by Jeanne M. Haskin

Because the images produced on the outward surface of lenses in human eyes are in fact mirror images, we will begin this discussion with some noteworthy physics regarding the property of spherical mirrors.

To start, I will quote at length from a college textbook, and comment as I go.

A spherical mirror is a reflecting surface with spherical geometry. If a portion of a sphere of radius R is sliced off along a plane, the severed section has the shape of a spherical mirror. Either the inside or the outside of such a section can be reflective. For inside reflections, the mirror is a concave mirror. For outside reflections, the mirror is a convex mirror.[1]

Here we see that a slim slice of a spherical mirror, which matches the shape of the human lens, can be reflective on one or both sides. The human lens, which receives a mirror image of an object in the visual field on its exterior surface, can therefore be likened to a mirror surface—in this case a convex lens.

It is also important to note that:

[A]s light passes from air into the eye, it moves through the cornea, aqueous humor, lens, and vitreous humor and then passes through the entire thickness of the neural layer of the retina to excite photoreceptors that abut the pigmented layer.[2]

The pigmented layer’s function, which is relevant to this paper, will be addressed a little later. For now, what is of interest is that, during its passage, light is bent three times: on entry into the cornea, and on entering and leaving the lens.[3]

When light is bent, it alters the incident angle at which it enters a new medium, each time bending occurs. In a normally functioning human eye, this does not interfere with perception. In an abnormally functioning eye, it is entirely possible that if we treat the lens as capable of forming a mirror image on one or both sides, that a virtual (unreal) image may be created as a result of the final light bending, when light passes out of the lens. And/or the lens could buckle into a concave shape, perhaps in response to the final light bending. Noting, as we progress, that the lens of the human eye is most highly elastic in children.[4]

To get to the heart of the matter, this would render the lens dispersive instead of converging, i.e. light scattering and productive of a virtual image. To illustrate why this happens, we need a little more physics.

Quoting again from Wilson and Buffa:

When rays parallel to the optic axis are incident on a concave mirror, the reflected rays intersect, or converge, at a common point called the focal point. As a result, a concave mirror is called a converging mirror.[5]

This was previously noted as the normal condition for reception of a mirror image on the exterior of the human lens. Note, however, that the state of the actual mirror is concave, whereas the human lens is convex. In other words, opposite terms produce the same effect. With that said:

[A] beam parallel to the optic axis of a convex mirror diverges on reflection, as though the reflected rays come from behind the mirror’s surface. Thus a convex mirror is called a diverging mirror. When you see diverging rays, your brain interprets or assumes there is an object from which the rays appear to diverge, even though there is none there. The true object is somewhere else.[6]

Noting again, that the terms are opposite for actual mirrors and human lenses, the term convex in the quote above would mean concave in a human context.

Quite crucially, “Since the reflected rays of an object at any distance from a convex mirror diverge, a diverging mirror will always form a virtual image.”[7]

However, even a normally shaped (convex) human lens could produce a virtual image if the object being viewed is between the focal point and the lens’s surface. Again, we are assuming that the human lens can be treated as a mirror on one or both sides since it receives a mirror image on the exterior of the lens.

There are, however, two lenses inside each human eye. Behind the iris is a crystalline lens, comprised of glassy fibers, which can cause the shape and focus of the lens to change.  Hence, for lenses in combination, Wilson and Buffa hold that a virtual image could be produced under the following conditions:

[I]f the lenses are close enough together that the image from the first lens is not formed before the rays pass through the second lens, then the image from the first lens is treated as a virtual object for the second lens.[8]

Now we turn to the issue of pigment. In both the vascular tunic (uvea) and sensory tunic (retina) of the human eye, there is a layer of brown pigment, which serves to absorb light and keep it from scattering. In the absence of such pigment, the light would be divergent (capable of producing a virtual image) or as Wilson and Buffa note, which could cause confusion.

By now we have reached the point where the production of a virtual image for any object at any distance, should be ringing alarm bells in terms of autistic children. If what they see is consistently unreal, then they live in a terrifying world where the only means to combat it is to insist on a rigidly structured routine, where they have a modicum of control. But the linkage does not stop here because the virtual world they see is transmitted to the hypothalamus, which has a verifiable impact on parenting and emotional attachment. The hypothalamus is part of the limbic system responsible for emotion. Finally, the hypothalamus links the nervous system to the endocrine system via the pituitary gland. This means that hormones, which have a role in sensory perception, digestion,[9] stress, and mood (such as aggression and self-loathing), are being released as a result of interaction with a virtual world and, more importantly, the child’s reaction and/or aversion to it. This happens before virtual images are sent on to the hypothalamus, leading to the conclusion that by the time the thalamus relays sensory signals to the cerebral cortex, all of these factors are inextricably added together before they become perception.

