Astigmatism: vision condition characterized by the inability, at any distance, to focus on the retina the image of a dot when you are watching at a point object. In most cases astigmatism is caused by an imperfection in the curvature of the cornea.
Astigmatism causes blurred vision both at near and far distance. The symptoms are related to the magnitude and type of astigmatism. When astigmatism is regular and mild, the patient can suffer from a slight vision worsening while when astigmatism is medium or high or in cases of irregular or mixed forms, the visual problems are often associated with accommodative asthenopia (eye strain).
The astigmatic eye tries to focus the images through accommodation in order to get a clear vision, but the same accommodative efforts may cause asthenopic symptoms, such as eye strain, headache, red eyes and blepharitis.
The first approach to the correction of astigmatism is the prescription of spectacles or contact lenses.
In the last decades many surgical treatments have been proposed to correct astigmatism when high and seriously hindering the quality of vision.
The surgical approaches include: refractive surgery with excimer laser, corneal incisions (astigmatic keratotomy), refractive cataract surgery with toric intraocular lens (when astigmatism treatment is combined with cataract surgery).
In mixed forms, the visual problems are often associated with accommodative asthenopia (eye strain).
Astigmatism is a vision condition characterized by the inability, at any distance, to focus on the retina the image of a dot when you are watching at a point object.
The word comes from the Greek “a-stigma”: “a”=without and “stigma”=dot, spot, point.
In the astigmatic eye the light rays cannot be focused on a specific point of the retina, where instead a complex image is formed by two perpendicular lines, called “focal”, separated by a focal gap.
In most cases astigmatism is caused by an imperfection in the curvature of the cornea (external astigmatism), but there can be also a form of “internal astigmatism” caused by imperfections in the crystalline lens or in the retina.
Corneal astigmatism can be regular or irregular.
Astigmatism causes blurred vision both at near and far distance. The symptoms are related to the magnitude and type of astigmatism. When astigmatism is regular and mild, the patient can suffer from a slight vision worsening while when astigmatism is medium or high or in cases of irregular or mixed forms, the visual problems are often associated with accommodative asthenopia (eye strain).
The astigmatic eye tries to focus the images through accommodation in order to get a clear vision, but the same accommodative efforts may cause asthenopic symptoms, such as eye strain, headache, red eyes and blepharitis.
The first approach to the correction of astigmatism is the prescription of spectacles or contact lenses.
In the last decades many surgical treatments have been proposed to correct astigmatism when high and seriously hindering the quality of vision.
