Effect of Fixation Training With Colored Light Targets on Traumatic Brain Injury-Associated Photophobia

A growing number of clinicians are regularly using fixation training, in which patients undergo daily sessions fixating on colored light targets on light boxes, to treat symptoms including photophobia associated with traumatic brain injury (TBI). While fixation training using various colored light targets is reported, blue light targets specifically appear to be used in this patient population more often than other light target colors. The College of Syntonic Optometry (www.csovision.org) estimates that there are roughly 500 practicing optometrists that utilize fixation training in the USA alone. However, evidence supporting this approach is primarily anecdotal, and there are no controlled, masked clinical trials published that evaluate the efficacy of this therapy against a control group.

Therefore, the goal of this study is to assess whether daily 20 min fixation training sessions using a blue light target alleviates symptoms of light sensitivity and alters pupil response more than daily 20 min fixation training sessions using red light targets in a masked cross-over clinical trial involving participants with chronic TBI-associated photophobia. In addition, we will determine if any improvement in symptomology correlates to any changes in pupil responses to red, blue and white light pulses and potential changes in other standard clinical measures of visual function. In short, this study will compare the effect of fixation training using a blue light target to the effect of fixation training using a red light target in participants with chronic TBI-associated photophobia.

Inclusion criteria

• 18 to 80 years old and subjects able to consent for themselves
• Completion of first session in entirety (participants who cannot complete the entire first visit will be considered as a screen fail)
• Best-corrected visual acuity of at least 20/32 in both the right and left eyes, and 20/25 using both eyes
• Prior head injury with current photophobia - A mild or moderate TBI occurring at least 3 months prior to visit, verified by a score of 2, 3 or 4 on OSU-TBI survey, and participant reports having experienced greater light sensitivity since their head injury

Exclusion criteria

• Pregnancy or suspected pregnancy - based on self-report
• Previous history of neurodegenerative disease (e.g. Alzheimer's, Parkinson's, multiple sclerosis, myasthenia gravis, seizures)
• History of pathology of the retina and optic nerve (includes retinal tears, diabetic retinopathy, glaucoma, macular degeneration, optic nerve atrophy)
• Currently on cholinergic medications, which affect pupil responses
• Prior participation in fixation training sessions within the past 2 years
• Experiencing a migraine during visit
• Prior history of severe TBI (score of 5 or 6 on OSU-TBI survey)