Many of our patients are not aware of the impact of stress on their visual health and function. Stress is a physical, mental or emotional reaction caused by a change that disturbs or interferes with the body’s normal equilibrium. The ocular impact of stress may range from mild discomfort to severe, debilitating vision loss.
Various lifestyle factors and activities can induce eye stress, such as performing more near work, working longer hours and using more technology. As technology continues to advance, it’s difficult to escape the need to use our eyes more frequently and for longer periods of time.
As practitioners, we need to take the time to educate our patients on the ocular impact of stress.
Near Point Stress
According to Arthur Marten Skeffington, O.D., the near work demands imposed by contemporary or modern society are incompatible with our physiological capabilities, and therefore provoke a stress response in which our eyes converge closer than accommodation.1 The resulting mismatch between vergence and accommodation leads to symptoms of asthenopia and the inability to sustain activity, inadequate visual efficiency and information processing, and ultimately, causes adaptive changes in the visual system.1
Because of these symptoms, many choose to avoid near work. Those who choose to allow their visual system to adapt may develop myopia or distortions in vergence and accommodative function.1
This proposed mismatch between convergence and accommodation has been postulated to arise from two possible sources. The first is related to factors intrinsic to reading and includes unnatural sustained immobilization, intense demands for attention, and mental effort needed for information processing and performance, in an artificial, two-dimensional setting.
Optometric Evaluation Steps for Patients with Headaches:
The second source involves the psychological status of the individual and includes the patient’s personality, cognitive-perceptual style (central-peripheral organization), attitude, intensity, emotional status, exposure to psychological stress and stress reactivity.
Either of these sources may activate the sympathetic nervous system fight-or-flight stress response.1
Near point stress symptoms may include blur, headache and diplopia. Additionally, patients may exhibit variations in phoria, vergence and accommodation. There is a tendency for esophoria, orthophoria, or the less desired exophoria, to occur at near due to over-convergence.1 Other signs include a low positive relative accommodation (PRA) finding, avoidance of near work, and maintenance of a near working distance that is either exceptionally close or far.
The prescription of low plus lenses for near use is a key component in treating patients with near point stress. It is believed that low plus lens prescription facilitates the resolution of the drive for convergence to localize nearer than accommodation, improves visual efficiency, minimizes interference with cognitive function and reduces the need for adaptation.1
The determination of whether plus lens prescription is indicated—as well as the amount to prescribe—is based on exam findings and the patient’s performance with the proposed lenses. The case history (including symptoms and the patient’s visual needs such as working distance and computer use), equalization of the NRA/PRA, observation of changes to the phoria, near point/dynamic retinoscopy findings, the patient’s subjective response, and probes of performance (i.e., observation of increased reading speed) with the lenses should all be considered.
Although several modifications exist, lenses may be prescribed as near vision only, traditional bifocal (distance and near) or computer bifocal (computer distance and near).
Computer Vision Syndrome
Computer use is an increasing activity that is certainly a contributor to near point stress. Estimates show that 75% of all jobs in 2000 involved computer usage.2,3 Since then, that number has undoubtedly increased, particularly when those statistics are combined with non-vocational computer use, such as e-mail, internet browsing, and smartphone and tablet technology.3 In 1990, about 15% of U.S. households owned a computer; in 2005, that number increased to 50%.2
Younger patients use the computer for fun as well as an educational resource.
The American Optometric Association applies the term computer vision syndrome (CVS) to include the broad spectrum of vision problems experienced at video display terminals (VDTs).4 Approximately 22% of VDT users experience musculoskeletal disorders, while 50% to 90% experience visual symptoms.4 These symptoms include eyestrain, tired eyes, irritation, redness, blurred vision and double vision.4 Accommodative spasm, as well as dry eye syndrome, are major contributors to CVS.4 Symptoms following sustained computer use were significantly worse than those experienced after viewing a hard copy of text.3
Treatment of CVS involves a multifaceted approach that includes both ocular therapies and ergonomic adjustments.2 Proper lighting, anti-glare screens, proper monitor positioning, increased font size or monitor size, frequent breaks, vision training or eye exercises, plus lens prescriptions (near adds are not just for presbyopes anymore) and lubricating eye drops have all been successful at alleviating symptoms.2,5,6
Migraines
Stress, or release from stress, has been implicated as a trigger for migraine headaches.7 Migraine is a common neurovascular disorder that includes a clinical spectrum of symptoms, with visual aura sometimes preceding or accompanying a headache.7,8 Photopsia, fortification spectra or the slow propagation of a scintillating scotoma across the visual field are the diagnostic features of the visual aura associated with migraines, and may occur in the presence or absence of head pain.9
Although the specific mechanism by which a migraine is triggered is still unknown, it has been attributed to an abnormal cortical function—likely cortical hyper-excitability or hyper-responsivity—through which the brain is susceptible to sensory overload.7
Migraines can be a debilitating source of distraction from work and family. Other conditions with symptoms mimicking migrainous aura that may present with headaches include vitreo-retinal traction, retinopathies, embolism, ischemia (transient ischemic attack), vascular and hypercoagulable diseases, arteriovenous malformation, carotid artery dissection, epilepsy, subarachnoid hemorrhage and occipital lobe tumor. We must rule these causes out with a comprehensive eye exam and proper referral for further evaluation, if warranted (
see “Optometric Evaluation Steps for Patients with Headaches.”).7
Although pharmalogic treatments for migraine are available, an eye care practitioner can use non-pharmalogic strategies in the management of this condition. One way is by encouraging the patient to maintain a headache journal that may reveal possible triggers to avoid. Food triggers, for example, may include chocolate, citrus fruits, onions, beans, nuts and fatty foods.7 Alcoholic beverages, caffeine and caffeine withdrawal have been implicated as well.7
