Joost Heutink

Purpose: Acquired brain injury (ABI) may cause homonymous visual field (VF) defects. Standard automated perimetry (SAP) is the gold standard for VF assessment, but it can be challenging in ABI. Continuous visual stimulus tracking (SONDA; Standardised Oculomotor and Neurological Disorders Assessment) simplifies the perimetric task to following a moving stimulus on a screen. We investigated whether tracking performance (agreement between gaze and stimulus position) measured with a SONDA‐based eye movement perimetry technique (SONDA‐EMP) (1) can detect visual function loss in patients with homonymous VF defects, (2) can quantify visual function loss (in terms of SAP Mean Sensitivity [MS]) and (3) shows a learning effect. Methods: Tracking performance was evaluated in 16 cases with unilateral ABI (median [IQR] age 66 [62–68] years; SAP MS 19 [15–21] dB; 8/8 with left‐/right‐sided VF defect) and compared to previously collected data of 36 controls (age 70 [67–72] years). All participants monocularly tracked a moving stimulus (Goldmann size III) at three Weber contrasts (40%, 160% and 640%), while their eye movements were recorded. Results: ABI significantly decreased tracking performance ( p < 0.0001) compared to controls at all contrasts, independently of VF defect side ( p = 0.53). Performance improved from 40% to 160% contrast ( p < 0.0001), but not from 160% to 640% ( p = 0.53). SAP MS correlated moderately to strongly with tracking performance ( r = 0.46 [ p = 0.07], 0.73 [ p = 0.01], 0.67 [ p = 0.004], for 40%, 160% and 640% contrast, respectively). Retesting showed no significant learning effect. Conclusion: SONDA‐EMP can detect visual function loss from ABI. The reduction in tracking performance depends on the amount of VF loss.

Purpose: Standard automated perimetry (SAP) is the gold standard for functional assessment in glaucoma. SAP can be too demanding for some groups of patients. Continuous visual stimulus tracking (SONDA: Standardized Oculomotor and Neurological Disorders Assessment) simplifies the perimetric task to following a moving stimulus on a screen. In this study we evaluated the screening performance of SONDA-based eye movement perimetry (SONDA-EMP) in glaucoma. To explore generalizability, we evaluated an experimental setup (SONDA-Eyelink) and a clinic-ready version (SONDA-Neon). Methods: SONDA-Eyelink and SONDA-Neon measurements were performed in 100 cases with glaucoma (36, 36, and 28 with early, moderate, and severe glaucoma, respectively) and 100 age-similar controls. Participants monocularly tracked a moving stimulus (Goldmann size III) at 40% contrast (both setups) and 160% (SONDA-Eyelink). Eye movements were continuously recorded. Outcome was the agreement between gaze and stimulus position. We used previously collected glaucoma case-control data to build a continuous ‘glaucoma screening score’. This score was used for an ROC-analysis applied to the current, independently collected dataset. We predefined good screening performance as: at 95% specificity, a sensitivity of at least 50%, 90%, and 100% for early, moderate, and severe glaucoma, respectively. Results: At 95% specificity, the sensitivity of SONDA-Eyelink was 58, 94, and 100% at 40% contrast and 56, 97, and 100% at 160% contrast for early, moderate, and severe glaucoma, respectively. Sensitivity was 53, 94, and 100% for SONDA-Neon. Conclusions: SONDA-EMP is a novel, fast, and intuitive method to screen for visual function loss in glaucoma.

Individuals with homonymous hemianopia (HH) may benefit from adopting compensatory crossing and scanning strategies to successfully cross streets. In this study, we explored the effect of HH on street crossing outcomes, crossing behavior and scanning behavior in a virtual environment. Individuals with real HH (N = 18), unimpaired vision (N = 18), and simulated HH (N = 18) crossed a virtual street displayed through a head-mounted display. Virtual cars approached from both directions, traveling at a speed of either 30 or 50 km/h. Participants' crossing and scanning behaviors were recorded and analyzed across groups and the two car speeds. Although individuals with real and simulated HH took more time to cross compared to individuals with unimpaired vision depending on the car speed, the number of collisions and time-to-contact after crossings did not differ between groups. We observed no differences in the selection of car gaps, crossing initiation, and scanning behavior between groups. Our findings suggest that individuals with real and simulated HH align their crossing behavior to their visuomotor capabilities by using varying compensatory strategies. HH did not alter scanning behavior before crossing a virtual street. Despite its current shortcomings, virtual reality holds promise for street crossing research and rehabilitation.

