Brain Lesions

More than 50% of the brain is involved in the visual system. Therefore, many brain lesions will manifest as a vision, eye movement or alignment problem.

• Brainstem lesions

Often result in diseases or syndromes associated with weakness of one side of the body or face. These patients may also have gaze palsies, where they can’t move their eyes to one side.

• Non-brainstem lesions

Cavernous sinus syndrome – the 3rd, 4th and 6th cranial nerve passes through the cavernous sinus which is an area in the brain. If this has pathology, all the nerves may be effected.

• Supranuclear lesions

A lesion in the higher part of the brain. Often, those with supranuclear lesions have problems with saccades (looking from one spot to another), or have parts of their visual field missing. Their horizontal or vertical gaze pathways may also be affected, causing loss of ability to look to one, or multiple directions. This is the case for those with Progressive Supranuclear Palsy.

Parinaud Syndrome – has eye movements of a loss of up gaze, and convergence retraction nystagmus on attempted up gaze. This can indicate a specific tumour on the pineal gland.

Skew deviation – a disturbance of the vestibular pathway which is in charge of balance. They will present with a vertical deviation and dizziness. They may also perceive the world as tilted.

Up-beat nystagmus can also be a sign of a brain lesion.

• Internuclear lesions

Internuclear ophthalmoplegia (INO) will present with a limitation of adduction in one eye, and abducting nystagmus in the other.

Skew deviations and INOs can be seen together, particularly in patients with Multiple Sclerosis.

Brain lesions which involve the visual pathway will also have a visual field defect.

This is all a lot to grasp so don’t worry too much… You will learn more about brain lesions in detail when studying Orthoptics at University.

Just by looking at eye movements and ocular presentation, Orthoptists can detect a lesion in one specific part of the brain. They will often be the first clinician to diagnose a neuro issue, without the help of a brain scan.

Orthoptists will also manage any symptoms in clinic, such as diplopia (double vision) or oscillopsia (wobbling of vision due to nystagmus). Suitable referrals will then be made for further investigations.