Vision systems evolve over generations based on the needs of the users and the environment. In humans, evolutionary pressures led to the development of the need for clear distance visual acuity and binocular three-dimensional (3D) stereoscopic vision. These visual skills enabled us to effectively respond to threats in the environment that were distant and constantly changing, and improved our odds of being the hunter rather than the hunted. When Johannes Gutenberg developed the process for modern book printing in the mid 15th century, he set in motion the shift in visual demands away from the importance of seeing clearly at distance and toward a time intensive two-dimensional near-point task such as reading....read more....

1. Asthenopia:
mieyecare
2
A Technology Induced
Visual Impairment
writerS Dominick M. Maino and Christopher Chase
As technology advances, eye strain and other
symptoms of asthenopia are on the rise.
Vision systems evolve over generations of diminishing size. For example, films Asthenopia, which includes eye strain and
based on the needs of the users and the that were once projected onto a screen several other symptoms (figure 1), often
environment. In humans, evolutionary that spanned the width of a wall can now occurs in patients whose visual systems
pressures led to the development of the be viewed on a handheld screen that is a are capable of performing near-vision tasks
need for clear distance visual acuity mere 5cm x 7cm. The technology-induced for limited durations of time. It should be
and binocular three-dimensional (3D) visual impairments we are witnessing noted that asthenopia does not occur as a
stereoscopic vision. These visual skills today are the result of our vision consequence of any weakness within the
enabled us to effectively respond to threats information processing system attempting ocular musculature system, but rather
in the environment that were distant to undo a millennia of evolution and from the sustained near point demands
and constantly changing, and improved adjust to a relatively sudden change in now placed upon a visual system primarily
our odds of being the hunter rather than the demands placed upon our vision. designed for distance tasks. This is
the hunted.1 When Johannes Gutenberg frequently caused by a lack of appropriate
developed the process for modern book cortical output that is necessary for
printing in the mid 15th century, he set in Figure 1. Symptomatology of Asthenopia accurate accommodative and fusional
motion the shift in visual demands away (modified from AOA Optometric Clinical Practice Guideline) vergence system responses, and for the
from the importance of seeing clearly at Headaches (including migraines) demands of the task.1 As seen in figure
distance and toward a time intensive 2, there are a number of etiologies for
Nausea
two-dimensional near-point task asthenopia, but a recent study of 30 to 40
such as reading.2 General fatigue year-old myopic subjects with asthenopia
Sleepiness (N=253) found that the most frequently
The emergence of mass-produced print
materials, such as books and newspapers, Diplopia
has resulted in patients experiencing eye Photophobia Figure 2. Etiology of Asthenopia
strain, and for some individuals, resulted (AOA Optometric Clinical Practice Guideline)
Blurred vision
in academic and work limitations.3,4
As technology has advanced and Eye strain Type of Specific Diagnostic Categories
electronic media become more dominant, Eye soreness / pain behind or inside eye Dysfunction
eye strain has progressed to a problem Burning / tearing eyes Accommodative Accommodative Insufficiency
encountered on a daily basis, with Ill-Sustained Accommodation
potentially serious health implications.1 Dryness (although there are other causes of this,
including prolonged computer use) Accommodative Infacility
This problem will continue to grow
in scope as patients spend increasing Difficulty reading Vergence Paralysis of Accommodation
amounts of time performing near-vision Irritability Spasm of Accommodation
tasks via digital media and as advances
Poor concentration Vergence Dysfunction
in these devices result in viewing screens
mivision • 47

2. mieyecare
encountered oculo-visual problem was ill- three to seven times each week. And, occurred in fewer respondents than
sustained accommodation (54 per cent).1,5 figure 6 highlights the negative impact the other symptoms listed, but high
These findings corresponded with a 2001 of symptoms. percentages of these respondents tended to
study of 18 to 38 year-old subjects that experience these symptoms at least three
reported accommodative disorders in 61 times or more each week (headaches after
per cent of subjects.6 near work 42 per cent; pain inside the eye
33 per cent)(figure 5). Not surprisingly,
How Prevalent Is Asthenopia?
a pain-related symptom had the highest
Gauging the prevalence of this disorder
percentage of patients who found their
has proven difficult for three reasons: “The technology- occurrence to be very bothersome
(headaches after near work, 44 per cent),
1) If only one or two symptoms of a induced visual which was almost twice as high as the
wide-ranging symptomatology are
next symptom.8 This 3,800-patient survey
assessed, then the frequency and
impact of asthenopia are bound to
impairments we are shows that a large number of patients
suffer from asthenopia and the associated
be underestimated;
witnessing today are symptoms are experienced repeatedly
2) Patients experiencing these symptoms during the week and have a negative effect
may not always schedule an examination the result of our vision on the individual’s quality of life.
