The importance of contrast sensitivity testing in children

Aim: To discuss the information contrast sensitivity (CS) testing can provide over visual acuity testing, and review the literature relating to CS deficits in children to determine whether there is an optimum test available. Methods: A literature search of databases available through the University of Liverpool library was performed. All searches related to the importance of CS in children, paediatric conditions affecting CS and current clinical tests available for the assessment of CS. Results: Many paediatric conditions exist where CS is defective, often despite ‘normal’ visual acuity (VA): for example, optic pathway gliomas, myopia and primary congenital glaucoma. The finding of a loss of CS has been found to be more prominent and disturbing to an individual than a loss of VA, emphasising the importance of CS assessments in children. Therefore, the clinical assessment of CS in children is valuable in terms of strategies to support the child and establishing the individual’s functional level of vision. Unfortunately, current paediatric clinical tests of CS have failed to demonstrate the same standards and repeatability and reliability as adult tests for the assessment of CS. Conclusions: The range of functional deficits that accompany paediatric ocular disease require more assessments for full evaluation of visual function than standard VA tests. However, reliable assessments for paediatric CS are limited. A new paediatric CS test may be of clinical value

Corrigendum: Using a Computerised Staircase and Incremental Optotype Sizes to Improve Visual Acuity Assessment Accuracy

This article details a correction to: O’Connor, A., King, C., Milling, A. and Tidbury, L., 2022. Using a Computerised Staircase and Incremental Optotype Sizes to Improve Visual Acuity Assessment Accuracy. 'British and Irish Orthoptic Journal', 18(1), pp. 93–100. DOI: http://doi.org/10.22599/bioj.271

Using a Computerised Staircase and Incremental Optotype Sizes to Improve Visual Acuity Assessment Accuracy.

BackgroundGiven the impact of visual acuity results on diagnosis and management, it is essential that the test is accurate, determined by factors such as test-retest variability. Standardisation improves accuracy, which can be performed via a computerised staircase methodology. Standard clinical tests with scoring of 0.02 per optotype implies an incremental score per optotype despite optotype size remaining constant on each line. The aim of this study is to establish if near continuous incremental optotype display and scoring improves test-retest variability compared to current testing methods.MethodsA computerised three up, one down adaptive staircase was used to display Kay Picture optotypes on an LCD monitor. Three methods of visual acuity assessment were undertaken: ETDRS, Kay Pictures and computerised Kay Pictures. Tests were performed twice under standard clinical conditions.ResultsOne hundred nineteen adults were tested. Test-retest variability for computerised Kay pictures was 0.01 logMAR (±0.04, p = 0.001). Good levels of agreement were observed for computerised Kay pictures in terms of test-retest variability, where the test had the smallest mean bias (0.01 logMAR compared to 0.03 and 0.08 logMAR for Kay Pictures and ETDRS respectively) and narrowest limits of agreement. Participants performed better in computerised Kay pictures than Kay Pictures by 0.03 logMAR, and better in ETDRS than computerised Kay pictures by 0.1 logMAR.ConclusionComputerised Kay pictures exhibited a low test-retest variability, demonstrating it is reliable and repeatable. This repeatability measure is lower than the test-retest variability of the ETDRS and Kay Pictures tests

Evaluation of a New Method to Track Changes in Vision at Home for Children Undergoing Amblyopia Treatment.

PurposeA new amblyopia tracker app has been designed to provide parents with a method of monitoring a child's vision by presenting a single optotype size that the tester moves to identify the furthest distance the optotypes can be seen. The aim of this study is to evaluate this methodology in adults, comparing the findings to visual acuity (VA) measured with the iSight app and to determine the test retest variability.MethodsAdults, aged 18-39 years, with no known eye condition and VA ≤ 0.7 logMAR were recruited. Bangerter filters were used to simulate amblyopia, where VA was reduced below 0.0 with an interocular difference of at least 0.2 logMAR. Testing for both apps was performed monocularly, with the test order being randomised.ResultsData from 32 subjects were analysed. For the test retest variability analysis, paired t-tests showed no statistically significant difference between the tests for either eye, either app or the interocular acuity difference (p > 0.3 in all cases). Bland Altman plots showed similar limits of agreement between the two apps. When comparing measurements between the apps there was no statistically significant difference on the first or second test, either eye or the interocular acuity difference (p > 0.5 in all cases).ConclusionThe results support the theory that changing distance is a valid method of assessing VA as the measurements agree well with the standard approach of reducing optotype size. Test retest variability is similar between the two apps and there is good agreement between the measurements

Undergraduate orthoptic students’ views of the use of Virtual Reality in teaching and learning

This study ascertains undergraduate perceptions of the use of Virtual Reality (VR) within undergraduate studies. Fifty undergraduate orthoptic students were surveyed through an online questionnaire, where questions were based around students understanding of VR, teaching methods in higher education and the value of VR in learning and teaching. Ninety-two percent of students surveyed reported experience of VR on at least one occasion and 55% of all surveyed felt that VR has a valuable role within higher education. For those who do not use VR regularly, 24% reported this being due to a dislike of the headset, and 14% stated that it was due to cyber-sickness. Twenty-seven per cent indicated the lack of use was due to insufficient content. Overall, perception of VR as a learning tool is generally positive or comes with some uncertainty; however, there are factors identified that may prevent use within the curriculum. Development of educationally specific content to orthoptics and increased access to the technology is indicated to enhance student learning.</jats:p

Comparison of current paediatric contrast sensitivity assessments using simulated reduced contrast thresholds.

PurposeThere are limited tests of contrast sensitivity (CS) for use in children. The Hiding Heidi (HH) is suitable for all cognitive abilities, but has a ceiling effect. The Double Happy (DH) test has comparable thresholds to the Pelli Robson (PR), however the ability to detect changes in contrast has not been established. This study aims to compare contrast thresholds and agreement between HH and the DH, comparing to the PR chart in normal conditions and under reduced visual and lighting conditions.MethodsTests were repeated under different conditions to reduce the contrast. Room illumination was 20,900{plus minus}2% lux in bright conditions and 2,000{plus minus}2% lux in dim conditions, both conditions were repeated with the addition of simulation spectacles to reduce the clarity of vision. Participants' CS was measured uniocularly using the PR, HH and DH tests.Results50 participants, age 18-62 years (mean{plus minus}standard deviation: 24.5{plus minus}7.98), were assessed. On HH 94% (n = 47) reached the maximum score, with the DH it was 18% (n = 9). The difference in reduction between conditions was smaller with HH in comparison to PR and DH, but significantly different from baseline conditions. Under dim conditions the reduction in PR and DH was -0.21 logCS units, but only -0.04 logCS for HH.ConclusionThe DH test has better agreement with PR than HH and is better at detecting CS changes, highlighting the advantages of use in clinical practice