What is a Lazy Eye?
One of the most common questions I am routinely asked is, “What is a lazy eye”. This is a commonly used term and people use it interchangeably for two different conditions. The actual terminology is either amblyopia or strabismus.
Strabismus, or a crossed eye, is a condition where both eye are not looking in the same direction at the same time. Most commonly just one eye will be turned in or out, but sometimes the eyes will alternate between the right eye and the left eye turning in or out. This is typically caused by either poor muscle control or a high amount of hyperopia, also known as farsightedness.
Our brains do not tolerate double vision very well so if the two eyes are seeing two different images at the same time it creates confusion and the brain will learn to ignore the images being transmitted by one of the eyes. Unfortunately this may cause a permanent reduction of vision in that eye. It will also cause a reduction of depth perception or 3D vision. Because we are not born knowing how to see we must learn this skill. This process begins at birth and continues thru approximately 5 or 6 years old. I’m sure you can understand how important it is that we learn to see the correct way! Many times we can determine that a problem exists before a child reaches one year of age.
If a problem is detected, treatment options may include either glasses or vision therapy. Occasionally surgical intervention is required, although this is a last resort and more often needed for a very young child. If the eye turning becomes constant and is not treated, it can lead to permanent reduction of vision in one eye, a condition called amblyopia. This leads us to the second condition that is often called lazy eye.
Amblyopia is a condition where the brain learns to ignore the image and information from one eye. This may occur because of strabismus and the brain actively ignores the double image, or it may occur because of another stress on the visual system. Most commonly this condition develops because there is unequal vision between the two eyes. This could be caused by the existence of a high amount of farsightedness in one eye or there could be something blocking the vision, like a cataract.
Essentially, if the work and demand of using two eyes to see is too high, then the brain will find an easier route. Often this route is to favor the “easier” eye and ignore the problematic eye. This will take place in the early years as vision is developing. Unfortunately, when the brain is ignoring the images transmitted by one eye, you will not always see that eye turn. In fact, many times parents will not notice any problem at all! The child uses one eye to see planes in the sky and small things in the carpet and it is assumed they are using both eyes. The child doesn’t know a problem exists because they have no reference for what “normal” vision looks like.
Amblyopia is a condition that is preventable with early eye examinations. It is possible to determine if existing conditions make the development of amblyopia a possibility as early as one year of age. Certainly, having an eye examination by the time a child is three years old will pick up on any problems. This is still early enough to treat the condition using glasses to balance out vision between the two eyes, making it easier for the brain to process images from both eyes. Prevention is key with amblyopia!
Get Your Eyes Checked Today
If you have questions or concerns about “Lazy Eye” please contact our office at 763-271-2020 or via our Contact Form. If you’d like to schedule an appointment, we have an Online Appointment Request Form available as well.
Dr. Mary Gregory
Uptown Eye Care
560 Cedar Street
Monticello, MN 55362