutaneous T-cell lymphoma usually occurs in advanced disease, and carries a poor prognosis. This patient was immunocompromised due to advanced malignancy, and there was a high suspicion of infection as the primary cause of corneal ulceration. This case highlights that it is important to consider direct tumour infiltration as an initiating or contributing factor for corneal ulceration in such patients.