Background Research

Background Research

Introduction

Although technology is continuously advancing and working to improve the lives of those with disabilities, living with visual impairment continues to be a great challenge. The World Blind Union estimates in 2015 that there are 285 million people in the world that are either legally blind, visually impaired or partially sighted [1], and 40 million of those people are completely blind, and it is also estimated that this is most likely to double by the year 2050. Those who are classified as blind, 75% of them have some residual vision. Blindness is considered to be the loss of sight, not the loss of response to change in light. Alberta Orr, of the American Foundation for the Blind, states, "Many visually impaired persons are extremely sensitive to bright light and glare and wear sunglasses to reduce the amount of light on the retina. [2]" Therefore this project uses light as an experimental way to connect someone with a visual impairment to their surroundings, and abandon traditional aides such as a seeing-eye cane.

Light Sensitivity 

The focus of this project relies on light sensitivity, which is a discomfort to the user when exposed to light. The majority of those who are blind or have a visual impairment have a strong sensitivity to light. Long exposure to sunlight or fluorescent light can cause discomfort in the person. But a short exposure, or a flash, from complete darkness to a small light source can easily be detected. This sensitivity is referred to Photophobia.

How Do Eyes Work?

Light rays enter the eye through the cornea, which is a clear tissue at the front of the eye, and the cornea focuses the light as it enters. Located behind the cornea, is the iris, this is the colorful part of the eye giving someone the characteristic such as blue or brown eyes.  In the center of the iris is a black circle, called the pupil, which is an opening that allows light into the eye. The pupil changes size to control the amount of light entering the eye, this is done by muscles in the iris. In a dark room, your pupil increases to allow more light to enter enabling you to adapt and see better in the dark, while in bright daylight the pupil shrinks to reduce the amount of light and prevent damage to the retina.  After the light passes through the cornea and the pupil the light then passes through a lens, much like the lens of a camera, which focuses the light onto the back of the eye. The lens is held in place by a bunch of fibers, which are attached to the ciliary muscles, the ciliary muscles change the shape of the lens to let the eye change it’s focus on objects at different distances. To see an object at close range the ciliary muscles compress the lens and make is smaller and thicker, and expands and thins the lens when trying to focus on objects a far distance. The lens is focusing the light onto the retina, which is the “back wall” of the eye. The retina has millions of light sensitive cells called, rods and cones. Rods see in black, white and shades of gray, and help to determine the shape and form of objects. Rods are what also helps us see in the dark. While cones are sensitive to one of three colors, red, green or blue, and allow us to see millions of different colors. Cones need more light than rods to work. Behind the retina is the optic nerve, which carries messages to the brain about what the eye is seeing. Rods and cones translate the image into nerve messages which is then carried along the optic nerve to the brain, which is then translated in the brain.

Bellow is a labelled diagram of the anatomy of an eye:

  

Figure 1: The anatomy of an Eye [3]

An example of we can better understand rods and cones can be shown in the example bellow as an optical illusion provided by Crash Course [4], look at figure 2, the picture of a neon yellow and turquoise flag, for approximately 20 seconds and then immediately stare at the following figure, figure 3, which is a black picture.

 

Figure 2: Optical Illusion to Demonstrate Rods and Cones

Figure 3: Blank Photo to Demonstrate Previous Optical Illusion

During this demonstration, if you observed the flag long enough before looking you most likely saw an image that looked like this;

Figure 4: Result of Optical Illusion

Why did our eyes see this image? There are two reasons this illusion works, the first begging with the fact that our Photoreceptors can make us see after images. Some stimuli, such as bright colors or lights are so strong that our photoreceptors will continue firing action potentials even after we close our eyes or look away.

            The other part of the illusion has to do with another bug in our visual programming: And it is because out cones get “tired.” For example, with the flag, you looked at an image with bright turquoise stripes. Because your retinas contain red, green and blue- sensitive cones, the blue and green got tired after a while, leaving only the red still working. Then you looked at a white screen, which included all colors and wavelengths of visible light, so your eyes were receiving red, blue and green light but only the red cones were able to respond. As a result, the striped turned red.

            The same thing happened to the rods. Except, they only register black and white, it was like the afterimage was like a negative of a photograph- dark replace with light. Therefore, the black stars and stripes, turned white.

