This article is more than 5 years old. Information may no longer be current.
Symptoms caused by 3D media offer opportunities to optimize vision
Click Here to Manage Email Alerts
As part of a society growing ever more immersed in 3D technology, including 3D movies, TV and video games, our ability to see in three dimensions has become more important. Recent studies have shown that viewing stereoscopic 3D can have a significant effect on visual and physical comfort; however, this may point to an underlying binocular vision problem, for which the 3D technology itself may be a useful tool in prescribing treatment.
According to Michael R. Dueñas, OD, chief public health officer for the American Optometric Association, discomfort while viewing stereoscopic 3D (S3D) content can point to unequal refractive errors, hyperopia, convergence insufficiency, small angle eye turns, intermittent suppression and amblyopia.
“Basically, lack of depth and discomfort in viewing 3D should not make one say that there’s a problem with the 3D mechanics, but that there may be a problem within the individual vision performance,” Dueñas said in an interview with Primary Care Optometry News.
A recent study published in Optometry and Vision Science investigated the prevalence and magnitude of perceived immersion and viewing symptoms with S3D viewing and found that viewing the S3D content can lead to more severe cases of blurred vision, double vision, dizziness, disorientation and nausea.
Donna Matthews, OD, installed a 3D TV in her office to screen patients for convergence issues. She found that 30% of patients viewing the 3D images experience discomfort.
Source: Matthews D
The study included 203 subjects, a mix of teenagers and adults, who watched a movie in 2D or 3D while sitting at different angles and distances. Questionnaires were used to evaluate their visual and physical comfort before and after viewing the movies, as well as to document prior viewing symptoms.
According to the results, 12% of subjects viewing the 2D version of the movie reported increases in measured symptoms during and/or after viewing, while 21% of subjects watching the 3D version reported symptoms during and/or after viewing. The 3D version also induced more pronounced and more frequent symptoms of visual discomfort than 2D.
“Movie viewing itself likely causes general ocular and physical symptoms associated with performing sustained visual tasks,” the study authors said. “However, 3D viewing is specific in causing blurred vision and double vision.”
Using 3D as a diagnostic tool
Researchers at the College of Optometry at Pacific University have found that while S3D can indeed cause discomfort, it may also hold the key to identifying underlying factors behind that discomfort, which would be a useful tool in fixing those vision problems.
Vision tests implementing S3D are currently in development there, according to James E. Sheedy, OD, PhD, head of the Vision Ergonomics Research Laboratory and director of optometry research at Pacific.
“Our S3D testing regimens cover underlying binocular and accommodation vision problems, as well as some of the basics, like identifying visual acuities, whether there’s refractive error or amblyopia, and also stereoacuity,” Sheedy told PCON.
James E. Sheedy
“The testing we do and the functions we’re measuring are widely applicable, so I believe this is going to enable optometrists to more powerfully assess why their patients are experiencing discomfort,” Sheedy said.
Sheedy also cited another benefit of 3D, which is that it naturally enables a presentation of a separate image, one to each eye, making it easy to test each eye individually when the patient has both eyes open.
“And unless the patient plays around with their eyes a little bit, they don’t know which eye you’re testing,” he added.
Difficulty viewing 3D media or visual symptoms experienced afterwards may indicate a vision problem.
Source: Dueñas MR
The Pacific Eye Clinic
Pacific University also has a clinic focused on 3D vision, which is supported by industry juggernauts such as THX, LG, Planar and Nike, Sheedy said.
“We’ve put in a 3D movie theater equipped with a digital 3D projector, complete with a 4-foot screen and also a large plasma 3D display. We also utilize active 3D glasses and a 3D Playstation 3 video game system. We use these as diagnostic tools,” James Kundart, OD, MEd, FAAO, director of the 3D eye clinic, said in an interview with PCON.
“These 3D movies are a wonderful screener for us,” Kundart said. “I thought there would be only two kinds of people: those who could see 3D movies and those who couldn’t. But there’s this big group of people who can see the 3D in the movie but then get a headache after a short time.”
Most people who come into the 3D eye clinic complain about their experience driving or working at their computer or with their microscope; very few come in asking for help because they had difficulty or discomfort viewing a 3D movie, he said.
“Some patients call up for the service directly,” Kundart said. “With others, it’s an internal consultation service, so if a patient is turning out to have some kind of muscle misalignment or other issue with depth, then we send them over to the 3D exam area, perhaps while their eyes are dilating, perhaps before. In there, we work them up there as a part of our routine exam and see if we can enhance their glasses prescription with a prism, or some other optical means, in order to restore comfort and depth.
“Imagine the patient sitting in an optometric exam chair, and right beside the eye chart is a screen playing a 3D movie,” Kundart continued. “You do your regular exam, then at the end you look at the 3D and make sure it’s optimized. It takes the eye chart to one more dimension. There’s room on our prescription pads to do a little more, and it’s not something that would show up in a regular exam if you’re just checking for near, far and astigmatism.”
James Kundart
Kundart said he will test symptomatic patients with digital red lens testing, “a procedure I call associated phorometry,” he said.
“I filter the eyes with red/green anaglyphs, and the symptomatic patient generally sees diplopia,” he explained. “Then I use step prism in a forced-choice routine on our digital phoropters, asking the patient which is better, one or two, as usual. I do this for both horizontal and vertical prism. When I find a combination that works with this systematic search, then I show the 3D targets (a movie, video game or other static target) and trial the frame prescription.”
