Video-game vision therapy

Excerpted from page 18 of the April 2016 edition of AOA Focus.

Vision therapy isn't a game—or is it?

It depends who you ask at the neuro-optometric practice of Mary VanHoy, O.D., in Indianapolis, Indiana.

"Come on, we've got to go," Dr. VanHoy recounts telling her 5 p.m. patient, well past the office's 6 p.m. closing time.

"Just one second. I've got to hit all these bubbles," came the reply, not from the 7- and 8-year-old patients in the therapy room, but the Oculus-Rift-wearing 54-year-old college professor with convergence insufficiency.

No, this wasn't some research trial gone long. It's an increasingly common scene in vision therapy: using, for all intents and purposes, video games to supplement the tried-and-true Marsden ball or Brock string.

Video games aren't exactly a standard bearer for healthy lifestyles—polarizing opinions span time—sucker to art form. Yet, therapeutic innovation in eye care might add to that debate as AOA Focus takes a look at the good, the bad and the ugly of video games.

The good: Novel devices give docs, patients 1UP

Gazing side to side in virtual reality (VR) goggles, reaching out to pop 3-D bubbles, Dr. VanHoy's Ph.D.—holding patient wasn't the archetypal "gamer." But as he began vision therapy to improve a lifelong slow reading speed, the casual observer couldn't tell the difference.

Designed with amblyopia in mind, Dr. VanHoy's system uses an Oculus Rift VR headset to display separate images in each eye, creating a 3-D effect. Dr. VanHoy adjusts the contrast or adds partial occlusion to favor the weaker eye, thereby making it work harder in a series of games. Patients generally play one 10-minute session weekly, and in conjunction with other traditional vision therapies.

Like a consumer video game, these vision trials feature levels, power-ups and points to engage users, all the while strengthening their eyesight.

"I never grew up with video games, but this is something easy to break the ice and show that vision therapy isn't boring," Dr. VanHoy says.

The National Eye Institute estimates two or three out of every 100 children are affected by amblyopia, a condition that, if left untreated through childhood, will persist as the most common cause of monocular visual impairment in young to middle-age adults.

Traditionally, patching or atropine drops are used to treat amblyopia. The former involves covering the unaffected eye for weeks, forcing the brain to use the weaker eye; the latter blurs vision in the stronger eye to achieve the same goal. Both techniques were thought to work only in children under 10-important connections between the eye and brain are still developing through this age—but studies indicate that even adults might find some improvement.

Teng Leng Ooi, B. Optometry, Ph.D.—a professor at The Ohio State University College of Optometry—and a team of researchers looked into this question with a 2014 study, funded by the National Institutes of Health, that used a video game approach.

Knowing that it was possible to make an eye see or suppress based on special configuration of visual stimuli, researchers designed a game similar to Pac-Man that effortlessly makes the players' weak eye suppress the strong eye. Using 3-D glasses to filter images, the player's dominant eye would see only horizontal lines, while the weak eye saw disks filled with differently oriented lines. Players then navigated a Pac-Man character to a disc with the corresponding oriented lines.

"When you patch, you totally take away the vision of the dominant eye. With this game, the retina of the dominant eye has an image, but it doesn't get to the player's conscious perception because of the suppression mechanism," Dr. Ooi says, adding researchers called this the "push-pull" mechanism-forcing the weak eye to see (push), while also forcing it to suppress the strong eye (pull). And it seems to work. Researchers noticed reduced sensory eye dominance and improved depth perception in subjects with amblyopia, as well as improvement in visual acuity in their weak eyes.

"We have assessed the subjects' vision between 3 and 6 months after termination of the video game training and found that the improvements were retained. This shows that we've obtained long-term clinical plasticity," Dr. Ooi says. "We don't yet know if the effect will last permanently. It depends on the severity of the problem to begin with, but future studies will follow the subjects for a much longer period."

Amblyopia makes the headlines, but there's also promise in post-stroke and post-concussive syndrome patients, as well as patients with other vision concerns. Miki Lyn D'Angelo, O.D., owner of a vision therapy practice on Long Island, New York, uses her in-office system to work on vergence, saccades, visual memory, accommodative problems and more.

