Investigation of the Relationship Between Subjective Symptoms of Visual Fatigue and Visual Functions

Evaluation and application of a Chinese version symptom questionnaire for visual dysfunctions (CSQVD) in school-age children

Objective

To develop and evaluate a Chinese version of the Symptom Questionnaire for Visual Dysfunctions (CSQVD) to quantify visual dysfunction symptoms in school-age children with various eye diseases, and to explore the relationship between ophthalmological disorders and visual dysfunction symptoms.

Methods

Following standard scale adaptation procedures, the Symptom Questionnaire for Visual Dysfunctions (SQVD) was translated into Chinese (CSQVD). We employed random sampling to survey 198 outpatients aged 7-18 to assess the psychometric properties of the CSQVD. Using the reliable and validated questionnaire, we evaluated the determinants of visual dysfunction symptoms among 406 school-age patients at an eye center. The CSQVD scores were correlated with demographic and clinical variables, including gender, age, eye position, refractive power, and best-corrected visual acuity. Univariate analysis identified potential risk factors, followed by binary logistic regression and multiple linear regression analysis on factors with a P-value <0.05.

Results

The CSQVD scale's critical ratio (CR) values ranged from 6.028 to 10.604. The Cronbach's Alpha coefficient was 0.779, and Spearman-Brown split-half reliability was also 0.779. The I-CVI varied from 0.83 to 1.000, the S-CVI/Ave was 0.857, and the KMO value was 0.821. Multifactorial regression analysis indicated that high myopia (OR ​= ​5.744, 95% CI [1.632, 20.218], P ​= ​0.006) and amblyopia (OR ​= ​9.302, 95% CI [1.878, 46.058], P ​= ​0.006) were significant predictors of CSQVD symptoms. Multiple linear regression analysis showed that BCVA of amblyopic eyes (B ​= ​-5.052, 95% CI [-7.779, 2.325], P ​= ​0.000) and SE power (B ​= ​-0.234, 95% CI [-0.375, 0.205], P ​= ​0.001) significantly affected the CSQVD scale scores.

Conclusions

The Chinese version of the SQVD scale (CSQVD) demonstrates good feasibility, discriminatory power, validity, and reliability in assessing Chinese school-aged children. Furthermore, those who have severe myopia and amblyopia reported more visual dysfunction symptoms.

Decoding visual fatigue in a visual search task selectively manipulated via myopia-correcting lenses

Introduction

Visual fatigue resulting from sustained, high-workload visual activities can significantly impact task performance and general wellbeing. So far, however, little is known about the underlying brain networks of visual fatigue. This study aimed to identify such potential networks using a unique paradigm involving myopia-correcting lenses known to directly modulate subjectively-perceived fatigue levels.

Methods

A sample of N = 31 myopia participants [right eye-SE: -3.77D (SD: 2.46); left eye-SE: -3.75D (SD: 2.45)] performed a demanding visual search task with varying difficulty levels, both with and without the lenses, while undergoing fMRI scanning. There were a total of 20 trials, after each of which participants rated the perceived difficulty and their subjective visual fatigue level. We used representational similarity analysis to decode brain regions associated with fatigue and difficulty, analyzing their individual and joint decoding pattern.

Results and discussion

Behavioral results showed correlations between fatigue and difficulty ratings and above all a significant reduction in fatigue levels when wearing the lenses. Imaging results implicated the cuneus, lingual gyrus, middle occipital gyrus (MOG), and declive for joint fatigue and difficulty decoding. Parts of the lingual gyrus were able to selectively decode perceived difficulty. Importantly, a broader network of visual and higher-level association areas showed exclusive decodability of fatigue (culmen, middle temporal gyrus (MTG), parahippocampal gyrus, precentral gyrus, and precuneus). Our findings enhance our understanding of processing within the context of visual search, attention, and mental workload and for the first time demonstrate that it is possible to decode subjectively-perceived visual fatigue during a challenging task from imaging data. Furthermore, the study underscores the potential of myopia-correcting lenses in investigating and modulating fatigue.