Types of Visual Impairment

The most common cause of blindness in 2010 were Cataracts, Glaucoma, and age related Macular Degeneration therefore the scope of the project has been suited for these three types of visual impairments as well as Diabetic Retinopathy since this is also one of the top cause of visual impairment and blindness globally, but also a major issue within America. 

     Figure 5: Leading Causes of Blindness

The chart depicted above was created for an article written by Catey Bunce and Richard Wormald, to discuss the "leading causes of certification of blindness and partial sight in England and Wales" [5] and although this article surveys England, this chart is a global perspective on the issue. From this article, the top cause was established and therefore became the scope of research and application for this design. 

            Since the concept of this design relies on the ability of the user with the visual impairment to detect a change in light from complete darkness to a strong light source, each visual impairment needs to be researched to determine what the user is able to detect and how long it may take for the user to be aware of a change from complete darkness to a flash. And although the project research is focusing on the four leading causes of blindness, the overall focus of the device expands beings that. Many people who have visual impairments are actually very sensitive to light changes, and therefore this project would drive effective. 


1. Cataracts

The National Eye Institute [6] gives a perspective into what cataract vision looks like: 

 

Figure 6: What Normal Vision Can See

Figure 7: What Cataract Vision Can See

The two images above show a before and after perspective of what someone with cataracts can see, and this vision can deteriorate until the person can eventually only detect shape or shadows. 

                    Cataracts is an age-related disease with a few people getting slight detection of it in their middle-ages, and many start loosing vision over the age of 60. Cataracts is a clouding of the lens and it is estimated that over 50% of people above the age of 80 have cataracts or had surgery to remove it. 

                    Treatment for cataracts is both effective and successful, sugary is the main method of treatment to remove the film over the lens. This is done in two methods, one is called Phacoemulsification, in which a small probe is inserted into the lens, that uses ultrasonic waves to break up the lens and create space for the cataracts to be removed by suction. Another method is Extracapsular surgery, in which the cloudiness is removed by an incision and the rest is removed by suction. These treatments have proved effective, but cataracts is a very common type of visual impairment and there are many cases in which people have multiple visual impairments, for example, people with age-related Macular Degeneration are also commonly exposed to cataracts. Therefore, this visual impairment was included for the team to have a better understanding of how those with visual impairments tend to be more sensitive to changes in light. 

2. Glaucoma 

As shown before by the National Eye Institute, they give the same perspective but this time showing the effects of Glaucoma;

Figure 8: What Glaucoma Vision Can See

Glaucoma is defined as several related eye disorders that affect the optic nerve, which carries information from the eye to the brain, and resulting in irreversible loss of vision. There is no cure for Glaucoma. The cause for Glaucoma in most cases is believed to be cased by an increase pressure within the eye. It is beneficial for early diagnoses, because it takes a long time to actually affect vision and be noticeable, and by that time the nerve is usually 50% dead. Treatments for Glaucoma include, decreasing the pressure on the eye through eye drops, or laser surgery, or actual surgery to manage the pressure on the eye.

 3. Macular Degeneration

Here is the same picture, but this time it is demonstrating what a person with Macular Degeneration sees;

Figure 9: Age-related Macular Degeneration

Age- related Macular Degeneration, abbreviated as AMD, is a common cause of vision loss of those over 50. AMD causes damage to the macula, which is a small spot near the center of the retina, which allows us to see objects straight ahead. To demonstrate the location of the macula, a similar figure by the National Eye Institute, similar to the diagram in figure 1 is shown bellow, the difference between them is that the macula is labeled.

Figure 10: Eye Anatomy Including Macula

The macula is made of many light-sensing cells that provide sharp, central vision, and is the most sensitive part of the retina. When the macula is damaged, central vision begins to become disoriented, blurry or even could be completely lost, and an example of this shown in figure 9.

AMD is a slow developing disease, and loss of vision takes a while to occur. It is very common in those who smoke, as well as those who have family history of AMD. And although AMD does not lead to complete blindness, it is hard to complete everyday activities.


4. Diabetic Retinopathy 

Here is the same picture, but this time it is demonstrating what a person with Diabetic Retinopathy sees;

Figure 11: Diabetic Retinopathy

Diabetic Retinopathy happens when the damage caused by diabetes begins to affects blood vessels in the retina. It is the most common cause of vision loss among people with diabetes. Diabetic macular edema (DME) is a result of Diabetic Retinopathy, which is a swelling of the macula, demonstrated in figure 10.

