Vertical Deviations

A vertical deviation is the upwards or downwards turn of an eye.

Hyper = higher eye

Hypo = lower eye

A hyperphoria/hypophoria is a latent squint. This means the eyes are straight without dissociation (covering of the eyes) and corneal reflections will be symmetrical. It is important to specify which eye is higher than the other.

Left hyperphoria = Right hypophoria.

• On cover-uncover test, the fixing eye will not move.
• On alternate cover test, the higher (hyperphoric) eye will move with a downwards motion to fix, and the lower (hypophoric) eye will move with an upwards motion to fix.

A hypertropia/hypotropia is a manifest squint. This means one eye is turning upwards/downwards all the time and corneal reflections will show a vertical misalignment.

• On cover-uncover test, the higher (hypertropic) eye will move down to fix, of the lower (hypotropic) eye will move up to fix.
• On alternate cover test, the vertical movement may increase.

Some of the main causes of a vertical squint include:

• Blow out fracture – when there is a fracture of the orbital floor bone, muscles can get trapped, preventing the eye from moving upwards.
• Grave’s Orbitopathy/Thyroid Eye Disease – typically, the inferior rectus muscle is the first to swell, resulting in a restriction of elevation.
• 3rd cranial nerve palsy – the superior rectus muscle depresses the eye. If this isn’t working properly, the eye will sit upwards.
• 4th cranial nerve palsy – the superior oblique muscle depresses the eye, if this isn’t working properly, the eye will sit upwards.
• 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.

It is the role of an Orthoptist to differentially diagnose these causes when a vertical deviation is presented in clinic.