Temporal trend of anisometropia incidence in Chinese school-aged children before and during the COVID-19 pandemic

Objective

To analyze and compare the temporal trends in the incidence of anisometropia among Chinese school-aged children both before and during the COVID-19 pandemic, and to investigate the impact of the pandemic on the incidence of anisometropia.

Methods

We conducted a retrospective study comprising six distinct and independent longitudinal cohorts, each including children aged 6 to 13 years who visited the Joint Shantou International Eye Center between January 2010 and December 2021. Children were grouped into cohorts based on the year of their first eye clinic visit: 2010, 2012, 2014, 2016, 2018, or 2020. Only children without anisometropia at initial visits, followed for 18 ± 6 months, were included. The cumulative incidence and risk factors of anisometropia were analyzed using Kaplan-Meier estimation and Cox proportional hazards regression models. Subgroup analyses were performed based on sex, age groups, initial refractive error status, and initial interocular SE difference. Anisometropic children were further categorized into myopic and non-myopic, with subsequent subgroup analyses conducted.

Results

Of 11,235 children were recruited from six cohorts (2010: n = 1,366; 2012: n = 1,708; 2014: n = 1,896; 2016: n = 2,354; 2018: n = 2,514; 2020: n = 1,397), 869 children developed anisometropia during a mean follow-up of 17.5 ± 3.7 months. After adjustment of confounding factors, we found that the risk of anisometropia remained relatively stable before 2020 but significantly increased in the 2020 cohort (adjusted HR 2.93, 95% CI 2.23 to 3.86; p < 0.001). This trend persisted in studies of spherical anisometropia (adjusted HR 2.52, 95% CI 1.60 to 3.97; p < 0.001) and cylindrical anisometropia (adjusted HR 2.91, 95% CI 1.69 to 3.62; p < 0.001). Older age and a greater initial difference in SE between the two eyes were also significantly associated with a higher risk of developing anisometropia (p < 0.001). Subgroup analyses consistently showed increased risk in the 2020 cohort.

Conclusion

This study reveals a concerning rise in anisometropia incidence among Chinese school-aged children during the period of the COVID-19 pandemic. These findings highlight the worrisome rise in anisometropia risk during the COVID-19 pandemic and emphasize the importance of early detection and management to safeguard children's visual health.

Perceptual Learning Based on the Lateral Masking Paradigm in Anisometropic Amblyopia With or Without a Patching History

Purpose

Perceptual learning (PL) has shown promising performance in restoring visual function in adolescent amblyopes. We retrospectively compared the effect of a well-accepted PL paradigm on patients with anisometropic amblyopia with or without a patching therapy history (patching therapy [PT] group versus no patching therapy [NPT] group).

Methods

Eighteen PT and 13 NPT patients with anisometropic amblyopia underwent monocular PL for 3 months. During training, patients practiced a Gabor detection task following the lateral masking paradigm by applying a temporal two-alternative forced choice procedure with the amblyopic eye. Monocular contrast sensitivity functions (CSF), visual acuity, interocular differences in visual function metrics, and stereoacuity were compared before and after training.

Results

PL improved the visual acuity of the amblyopia eyes by 0.5 lines on average in the PT group and 1.5 lines in the NPT group. A significant reduction in the interocular difference in visual acuity was observed in the NPT group (P < 0.01) but not in the PT group (P = 0.05). Regarding CSF metrics, the area under the log CSF and cutoff in the amblyopic eyes of the NPT groups increased after training (P < 0.05). In addition, the interocular differences of the CSF metrics (P < 0.05) in the NPT group were significantly reduced. However, in the PT group, all the CSF metrics were unchanged after training. A total of 27 of 31 patients in both groups had no measurable stereopsis pretraining, and recovery after training was not significant.