Using 3D in everyday practice
While the story of 3D in vision screening is currently being written, there are still ways for optometrists who do not specialize in 3D to incorporate this technology into their offices.
Donna Matthews, OD, a private practitioner in Birmingham, put a 3D TV in her office in 2011 and has since developed a set of 3D pictures to show anyone who would stop long enough to look at them. She reported that, based on verbal and physical responses, roughly 30% of those who viewed the TV experienced discomfort.
“Currently I show a set of up to 10 photos viewed on a passive 3D TV,” Matthews told PCON in an interview. “The content of the photos requires the patient to use varying amounts of convergence to view the images in 3D and represents the extremes of convergence required to perceive the 3D. Patients who can fuse all 10 images without expressing discomfort are not tested further, but those who either give up altogether or express difficulty are prime candidates for further testing.”
She did admit that there are some logistical challenges in establishing a consistent protocol for testing in the exam room, as the TV is situated in the waiting area, but she believes that this problem can be rectified with a handheld tablet, such as the Gadmei T863 3D tablet, which has an auto stereoscopic (no glasses required) 3D screen.
Donna Matthews
“Implementation of this device will make it possible to correlate symptoms, such as discomfort with near 3D viewing, with actual binocular status,” Matthews said.
“It’s a simple and engaging application of a new technology to elicit underdiagnosed common and chronic binocular problems, which have a significant impact on how easily and for how long schoolchildren and working adults can effectively attend to near tasks,” she added.
Using 3D as a vision screening tool
While such a mode is still years away from coming to fruition, a vision screening system based on the latest 3D technology would be able to achieve a significantly higher sensitivity than standard Snellen charts, according to Dueñas. A screening test like this would, therefore, be able to catch more people who have underlying and underdiagnosed vision problems and would also hold the potential for mass screening, considering the popularity of 3D in our society.
“The biggest problem we have in eye care is that the methodology we’ve been using for vision screening has been insufficient,” he said. “The eye chart was developed 150 years ago by Dr. Snellen. The sensitivity of using that in screening is only 27%, so that means it’s 73% inaccurate. So, if we have 100 children who are screened with an eye chart, and if all of them have at least one underlying vision problem, we only correctly identify 27 of them, and the other 73 we send back to class.”
These students who get sent back to class often get mislabeled and misdiagnosed, Dueñas said, many of them ending up at psychologists’ offices to be put on attention deficit-hyperactivity disorder medications, because not being able to concentrate and participate correctly in class relates to ADHD symptomatology.
“We [the AOA] believe that as many as 20% of students currently being treated with ADHD medications may only have a vision problem,” he said.
“I always say that it would be great if vision problems could be like dermatological problems, where you could look in the mirror and see the problem for yourself,” Dueñas said. “But most vision problems are asymptomatic, such as uncorrected refractive errors and amblyogenic factors. [Media using] 3D provides that mirror, so if we’re noticing that a child is not effectively seeing the 3D imagery, that’s actually a blessing in disguise.”
The AOA and 3D
According to Dueñas, the AOA feels that 3D and its effect on the visual system is one of the most significant things to hit optometry in the last 150 years, and that making the most of that is incredibly important in terms of improving population health. As such, the AOA plans to play a major role in bringing forward the potential benefits of 3D to public health.
In line with that plan, the AOA has developed several partnerships with the 3D consumer electronics industries and cinema studios to discover a number of important aspects of 3D and its effect on the visual system, Dueñas said.
The AOA has also created a public website, www.3deyehealth.org, to spread awareness of the effects of 3D viewing and what they may mean for your vision, he said.
“The biological plausibility is there,” Dueñas said. “We know that static stereoacuity is roughly about 43% sensitive, so because of the way 3D uses tracking, accommodation and a number of other factors, we believe the sensitivity will be much higher. Hopefully, in the near future, we’ll have a screening methodology using 3D that will have 90% sensitivity or greater.”
“Also,” he added, “there exists the potential for mass screening, if only in terms of a preventive message to movie-going audiences and people with 3D televisions.
“Is it there yet? No,” Dueñas added. “The book on 3D in secondary prevention and vision screening is currently being written, but it’s not the final chapter yet. It’s something new and it’s something already having a positive impact, so we believe that will continue.” – by Daniel R. Morgan
References:
- Yang S et al. Stereoscopic viewing and reported perceived immersion and symptoms. Optometry and Vision Science. 2012;89(7):1068-1080.
For more information:
- Michael R. Dueñas, OD, can be reached at (703) 837-1008; mobile: (860) 792-1095; mrduenas@aoa.org.
- James Kundart, OD, MEd, FAAO, can be reached at the College of Optometry, Pacific University, UC Box 692, 2043 College Way, Forest Grove, OR 97116-1797; (503) 352-2759; (503) 352-2020; fax: (503) 352-2929; kundart@pacificu.edu.
- Donna Matthews, OD, can be reached at 2014 Morris Ave, Birmingham, AL 35203; (205) 328-1744; fax: (205) 328-4270; donnamat@aol.com; drdonnamatthews.com.
- James E. Sheedy, OD, PhD, can be reached at Pacific University College of Optometry, 2043 College Way, Forest Grove, OR 97116; (503) 352-2884; fax: (503) 352-2261;jsheedy@pacificu.edu.
Disclosures: Dueñas, Kundart, Matthews and Sheedy have no relevant financial disclosures.