"I have a 78-year-old patient with severe convergence insufficiency who went to Florida for the season with an HTS system—essentially a video game she plays at home to maintain the skills she learned during active, in-office therapy," Dr. D'Angelo says. "I've done therapy as well with children as young as 3 and 4 with the computer-based system where the kids can see the (3-D) box popping out at them."

She adds, "Usually there's surprise and when patients see the system they ask, 'what do you mean this is helping my eyes?' Because it really is just a game to them."

That feeling is compounded in Dr. D'Angelo's younger patients who experience a certain familiarity with the therapy system. An Xbox controller, a 60-inch flat-screen TV and liquid crystal glasses that alternate between transparent and opaque depending on the displayed targets make the average 20-minute gaming session feel like just that—a game.

Another popular neurovision rehabilitation system incorporates a Nintendo Wii balance board to work on the integration of multiple systems, particularly the vestibular and visual-motor systems, giving patients a direct feedback mechanism to learn and correct their deficiencies.

The recent attention, and success stories, on incorporating gaming devices into vision therapy have even drawn interest from the ophthalmology community, currently conducting its own pediatric research.

"Video games really are the future in helping drive home that vision therapy works," Dr. D'Angelo says. "There's so much news about this technology right now that it's really taking off. It's the way of the future."

The bad: The flip side of the equation

Pew Research reports half of Americans played some form of video games in 2015, be it on a computer, TV or mobile device, and the preponderance of those devices is increasing.

According to AOA's 2015 American Eye-Q^® survey, one in five children received his or her first smartphone or tablet at age 5 or younger. Furthermore, one in three adult respondents used a digital device in excess of eight hours daily.

Americans spend a significant amount of time on digital devices, so what is it doing to our eyes?

Between ultraviolet and infrared radiation is the visible light our eyes process within the electromagnetic spectrum, and toward the UV end is blue light, currently a topic of intense scrutiny. That spotlight compelled global tech firms Amazon and Apple to add special blue-blocking features on e-readers and tablets, tinting screens orange in low light. Why the return of blue blockers? It's about hormones.

Gregory Good, O.D., Ph.D., a member of the AOA Commission on Ophthalmic Standards, writes in the AOA's "Light and Eye Damage" fact sheet that "short wavelength light (blue light) has been shown to have substantial effects upon alertness, vigilance and general wakefulness," as "stimulation of the intrinsically photosensitive retinal ganglion cells can suppress melatonin levels," responsible for circadian rhythms.

"While the intensity is much lower than from solar radiation, extended blue light exposure from handheld devices can have substantial negative effects on sleep cycles," Dr. Good says.

A 2014 study published in the journal Photochemistry and Photobiology suggested bright lighting before bedtime could alter circadian rhythms. The study found subjects who maximized lighting (65 lux) before bed, versus those who minimized lighting (3 lux), fell asleep about 14 minutes later but awoke at the same time. A Harvard sleep researcher found even 8 lux (about the brightness of a table lamp; twice that of a night light) can have effects.

However, blue light could suppress melatonin more powerfully, according to a 2015-updated Harvard Health Letter from the Harvard Medical School. When comparing the effect of 6.5 hours of blue light exposure with the comparable brightness and exposure to green light, researchers found "blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours)," the letter notes.

Felix Barker II, O.D., a member of AOA's Evidence-Based Optometry Committee, says as we've extended our daytime through artificial lighting, we put that night cycle at risk.

"The issue with electronic devices is that they have a higher fidelity for a full-spectrum simulation," Dr. Barker says. "A computer screen with white light—that means you have a reasonably flat spectrum from blue energy to red energy—simulates daylight more so than an incandescent bulb. And, as a matter of fact, some energy-saving lighting (e.g., LED) that's being introduced also has a closer simulation to daylight."

Researchers have analyzed this on a wavelength-by-wavelength basis, and in terms of regulating hormones, the shorter wavelength—i.e., blue—is much more efficient at triggering the light-dark change. That's why some recommend limiting exposure to computer screens and these light sources earlier in the evening or by wearing blue-blocking lenses to prevent it from intruding on sleep, Dr. Barker says.