Conclusions

PL based on a lateral masking training paradigm improved visual function in anisometropic amblyopia. Patients without a patching history achieved greater benefits.

Translational Relevance

PL based on a lateral masking training paradigm could be a new treatment for amblyopia.

Visual fatigue a comprehensive review of mechanisms of occurrence, animal model design and nutritional intervention strategies

When the eyes work intensively, it is easy to have eye discomfort such as blurred vision, soreness, dryness, and tearing, that is, visual fatigue. Visual fatigue not only affects work and study efficiency, but long-term visual fatigue can also easily affect physical and mental health. In recent years, with the popularization of electronic products, although it has brought convenience to the office and study, it has also caused more frequent visual fatigue among people who use electronic devices. Moreover, studies have reported that the number of people with visual fatigue is showing a trend of increasing year by year. The range of people involved is also extensive, especially students, people who have been engaged in computer work and fine instruments (such as microscopes) for a long time, and older adults with aging eye function. More and more studies have proposed that supplementation with the proper nutrients can effectively relieve visual fatigue and promote eye health. This review discusses the physiological mechanisms of visual fatigue and the design ideas of animal experiments from the perspective of modern nutritional science. Functional food ingredients with the ability to alleviate visual fatigue are discussed in detail.

Development of a new 17-item Asthenopia Survey Questionnaire using Rasch analysis

AIM

To develop the 17-item Asthenopia Survey Questionnaire (ASQ)-17 by Rasch analysis, and to generate a predictiveness score.

METHODS

Totally 739 participants were recruited and 680 were involved in the result analysis in this prospective, cross-sectional study. Three rounds of Rasch analysis were used to analyze the psychometric characteristics of items and options.

RESULTS

Phase 1 assessed the original ASQ-19, adjusted the item scoring mode to a four-point Likert response rating scale and combined the 18th and 19th items into a new item. Phase 2 deleted the 11th item. Phases 3 and 4 assessed the new ASQ-17. All the evaluation indexes of ASQ-17 were acceptable. The Infit and Outfit MnSq values of items were 0.67-1.48, the variance explained by the principal component and the unexplained variance explained by the first contrast were 53.90%-59.40% and 1.50-1.80 in three dimensions. The curve peaks of scores in each dimension were separated and in the same order. The PSR and PSI values were 2.80 and 0.89, respectively. The mean scores of dimensions A (9.5±4.1 vs 3.5±3.2), B (7.3±3.3 vs 2.5±2.7), C (4.3±2.2 vs 1.4±2.0) and total (21.1±8.1 vs 7.4±7.0) in asthenopia participants were significantly higher than those without asthenopia (all P<0.001). The area under the curve in two groups was 0.899 (P<0.001). Youden's index was up to the maximum value of 0.784 when the cut-off value was 12.5.

CONCLUSION

ASQ-17 has stronger option sorting and suitability than ASQ-19. It is an effective assessment tool for asthenopia with an optimal cut-off threshold value of 12.5, which is suitable for diagnosis and curative effect evaluation.

Effects of school myopia management measures on myopia onset and progression among Chinese primary school students

BACKGROUND

Schools play an organizational role in managing myopia-related behavioral habits among students. We evaluated the effects of school myopia management measures on myopia onset and progression in a school-based prospective 1-year observational study.

METHODS

In total, 8319 children from 26 elementary schools were included. Online questionnaire completed by a parent, in which school myopia management experience including outdoor activities in recess or physical education class, teachers' supervision, and teaching facilities. Variables were defined as implemented well or poorly, according to the Comprehensive Plan to Prevent Myopia among Children and Teenagers. Children underwent ophthalmic examinations, and the incidence and progression of myopia from 2019 to 2020 were estimated. Multilevel logistic regression models were constructed to analyze the association between school management measures and myopia development in 8,9 years and 10,11 years students.

