SMART PHONES and tablets are part of a growing category of devices causing a massive increase on the visual demand of our patients. Included in this category are both virtual reality (VR) and augmented reality (AR). (See “Glossary,” p.17.) As a result, O.D.s find the need to understand the impact these devices have on their patients, mainly near-point visual stress and asthenopia (potentially leading to myopia and accommodation and vergence issues) as well as steps to take to allow patients to spend more time on task and be more productive and efficient while reducing eye strain.
SIGNS/SYMPTOMS
The first sign of near-point visual stress is the tendency for patients to get closer to the device by hunching over or pulling the device very close to their faces. This may seem counterintuitive, as we know that the closer the working distance, the greater the amount of visual stress. If so, why do we do it? The prevailing thought is that this is part of the general reaction to stress. Under stress, we pull items closer, we move less, we blink less often, we hold our breath, and other physiological changes occur.
Optometrically, we see the shortened working distance first and then we see an esophoria at near. Later, we see the loss of the natural refractive buffer of +0.75, which allows patients to absorb stress. This shift toward a plano distance refraction, or even into low myopia, may show some against-the-rule astigmatism, the hallmark sign of an accommodative dysfunction. After working on these devices, any more shift toward myopia causes patients to experience worsening distance blur.
All VR and AR devices have binocular headsets. Users of these devices who have problems will complain that they can’t see what they want or need to, so that they may continue competing or enjoying their experiences. Others may complain that the use of these devices causes a heightened form or more concentrated form of asthenopia, such as a pulling sensation of the eyes, burning or tearing or a headache (usually in the frontal area of the head).
Another complaint of device users is increased dry eye symptoms thought to occur secondary to staring longer at the screens without blinking. Reading has shifted to electronic devices where the print is smaller, the contrasts can be much higher, and engagement factors are far more intense as more entities compete for our attention. For example, banner ads encourage many of us to ignore large portions of the screen and to restrict our functional visual field to a very small area right around our fixation point. That intense engagement leads to a reduction in the blink rate as well as a decrease in respiration volume and frequency.
There are a few specifics to the VR experience: Older VR models produced lag time between the user’s movement and the scene shift inside the viewer. In some cases, this caused mild motion sickness, but in some situations, it was much worse! Often people describe a fishbowl affect (similar to a high base curve lens). The greater the lag time, the greater the discomfort experienced. With the modern units, lag times have been reduced. As the technology increases, this should become less of a problem.
Glossary
- Augmented Reality: A technology that superimposes a computer-generated image on a user’s view of the real world, thus providing a composite view. A very crude example of this is Pokéman Go where the players’ figure is seen moving around on a map in the real world. As you move or turn, the scene moves with you.
- Virtual Reality: Users experience a computer-generated simulation of a 3D image or environment that can be interacted with in a seemingly real or physical way by using special electronic equipment, such as a helmet with a screen inside or gloves fitted with sensors. The main difference here is that nothing from the “real” world is visible to the wearer of the device. An example is the Playstation VR.
DIAGNOSIS
Questionnaires developed by optometry can help identify near-point stress problems. These can signal the need for extra testing to provide a diagnosis. A diagnosis might indicate a basic treatment or referral to a colleague. Examples of questionnaires include the Convergence Insufficiency Symptom Survey (CISS) (tinyurl.com/AOA-CISS ), which is available online from many sources. There are also a number of Computer Vision Syndrome (CVS) questionnaires available online. (One such worksheet can be found in the July 2012 issue of OM.) These surveys can be taken before you see the patient, and you can have the results before you start to acquire patient history, providing you with a head start in identifying tests and causes of the symptoms.
- Near Point of Convergence (NPC). Slowing the target’s speed allows the eye care practitioner to see when one eye loses fixation. In the case of near-point stress, often, there is a considerable lag between when the patient reports seeing double and when the doctor sees one eye turn outward or simply stop converging.
- Cover test and phorias at distance and near. In the early phase of near-point stress, the patient exhibits shifts into esophoria on the near findings in both the cover test and the near phoria. Specifically, the near cover tests and near phoria typically show a small to moderate amount of exophoria at distance, while one or both of these near tests shows orthophoria or a slight esophoria.
