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Asthenopia:A Technology Induced Visual Impairment


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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 more....

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Asthenopia:A Technology Induced Visual Impairment

  1. 1. Asthenopia: mieyecare 2A Technology InducedVisual Impairment writerS Dominick M. Maino and Christopher ChaseAs technology advances, eye strain and othersymptoms of asthenopia are on the rise.Vision systems evolve over generations of diminishing size. For example, films Asthenopia, which includes eye strain andbased on the needs of the users and the that were once projected onto a screen several other symptoms (figure 1), oftenenvironment. In humans, evolutionary that spanned the width of a wall can now occurs in patients whose visual systemspressures led to the development of the be viewed on a handheld screen that is a are capable of performing near-vision tasksneed for clear distance visual acuity mere 5cm x 7cm. The technology-induced for limited durations of time. It should beand binocular three-dimensional (3D) visual impairments we are witnessing noted that asthenopia does not occur as astereoscopic vision. These visual skills today are the result of our vision consequence of any weakness within theenabled us to effectively respond to threats information processing system attempting ocular musculature system, but ratherin the environment that were distant to undo a millennia of evolution and from the sustained near point demandsand constantly changing, and improved adjust to a relatively sudden change in now placed upon a visual system primarilyour odds of being the hunter rather than the demands placed upon our vision. designed for distance tasks. This isthe hunted.1 When Johannes Gutenberg frequently caused by a lack of appropriatedeveloped the process for modern book cortical output that is necessary forprinting in the mid 15th century, he set in Figure 1. Symptomatology of Asthenopia accurate accommodative and fusionalmotion the shift in visual demands away (modified from AOA Optometric Clinical Practice Guideline) vergence system responses, and for thefrom the importance of seeing clearly at Headaches (including migraines) demands of the task.1 As seen in figuredistance and toward a time intensive 2, there are a number of etiologies for Nauseatwo-dimensional near-point task asthenopia, but a recent study of 30 to 40such as reading.2 General fatigue year-old myopic subjects with asthenopia Sleepiness (N=253) found that the most frequentlyThe emergence of mass-produced printmaterials, such as books and newspapers, Diplopiahas resulted in patients experiencing eye Photophobia Figure 2. Etiology of Asthenopiastrain, and for some individuals, resulted (AOA Optometric Clinical Practice Guideline) Blurred visionin academic and work limitations.3,4As technology has advanced and Eye strain Type of Specific Diagnostic Categorieselectronic media become more dominant, Eye soreness / pain behind or inside eye Dysfunctioneye strain has progressed to a problem Burning / tearing eyes Accommodative Accommodative Insufficiencyencountered on a daily basis, with Ill-Sustained Accommodationpotentially serious health implications.1 Dryness (although there are other causes of this, including prolonged computer use) Accommodative InfacilityThis problem will continue to growin scope as patients spend increasing Difficulty reading Vergence Paralysis of Accommodationamounts of time performing near-vision Irritability Spasm of Accommodationtasks via digital media and as advances Poor concentration Vergence Dysfunctionin these devices result in viewing screens mivision • 47
  2. 2. mieyecareencountered oculo-visual problem was ill- three to seven times each week. And, occurred in fewer respondents thansustained accommodation (54 per cent).1,5 figure 6 highlights the negative impact the other symptoms listed, but highThese findings corresponded with a 2001 of symptoms. percentages of these respondents tended tostudy of 18 to 38 year-old subjects that experience these symptoms at least threereported accommodative disorders in 61 times or more each week (headaches afterper 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 highestGauging the prevalence of this disorder percentage of patients who found theirhas 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 thewide-ranging symptomatology are next symptom.8 This 3,800-patient surveyassessed, then the frequency andimpact of asthenopia are bound to impairments we are shows that a large number of patients suffer from asthenopia and the associatedbe underestimated; witnessing today are symptoms are experienced repeatedly2) Patients experiencing these symptoms during the week and have a negative effectmay 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 Atdue to the perception that no treatment information processing Greatest Risk?options exist; and All patients are at risk of developing3) Patients may perceive these symptoms system attempting to asthenopia, but the extent of that riskas an expected result associated with varies from individual to individual. Mostthe near task performed while wearing undo a millennia of patients report symptoms of vergencespectacles