RESULTS

From 2019 to 2020, the incidence of myopia among primary school students was 36.49%; the mean difference of spherical equivalent in myopic children was - 0.29 ± 1.22 diopters. The risk of incident myopia was reduced by 20% in 8,9 years participants with well-implemented class recess compared with those with poorly implemented class recess (adjusted odds ratio [aOR]: 0.80, p = 0.032). PE outdoor time was significantly associated with myopia incidence in 10,11 years students (aOR: 0.76, p = 0.043). Compared with poorly implemented reading and writing posture, desk and chair height, 10,11 participants with well-implemented desk and chair height were less likely to have rapid myopic progression (p = 0.029, p = 0.022).

CONCLUSION

In Shanghai, children's myopia is associated with better implementation of school myopia management measures. The present findings suggest that outdoor activities during class recess or PE class, providing suitable desks and chairs, and adequate instruction in reading and writing postures might protect against pathological eye growth. An age-specific myopia prevention and control programs in school is of primary importance.

Assessment of precision and reliability of a novel computerized heterophoria test

Purpose

To assess the precision and reliability of a novel computerized heterophoria test (CHT).

Methods

One hundred and three subjects aged 20 to 48 (27.37 ± 5.15) were recruited from Wenzhou Medical University. All subjects with corrected spectacles were examined with CHT and a prism-neutralized objective cover test (POCT) in a randomized order. They were then re-examined with CHT within 1 week. Their heterophoria was measured at three different distances (3 m, 0.77 m and 0.4 m); the average was recorded after three consecutive measurements. Inter-examiner repeatability, intra-examiner repeatability of CHT and agreement between CHT and POCT were evaluated.

Results

There was no significant difference among repeated measurements using CHT (all p > 0.05). The difference between POCT and CHT was statistically significant at three distances (all p < 0.001). However, the mean absolute difference was 1.20^△, 1.93^△, and 2.41^△, all of which were significantly smaller than the permissible range of error (4^△) at three different distances (all p < 0.001).

Conclusion

The CHT demonstrated excellent inter- and intra-examiner repeatability, as well as good correlation with POCT. The differences between CHT and POCT were within the permissible range of error, indicating that CHT could provide a precise and reliable measurement for clinical applications.

Polyunsaturated Fatty Acids (PUFAs): Sources, Digestion, Absorption, Application and Their Potential Adjunctive Effects on Visual Fatigue

When the eyes are exposed to the environment, they are easily affected by strong light stimulation and harmful substances. At the same time, prolonged use of the eyes or incorrect eye habits can cause visual fatigue, which mainly manifests as eye dryness, soreness, blurred vision, and various discomforts. The main reason for this is a decline in the function of the eye, especially the cornea and retina on the surface of the eye, which have the greatest impact on the normal function of the eye. Research has found that supplementation with appropriate foods or nutrients can effectively strengthen the eye against external and internal stimuli, thereby alleviating or avoiding visual fatigue. Among these, supplementation with polyunsaturated fatty acids has been found to be effective at protecting eye health and relieving visual fatigue. This article summarizes the sources of polyunsaturated fatty acids (including the main dietary sources and internal synthesis), the mechanisms of digestion and absorption of polyunsaturated fatty acids in the body and the safety of polyunsaturated fatty acid applications. It also reviews the mechanism of action of polyunsaturated fatty acids in aiding the relief of visual fatigue based on the mechanism of impaired function or structure of the ocular surface and fundus in the hope of providing some reference and insight into the development and application of polyunsaturated fatty acids in functional foods for the relief of visual fatigue.

