The term “lazy eye” is one you’ve probably heard before, but did you know that a lazy eye is not always something that can be seen?
Generally speaking, a lazy eye is an eye that the brain simply does not know how to use. The technical term for a lazy eye is “amblyopia.” A really easy analogy can be made when you consider whether a person is right-handed or left-handed. A right-handed person is very skilled when using his right hand. He can write and often do things that require great precision with his right hand. To look at him, you wouldn’t know which hand he prefers to use, as both the right and left hands look the same. But his brain has a definite preference for his right hand and it’s the hand he always uses for challenging tasks.
When a task calls for good depth perception, a person with good vision in each eye and eyes that are properly aligned on the same target will use both eyes together to provide good vision. When a lazy eye is present, the brain does not know how to use both eyes together and so it relies primarily on the stronger eye, never achieving true depth perception.
There are a number of things that can cause a lazy eye. Having much better vision in one eye than the other due to a significantly different eyeglass prescription in each eye can cause a lazy eye. Being born with a cataract that makes the vision poor in one eye during early childhood when the brain is learning how to use both eyes can cause a lazy eye. Having one eye that is not properly aligned and is turned in the wrong direction can cause a lazy eye. Notice that only in the case of a misaligned eye might is it obvious that there is a vision problem. In all three of the causes listed for a lazy eye, vision can be improved and the brain can learn how to use the eye, if the proper diagnosis is made and treatment prescribed at a young enough age. This is why it is so important for young children to have an eye examination by an eye care professional to screen for vision problems. This is especially true where there is a family history of amblyopia. There are a limited number of years in childhood where treatment for a weaker eye can successfully prevent the development of a lazy eye. As we age, it is more difficult for the brain to learn how to use a weaker eye….kind of like that saying about teaching an old dog new tricks.
The bottom line is that a vision screening at school or at a school physical is not a complete eye examination and all children should have a complete eye examination by the time they begin kindergarten. The good news is that in most cases, if detected early enough, the vision can be improved to prevent the development of a lazy eye. The even better news….a lazy eye can’t spread to the entire body, so we can’t quite explain the lazy-itis that so often afflicts teenagers. Good luck with that!
Dr Amanda Weiss is an Optometrist at SeaView Eyecare in Wellington, FL. She completed a residency in Family Practice Optometry and enjoys providing eye care for adults and children. She has a particular interest in dry eyes and hard-to-fit specialty contact lenses. Seaview Eyecare is located in the WholeFoods Shopping Center. Seavieweyecare.com 561.790.7290.