Visual fatigue and accommodation in digital device users

Paper title: Changes in accommodation with visual fatigue among digital device users

Authors: Sivaletchumi Sigamani (1), Chiranjib Majumder (2), Sheiladevi Sukumaran (2)

1. School of Optometry, Faculty of Medicine and Health Sciences, University College Sedaya International (UCSI) University, Kuala Lumpur, Malaysia
2. Optometry and Vision Science Program, Research Community Health Centre, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia

Date: Oct 2022

Reference: Sigamani S, Majumder C, Sukumaran S. Changes in accommodation with visual fatigue among digital device users. Med Hypothesis Discov Innov Optom. 2022 Summer; 3(2): 63-69.

[Link to open access paper]

Visual fatigue has become more common with increasing use of digital devices and visual display units (VDUs).¹ Symptoms can decrease visual performance, vary in severity including external symptoms such as dry eye, burning, discomfort and weeping and internal symptoms such as blurring or moving text, headache, eye pain, double vision and glare.^2-5 Subjective symptoms can be associated with the response of the visual system under these conditions.

This study aimed to assess the accommodative changes under varying levels of visual fatigue for university students who used digital devices for 3 or more hours per day.

A total of 86 students with a mean age of 22 (19-26 yrs) and a majority of Chinese ethnicity were enrolled to this cross-sectional study. Eye examinations were performed, including measuring amplitude of accommodation (AA), accommodation facility (AF) and monocular estimation method (MEM). The students reported their visual fatigue symptoms using questionnaires and were categorised according to their scores into either low, moderate or high visual fatigue groups.

Most students fell into the low visual fatigue group (54.66%). The moderate (19.77%) and severe (25.8%) visual fatigue groups were combined. The accommodation measurements were then compared between the two groups. 

There were no significant correlations found between the accommodation values and the different categories of visual fatigue. The lag and lead of accommodation measured by MEM did not correlate with any fatigue level. However, the binocular amplitude of accommodation and monocular accommodation facility were found to be significantly different between the two groups. The mean AA was 12D and 11.21D for the low and the combined moderate and severe group, respectively. The mean AF (right eye only) was 10.85D and 8.84D, respectively.

1. Prolonged use of digital devices may lead to some visual fatigue symptoms, particularly when used for 3hrs or more. Eyecare practitioners should consider asking patients about their digital screen time and provide advice on managing symptoms from screen use
2. The lower fatigue group showed better amplitude of accommodation and monocular accommodative facility. There was also a weak association found between the accommodation values of AA and AF for right, left and both eyes decreasing as the fatigue symptoms increased

This suggests that routinely measuring accommodation and binocular vision function is important to identify those who may experience visual fatigue with digital use.

This study featured university age students. Although online classes are less common with schools reopening following the COVID-19 pandemic, it would be useful to know if the results of this study would also apply to younger age groups with developing visual systems who use digital devices outside of school for homework and recreation.

It would also be valuable to know how long digital devices can be use before fatigue symptoms are experienced. One study has suggested ocular fatigue and ocular surface changes can be apparent after 2hrs use.⁶

Previous studies^7,8 have found an increasing in lag of accommodation for higher visual fatigue discomfort. A different questionnaire design was used to assess and score visual fatigue symptoms. However, this study found no significant difference for accommodative lag between the fatigue groups. This may be due to combining the moderate and severe groups before analysing the effects, the number of participants in each group or the questionnaire used.

Title: Changes in accommodation with visual fatigue among digital device users

Authors: Sivaletchumi Sigamani, Chiranjib Majumder and Sheiladevi Sukumaran

Purpose: Visual fatigue is categorized as a complex phenomenon that decreases visual performance. The aim of the present study was to assess changes in accommodation at different levels of visual fatigue among students of a Malaysian private university using digital devices

Methods: In this cross-sectional study, students regardless of sex and ethnicity were included. A comprehensive eye examination was performed. After estimating the level of visual fatigue, the amplitude of accommodation (AA), accommodation facility (AF), and monocular estimation method (MEM) were measured. The visual fatigue questionnaire was filled out by the participants. Participants were categorized based on the visual fatigue scores into low, moderate, and high visual fatigue groups. Moderate and severe visual fatigue groups were combined, as the distribution of participants was uneven across the groups. Accommodation parameters were measured for each group and compared between the two groups, i.e., the low visual fatigue group and the combined moderate to severe visual fatigue group.

Results: We enrolled a total of 86 students, including 29 (33.72%) men and 57 (66.28%) women, with a mean (standard deviation [SD]) age of 22.02 (1.51) years and age ranging from 19 to 26 years. By ethnicity, there were 69 (80.23%) Chinese, five (5.81%) Indian, four (4.65%) Malay, and eight (9.30%) participants from other ethnicities. Most participants were in the low visual fatigue group (54.65%), followed by the severe (25.58%) and moderate (19.77%) visual fatigue groups. AA for both eyes and AF for the right eye differed significantly between the two groups of visual fatigue: low (Group 1) and moderate-to severe (Group 2) (both P < 0.05). None of the accommodative parameters correlated with visual fatigue (P > 0.05).

Conclusions: Binocular AA and monocular AF significantly differed between the visual fatigue groups, but MEM was comparable. However, none of the accommodative parameters correlated with visual fatigue.These perceived vision dysfunctions could affect the visual skills of students. Therefore, future studies on the relationship between the observed dysfunctions and students’ reading performance are necessary.

[Link to open access paper]