The 23-item Screening Visual Complaints questionnaire-acquired brain injury (SVCq-abi) was constructed to assess visual complaints in individuals with acquired brain injury (ABI). This cross-sectional study determines the validity and clinical applicability of the SVCq-abi in an ABI sample. The SVCq-abi was administered to 156 individuals with ABI (mean [SD], 58 [13] years, 36% female) following a neurorehabilitation programme (65% inpatient, 35% outpatient). Confirmatory factor analysis (CFA) was performed to determine the fit of a 5-factor model, and scale reliability was examined. Additionally, we assessed the distribution of responses on the SVCq-abi and the effect of key clinical variables on SVCq-abi subscale scores. CFA confirmed a 5-factor model with good fit statistics, except for the Standardized Root Mean-square Residual. Scale reliability ranged from weak to good. Most individuals (78%) reported at least one visual complaint. Outpatients reported more luminance-related and ocular discomfort complaints than inpatients. No significant effect was observed on subscale scores based on administration method, history of ophthalmic disease, time since ABI diagnosis, and age. CFA determined a 5-factor structure of the SVCq-abi, with sufficient scale. Individuals with ABI experienced a range of visual complaints. The SVCq-abi showed broad clinical applicability and may be a valuable tool for clinical practice.

Homonymous Visual Field Defects (HVFDs) often cause reading difficulties. Self-reported reading difficulties and reading intervention goals remain however understudied. This study explores the prevalence of self-reported reading difficulties in 24 individuals with HVFDs, compared to their pre-HVFD experiences and to 160 matched controls. A comparison between left- and right-sided HVFDs is also included. Additionally, we examined which reading skills and reading objects individuals with HVFDs wished to improve. Using the novel Hemianopia Reading Questionnaire, we found that individuals with HVFDs reported poorer reading efficacy, poorer reading skills and poorer reading of different objects compared to pre-HVFD levels and control participants. However, love for and the importance of reading appear unaffected by the HVFD. Reading speed and orientation were the most affected skills after HVFD. Individuals with right-HVFDs reported lower reading speed compared to individuals with left-HVFDs. Reading books was the most desired goal for improvement, yet reading books was also the most abandoned object after HVFD. Overall, the current study indicates the importance of reading in individuals with HVFD and highlights that self-reported reading difficulties occur in a broad range of difficulties related to efficacy, skills and reading objects and should be incorporated in future effect measures of HVFD-intervention studies.

Introduction: Virtual reality environments presented through head mounted displays (HMDs) hold promise for training or studying mobility activities, such as cycling, walking, and street crossing. Yet, the limited field of view (FoV) of HMDs may influence scanning behaviour, reducing the translatability of findings to real-life situations. This study aims to (i) investigate how a reduced FoV influences scanning behaviour during mobility activities, and (ii) whether these alterations in scanning vary across these activities. Method: Sixteen participants performed a real-life walking, cycling and street crossing activity twice; once with and once without a reduced FoV. A mobile eye-tracker with a built in gyroscope recorded scanning behaviour. Scanning behaviour was evaluated in terms of saccadic frequency and amplitude, horizontal head movement frequency and amplitude, and the horizontal and vertical eye position. Results: The participants performed more horizontal head movements with larger amplitudes during the reduced FoV compared to the normal FoV. Additionally, they distributed their horizontal eye position more towards the central regions and less towards their peripheral regions. Overall, the range of both horizontal and vertical eye position decreased. The impact of the reduced FoV on horizontal head movement amplitude, horizontal eye position, and vertical eye position varied across activities. Conclusion: Generally, individuals seem to compensate for a reduced FoV by making more horizontal head movements with large amplitudes, while reducing the eye position distribution. Consequently, caution is advised when translating outcomes on scanning behaviour observed in HMDs to those expected in real-life situations.

