Most cases of squints are mild to moderate and involve the horizontal muscles. In such cases, simple techniques of recession/resection of the horizontal muscles (medial rectus and horizontal rectus) are all that are needed to restore the position of the eyes. However, there are occasionally difficult squints that call for special techniques and can only be treated by doctors who are proficient in performing challenging cases.
Examples of challenging cases are these three patients who presented with severe convergent squints and high myopia of more than -12.00. Some of the eyes are so far pulled inward that the cornea became invisible. They all suffered from a condition called myopic strabismus fixus. In this condition, the eye globes were abnormally elongated and prolapsed between the superior and lateral rectus (as shown by the diagram and the MRI scans). Simple recession/resection would not be enough to restore the positions of these eyes.
A 35 year-old woman with -15.00D both eyes and bilateral severe convergent
squints. The left cornea was almost invisible. She had problems
seeing due to the severe squints.
A 60 year-old man with bilateral severe convergent squints and dislocated lenses
due to high myopia. He was referred for squint correction so that surgery
could be performed to remove the dislocated lenses.
A patient with high myopia and a right severe convergent squint. The right vision
has been poor since young and patient wished for restoration
of the eye position for cosmetic reason.
MRI showing prolapse of the globes between the superior and lateral
rectus in a patient with myopic strabismus fixus.
Diagram showing prolapse of the globe between the superior and lateral rectus
so that the eye becomes severely inward turning.