or report them while being examined
Which Patients Are At
due to the perception that no treatment information processing Greatest Risk?
options exist; and
All patients are at risk of developing
3) Patients may perceive these symptoms system attempting to asthenopia, but the extent of that risk
as an expected result associated with varies from individual to individual. Most
the near task performed while wearing undo a millennia of patients report symptoms of vergence
spectacles or contact lenses. dysfunction between the ages of 10 and
Research by Sheedy and associates shows
evolution” 39, when the amount of near work is
greatest.1 Many individuals with chronic
two different afferent pathways for the problems have learned to live with their
symptoms of asthenopia. The symptoms condition and may not voluntarily reveal
can be divided into associations with their symptoms. Young children (pre-
either external or internal factors. school and early grades) may have fewer
External symptom factors (burning, Results show that patients frequently
experienced asthenopic symptoms with as near-vision demands; more importantly,
irritation, tearing and dryness) are related many children no matter their age are
to dry eye while internal symptom factors many as 58 per cent experiencing
eye strain and 69 per cent tired eyes often unable to describe their symptoms.
(ache, strain and headache behind the These children often do not report the
eyes) are related to accommodative or (figure 3). Many of the symptoms that
involved a painful sequelae, such as symptoms associated with asthenopia
binocular vision stress.7 because they consider them as being what
headache after near work and pain inside
A study was conducted that included the eye, occurred less frequently but still is normally experienced by all.1
3,800 vision-corrected (contact lenses or affected 29 per cent and 19 per cent of Those whose occupations require
spectacles) patients from China, Japan, patients, respectively (figure 3). Patients considerable amounts of close work are at
Korea, France, Italy, the United Kingdom from Asia demonstrated the greatest an especially high risk. Studies have noted
and the United States that allowed for propensity for all symptoms of asthenopia that computer operators are particularly
the determination of the prevalence, (figure 4). These data suggest that the susceptible to asthenopia because a
frequency and impact of asthenopia symptoms of asthenopia are prevalent and high percentage of computer users with
upon the individual.8 The next set of that practitioners should be proactively symptoms have binocular vision problems
four figures show the findings from this inquiring if their patients are experiencing and ocular discomfort increases with the
study. Figure 3 shows the percentage of any of these symptoms.8 extent of computer use.9-12
patients experiencing symptoms. Figure 4
identifies the symptoms by region. Figure Pain-related symptoms, such as headaches In a study of 419 computer operators in
5 pinpoints the symptoms experienced after near work and pain in the eyes, India, 46 per cent suffered from asthenopia
48 • mivision

3. during or after working on a computer.13 In playing video games, or keeping up with patients. The use of various electronic
a study conducted in Japan, 72 per cent of friends and family by using Facebook and media, including mobile phones,
office workers who work with computers other forms of digital social media. electronic messaging and texting, the
indicated that they suffered from eye strain Internet, standard high definition and
and/or pain.14 These results were similar Any individual with an undiagnosed 3D televisions, and 3D movies and video
to another Japanese study, where 70 per binocular vision dysfunction is at games, increases the demands placed
cent of computer users reported various significant risk for these technology- upon an already taxed vision system.
degrees of visual fatigue.15 A Norwegian induced visual impairments as well.
study of soft contact lens wearers and Research shows that up to 56 per cent The Future Is Now: 3D
those who had undergone successful of those 18 to 38 years of age exhibit With the success of the 3D films and
LASIK surgery also reported 70 per cent signs and symptoms associated with a the development of 3D television and
of patients experiencing some symptoms of functional vision anomaly and more video games, exposure to this form of
asthenopia, with 63 per cent complaining than 40 per cent of optometric doctoral entertainment is expected to increase in
of headaches.16 students may have a binocular vision the near future. Last year, more than 20
dysfunction.6,18 Gur, Ron and Heicklen- 3D feature films were released. ESPN is
Klein found a significant reduction in already providing programming in 3D,
accommodative and vergence function and the Discovery Network announced
among computer office workers over a the launch its own 3D channel in 2011.23
five-day work week, suggesting that those In the US, DirecTV began offering its
with dysfunctional binocular system may subscribers three channels dedicated to
“The use of various be particularly susceptible to symptoms 3D in 2010.24
due to computer use.19
electronic media, As Sony, Nintendo and other companies
add 3D capabilities to their products,
Factors Leading to Increased
including mobile Asthenopia
video game playing is also becoming a
significant contributor to the amount
The performance of near-vision tasks
of time spent viewing images in 3D.
phones, the Internet… occurs during school, at work and while
It should be noted that the Nintendo
engaging in recreational activities. Many
3DS system is a handheld device, forcing
increases the demands individuals may not realise the cumulative
users to view 3D images on a very small
effect that this can have on their visual
visually demanding screen.25
placed upon an already system and general sense of wellbeing.
