Dullness or obscurity of sight for no apparent organic reason, therefore not correctable with glasses or surgery. Sometimes called a lazy eye, wherein one eye becomes dependent on the other eye to focus, usually developed in early childhood. Often associated with strabismus. The conditions that most commonly cause amblyopia are eye misalignment (strabismus), a significant difference in spectacle prescription (refractive error) between the two eyes (anisometropia), or interruption of the light path of one of the eyes (by cataract, scar, tumor, etc.). If amblyopia is not treated before the age of 8, the visual deficit is usually permanent. Also referred to as ?lazy eye?. A failure of development of the part of the brain which processes vision, which can arise if the eye in question is misaligned with the dominant eye, or is significantly out of focus or is prevented from seeing clearly (eg by cataract) during the first 7 years or so of life when the visual system is still developing. It is usually reversible during this time by treating its cause and patching the other eye, but becomes irreversible once the visual system is mature. Amblyopia, or lazy eye, is reduced visual acuity that cannot be improved by wearing eyeglasses.
Age-related macular degeneration, a disease that damages the macula, the central part of the retina, leading to a loss of central vision and leaving only the peripheral or lateral vision intact.