Could blue light negatively impact the eye in other ways? A British study  published in the January 2016 edition of Eye journal concluded that, from a damage perspective, the blue light from digital devices was no riskier than staring at southern England's clear, blue sky.

Researchers compared subjects' average blue light exposure with the safe exposure limit outlined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and found this artificial light produced lower levels of exposure than a summertime sky in Chilton, England, which was, even then, only about 10% of the ICNIRP limit, according to Reuters news agency.

Although it did not address circadian rhythms, the study concluded that blue light exposure—even from hours of screen time—isn't likely to damage the retina. That is to say, however, researchers cautioned that children's eyes may be more sensitive to blue light.

"We do know that children's eyes transmit a greater proportion of the blue energy to the retina, and the long-term potential impact of that is not known," Dr. Barker says.

Dr. Barker, who contributed to AOA's Comprehensive Pediatric Eye and Vision Examination guideline, says there are no specific indications that too much light can prevent proper growth of children's eyes, but the impact on circadian rhythm (i.e., sleep/wake cycle) is something parents should consider.

"We can say that the development of computer screens and televisions in the past 50 years has definitely changed our relationship to light," he says. "The affinity that young children have for these devices is obvious, so it may have an impact on the growth and development of future generations.

We're not aware of what that might be, and more research is needed.

"Parents used to say how much TV children can watch because they were worried about learning and the medical status of the child, and this just adds one more factor—these possible physiological effects."

Blue light is only one concern of prolonged screen time. Think of video games and many conjure an image of kids surrounding a TV for hours on end. This kind of prolonged indoor time might have its own risks.

Studies indicate potential links between increased active time outdoors with reduced myopia rates. A 2015 Chinese study published in JAMA saw a 23% relative reduction in incident myopia after three years when study group schools included a mandatory 40-minute outdoor class and parents stressed outdoor activity after school.

A previous study from The Ohio State University College of Optometry in 2014 sought to identify the reasons behind such an observed correlation—also noted in a 2007 study—potentially identifying ultraviolet B rays as a catalyst in vitamin D production to bolster eye tissue.

Ida Chung, O.D., AOA InfantSEE^® and Children's Vision Committee member and pediatric guideline expert, says the research does indicate more time spent outdoors at a younger age can help delay onset of myopia and progression. Yet, with children adopting digital devices earlier, outdoor time can fall by the wayside.

"The other implication for children is digital eyestrain or computer vision syndrome," Dr. Chung says. "Perhaps in the past we diagnosed vision problems related to computer use in adults. Now we are increasingly finding these conditions in children, and even preschoolers. We should expect more children to have symptoms of digital eyestrain because of the increase in visual demand from using these kinds of devices."

The emergence of digital devices is changing the conversation between eye doctors and their pediatric patients, Dr. Chung says. She's expecting children to be using devices at a very early age, and therefore accommodation and binocular function are areas that Dr. Chung is sure to check, even at very young ages.

"Visual skills that we associate with school readiness I think are now life-readiness skills because of what children's eyes are exposed to at a young age," Dr. Chung says. "It's a point in the pediatric guideline, as well, that testing for efficient visual skills, and not just eyesight, factors in directly with how frequently children should be getting comprehensive eye exams, and how screenings cannot replace this."

The ugly: Wearables and uncharted territory

Wearable technology is the next progression in the digital revolution as laptops have moved to smartphones, to tablets, to watches and glasses. Products such as Google Glass fizzled before the consumer launch pad, yet there's still interest in keeping digital technology close at hand—and close to the eyes.

Forbes Magazine reports more than 41,000 patents were published on wearable technology between 2010 and May 2015, and in 2014, Morgan Stanley predicted wearables to "become the fastest-ramping consumer technology device to date," with potential for being a $1.6 trillion business.

Wearables are on the horizon. Although it's too early to see how this technology manifests, it is safe to say as digital screens go, so go video games. And eye care will be in lockstep.

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