            More than half of the 18 million Americans who have have diabetes are effected by diabetic retinopathy to some extent. The treatment to prevent and control the disease is close control of diabetes. If the disease digresses, surgery is needed to protect sight.

5. Other Common Visual Impairments

Other common visual impairments include Retinitis Pigmentosa, the effects of this visual impairment is shown below;

 

Figure 12: Retinitis Pigmentosa

Retinitis Pigmentosa is an inherited disorder that results from harmful changes in any one of more than 50 genes. Genes carry instructions for creating proteins which are needed within the retina, referred to as photoreceptors. In the early stages of Retinitis Pigmentosa, rods are more severely affected than cones, resulting in night blindness and progressive loss of the visual field, the area of space that is visible at a given instant without moving the eyes. Eventually, the cones begin to breakdown, and more of the visual field is loss resulting in tunnel vision, shown in figure 12.

Ways of Sight


1. Seeing Eye Cane 

Traditionally a white cane is used to assist someone with a sight deficiency. The traditional cane is used to detect objects within close range such as curbs and walls but it poses a hazard to both the user and their surroundings. These canes only are limited to objects on the ground and therefore can not detect hanging ledges or moving objects. Overall this is the cheapest option available for somebody with a visual impairment. 

            There are also certain traffic laws that are accustomed to someone with a seeing eye cane in several countries, and this may be beneficial in this circumstance compared to the goggles presented in this project because in countries, like America, those with a seeing eye cane have the right away, the proposed adjustment to this would be to grant right away to those with the goggles, but the complication with this would be the drivers ability to distinguish the goggles. 


2. Assistant Animals 

An alternative to the traditional cane is the use of service animals. This alternative allows the user to have more interaction to the environment. But some downsides of this form of assistance would be the care and expense for the animal as well as if the person has allergies. 

Why Do Blind People Wear Sunglasses?

Many people who are blind, wear sunglasses to protect their eyes from photophobia, which can cause discomfort or dizziness. This is why the design of this project utilizes goggles as an apparatus, so the user can both have a form of navigation as well as protection from the sensitivity. Users would have to wear sunglasses to protect their eyes regardless of the visual aid, and therefore only has a double benefit.

Can Blind People Detect Light?

People who are going blind often first deal with vision impairment, which then progresses into blindness. Blindness can affect one or both eyes, and doesn't necessarily cause total darkness. Many people who are considered visually impaired can still see some light or shadows, but cannot see anything clearly. And those who are completely blind can tell the change from completely dark to a light source, and even sometimes the position of the light whether it is to the right or to the left of them. Tommy Edison, an American YouTube channel star, radio presenter and film critic, has been blind since birth. He records his experience and answers questions through comedy in a series called “The Tommy Edison Experience.” In one episode titled “What Do Blind People See?” he says that he can’t see anything, color and seeing are vague concepts to him. But he said he says, “All I see is light or dark. That’s it. I mean, the presence, or absence of light in a room, or in a space. That’s all I can distinguish. There are no shapes, there are no shadows.” He compares this to walking into a lobby with sunlight coming in through the window, he can see the light. His video is shown bellow.

Video 1: What Do Blind People See? [7]

Technology that Builds on This Idea and its Cost

Advances in technology and research for aiding visually impaired people throughout the world have grown over recent decades. Most popular of these advances is ultrasonic detection systems that communicate with their users through the means of touch and sound, due to practicality and efficiency in real world application. A few modern examples of technological innovations that are currently aiding the visually impaired are the “Smart Glasses” developed by Oxford University [8], which are bionic goggles that can detect light and shapes and display them on their own lenses. Another example is eSight [9], which are goggles that can zoom up to fourteen times the magnification of normal vision. The TripleTalkMini [10] is another piece of technology made to assist the blind, through specifically converting written text to electronic speech. This is a more limited, or simply, more specific and different approach to aiding the blind and visually impaired. These are variations of the modern approaches to combating blindness and visual suffering throughout the world.

Our Approach

Our goal is to eliminate the instability and difficulty of the navigation of those visually impaired. By utilizing 3D printing technology, light and ultrasonic sensors, an electronic visual aid can be developed to replace seeing eye canes for the visually disabled. Through a continuous feedback loop that identifies the position of and distance from surrounding objects, a visual aid headset for one’s eye produces light to indicate to its user that objects are present and one must acknowledge them appropriately. 

