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What is a Concussion?

It is estimated that 4-5 million concussions occur annually, making a concussion the most common type of traumatic brain injury.

A concussion is a type of traumatic brain injury that changes the way your brain functions. The vast majority of concussions do NOT result in a loss of consciousness, making diagnosis more challenging than previously thought. The majority of concussions result by blunt trauma, or a blow to the head. In children, the most common cause of concussions is sports, specifically contact sports such as football, soccer, lacrosse, and hockey. Concussions can also be caused by violent shaking of the head or upper body, so direct contact in the form of a "bump of the head" or "getting your bell rung" is not required to cause a concussion. In adults, motor vehicle accidents and falls are the most common causes of concussions.

Facts About Concussions

Fewer than 10% of sports-related concussions have associated loss of consciousness.

A review article published in Pediatrics in 2010 has helped to dispel the myth that a loss of consciousness, or “blacking out”, is a required component of a concussion.

Having had one concussion makes you more susceptible to another

The increased risk of repeat concussions is one of the several reasons why the decision to return to play should be made with the athlete’s health care team.

Car accidents and falls are the most common cause of concussions in adults

Seemingly mild “bumps on the head” can have drastic neurological effects. These neurological effects can in turn affect the visual system, making daily tasks such as reading or driving extremely difficult (if not impossible).

Symptoms of a Concussion

Concussion Symptoms at Artisan Optics Boise Idaho

Visual Effects of a Concussion

67% of the neural connections within the brain are involved with some aspect of vision, whether it is visual input, visual perception, or visual integration. With so many of the connections within the brain involved with the process of vision, it is no wonder that vision problems are so common following an acquired brain injury.

There are several potential visual side effects of a concussion that are consistent with other forms of mild traumatic brain injury (mTBI). Some of these may improve with time, others may be unchanging, while others respond very well to active treatment.

Concussions can have the following effects on the visual system:

Accommodative Insufficiency – This condition is a reduction in eye focusing ability that results in blurry vision at near, even in young athletes. Near vision may be constantly blurry or may pulse in and out of clarity during near activities like reading.

Blurry Vision - Blurry vision following a concussion can occur at distance, near, or both.

Convergence Insufficiency – This inability to use the eyes comfortably at near can result in a number of symptoms including: headaches, eyestrain, fatigue, or even double vision during near activities.

Double Vision – There are several causes of double vision, which is why anyone who sees double (even intermittently) should be evaluated by an optometrist with advanced training in neuro-optometry, binocular vision, and vision therapy.

Light Sensitivity – Photophobia, or light sensitivity, can result from various types of acquired brain injuries (including concussions).

Ocular-Motor Dysfunction – Deficiencies in eye movement abilities are quite common following concussions and other forms of mild traumatic brain injuries. These eye movement deficits can pose challenges with many activities of daily life, including reading and driving.

Reduced Cognitive Abilities With Visual Tasks - Visual perceptual deficits can be caused by concussions and have dramatic effects on academic and even athletic success.

Reduced Visual Processing Speed or Reaction Time – Prolonged visual processing speed can slow down an athlete both on and off the field. The speed with which an athlete processes visual information affects many aspects of athletic competition, including: reading the field of play, judging the speed of a moving ball or puck, and judging the speed of other players on the field.

Post Concussion Testing

The visual and visual perceptual effects of a mild traumatic brain injury, such as a concussion, have been well known for quite some time. This is why ImPACT concussion testing has included so many visual perceptual components to the testing protocol. Some of the areas of visual perception that are assessed using the ImPACT system include:
  • Design discrimination
  • Non-verbal problem solving
  • Selective attention time
  • Visual attention span
  • Visual working memory
  • Visual processing speed
  • Visual reaction time
  • Visual recognition memory
While ImPACT testing does a great job of measuring many components of visual perception, it is not equipped to assess the effects on the visual system that will result in headaches, eyestrain, double vision, blurry vision, or reading difficulties. For this reason, any athlete who has suffered a concussion and has noticed a change in vision, balance, academic success, or overall comfort should have a neuro-optometric assessment with an optometrist who has received advanced training in neuro-optometry and binocular vision.
Dr. Ryan Johnson is Idaho’s only optometrist who has received residency training in neuro-optometry, binocular vision, and vision therapy. During a Neuro-Optometric Assessment, he evaluates the following areas of your visual system:
  • Visual acuity (clarity of vision)
  • Refractive error (presciption)
  • Visual field (the extent of your peripheral/side vision)
  • Fusion (the brain’s ability to simultaneously perceive information from each eye at the same time)
  • Eye movements
  • Accommodation (eye focusing)
  • Vergence (eye teaming)
  • Visual perceptual skills
  • Visual processing speed
  • Visual integration
  • Working memory

Concussion Management: The Visual Component

Many of the visual conditions that result from a concussion can be successfully managed by a doctor with both knowledge and experience in the areas of neuro-optometry, binocular vision, and vision therapy.

Following a Neuro-Optometric Assessment, our residency-trained neuro-optometrist will determine if glasses, contact lenses, vision therapy, or a combination of treatments is best to address your visual conditions.

The good news is that some of the most common visual effects of mild traumatic brain injury (accommodative insufficiency, convergence insufficiency, and ocular motor dysfunction) are all conditions that respond to vision therapy.  For our concussion patients, we recommend the experts at Advanced Vision Therapy Center. Their research-based approach to vision therapy and sports vision therapy has helped many of our patients recover from concussions and other forms of acquired brain injury.

Dr. Ryan C. Johnson: Neuro-Optometrist

A native of Boise, Dr. Johnson graduated from Boise State University with a bachelor's of science in kinesiology. Dr. Johnson graduated from Southern California College of Optometry before pursuing a residency in binocular vision, vision therapy, and neuro-optometry at the University of California, Berkeley.

Dr. Johnson is Idaho's first residency trained optometrist in neuro-optometry, binocular vision and vision therapy. With his residency training, Dr. Johnson's clinical experience and expertise is in the areas of strabismus, amblyopia, binocular vision dysfunction, acquired brain injury, vision rehabilitation and the visual system as it relates to brain function.

Dr. Johnson also combines his knowledge of exercise science from his undergraduate work with his understanding of the visual system to provide sports vision training to enhance visual performance for athletes of all ability levels - bringing vision rehabilitation and sports vision training to Idaho.

Dr. Johnson is a member of the American Optometric Association, Idaho Optometric Physicians, College of Optometrist in Vision Development (COVD) and the American Academy of Optometry (AAO). He also serves as clinical director at Advanced Vision Therapy Center.

Accepting new patients.


Schedule your appointment with Dr. Ryan C. Johnson or call us at 208.377.8899.