Can Astigmatism Cause Vision Loss? Effects, Symptoms, and Treatment

Can Astigmatism Cause Vision Loss?

Understanding Astigmatism

By Ben Wilkinson, FRCSC

Astigmatism is a common optical condition that affects the way light is focused in the eye, leading to blurred or distorted vision. A normal magnifying lens is perfectly round, with the curve being uniform. In the case of astigmatism, the lens is more oval-shaped, with different curvatures along the longer and shorter axes. This is analogous to imagining an oval magnifier, where one diameter is steeper than the other. This difference in curvatures can be described in two ways: by providing the weaker axis strength and the difference, or by giving the stronger axis and the minus power. For example, a prescription of 5.00 -2.00 x 90 can be equivalently described as 7.00 2.00 x 180.

The Perfect Eye and Astigmatism

The perfect eye is perfectly round, with a prescription of 0.00. Any distortion in the shape of the eye can result in astigmatism. The most common cause is hereditary, where the eye grows slightly oval. Other causes include external factors such as a lump on the eyelid rubbing against the eye, a tumor in the orbit pushing on the eyeball, or other structural changes.

Effects and Symptoms of Astigmatism

Development of Vision

Up to the age of 12, glasses can help the eyes develop normal sharpness of vision. However, after the age of 12, glasses are no longer effective in correcting any amount of lazy eye (amblyopia) or below-average vision associated with astigmatism. While the so-called plastic period of childhood development is over, wearing glasses can still help sharpen the vision and better adapt the eyes to the available vision.

Treatment Options

Astigmatism can be treated through the use of glasses, contact lenses, or corneal surgery. Soft contact lenses can usually ignore small amounts of astigmatism, but if the vision is still not clear, it may be necessary to use hard or toric contact lenses. Toric lenses are specifically designed to fit the astigmatic shape of the eye and are more expensive to make.

Can Astigmatism Cause Vision Loss?

While astigmatism itself does not typically cause vision loss in the traditional sense, it can contribute to reduced visual clarity and quality of vision. If left untreated, the effect of astigmatism can worsen, leading to progressively blurred or distorted vision over time. However, the rate at which this happens can vary significantly from one person to another. Some individuals may not experience any significant vision loss for years, while others might start noticing changes within a few months.

Conclusion

Astigmatism is a common condition that can affect the clarity of vision. While it does not directly cause vision loss, it can impact the quality of vision. Treatment is available and can help manage the condition, preventing further deterioration of vision. Regular eye examinations and timely intervention are crucial in maintaining optimal eye health.