Isolating what kind of sensor and material to use is our main technical challenge, as well as determining how to accommodate any scenario in any environment if the final product is to universal practical use. The main tasks necessary for completion include a detailed structural design must be developed and measured as to accommodate all head shapes before production, and the final product must be realistically tested with multiple qualifying volunteers to ensure its real world functionality and accuracy.

Safety

There a few slight safety concerns with the device, these include: the user’s sensitivity to light, the user’s ability to detect a light source quickly, the user’s ability to detect the position of the light in the goggles, the heat of the LED's close to skin, and the efficiency of the product when introduced to water such as sweat and rain. 

               Photophobia is common among those who are blind or have a visual impairment, this is a strong sensitivity to lights. A short exposure of a non-intense light will not cause migraines or discomfort in most users, but if the user is very sensitive to light this could cause some issues. The solution to this is to use lower wavelength colors such as red at a lower intensity, and this could be manipulated within the code, but for the prototype purposes and testing the colors were kept on a swirl to see which one was the easiest for a user to detect. 

            Certain types of visual impairments prevent some users from being able to locate the position of the light source, while the device will still be useful in notifying the user that there is an object a close range, they will not be aware of the position. Also, if it takes a while for the user to realize that the light is on, it may be already to late and this would prove the device ineffective.

            Other safety hazards such as heat of the LED’s and effectiveness with water were taken into thought during construction and material. Although the LED’s will only stay lit for a few seconds, the group tested them in coiled up for 6 hours, and they only got relatively warm to touch, not burning hot. Also, to take into factor that they were coiled and close together making it easier for them to reach higher temperatures, while in the apparatus- they are spread out. For sweat and water proof, the team designed an encasement so the components do not get wet, as well as ordering waterproof LED’s and sealing all wiring.

The Real Approach

In future improvements of this project, developing a way to identify obstacles approaching from behind a user without overwhelming or confusing them would provide a safer and more thorough apparatus, however this would require additional appropriate financing and resources.


           An additional adjustment that could completely eliminate current issues would be an entirely redesigned approach to the problem statement. Specifically, developing an installation that is directly incorporated into the infrastructure of any given street could guide a visually impaired person by simultaneously avoiding the need to buy an expensive apparatus. This could be achieved by lining streets with stable (waterproof, physically strong, and out of civilian reach) electronic receptors that would send and receive signals from an ear piece in one or both ears of a visually impaired person. Signals acting as communication between the receptors and earpieces would identify for the user where the streets and sidewalks are, buildings, and could even extract specific building and street names for the user to learn upon request if the system could be synched up and constantly update with google maps, only considering Google agreed to participate. One might suggest this as an expensive, physically large, and time consuming proposal to incorporate throughout the world and that it because of this, it would not be feasible to approach. However, this could be solved by simply making it the government's responsibility with funding redirected from military reserves. For example, in America, military spending made up approximately 57% of the country's discretionary spending in 2015, according to nationalpriorities.org. By simply reallocating a small fraction of this funding towards national infrastructure, this project could become a reality in a realistically short span of time. This would also make the wellbeing of the country’s citizens the direct responsibility of the government rather and save individuals from conversely spending money on an expensive apparatus that they should not have to. This approach could not only aid those visually impaired, but those who are completely blind, which is another reason why this is the most preferable and appropriate to develop [11].

We're Getting Closer to a Cure for Blindness

In recent years’ scientist have been creating methods of treatment to sustain sight in those who are visual impaired and some have even been able to completely restore sight. Some of these methods include Gene Therapy, Stem Cells and Bionic Eyes. 

          Gene Therapy is a very new research field, only 5 years ago in 2011 the University of Pennsylvania conducted a study [12] with patients that had a hereditary disease Leber Congenital Amaurosis, therefore they all had mutations in their RPE65 gene. This gene, according to the U.S. National Library of Medicine, "provides instructions for making a protein that is essential for normal vision" [13]. The patients were given a non-harmful virus that would implant this gene. Only half of the patients showed improvement, and in the following years the University plans to continue their research and see if the experiment is safe. 

          Other ways science has impacted visual impairment is with injections and surgery. Eye injections and sugary are used to treat Macular Degeneration and Cataracts. And although neither of these can cure the patient, they can prolong the individuals sight.

