As a consequence there needs to be a list of the types of strabismus squints to fully understand each one, and making up a full list is not easy.
There are four ways that strabismus is categorised, with some categories having sub-categories:
♣ According to how easy a particular type of strabismus can be detected:
o If obvious to anyone it is called “manifest” and goes by the name heterotropia
o If not immediately obvious to the untrained eye then it is described as “apparent” but not given any medical name
o Finally, if the strabismus is detected by an optometrist or ophthalmologist then it is called “latent” and goes by the name heterophoria
♣ By following the section numbering system defined by the World Health Organisation (WHO) – in particular the section numbered H49 to H50 “Disorders of Ocular Muscle, Binocular Movement, Accommodation and Refraction”:
In this system a further four sub-categories are defined:
o H49.3 – Ophthalmoparesis, concerned with paralysis of muscles of the eye
o H49-4 – Progressive opthalmoparesis, concerned with weakness of the external muscles of the eye
o H50.0 & H50.3 – Esotropia, where the eyes turn or squint inwards
o H50.1 & H50.3 – Exotropia, where the eyes in this case turn or squint outwards
♣ Depending on which part of the body is primarily involved:
o The brain may not be functioning fully
o The eye muscles may not be functioning correctly
♣ The Final method of categorising is do with the age and method of acquiring the squint:
o Congenital at birth
o Acquired during childhood or somewhat later
o Acquired via another disorder or action such as during cataract
Diagnosis of Strabismus
Screening for strabismus if thought to be of concern can be carried out through a Hirschberg Test, which involves flashing a light into the eyes – reflections from the eyes should point directly to one location, otherwise they are not symmetrical.
A full eye examination by an optometrist or ophthalmologist will deliver not only the fact a squint is present but the type and extent of treatment required.
With very young children care needs to taken during diagnosis so that “pseudostrabismus” is not mistakenly diagnosed – this can be the case if the child has not matured sufficiently.
What to do if a strabismus is diagnosed
The various types of strabismus diagnosed all require more than just an eye patch to be worn for treatment.
Eye therapy sessions and minor surgery may need to be undertaken in combination – any eye surgery does NOT involve the eye itself, but instead it is the MUSCLES that are involved.
In cases of adults botox injections, similar to those used for cosmetic plumping up of skin to remove wrinkles, can be applied to stronger muscles to enable weaker ones to begin to work more and “catch up” as it were.