Characteristics and predictive factors of visual function improvements after monocular perceptual learning in amblyopia

Monocular perceptual learning has shown promising performance in restoring visual function in amblyopes beyond the critical period in the laboratory. However, the treatment outcome is variable and indeterminate in actual clinical and neuroscientific practice. We aimed to explore the efficacy of monocular perceptual learning in the clinical setting. By combining continuous monitoring of perceptual learning and clinical measurements, we evaluated the efficacy and characteristics of visual acuity and contrast sensitivity function improvement and further explored the individualized effect after perceptual learning. Amblyopes (average age:17 ± 7 years old) were trained in a monocular two-alternative forced choice identification task at the 50% contrast threshold of the amblyopic eye for 10-15 days. We found that monocular perceptual learning improves both visual acuity and contrast sensitivity function in amblyopia. The broader activation of spatial contrast sensitivity, with a significant improvement in lower spatial frequencies, contributed to improving visual acuity. Visual acuity changes in the early stage can predict the endpoint treatment outcomes. Our results confirm the efficacy of monocular perceptual learning and suggest potential predictors of training outcomes to assist in the future management of clinical intervention and vision neuroscience research in amblyopia beyond the critical period of visual plasticity.

Taurine: A Source and Application for the Relief of Visual Fatigue

According to reports, supplementation with appropriate doses of taurine may help to reduce visual fatigue. Presently, some progress has been made in research related to taurine in eye health, but the lack of systematic summaries has led to the neglect of its application in the relief of visual fatigue. This paper, therefore, provides a systematic review of the sources of taurine, including the endogenous metabolic and exogenous dietary pathways, as well as a detailed review of the distribution and production of exogenous taurine. The physiological mechanisms underlying the production of visual fatigue are summarized and the research progress of taurine in relieving visual fatigue is reviewed, including the safety of consumption and the mechanism of action in relieving visual fatigue, in order to provide some reference basis and inspiration for the development and application of taurine in functional foods for relieving visual fatigue.

Optimum display luminance under a wide range of ambient light for cockpit displays

The self-luminous cockpit displays need to be adaptive to a wide range of ambient light levels, which changes from very low illuminance to very high levels. Yet, current studies on evaluation and luminance setting of displays in bright surroundings are still limited. In this study, a three-dimensional visual ergonomic experiment was carried out to investigate how bright a cockpit display should be to meet aircrew operational requirements under different illuminance. A lab study with a within-subjects (N = 12) design was conducted in a simulated cockpit. According to the Weber-Fechner's Law, human observers evaluated five display luminance conditions (10¹, 10^1.5, 10², 10^2.5, 10³ cd/m²) under five ambient illuminance conditions (10°, 10¹, 10², 10³, 10⁴ lx). Visual performance, visual fatigue and visual comfort were used as evaluation bases, which were measured by d2 task, subjective fatigue questionnaire and visual perception semantic scales. Nonlinear function fitting was used to calculate the optimal luminance under a certain illuminance. Finally, curvilinear regression was used to analyze the illuminance and its corresponding optimal luminance. Based on Silverstein luminance power function, a luminance adjustment model with the form of power function was obtained. The proposed three-dimensional model fits the experimental data well and is consistent with the existing studies. It can be regarded as a supplement and optimization of the previous model under high ambient illuminance. This study can contribute not only to the pleasing luminance setting of panel displays in aircraft cockpits but also to other self-luminous devices, such as tablet devices, outdoor monitoring equipment and advertising screens.

Neural Research on Depth Perception and Stereoscopic Visual Fatigue in Virtual Reality

Virtual reality (VR) technology provides highly immersive depth perception experiences; nevertheless, stereoscopic visual fatigue (SVF) has become an important factor currently hindering the development of VR applications. However, there is scant research on the underlying neural mechanism of SVF, especially those induced by VR displays, which need further research. In this paper, a Go/NoGo paradigm based on disparity variations is proposed to induce SVF associated with depth perception, and the underlying neural mechanism of SVF in a VR environment was investigated. The effects of disparity variations as well as SVF on the temporal characteristics of visual evoked potentials (VEPs) were explored. Point-by-point permutation statistical with repeated measures ANOVA results revealed that the amplitudes and latencies of the posterior VEP component P2 were modulated by disparities, and posterior P2 amplitudes were modulated differently by SVF in different depth perception situations. Cortical source localization analysis was performed to explore the original cortex areas related to certain fatigue levels and disparities, and the results showed that posterior P2 generated from the precuneus could represent depth perception in binocular vision, and therefore could be performed to distinguish SVF induced by disparity variations. Our findings could help to extend an understanding of the neural mechanisms underlying depth perception and SVF as well as providing beneficial information for improving the visual experience in VR applications.

