Concussion and mild traumatic brain injury have received more media and literature attention in recent years and our understanding of these conditions is increasing. Optometrists are perfectly placed to help those individuals with concussion and often simple changes can make enormous differences to the lives of people who have suffered any neurological event.
Post-trauma vision syndrome (PTVS) was first coined in the mid-90s by Bill Padula who recognised many people who suffer a traumatic brain injury (TBI) will present with a characteristic set of clinical findings. These include exotropia or high exophoria, convergence insufficiency, accommodative issues, low blink rate, spatial disorientation, poor fixations, poor pursuits and unstable ambient vision. PTVS may also affect gait, posture and musculoskeletal presentation.
Recent literature has also shown a significant proportion of mild traumatic brain injury (mTBI) sufferers experience visual issues, especially relating to the oculomotor system and accommodative and vergence deficits¹,². The prevalence of visual midline shift syndrome (VMSS) after TBI has also recently been estimated to be very high³.
Examination of a patient with PTVS often requires more time and empathy during assessment and it may be necessary to spread the assessment over more than one visit. Examination should include most of the procedures used in a standard assessment, as well as additional procedures aimed at probing performance. Refractive changes after a mild TBI have been well documented with a myopic shift being more likely⁴,5,6. Subjective binocular and monocular accommodation measurement should be attempted and repeated. It is not uncommon for this population to have near-to-normal initial findings then, as the patient fatigues, to find the repeat measurements significantly reduced. Similarly, near point of convergence (NPC) should be repeated, especially as reduced NPC is one of the most prevalent findings after TBI.
Use of the King-Devick Test to assess saccadic function has also recently received attention, both in New Zealand and overseas, and its efficacy in assessing concussion on the sidelines of sporting events is promising⁷,⁸. The possibility of VMSS should not be overlooked and, although assessment initially requires a little experience, it is relatively easy to perform.
