What is eye misalignment?
Eye misalignment problems are commonly found in children, usually caused by an inability of the eyes to work together. Each one of our eyes views objects at a slightly different angle. When they are aligned and healthy, the eyes work in sync to provide clear, single vision. This is called ‘binocular vision.’
There are many different types of eye alignment problems:
- Phoria: a person’s eyes are sometimes in misalignment
- Tropia: a person’s eyes are always in misalignment
- Strabismus (or cross-eyes): when a person’s eyes are not aligned with each other, and both eyes do not look at the same place at the same time. Strabismus can be large or small; it can also be constant or intermittent.
What is the difference between phoria and tropia?
If an eye doctor (optometrist) examines a patient who has eye strain and sees double only when the eye muscles are tired, or at the end of the day, this person probably has a phoria.
Phoria is a normal, temporary eye condition that won’t disrupt everyday life. It is a misalignment of the eyes that can occur when we are tired. Phorias is the result of a deviation in binocular vision,eyes are not able to look at an object at the same time.
Tropia is a very different eye health condition to phoria.
A patient with tropia has one eye turned in and crossed, and the eye never straightens. For people with tropia, the brain gets used to only relying on one eye, and ignores the images from the misaligned eye.
If the misalignment won’t correct itself, the result can be amblyopia or ‘lazy eye.’ The stronger eye will need to work harder, and the eye which is used less ‘tunes out.’
Many people mistakenly think that a person who has a crossed or turned eye (strabismus) has a ‘lazy-eye,’ but lazy-eye (amblyopia) is a type of poor vision in one eye only. Strabismus and amblyopia are not the same condition, amblyopia usually develops as a result of strabismus.
What are the symptoms of strabismus?
Although symptoms are difficult to spot, usually, someone with strabismus will have the following symptoms:
- Crossed eyes
- Experience frequent double vision
- Trouble with reading
- Motion sickness
What should you expect during your eye exam?
As part of a normal vision screening, your Eyecare Plus optometrist will look for signs of strabismus or amblyopia. All children, ages three to five, should have their vision checked, but babies and children with strabismus should be checked right away to prevent amblyopia.
Prescribed glasses are usually adequate enough to treat strabismus in children. Sometimes a child will be given a patch to wear over the straight eye for a few hours each day. This trains the weaker eye to get stronger. If the child won’t or can’t wear a patch, atropine eye drops might be prescribed. Working on the same principle as the eye patch, atropine temporarily blurs the vision in the strong eye and makes the weaker eye work harder and get stronger. If the case of strabismus has developed into amblyopia, further treatment is required.
Why do babies’ appear to have crossed eyes?
Often before their facial features are fully developed, babies give the false appearance that their eyes are misaligned or they have crossed eyes. Parents of very young babies are often alarmed when one or both or their eyes appear misaligned or crossed. This is called ‘pseudostrabismus’ or ‘false strabismus’.
The crossed eye appearance on a baby’s face is because there is less space (the white area) between the coloured part of the eye (iris) and the corner of the eye toward the nose. This is especially noticeable in pictures. As a baby grows, these features usually change and the appearance of crossed eyes goes away.
Pseudostrabismus is common in babies from birth to about 18 months old. A clinical diagnosis of pseudostrabismus is reached after ruling out the presence of actual strabismus. While pseudostrabismus can be outgrown and does not require treatment, strabismus does not go away on its own without treatment.
To find out more about eye misalignment contact your local Eyecare Plus optometrist.