- Fused cross cylinder (FCC); positive and negative relative accommodation (PRA & NRA) and near retinoscopy. The FCC, PRA/NRA and near-point retinoscopy help identify the accommodative component of the visual stress (i.e. near-point visual stress) and whether plus lenses for near work will help relieve it. Specifically, these FCC and PRA tests can indicate the intensity and duration of the visual stress, while the near-point retinoscopy implies which patients will benefit from relative plus lenses at near or for specific tasks. Near-point retinoscopy may support the use of lenses to reduce visual stress even when the FCC and PRA are reduced and indicate limited plus acceptance. There are several near-point retinoscopy procedures, such as Stress Point, Monocular Estimated Method, Bell and Book, and it can take some time and practice to become proficient in some of them. However, the enhanced ability to diagnose visual stress and prescribe task-specific lenses can make the investment very worthwhile.
About 3D
3D movies and televisions present another binocular challenge. Around 2009, there was a major push toward 3D movies and 3D televisions, which never moved to adoption at the rates many predicted. Studies show that about 10% of the population saw little 3D effect, and another larger percentage experienced discomfort after even a few minutes in the 3D environment. This caused a problem for many families where one or more members either could not appreciate the 3D or experienced discomfort. Interest in the new technology waned; it now seems to survive most popularly in special use cases for 3D displays, such as in gaming. Optometrists can help many of these people acquire the ability to use both eyes together and to enjoy the immersive 3D experience through prescribing and vision therapy, when appropriate.
MANAGEMENT
Identify the unmet needs, and address them. For example, if a binocular dysfunction is evident and is manifesting as a convergence insufficiency, then either directly provide vision therapy or refer to a colleague who offers these services in your area.
A number of device users will benefit from an “occupational” ophthalmic lens specifically designed for the task at hand, such as my own setup. I have a high 7x28 trifocal with the add cut by 0.50D from my standard add in my everyday pair. This gives me a wide area of excellent optics high up, so I don’t have to tip my head back, and allows for screens to be further away from me. Also worth noting are AR coatings, which I prescribe for a majority of my patients.
If the issue is related to visual hygiene, counseling on work distance and time on task might help the patient. One resource you might like to have on hand is a pamphlet on Visual Hygiene available through The Optometric Extension Program Foundation (tinyurl.com/OEPF-VH ). The AOA also has information on CVS on its website (tinyurl.com/AOA-CVS ), which you can direct your patients to or add the information to your office website.
In the case of dry eye complaints, optometrists use a variety of treatments for dry eye disease (DED), but seeing it in the context of this intense engagement can provide additional benefits. Helping our patients reduce visual stress while engaged on their screens can aid in resolving DED symptoms. For example, counsel your patients to use the 20, 20, 20 rule; every 20 minutes look up at 20 feet for 20 seconds.
IMPROVE QUALITY OF LIFE
Electronic devices have increased the number of people suffering with these symptoms. Through the use of the full scope of our optometric services, we have the diagnostic measures and tools to make a major change in the quality of life for the patients of the 21st century. OM
Blue Light Exposure
Consumers are exposed to blue light, emitted from the sun, and, to a lesser degree, electronic devices, with an increase in digital device use. “With an increase in digital technology, there has been an increase in blue light exposure. In turn, many individuals suffer from the physical eye discomfort after screen use for longer than two hours at a time, also known as digital eye strain,” according to The Vision Council’s “2017 blue light/digital eye strain report.” Also from the report:
- More than 87% of Americans use digital devices for more than two hours per day. This occurs amongst the majority within the following age groups: 91.6% of people 18 to 39; 88.6% of those 40 to 59 and 78.5% of those 60 and older.
- More than 52% of people use two digital devices simultaneously.
Although digital eye strain is not a true diagnosis (it does not have an ICD-10 code) discussing it can help raise consumer awareness, says Brian Chou, O.D., F.A.A.O., F.S.L.S. In addition, augmented and virtual reality devices bring screens closer to the eye, raising some concerns for many practitioners in terms of the intensity of blue light emissions from these devices, even though it’s a relatively small emission compared to the sun. (The sun’s blue light emissions are more than 100x more intense than electronic devices, according to Points de Vue, International Review of Ophthalmic Optics, an Essilor publication.)
There seems to be some disconnect between the O.D.’s awareness of blue light and the patient’s. Specifically, 49% of consumers had never heard of blue light and 58% of those who had, believe it comes from digital devices, however only 17% believe it to come from the sun, according to a recent Transitions Optical survey. Only 36% of eye care practitioners (ECP) claim to know a lot about blue light, and although only 59% of ECP respondents believe the sun is a source of blue light, this number is on the rise.
When addressing blue light with his patients, Dr. Chou discusses the importance of sun protection.
“I let patients know that there is mounting evidence that blue light may cause problems to their eyes years down the road. I don’t try to separate talking about blue light from sun protection,” says Dr. Chou. “By just discussing sun protection, that addresses the main concern that I have as an eye care practitioner.”
— Optometric Management
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