Trauma and Vision Loss  

The healthy function of our eyes is extremely critical for every aspect of our life. Our eyes are complex sensory organs that are designed to optimize vision under various lighting conditions. The basic elements of the human eye are similar to those of the average photography camera. For people, the ultimate purpose of our visual process is to respond with the appropriate cognitive and motor response to the outside world. Sight is far more than just visual acuity; the vision process is a complex, learned and developed set of functions that have evolved into a multitude of skills since birth. Research indicates that up to 85% of our cognitive abilities, our perception, and our learning are tied to our vision process.

Unfortunately, visual-perception disorders are one of the most common residual impairments that are associated with head injuries, and a high number of victims that recover from a traumatic brain injury will have what are called binocular function problems.

The vision process is broken down into three main categories: 

1. visual acuity and visual field
2. visual motor abilities 
3. visual perception

• Visual Acuity – This simply refers to the clarity of sight.
• Visual Field – This refers to the central and peripheral range, otherwise called the panorama 
  of vision.
• Visual Motor Abilities – This refers to the alignment of the eyes and when the eyes are properly aligned it is referred to as phoric.
• Visual Perception – Visual-motor integration has to do with eye-foot and eye-body coordination. Visual-auditory integration has to do with relating to what one sees and hears. Visual memory refers to recalling information that has been seen through the eyes. Visual closure is the ability to mentally complete a visual picture based on seeing just parts of something. The spatial relationship is the ability to know where you are in relation to objects around you and to know the physical relationship between objects around you. Figure discrimination is the ability to discern an object from its background.

Traumatic Brain Injuries & Vision Loss

There are a number of visual problems that arise from head injuries and the most impairing are visual field loss, intractable double vision, and visual/balance disorders.

• Visual Field Loss – With this type of vision loss the patient has lost half of their field of vision. This causes the individual to be particularly vulnerable to further injury from bumping into things or being struck by approaching objects, or from falling.
• Double Vision (diplopia) – Double vision (diplopia) is a serious and extremely uncomfortable condition that can affect patients with a brain injury. Vision therapy, lenses and prisms can often help the patient achieve alignment of the eyes; however, if lenses, prisms, and/or therapy prove unsuccessful, then intractable diplopia can follow.
• Visual Balance Disorders – Head injuries can cause Visual Medline Shift Syndrome (VMSS), oculomotor dysfunction in fixations, nystagmus, and other disruptions of the central and peripheral visual processing. These disorders are treated with lenses, prisms, and visual rehabilitation techniques.

Traumatic optic neuropathy (TON) refers to an acute injury to the optic nerve that is secondary to trauma (as from an accident or an act of violence). Patients with traumatic optic neuropathy (TON) can have varying degrees of vision loss which may include: a decrease in visual acuity, visual field abnormalities, or loss of color vision. The vast majority of TON cases are seen in males (up to 85%), with the average age being around 34 years. The greatest causes of TON are motor vehicle accidents and bicycle accidents, followed by falls and assaults. TON is also associated with penetrating orbital trauma (gunshot wounds, stab wounds and also foreign bodies).