Post Traumatic Vision Syndrome

Original Editor - Yagdutt Top Contributors - Yagdutt Yagdutt, Kim Jackson, Nupur Smit Shah and Carina Therese Magtibay

Top Contributors - Yagdutt Yagdutt, Kim Jackson, Nupur Smit Shah and Carina Therese Magtibay  

Introduction

Post traumatic vision Syndrome occur after a traumatic brain injury(TBI) or Cerebrovascular insult or a neurovascular incident( Cerebral palsy, multiple sclerosis, concussion whiplash). Inherent Visual processing mechanisms are affected causing altered ability to comprehend and process visual and sensory feedback causing dysfunction in vision. Following a neurological insult various symptoms related to vision like headaches, diplopia, vertigo, asthenopia, photophobia, inability to focus and track on objects

Clinical Signs and symptoms

Binocular vision and accommodative disturbances in vision are common after mTBI. Oculomotor deficits in accommodative and binocular vision dysfunctions may occur from damage to the cranial nerves( Oculomotor, trochlear and abducens nerve). Exotropia and Exophoria are common after a neurological event. There are also difficulty in convergence and difficulty in accommodation and increased myopia (Blurred near vision). Patient also suffer from oculomotor dysfunction leading to vision problems. Patient report to have symptoms like double vision(Diplopia)Dizziness, Nausea, eye Strain(asthenopia), Sensitivity to light(Photophobia) and perceived movement of print or stationary Objects.

In addition to visual motor function there could be balance and posture can be affected as there can be midline shift. In Case of Homonymous hemianopsia(Loss of Vision on one side) there is a midline shift affecting Balance and posture leading to instability and frequent falls. Due to visual mismatch and processing errors patient report vertigo, dizziness, and balance problems(2).

Symptoms generally are better in morning. Symptoms get worse with activity and in busy high visual sensory environment. Sleep disturbances are also noticed in Post traumatic vision syndrome .

Special tests

Cranial nerve testing – motor weakness in Cranial nerve 3, 4, or 6 may be contributing to diplopia, or vertical imbalances.

Most commonly patients with PTVS experience difficulties with eye tracking, eye teaming/convergence, and eye focusing problems, which may be noticed using the following tests:

Single and double Maddox rod testing.

Nuclear eye movements (Ductions).

Supranuclear eye movements – versions, pursuits, saccades, convergence, vestibulo-occular reflex.

Visual field testing – can give information on what type of loss if any the patient is experiencing

Visual Acuity at 10 feet – using letters and shapes – can help indicate possible neglect or field of vision loss

Special tests- Visual inattention/ neglect testing – often present with PTVS from a TBI.

Aneisokonia testing – may show discrepancies in object size between eyes

Hirschberg test & Cover Test: test for ocular alignment

Management

• Management strategies are based off specific dysfunctions that were discovered during the assessment. Goal is to treat as early as possible after onset of PTVS to avoid habitual compensations from developing. If any oculomotor control dysfunctions are present, using specific oculomotor training through vision exercises and computer-based programs. -Optical devices (lenses, prisms, or sectoral occlusion) can be used to help improve spatial orientation, posture and balance, and address issues regarding convergence, focus and binocular dysfunction. Combining vision exercises with optical devices has also been shown to be effective at managing the above dysfunctions (2,7,8). Referral to optometrist to investigate if prism lenses are indicated when suspected(8) .