Nearsighted means that a person can see objects clearly up close but sees blurred in the distance. The more negative the prescription (ie -6.00) the closer someone will have to hold something to be able to see it without glasses.
Farsighted means that a person can see objects clearly far away but may see blurred when looking up close. Children are usually slightly farsighted and do not typically have problems seeing up close since they have a very good ability to focus when they are young. The more positive the prescription (ie +5.00) the farther away you would have to place an object in order to see it clearly.
Astigmatism is simply a particular glasses or contact lens prescription that indicates stronger power in one angle (axis) than in another. Astigmatism causes distortion both at distance and at near. Imagining the distortion or stretching caused by a funhouse mirror can be a helpful comparison.
Amblyopia means that the eye is not seeing as well as it should despite being a healthy eye. This typically happens when a child favors one eye for a number of different reasons leading to the other eye having poorer and poorer vision. A lazy eye does not necessarily look any different than the other eye.
Amblyopia is best treated with glasses (to provide a clear image) and patching of the better seeing eye (to force the body to use the less favored eye). We recommend an adhesive (sticky) patch as the best treatment. Occasionally your doctor may discuss the use of a dilating eyedrop called atropine as another option for children that are unable to patch.
Patches come in a variety of colors and patterns which can help children accept them. Pairing patching with a fun activity like TV watching or tablet use can also be very effective. Some children have very good results with using a patch chart to keep track of their progress.
Strabismus means that the two eyes are misaligned. In children, this is most often crossing (esotropia) of one or both eyes. It is also possible for one eye to turn outwards (exotropia) or to turn upwards or downwards (hypertropia/hypotropia) in relation to the other eye.
Accommodative esotropia, or refractive esotropia, refers to eye crossing that is caused by the focusing efforts of the eyes as they try to see clearly. Patients with refractive esotropia are typically farsighted (hyperopic). This means that the eyes must work harder to see clearly, particularly when they are focused up close. This focusing effort is called accommodation. The closer an object is to the eye, the greater the amount of accommodation that is required. A side effect of the accommodative effort can be excess convergence or crossing of the eyes.
No, in fact most children are farsighted but the majority of them do not have any esotropia. Most children are only slightly farsighted, and thus the accommodative effort they make to see clearly is not significant. The more farsighted a person is, however, the greater the amount of effort they must exert and the more likely they are to cross their eyes. Therefore, while two individuals may have the same eye prescription strength, one may have eye crossing and the other may have perfectly straight eyes. Heredity plays a role in determining which children develop esotropia.
Initial treatment for accommodative esotropia usually involves the prescription of eyeglasses or contact lenses to correct the patient’s farsightedness (hyperopia). By letting the eyeglasses do the work, the eyes can relax their focusing or accommodative effort. In turn, this will reduce the convergence or crossing stimulus and the eyes will straighten as they relax. Glasses or contacts which are used to treat accommodative esotropia should be worn full time.
Congenital or more accurately, infantile esotropia is a large degree of crossing of the eyes that typically occurs before the first year of life and is typically not improved with glasses. These infants often need to have eye muscle surgery to straighten the position of their eyes and allow them to use both eyes together.