Purpose: Visual complaints are a common consequence of acquired brain injury (ABI). Yet, they may be overlooked in clinical practice. The present study aims to develop a screening instrument for assessing visual complaints in individuals with ABI and evaluate its psychometrics properties in a community sample. Methods: We constructed the Dutch Screening Visual Complaints questionnaire-acquired brain injury (SVCq-abi), a self-report 23-item questionnaire. A Dutch community sample of 1159 participants (Mean [SD] age, 60 [16] years) completed the SVCq-abi and other questionnaires on visual disturbances, executive functioning, mental health, and autistic traits. Confirmatory factor analyses were performed for 5 models (1-factor, 3-factor, 5-factor, second-order, and bifactor) on a random split of half of the sample, and cross-validated on the other half. In addition, we evaluated floor and ceiling effects, scale reliability, test-retest reliability, as well as convergent and divergent validity. Results: A 5-factor structure of the SVCq-abi was adopted which showed an excellent model of fit, with all item loadings exceeding 0.5. The SVCq-abi subscales demonstrated various floor effects, acceptable scale reliability, moderate to good test-retest reliability (ICC = 0.65 to 0.73), along with sufficient convergent (r² = 9% to 32%) and divergent validity (r² = 2% to 13%). Conclusions: The SVCq-abi shows fundamental psychometric properties and the factor analysis provides support for a 5-factor structure. Further validation of the SVCq-abi in individuals with ABI is essential.

Purpose: The 6-item Vision-related Quality of life and Limitations questionnaire (VQL-6) is a screening instrument that signals a need for additional low vision care in patients with chronic ophthalmic diseases. This study aims to (1) determine the optimal scoring method for the VQL-6 and (2) evaluate its discriminative capacity for clinical use. Methods: Patients with glaucoma and retina- and cornea-related disorders completed the VQL-6 and participated in an interview designed to distinguish between patients with and without a need of additional care. For the two subscales (general health and quality of life, HQOL, and vision-related limitations, VL) we compared a scoring model with equal item weights to a cross-validated model using regression weights. The optimal scoring method and discriminative capacity of the subscales were determined using receiver operating characteristics (ROC) analysis, with the interview outcome as gold standard. Sensitivities were evaluated at specificities of 90 and 95%. Results: In 297 interview assessments, 96 patients (32%) appeared to need additional care. Both scoring models demonstrated very similar area under the ROC curves (AUC). The selected equal weight model yielded an AUC of 0.91 (95% confidence interval 0.87-0.94) for VL and 0.71 (0.65-0.77) for HQOL. For VL, sensitivity was 72 and 64% at 90 and 95% specificity, respectively. Corresponding HQOL sensitivities were 34 and 17%. Conclusions: The subscale VL shows excellent discriminative capacity and outperformed HQOL. Future studies should explore the feasibility of the VQL-6 in clinical practice.

The ability to read is important for daily life functioning. Individuals with homonymous visual field defects (iwHs) after brain injury experience frequent reading difficulties. The current study presents a novel self-report questionnaire aimed at measuring the wide variety of reading difficulties iwHs can experience: the Hemianopia Reading Questionnaire (HRQ). The 24-item HRQ was developed with help from clinical experts and experts by experience and was inspired by existing reading questionnaires for adults. The three tested subscales of the HRQ assess the relationship to reading, reading skills and daily life functional reading. The factor structure, reliability, convergent validity and divergent validity were examined in a large community sample (i.e., individuals without homonymous visual field defects) with a comparable distribution of age, gender and level of education to those who have suffered a stroke (N = 998). Two competing hypothesized models were tested and a good fit was found for a three-bifactor model of the HRQ. The reliability of the three subscales was found to be good (ω range 0.93–0.99), as well as the convergent and divergent validity (9 out of 12 Spearman’s correlations, according to expectations). The results support further use of the HRQ in iwHs, especially in the context of reading rehabilitation. Suggestions for clinical and scientific use and future psychometric research on the HRQ are provided.

Reading difficulties are amongst the most commonly reported problems in individuals with homonymous visual field defects (HVFDs). To be able to provide guidance for healthcare professionals considering offering reading training, researchers in this field and interested individuals with HVFDs, this systematic review aims to (1) provide an overview of the contextual and intervention characteristics of all published HVFD interventions and (2) generate insights into the different reading outcome measures that these studies adopted. A search on PsycINFO, MEDLINE and Web of Science was conducted up to February 2, 2023. All intervention studies for HVFD in which reading was measured were included. Data was collected about the intervention type, session duration, number of sessions, the intensity, duration, circumstance of the interventions, country in which the intervention was studied and reading measures. Sixty records are included, describing 70 interventions in total of which 21 are specifically reading interventions. Overall, adjusted saccadic behaviour interventions occur most in the literature. A wide range within all intervention characteristics was observed. Forty-nine records reported task-performance reading measures, and 33 records reported self-reported reading measures. The majority of task-performance measures are based on self-developed paragraph reading tasks with a time-based outcome measure (e.g. words per minute). Future research could benefit from making use of validated reading tests, approaching the measurement of reading mixed-methods and providing participants the possibility to supply outcomes relevant to them.