The workplace is a significant source of Three-dimensional viewing contributes
taxed vision system” demanding near-point tasks, with many an additional level of burden to the
jobs requiring the use of a computer for overload of near-vision tasks that visual
up to eight hours per day.20 In 2003, 56 systems are already struggling to perform.
per cent of those employed (77 million Individuals who have poor convergence,
employees) used a computer at work. Some accommodation, and visual tracking
occupations have a greater proportion of abilities – all of which are necessary for
Computer users are not the only
computer users, with the rates for managers single, clear and comfortable 3D viewing
professions that are at risk for developing
(about 80 per cent) and sales/office workers – may experience blurred vision, diplopia,
asthenopia. A survey of 380 radiologists
(67 per cent) being particularly high.21 dizziness and headaches when exposed to
found that 36 per cent reported eye
Additionally, 77 per cent of those working this type of media.
strain.17 Professions (for example, lawyers,
from home were computer users as well.22
accountants) that involve other types of Only now are we beginning to study
Computer use is not the only source of
intensive near work, such as extensive those who experience symptoms while
demanding near-vision tasks. Reading
reading of printed materials, also viewing 3D content. Patients with this
work-related printed materials can also
increase a person’s risk for developing newly coined “3D Vision Syndrome”
significantly contribute to the stressors
asthenopia.1 Those who are not employed, require further clinical intervention and
placed upon the vision system.
including retirees, should not be viewed research.26 Even patients who haven’t
automatically as being at lower risk, as An overabundance of work-related required any kind of vision correction in
they may spend a substantial amount of near-vision tasks is not the only reason the past can experience discomfort while
time on the Internet seeking employment, why asthenopia is increasing in our watching 3D.27 In one study of young
mivision • 49

4. mieyecare
adults with normal binocular vision, dysfunction. Because the patient may Treatment with Vision Therapy
almost half experienced significant not realise that not everyone sees the Asthenopia can be successfully treated
visual fatigue and discomfort while same way they do and that what they with vision therapy. The goals of vision
viewing 3D.28 The American Optometric are experiencing is not normal, only a therapy are to ensure that the patient
Association estimates that between three carefully taken case history can discover can visually function efficiently and
and nine million (and possibly more) the problems your patients may have in comfortably in school, at work and/or in
Americans have problems appreciating this area. Answers received from the athletic activities, as well as to relieve any
the 3D experience.29 With an increase patient should then be reviewed together symptoms. For accommodative therapy,
in these visually demanding tasks, not so it is clear that you and the patient treatment increases the amplitude,
only will the time spent performing are using the same words to define speed, accuracy and ease of the focusing
vision-intensive activities continue to add the same things.31,45 A comprehensive response. At the end of therapy, the
stress to our work day and recreational assessment of the individual’s binocular patient should be able to make rapid
activities, it will also require greater effort vision system should be conducted for and accurate accommodative responses
on our part to appreciate these many new patients experiencing adverse reactions without fatigue.
and quality of life-changing technologies. when performing near-point activities.
Vision therapy helps the patient to
If the practitioner is not comfortable
develop efficient visual skills and vision
testing for binocular disorders or in information processing. The therapeutic
providing optometric vision therapy, the procedures re-educate the brain so that
patient should be referred to an eye care the individual can achieve single, clear,
practitioner who is.45 Such practitioners comfortable, binocular vision that
have been certified by the College of
“Asthenopia is a Optometrists in Vision Development (an
improves eye coordination, focusing and
eye movement, which ultimately enhances
international organisation) and can be the 3D viewing experience.37-38 Studies
frequently encountered found by logging on to www.covd.org. have shown that office-based treatment
(in addition to home-based activities) is
visual impairment that All patients can be at risk for developing
efficacious and long lasting.39-40 In these
asthenopia, so practitioners should
studies, vision therapy intervention not
can seriously threaten a educate them on what it is and how it
only eliminated symptoms, but also
may develop. For those patients with a
improved functional abilities – both
patient’s quality of life” greater risk for asthenopia based on their
accommodation and vergence. These
visual demands, information should be
remarkable results lasted at least 12
provided concerning visual hygiene and
months post intervention. For patients
various methods for modifying their
who cannot attend in-office weekly
near viewing environment. Practitioners
vision therapy appointments, out-of-
should advise their at-risk patients to do
office therapy using computer
Consequences of Asthenopia the following:32-33
programs to improve vision function
Asthenopia often includes health-related
• hen performing computer work,
W are also effective.26,39,41
consequences such as headache, diplopia,
pain in and around the eyes and overall schedule periodic breaks where they look
feelings of fatigue (figure 1). A person’s away from the monitor (generally for
quality of life can be reduced as the every 20 minutes of computer use have
pain and discomfort associated with them look away for 20 seconds).
