Lens Rx prescribing for the patient with traumatic brain injury

Written by Carl Garbus, O.D., chair of the AOA’s Vision Rehabilitation Committee

When treating a patient with traumatic brain injury (TBI), my first step in vision rehabilitation treatment is to write a prescription that allows the visual system to maximize comfort and vision. Simple is better with this population. Most patients will be very successful with single-vision lenses that are specific for the given task (i.e., reading or distance). Generally, I avoid prescribing progressive lenses, as these lenses come with unwanted base down prism and can be very disturbing for patients with vestibular dysfunction and abnormal vestibular ocular reflex. I also find that progressives can adversely affect balance and gait in TBI patients. Be sure to discuss and explain the lens options to your patients, as the treatment choice is ultimately up to them.

Lens Rx prescribing is one of the most important elements to address the visual comfort of the patient. When there is a significant difference in the sphere or cylinder components between the two eyes, I consider balancing the prescription. Trial frame is extremely important, as the patient with TBI will soak up minus in the phoroptor. Balance the Rx in the trial frame.

Here are some examples of prescriptions I use for TBI patients:

Example 1
Refraction:

O.D. +1.00                   20/20
O.S.  +2.75 -.50 x 30    20/20
* right eye is the dominant eye

Possible Rx that needs to be trial framed

O.D. +1.00
O.S. +1.75

Note: Reduced the aniso over the nondominant eye

Example 2
Refraction:

O.D. -2.00 - 1.50 x 180      20/25
O.S. -3.00 - .50 x 180        20/30
* right eye is the dominant eye

Possible Rx that needs to be trial framed

O.D. -2.00 - 1.50 x 180
O.S. -2.50 - .50 x 180

Note: the equivalent spheres are equal

Example 3
Refraction:
O.D. -6.00       20/20
O.S. -3.00       20/30
* right eye is the dominant eye

Possible Rx would be contact lens or the Shaw lens. The Shaw is a specialty lens that uses calculations to match the magnification factor along with the patient's vergence ranges. The prismatic imbalance is removed from the equation.

One important tip is that the trial frame Rx can be evaluated both in the exam room and outside. Having the patient experience the Rx by walking and looking around the room can really determine the comfort of the Rx.

During the process of trial framing, I introduce special filters for those patients who are light sensitive. There are several filters that may be very helpful to these patients.

a. 20% and 30% blue - green
b. 20% and 30% green - blue
c. Blutec filter
d. FL-41

The combination of the comfortable spectacle Rx and filter may provide a strong impact on the function of the patient with TBI. Other considerations that are very important would be prism and partial occlusion. If you have any questions or comments, please contact vr@aoa.org.

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References:
Suter, P. & Harvey, Lisa (2011). Chapter 8, Photophobia, Light and Color in ABI, Vision Rehabilitation 
Zelinsky, D. (2017). NORA Conference: Utilizing Brain Mapping with Neuro-Optometric Rehabilitation. Visit DigiVisionMedia.com. 

Disclaimer: The information contained in this article represents the opinion of the author and not the AOA. These are not clinical practice guidelines, nor has the evidence been peer reviewed. There are additional aspects to this topic that may not be presented, or considered, based on the specifics of the case.