Vision-related symptoms, accommodative and binocular vision performance in young diabetics vs. normal controls

PURPOSE

To compare accommodative and binocular vision performance between young diabetic subjects and normal controls, and to investigate the correlation of accommodative/binocular indices with the severity of diabetes.

METHODS

Thirty young subjects with diabetes mellitus (DM) and 30 age-matched normal controls were recruited in this hospital-based cross-sectional study. DM was diagnosed by a haemoglobin A1c (HbA1c) higher than 6.5%. The status of vision-related symptoms was examined by the convergence insufficiency symptoms survey (CISS). All participants underwent a complete optometric examination including visual acuity measurement, objective and subjective refraction, accommodative and binocular vision assessments.

RESULTS

All study participants were between 18 and 40 years of age. There were no statistically significant differences in best-corrected visual acuity (BCVA), sphere, cylinder and spherical equivalent refraction (SE) between the diabetes and control groups. The median near point of convergence (NPC) was significantly more remote in diabetics compared with the control group. Mean accommodative amplitude (AA) and vergence facility (VF) and the median monocular accommodative facility (AF) were significantly lower in diabetic subjects compared with normal controls. In addition, the median accommodative lag in the diabetic group was significantly higher than the control group. A significantly higher percentage of the diabetic group were symptomatic (26.6%), compared with the controls (6.6%). The NPC and accommodative lag showed a significant positive correlation with the HbA1c level, while VF, AA and AF exhibited a significant negative correlation with HbA1c.

CONCLUSION

Aspects of accommodative and binocular vision performance are strongly affected by DM. There is also a significant correlation between accommodative and binocular disorders with the severity of DM. A significant percentage of young subjects with DM have severe vision-related symptoms.

Study of the Immediate Effects of Autostereoscopic 3D Visual Training on the Accommodative Functions of Myopes

Purpose

Stereoscopic viewing has an impact on ocular dynamics, but its effects on accommodative functions are not fully understood, especially for autostereoscopic viewing. This study aimed to investigate the changes in dynamic accommodative response, accommodative amplitude, and accommodative facility of myopes after autostereoscopic visual training.

Methods

We enrolled 46 adults (men = 22 and women = 24; age = 21.5 ± 2.5 [range = 18–25] years, spherical equivalent: −4.52 ± 1.89 [−8.88 to −1.75] diopters [D]) who visited the Eye & ENT Hospital of Fudan University. The study population was randomly divided into three-dimensional (3D) and two-dimensional (2D) viewing groups to watch an 11-minute training video displayed in 3D or 2D mode. Dynamic accommodative response, accommodative facility, and accommodative amplitude were measured before, during, and immediately after the training. Accommodative lag and the variability of accommodation were also analyzed. Visual fatigue was evaluated subjectively using a questionnaire.

Results

Accommodative lag decreased from 0.54 ± 0.29 D to 0.42 ± 0.32 D (P = 0.004), whereas accommodative facility increased from 10.83 ± 4.55 cycles per minute (cpm) to 13.15 ± 5.25 cpm (P < 0.001) in the 3D group. In the 2D group, there was no significant change in the accommodative lag (P = 0.163) or facility (P = 0.975), but a decrease in accommodative amplitude was observed (from 13.88 ± 3.17 D to 12.71 ± 2.23 D, P = 0.013). In the 3D group, the accommodative response changed with the simulated target distance. Visual fatigue was relatively mild in both groups.

Conclusions

The immediate impact of autostereoscopic training included a decrease in the accommodative lag and an increase in the accommodative facility. However, the long-term effects of autostereoscopic training require further exploration.