accomplishing particular activities can • ake sure there is proper lighting for
M
lead to patients no longer performing
them. Hayes and associates found a small
performing near-point tasks. “Treatments for
but significant relationship between • se proper ergonomics at the
U
ocular symptoms and global measures workstation. asthenopia are
of quality of life and a large association
between eye and physical symptoms.30
• Use a larger font for onscreen text. available, but as with
Symptoms associated with asthenopia • Blink often.
not only negatively affect a person’s any health problem, the
productivity and academic performance, Practitioners can also advise the patient
but also our ability to perform work- that specially designed near-point first step is diagnosis”
related and recreational tasks in an corrective lenses can help relieve the
efficient and comfortable manner.1 symptoms associated with asthenopia.
Strategies specific to computer operators
Treatment of Asthenopia should also be employed to reduce the
Treatments for asthenopia are available, incidence of asthenopia. In a study by Non-presbyopic patients, who
but as with any health problem, the Kotegawa and associates, computer are otherwise healthy but have
first step is diagnosis. The simplest way operators (20-29 years of age) who accommodative insufficiency, can benefit
to assess the presence of asthenopia had originally been undercorrected or from using multifocal spectacles to
due to internal factors is to stress the overcorrected experienced a reduction in reduce the asthenopia associated with
accommodative and vergence systems headache, eye strain and tired eyes after this focusing dysfunction.42-43 Because
during your examination.1 Practitioners receiving accurate refractive correction.34 some adult contact lens wearers exhibit
need to be proactive in determining The use of antireflective film on monitors decreased accommodative abilities,
the full extent of their patient’s near- and the use of certain colours (for consider using either near reading
vision activities. It is also important example, blue and white rather than green prescriptions in conjunction with the
to ask appropriate questions regarding and red) have also been shown to reduce single vision contact lenses or multifocal
any asthenopic symptoms typically the incidence of asthenopia in some contact lenses if asthenopia develops for
associated with binocular vision computer users.35-36 these patients.44
50 • mivision

5. Conclusions they can reduce their risk of developing To earn your CPD points from this article,
The world where people needed the ability asthenopia, such as by taking periodic answer the assessment available at:
breaks from watching a computer screen www.mivision.com.au/asthenopia-
to respond to stimuli that were distant,
potentially dangerous and constantly and paying attention to the ergonomics of technology-induced-visual-impairment 2
changing has been replaced with one their workstation. The use of corrective
where sustained near-point tasks are and therapeutic lenses will often help to Dr. Dominick M. Maino, OD, MEd, FAAO, FCOVD-A is a
relieve symptoms while implementing Professor of Pediatrics/Binocular Vision at the Illinois
dominant. This relatively new vision Eye Institute/Illinois College of Optometry and is in
demand will continue to develop in an individually prescribed program of private practice in Illinois. He serves as the editor of
magnitude as the time spent performing optometric vision therapy can frequently Optometry Vision Development and has authored
near tasks increases and as the size of completely eliminate the asthenopia. 200 books, chapters, and articles. Dr. Maino has
given more than 100 presentations worldwide.
electronic displays continue to decrease. Asthenopia is a frequently encountered
The inclusion of 3D viewing technologies visual impairment that can seriously
only further complicates the problem. threaten a patient’s quality of life. It Dr. Christopher Chase, Ph.D. is a Professor
of Optometry at Western University of Health
As a large proportion of patients are interferes with the quality of our work, Sciences College of Optometry in California.
candidates for developing asthenopia, our performance in school and our He has been studying reading and vision for
practitioners need to determine their level enjoyment at play. Asthenopia is a more than 20 years. Currently, he is exploring
of risk by asking appropriate questions prevalent condition that deserves our full accommodation dysfunction and its impact
attention so that, once diagnosed and on reading and eyestrain.
about their occupations, the activities
they pursue in their free time, and the treated, patients can pursue their interests
amount of time they spend performing to the best of their abilities without Disclosure: Editorial assistance provided by
near-point tasks. Practitioners also need experiencing pain or discomfort. BioScience Communications.
to educate their patients about ways
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mivision • 51