Patients can alleviate stress by improving and enhancing their accommodative and binocular vision skills with vision training activities, such as accommodative
flippers
Although a strong correlation between migraine headaches and refractive error or binocular anomalies does not exist, it is essential to manage these conditions, as it has been proposed that dynamic binocular seeing—normally a stress function—excites the migraine headache among visual pain sensitive individuals.7,8,10 This particular study found migraines to be relieved after fusion eye movement training through vision therapy.10
Colored, or precision tinted, lenses have been shown to alleviate discomfort from pattern glare, which can cause discomfort while reading printed text and has been associated with migraines.8 As an alternative to tinted lenses, colored overlays placed on top of reading material have been shown to improve text clarity as well.7
Myokymia
Eyelid myokymia, more commonly referred to as eyelid twitch, is thought to be stress-related. Myokymia consists of involuntary, fine, continuous, undulating contractions of the orbicularis oculi muscle.11 It tends to be unilateral, affects the lower eyelid and is transient. This condition can also occur due to severe fatigue, physical exertion or with excessive caffeine intake.11
Myokymia may last a few days, with intermittent spasms throughout the day—lasting up to several hours at a time.11 This condition rarely persists for several weeks or months. It is a benign, self-limited disorder typically managed conservatively with reassurance, rest and elimination or reduction of risk factors.11
Functional/Hysterical Vision Loss
Functional, or non-organic, vision loss is any visual impairment that cannot be explained by a pathologic or structural abnormality, and is a diagnosis of exclusion.12
Hysterical vision loss, which occurs outside the patient’s conscious awareness, needs to be distinguished from malingering, which is the purposeful feigning of symptoms for personal gain. Hysteria, also referred to as conversion disorder, is based on the Freudian concept that intolerable psychological conflict leads to the conversion of distress into physical symptoms.13
Organic Dysfunctions That Mimic Functional Vision Loss:
Stress is the predominant factor in conversion reactions, and can include trauma, fear, illness and failure at work.14 In addition to experiencing severe monocular or binocular visual acuity loss, patients may have constricted tubular or star-shaped visual fields.12-14 Although rare, some have reported red, yellow and purple chromatopsia.14
A comprehensive eye examination with creative chairside testing, dilated fundus exam, visual fields, imaging of the visual pathway and electrophysiologic testing are all essential to ensure that an organic dysfunction mimicking functional vision loss is not present either alone or in conjunction with functional loss (see “Organic Dysfunctions That Mimic Functional Vision Loss.” ).12,15,16
Once you confirm the diagnosis of functional vision loss, management may include frequent follow-up, patient reassurance and co-management with other specialties, including primary care and psychiatry.12
Streff non-malingering syndrome, also referred to as juvenile bilateral functional amblyopia, occurs in children and adolescents who are having behavioral and academic difficulties.17 It’s often the result of emotional stress in the child’s environment, such as divorce, neglect, low self-esteem or separation of family members.17
The syndrome is characterized by reduced distance and near visual acuity, reduced stereopsis, emmetropia to low hyperopic refractive status and no change in distance acuity with corrective lenses.17 Some believe it’s an autonomic nervous system disorder caused by an accommodative response to close work; this is in contrast to hysterical amblyopia, which has a primarily psychological etiology.18
While a psychological consultation is indicated for a patient with hysterical amblyopia, the application of low plus powered lenses, combined with vision training, is reported to be the most efficacious treatment for a patient with Streff syndrome.18
Video Games and 3D Hype
A discussion about stress and the eye wouldn’t be complete without mentioning the controversy surrounding the effects of 3D video games, movies and TVs. News reports and the Internet alike have recently been flooded with opinions about whether these new technologies are safe or harmful to our eyes. Since further research is still needed, eye care practitioners must rely on common sense for now.
As the new generation of 3D movies attracts crowds, an increasing number of patients are presenting to our offices with the common misconception that the movie is causing their eyestrain, headaches and blurred vision. Similarly, warning labels that advise parents to turn off the 3D function on handheld video games for children under age six are misleading them to believe such technology is detrimental to their children’s vision. We must explain to our patients that the use of 3D technology requires both eyes to function together and the symptoms they are experiencing are likely due to an underlying, undiagnosed vision problem—which may, in fact, be a blessing in disguise.
According to Martin Banks, Ph.D., professor of optometry and vision science at the University of California Berkeley, the artificial 3D technology causes a “vergence-accommodative conflict” because the viewer needs to focus at one distance (where light is emitting from the screen) and verge at another distance (wherever the 3D object appears in space).19 The natural linkage between vergence and accommodation is broken, forcing the eyes to work harder to keep images clear and single—a task that may be novel to some and thus may result in discomfort.
Diagnosing refractive and/or accommodative/binocular vision problems, managing them with glasses and/or vision therapy and educating our patients will enable them to embrace and enjoy technology, all the while proving to be an excellent practice builder for the optometric profession.
Often, our patients present to us concerned and fearful with symptoms they may not recognize as stress-related. As doctors, we are readily equipped not only to recognize, diagnose and manage these conditions, but also to reassure our patients and help them to relieve stress, which, in many cases, drastically improves their overall quality of life.
Dr. Amster, an assistant professor at Nova Southeastern University College of Optometry, specializes in pediatrics and binocular vision.
Dr. Amster would like to thank Sheena Jessee, O.D., Priyanka Patel, O.D., and Melanie Sturm for their assistance with the photographs.
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