or contact lenses. dysfunction between the ages of 10 andResearch by Sheedy and associates shows evolution” 39, when the amount of near work is greatest.1 Many individuals with chronictwo different afferent pathways for the problems have learned to live with theirsymptoms of asthenopia. The symptoms condition and may not voluntarily revealcan be divided into associations with their symptoms. Young children (pre-either external or internal factors. school and early grades) may have fewerExternal 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 areto 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 theeyes) are related to accommodative or (figure 3). Many of the symptoms that involved a painful sequelae, such as symptoms associated with asthenopiabinocular vision stress.7 because they consider them as being what headache after near work and pain insideA study was conducted that included the eye, occurred less frequently but still is normally experienced by all.13,800 vision-corrected (contact lenses or affected 29 per cent and 19 per cent of Those whose occupations requirespectacles) patients from China, Japan, patients, respectively (figure 3). Patients considerable amounts of close work are atKorea, France, Italy, the United Kingdom from Asia demonstrated the greatest an especially high risk. Studies have notedand the United States that allowed for propensity for all symptoms of asthenopia that computer operators are particularlythe determination of the prevalence, (figure 4). These data suggest that the susceptible to asthenopia because afrequency and impact of asthenopia symptoms of asthenopia are prevalent and high percentage of computer users withupon the individual.8 The next set of that practitioners should be proactively symptoms have binocular vision problemsfour figures show the findings from this inquiring if their patients are experiencing and ocular discomfort increases with thestudy. Figure 3 shows the percentage of any of these symptoms.8 extent of computer use.9-12patients experiencing symptoms. Figure 4identifies the symptoms by region. Figure Pain-related symptoms, such as headaches In a study of 419 computer operators in5 pinpoints the symptoms experienced after near work and pain in the eyes, India, 46 per cent suffered from asthenopia48 • mivision
  3. 3. during or after working on a computer.13 In playing video games, or keeping up with patients. The use of various electronica 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, theindicated that they suffered from eye strain Internet, standard high definition andand/or pain.14 These results were similar Any individual with an undiagnosed 3D televisions, and 3D movies and videoto another Japanese study, where 70 per binocular vision dysfunction is at games, increases the demands placedcent 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 of soft contact lens wearers and Research shows that up to 56 per cent The Future Is Now: 3Dthose who had undergone successful of those 18 to 38 years of age exhibit With the success of the 3D films andLASIK surgery also reported 70 per cent signs and symptoms associated with a the development of 3D television andof patients experiencing some symptoms of functional vision anomaly and more video games, exposure to this form ofasthenopia, with 63 per cent complaining than 40 per cent of optometric doctoral entertainment is expected to increase inof 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 forComputer users are not the only computer users, with the rates for managers single, clear and comfortable 3D viewingprofessions 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 tofound 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.22accountants) that involve other types of Only now are we beginning to study Computer use is not the only source ofintensive near work, such as extensive those who experience symptoms while demanding near-vision tasks. Readingreading of printed materials, also viewing 3D content. Patients with this work-related printed materials can alsoincrease a person’s risk for developing newly coined “3D Vision Syndrome” significantly contribute to the stressorsasthenopia.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’tautomatically as being at lower risk, as An overabundance of work-related required any kind of vision correction inthey may spend a substantial amount of near-vision tasks is not the only reason the past can experience discomfort whiletime on the Internet seeking employment, why asthenopia is increasing in our watching 3D.27 In one study of young mivision • 49
