Myopia is a refractive error that causes nearsightedness and blurred vision when looking at a distance. The condition is very common, affecting approximately 30 percent of the total U.S. population. The condition usually develops in childhood and gradually worsens throughout adolescence. In some cases, people develop myopia after Myopia is easily diagnosed with a comprehensive eye exam and corrected with various treatments, including glasses, contact lenses or refractive surgery.
Hyperopia is a refractive error that causes farsightedness and blurred vision when looking at objects up close. Approximately 1 in 2 people has some degree of hyperopia, which may also cause headaches and eyestrain. Hyperopia is typically genetic and usually develops in childhood. The condition is easily diagnosed during a comprehensive eye exam and treated with glasses or contacts.
Astigmatism occurs when the eye’s natural lens becomes misshapen. There can be varying degrees of corneal astigmatism, which often occurs in people with other vision impairments, such as myopia and hyperopia. Astigmatism is very common, causing blurry or distorted vision, as well as the potential for headaches or eye strain. A optometrist can diagnose astigmatism during a standard eye exam and prescribe treatment, such as glasses or contacts, to help treat it.
Amblyopia is a condition in which the brain does not form the connections it needs to process vision. This can result from an unequal refraction between each eye, from a very strong refraction in both eyes, from misaligned eyes, or from a physical impairment in the eye which clouds the vision. Amblyopia, often called “lazy eye” can often be corrected if found and treated when the child is young. A thorough dilated eye exam with refraction is usually all that is needed to diagnose and begin treatment of amblyopia. The child does not need to be able to read the eye chart. Treatment can include glasses, patching, or sometimes eye muscle surgery. Conditions which cause amblyopia can be hereditary and an ophthalmic exam for the amblyopic child’s siblings is also recommended.
Presbyopia is a refractive error in which the eye is no longer capable of focusing correctly. It is primarily age-related and occurs in all people – usually sometime after age 40. Presbyopia is a not a disease though it can make reading and viewing objects up close much more difficult. A comprehensive eye exam can evaluate visual acuity and diagnose presbyopia. Often, patients only require reading glasses to manage the problem, though prescription bifocals, trifocals or contact lenses may be necessary for some people.
Emmetropia is the term used to describe an eye with normal vision strength, curvature and eyeball length. People with emmetropia require no corrective lenses, as images come into natural focus on the retina.