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    By John D. Ferris, FRCOphth
    Squint Clinic
    Pediatric Ophth/Strabismus, Strabismus

    A superior oblique palsy can be a condition you are born with (a congenital palsy). The most common causes of a superior oblique palsy that occurs in later life are:

    1. Head injuries – these can range from major road traffic accidents to relatively minor bumps on the head playing sport.
    2. As a result of poor blood supply to the IVth cranial nerve. The poor blood supply is normally caused by a combination of factors such as high blood pressure, diabetes, high cholesterol and smoking. These are called microvascular palsies.
    3. Rarely inflammation in the region of the nerve or direct pressure on the nerve can cause a superior oblique palsy.

    To compensate for the vertical and torsional imbalance of their eyes a parent may notice the child will often tilt and / or turn their head to one side. The eye on the affected side may also shoot upwards when the child looks to the opposite side.

    Most children do not complain of double vision.

    Superior oblique palsies that occur in later life normally cause the adult to experience sudden onset of vertical double vision and the second image tends to be twisted to one side. This double vision is most marked when the patient looks downwards and this in turn causes great problems with reading, eating and going down stairs.

    Occasionally an adult with a congenital superior oblique palsy can no longer control their vertical squint and they develop eye strain and intermittent double vision.

    All patients will be seen by an Orthoptist and an Ophthalmologist. A detailed history will be taken and specific tests carried out to measure the squint and assess the strength of their binocular vision. Photographs may be taken as a visual record of any head posture. Older children and adults may have charts plotted to measure the size of the area of single vision and to measure the movements of their eyes in different directions.

    Drops may be used in order to examine the back of the eye and in children to check whether glasses are needed (refraction).
    In adults with an acquired superior palsy, blood tests and an MRI scan are carried out to investigate what could have caused the palsy.

    Most children with this condition do not have a lazy eye and have good binocular vision with the aid of their head posture. They do not normally need glasses.

    No treatment is needed if the child is developing equal vision in both eyes, has good binocular vision and does not have a troublesome head posture. In these cases only periodic observation in the clinic will be required.

    80% of microvascular superior oblique palsies will resolve within 3-6 months. However spontaneous recovery is less likely to occur if the superior oblique palsy has been caused by a head injury or a tumour.

    In adults it may be possible to have temporary plastic prisms fitted to the patient’s glasses that will reduce or in some cases completely correct the squint and double vision. As a rule prisms are used to treat small squints when surgery is not being contemplated or as a short-term measure for larger squints.

    If a child is finding it difficult to control their squint, even when they are using a head posture and/or if their binocular vision begins to deteriorate, surgery should be considered. If an acquired palsy has not resolved after 6-12 months surgery should also be considered.

    Republished, with permission, from www.squintclinic.com