And what are the effects of this unimaginably painful perception?

• About one in four children with autism hit, scratch or otherwise hurt themselves
• Children who engage in self-injury tend to have mood and behavioral changes, as well as cognitive impairment.
• Because self-injurious behavior is not rare in children with autism, it underscores the urgency of better understanding and developing treatments for self-injury, which can lead to hospitalization or even death.[10]

Naturally, there are different degrees of autism. Children who are referred to as extremely high-functioning may have trouble with remaining still or with interacting socially. For these children, who may have Comorbid autism, ADHD, there is help in the form of “Smartglasses.” These are wearable computers that provide real-time guidance through visual and audio cues to reduce symptoms of ADHD and/or to reward autistic children who learn to make eye contact and teach them how to respond to emotional facial cues.[11]  

However, there has yet to be a non-psychological/behavioral approach to helping low-functioning children with autism. For these children, loud, inappropriate behavior, difficulty with communicating, reacting poorly to physical touch or disruptions of their routine, plus challenges in learning basic skills and behaviors, including speech, are the norm.[12] They also exhibit the following:

• Unusual and even obsessive levels of focus
• Repetitive motion and activity
• Insistence and dependence on routine
• Lack of social skill and interaction
• Difficulty with verbal or other communication
• Anxiety in disruption or interaction

According to the CDC (Centers for Disease Control and Prevention) 1 in 59 children are identified with autism spectrum disorder each year.

Although there has been a massive controversy centered on vaccination as the cause for autism, it appears that the CDC’s guidelines for vaccination merely coincide with the identification of autism[13] because autism is a diagnosable condition within baby’s first year.[14]

As for why this paper on visual impairment is a novel approach to research, it is probably the case that an identification of autism, complete with aversion and disruptive behaviors, immediately places these children in a category of treatment that makes visual development an afterthought. Too, it is quite possible that a child can have perfect vision, but what he or she actually sees is truly unreal.

Although visual problems in autistic children are not unheard of (see the following links, where the use of prism lenses—to correct the refraction of light—is of particular interest), my approach to dissecting the issue and the conclusion I draw from it is certainly different.

https://www.covd.org/page/Autism

http://visionsource.com/blog/the-link-between-autism-and-vision-disorders/

https://visionhelp.com/optometrys-role-in-autism-spectrum-disorders/

http://www.visiontherapystories.org/vision_autism.html

https://www.spectrumnews.org/news/clinical-research-eye-problems-common-in-autism/

In any case, it is worth appealing to the medical community to investigate the allegations set forth in this paper in hopes of finding a novel cure[15]. Even if a handful of children should be helped as a result of a positive screening for a visual birth defect, the impact would be priceless.

Moreover, the unbearable stress on families[16] could be alleviated as well.

Notes:

[1] Wilson and Buffa, College Physics, Fourth Ed. (Prentiss Hall: NJ, 2000) pg. 715.

[2] Marieb, Elaine N., Human Anatomy and Physiology, Second Ed. (The Benjamin/Cummings Publishing Company: New York, 1992) pp. 510-511.

[3] Ibid.

[4] Ibid., pg. 512.

[5] Wilson and Buffa, pg. 715.

[6] Ibid.

[7] Ibid., pg. 716.

[8] Ibid., pg. 730.

[9] Neimark, Jill, “Autism: It’s Not Just in the Head,” DiscoverMagazine.com, April 2007 Issue.

[10] Zeliadt, Nicholette, “Large study shows self-injury common among children with autism,” Autism Research News, January 4, 2017.

[11] Anderson, Pauline, “Smartglasses Help Patients with Comorbid Autism, ADHD,” www.medscape.com, April 5, 2018. Also, Armstrong, Thomas, “’Smart Glasses’ Show Promise for Treating Autism,” American Institute for Learning and Human Development, April 18, 2018.

[12] “What are the Behavioral Extremes Seen on the Autism Spectrum?” https://www.appliedbehavioranalysisedu.org.

[13] Centers for Disease Control and Prevention, Data and Statistics.

[14] Mayo Clinic, Autism Spectrum Disorder.

[15] Note: It was long thought that lens transplants were unaffected by the immune system, thereby making them non-susceptible to rejection. This was recently disproved. Source: Thomas Jefferson University, “The eye is not immune to immunity,” Science Daily.com, January 25, 2018.

[16] Upon learning that both her first and second children were diagnosed with autism, one mother said, “There were days I considered shutting the garage door and letting the car run until I was dead.” Neimark, Jill, “Autism: It’s Not Just in the Head,” DiscoverMagazine.com, April 2007 Issue.