Overview
Our vision comes from light waves stimulating retinal photoreceptors and these photoreceptors transferring their signals through a multitude of other cells to the ganglion nerve cells. These ganglion cells bunch together and form the optic nerve. The optic nerve then sends the signal to the occipital lobe in the brain where vision is interpreted and recognized.
Amblyopia refers to a condition where the vision is sub-optimal despite a healthy eye. It is now known to be caused by the improper development of the visual system within the brain. The other term for this is a “lazy eye”. Amblyopia is usually unilateral (affects one eye) but sometimes bilateral (both eyes).
Signs and Symptoms
Signs
There are no signs of amblyopia other than slower brain transmission of visual information only noticed in highly specialized visual evoked potential testing.
Symptoms
Decreased vision. More difficulty recognizing letters in a row than the same letters one by one.
Causes and Risk Factors
Causes
Visual deprivation (congenital cataract, corneal scar, retinal dystrophy, droopy eyelid, etc., blocking vision so the brain never develops the vision in that eye), strabismic (one eye is turned and to avoid double vision the brain does not develop the vision in that eye), anisometropic (one eye has a prescription so different from the other that the brain only develops the vision from one eye), ametropic (the prescription is so high in both eyes that the visual system did not develop properly).