Astigmatism or Nearsightedness?

Nearsightedness, or myopia, as it is called medically, and astigmatism are two of the most common eye problems. To the untrained eye, it can be difficult to distinguish between the two. Though of course it is always advisable to seek advice from a medical professional when in doubt, there are a few key differences between the two that can help pinpoint the exact nature of the problem.


Nearsightedness is the single most common eye problem and it is characterized by a defect in the structures of the eye that do not allow it to properly focus the light that enters the eye through the retina. This condition is usually caused by a natural elongation of the eyeball over time. Because of this, it often gets worse for a period of time before settling, resulting in the need for regular checkups and potential prescription updates. The most common method of diagnosing this type of vision loss is through use of the Snellen Test Chart, which is the familiar rows of letters in ever decreasing sizes. Some doctors may also use other methods such as refraction and retinoscopy or with the use of computerized devices. It is typically and very easily corrected through the use of prescription glasses or contact lenses prescribed by an eye doctor after a thorough examination. These are designed and sculpted to focus the light back onto the retina in just the right way to allow the patient to see clearly once again.


Astigmatism is also common, though not quite as common as nearsightedness, and is slightly more complicated to correct. It is caused by the shape of the eye not being perfectly symmetrical, which results in the light that enters the eye not being perfectly symmetrical either. People with astigmatism may have trouble seeing fine detail, complain of blurred vision, or, in extreme cases, objects may appear to be “curved” to them. During diagnosis, a keratometer may be used to measure the exact curvature of cornea. A more advanced technology called corneal topography may also be employed, which involves the patient looking at a visual target while a computerized device scans their eye and takes hundreds of precise measurements. It then constructs a color map on screen based on the data it has collected. This map allows the doctor to see a comprehensive picture of the structure of the cornea. Astigmatism is treated by use of glasses or contacts that are specially designed not only to focus the light in just the right way, but also to compensate for the asymmetricality in the curvature of the patient’s individual eye or eyes.

Of course, these conditions are not mutually exclusive, and it is often common for an individual to have both nearsightedness and astigmatism at the same time. The best way to diagnose, treat, and prevent eye defects is through regular appointments with a licensed physician. They will be able to diagnose an individual’s specific problem and put them on the path to correction and recovery.