Alamo Optometry Blog

September 5, 2010

Amblyopia

Filed under: Uncategorized — gkblog @ 9:02 am

Amblyopia

 (As appeared in Alamo Today, September 2010, pg. 26)

            Amblyopia or “lazy eye” as it is commonly referred, by definition means an eye that is not correctable to 20/20 vision.  Many times in practice I find that patients are using this term incorrectly; they always say that they have a “lazy” or “bad” eye when with their glasses or contacts they see very well.  The important distinction that has to be made is that this refers to best-corrected vision, whether that is with glasses or contact lenses.  Most forms of amblyopia start in childhood; making it even more important for a child’s vision and eye health to be evaluated to ensure the eyes and vision are developing normally. 

            The most common form of decreased vision is from strabismus, or an eye turn.  If one eye is not focused on the same point as the other eye, that retina never receives a clear image, and therefore does not develop normally.  This is why it is mandatory that an eye turn be corrected with surgery and/or glasses at an early age.  Since the wiring between the eye and brain does not completely mature until about age 10-12, it is imperative that in this time frame vision must be maximized.  Compared to the other types of amblyopia, this is the most easily noticed by parents because of the obvious eye appearance and care is usually sought early on in development.

            The other main cause of amblyopia is refractive.  A refraction is a measure of the amount of nearsightedness, farsightedness, and astigmatism needed to be corrected to attain 20/20 vision.  When the prescription is extremely high, it is likely that the patient will not see a sharp 20/20.  Because of the optics of the eye in conjunction with the thickness of the lenses, a patient will still see well but not as clearly as someone with a lesser prescription.  Another variant of refractive amblyopia is anisometropia; this just means that the prescription between the eyes is very different.  An example is when one eye is very nearsighted and the other eye has no prescription.  Since the brain can only see well out of one eye, it tends to ignore the other eye because of the blurry vision.  However, since the eyes are generally straight and the child can see well, it is very difficult for parents and teachers to pick this up.  A child will generally respond well to visual tasks and will respond with the correct answers when asked about what they see.  However, they are seeing out of only 1 eye, and have poor or non-existent binocular vision or eye teaming due to the fact that the other eye cannot contribute good vision.  Again, this needs to be treated early with full-time glasses to maximize any vision that can be gained when the child is young.  The goal is to minimize the visual acuity difference between the eyes, maximize eye teaming skills, and to protect the “good” eye from trauma as much as possible to avoid having two eyes that do not see well.

            Some other less common causes of reduced vision are trauma and disease.  Most types of trauma to the eye can cause permanent damage to the eye.  Conditions such as a retinal detachment and chemical burn (acid or base) can cause permanent vision loss.  Diseases such as macular degeneration and glaucoma cause decreased vision in one or both eyes that cannot be fully corrected with glasses.  Amblyopia develops in these cases from either the macula in macular degeneration or the optic nerve in glaucoma becoming diseased and not being able to function properly.

             Even though all of the causes of decreased vision were not discussed here, it is clear that there are many reasons for children and adults to have their eyes checked on a regular basis to help maximize their current vision and prevent further vision loss.  Keep in mind we see patients of all ages and look forward to seeing you in the office.

 Dr. K. at Alamo Optometry is your hometown eye doctor for outstanding service, vision care, and designer eyewear.  He can be reached at 820-6622 or visit his office at 3201 Danville Blvd., Suite 165 in Alamo.  Visit our website at: www.alamooptometry.com and become a fan on our Alamo Optometry Facebook page.

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