  4. 4. mieyecareadults with normal binocular vision, dysfunction. Because the patient may Treatment with Vision Therapyalmost half experienced significant not realise that not everyone sees the Asthenopia can be successfully treatedvisual fatigue and discomfort while same way they do and that what they with vision therapy. The goals of visionviewing 3D.28 The American Optometric are experiencing is not normal, only a therapy are to ensure that the patientAssociation estimates that between three carefully taken case history can discover can visually function efficiently andand nine million (and possibly more) the problems your patients may have in comfortably in school, at work and/or inAmericans have problems appreciating this area. Answers received from the athletic activities, as well as to relieve anythe 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 focusingvision-intensive activities continue to add the same things.31,45 A comprehensive response. At the end of therapy, thestress to our work day and recreational assessment of the individual’s binocular patient should be able to make rapidactivities, it will also require greater effort vision system should be conducted for and accurate accommodative responseson 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 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 computerConsequences of Asthenopia the following:32-33 programs to improve vision functionAsthenopia often includes health-related • hen performing computer work, W are also effective.26,39,41consequences such as headache, diplopia,pain in and around the eyes and overall schedule periodic breaks where they lookfeelings of fatigue (figure 1). A person’s away from the monitor (generally forquality of life can be reduced as the every 20 minutes of computer use havepain and discomfort associated with them look away for 20 seconds).accomplishing particular activities can • ake sure there is proper lighting for Mlead to patients no longer performingthem. Hayes and associates found a small performing near-point tasks. “Treatments forbut significant relationship between • se proper ergonomics at the Uocular symptoms and global measures workstation. asthenopia areof quality of life and a large associationbetween eye and physical symptoms.30 • Use a larger font for onscreen text. available, but as withSymptoms associated with asthenopia • Blink often.not only negatively affect a person’s any health problem, theproductivity and academic performance, Practitioners can also advise the patientbut 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 theefficient and comfortable manner.1 symptoms associated with asthenopia. Strategies specific to computer operatorsTreatment of Asthenopia should also be employed to reduce theTreatments for asthenopia are available, incidence of asthenopia. In a study by Non-presbyopic patients, whobut as with any health problem, the Kotegawa and associates, computer are otherwise healthy but havefirst step is diagnosis. The simplest way operators (20-29 years of age) who accommodative insufficiency, can benefitto assess the presence of asthenopia had originally been undercorrected or from using multifocal spectacles todue to internal factors is to stress the overcorrected experienced a reduction in reduce the asthenopia associated withaccommodative and vergence systems headache, eye strain and tired eyes after this focusing dysfunction.42-43 Becauseduring your examination.1 Practitioners receiving accurate refractive correction.34 some adult contact lens wearers exhibitneed 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 readingvision activities. It is also important example, blue and white rather than green prescriptions in conjunction with theto ask appropriate questions regarding and red) have also been shown to reduce single vision contact lenses or multifocalany asthenopic symptoms typically the incidence of asthenopia in some contact lenses if asthenopia develops forassociated with binocular vision computer users.35-36 these patients.4450 • mivision
  5. 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 respond to stimuli that were distant,potentially dangerous and constantly and paying attention to the ergonomics of technology-induced-visual-impairment 2changing has been replaced with one their workstation. The use of correctivewhere 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 Illinoisdominant. This relatively new vision Eye Institute/Illinois College of Optometry and is indemand will continue to develop in an individually prescribed program of private practice in Illinois. He serves as the editor ofmagnitude as the time spent performing optometric vision therapy can frequently Optometry Vision Development and has authorednear 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 encounteredThe inclusion of 3D viewing technologies visual impairment that can seriouslyonly 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 HealthAs 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 forpractitioners need to determine their level enjoyment at play. Asthenopia is a more than 20 years. Currently, he is exploringof 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 activitiesthey pursue in their free time, and the treated, patients can pursue their interestsamount of time they spend performing to the best of their abilities without Disclosure: Editorial assistance provided bynear-point tasks. Practitioners also need experiencing pain or discomfort. BioScience educate their patients about waysReferences: 17. Vertinsky R, Forster B. Prevalence of eye strain 31. Maino DM. Identify binocular vision disorders.1. American Optometric Association Consensus Panel among radiologists: influence of viewing variables on Optometric Management. December 2009: www.on Care of the Patient with Accommodative or Vergence symptoms. AJR. 2005; 184:681-686. AccessedDysfunction. Optometric Clinical Practice Guideline: 18. 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