Proprioception

The Oxford Dictionary of Nursing [14] defines Proprioception as “the ability to use the senses in a coordinated way, by means of the action of proprioceptors, that enables a person to identify where parts of their body are located even when they are physiologically separate.” A common example to demonstrate this is if you were to close your eyes, and your friend rotated your arm, without looking or moving you would be able to tell where your arm is located, or how fast they moved it. Proprioception is the “unconscious” awareness of where the various regions of the body are located. It is commonly described as our “sixth sense” and is associated with being blindfolded and completing an activity such a fighting or jumping rope.

            Mobility of the visually impaired requires greater proprioception. When someone is unable to see they rely more on their sense and feel of depth and space with their body. Otherwise it would be harder to use body parts or reach out and touch objects, and making mobility virtually impossible.

            Yoga is a great way to enhance proprioception. A study was conducted to see if this was the same for those who are visually impaired, since they rely on it more [15]. The result of this experiment concluded that it significantly improved in a few students, improved overall in over half, but some had no change when it came to yoga. But this experiment shows that there are activities that can help improve this sense and overall help those with a visual impairment so they can navigate.

            The following video shows proprioception in action for someone who is blind. The man shown in the video is blind in one eye, and therefore covers his left eye. With his right eye (blind) open, he begins to rotate his arm and he is able to track his arm through movements of his right eye although he can not actually see his arm. He is able to do this because of proprioception.

Video 2: Blind Man Sees (Proprioception) [16]

Resources

[1] "World Blind Union." Home. N.p., n.d. Web. 25 May 2016.

[2] Chimthanawala, Kasim. "Why Do Many Blind People Wear Dark Glasses?" NATIONAL         JOURNAL OF HOMOEOPATHY Apr.2 (1996): n. pag. Web. 25 May 2016.

[3] "Eye Health: Anatomy - Airdrie Eye Doctors - Airdrie, Alberta." Eye Health: Anatomy  Airdrie Eye Doctors - Airdrie, Alberta. N.p., n.d. Web. 25 May 2016.

[4] Crashcourse. "Vision: Crash Course A&P #18." YouTube. YouTube, 2015. Web. 25 May        2016.

[5] Bunce, C., W. Xing, and R. Wormald. "Causes of Blind and Partial Sight Certifications in         England and Wales: April 2007–March 2008." Eye 24.11 (2010): 1692-699. Web.

[6] "National Eye Institute." National Eye Institute. N.p., n.d. Web. 25 May 2016.

[7] TommyEdisonXP. "What Do Blind People See?" YouTube. YouTube, 2013. Web. 25 May      2016.

[8] "Obstacle Detection Gadget for Visually Impaired Peoples." Academia.edu. N.p., n.d. Web.      11 May 2016.

[9] "'Smart Glasses' May Be the Newest Aid for the Visually Impaired." South China Morning      Post. N.p., n.d. Web. 11 May 2016.

[10] Forbes. Forbes Magazine, n.d. Web. 11 May 2016.

[11] "Federal Spending: Where Does the Money Go." N national Priorities Project. National         Priorities Project, n.d. Web. 13 Apr. 2016.

[12] Ashtari, Manzar, Laura L. Cyckowski, Justin F. Monroe, Kathleen A. Marshall, Daniel C.      Chung, Alberto Auricchio, Francesca Simonelli, Bart P. Leroy, Albert M. Maguire,      Kenneth S. Shindler, and Jean Bennett. "The Human Visual Cortex Responds to Gene        Therapy–mediated Recovery of Retinal Function." Journal of Clinical Investigation J.   Clin. Invest. 121.7 (2011): 2945. Web.

[13] "RPE65." Genetics Home Reference. N.p., n.d. Web. 25 May 2016.

[14] Martin, Elizabeth A., and Tanya A. McFerran, eds. "Proprioception." A Dictionary of  Nursing. 6th ed. N.p.: Oxford UP, 2014. Print.

[15] Mohanty, S., B. Pradhan, and R. Nagathna. "The Effect of Yoga Practice on Proprioception    in Congenitally Blind Students." British Journal of Visual Impairment 32.2 (2014): 124   35. Web.

[16] MatbouleITS. "Blind Man Sees.MOV." YouTube. YouTube, 2012. Web. 25 May 2016