Headaches may worry people that something is wrong with their eyes. The most common question I get is, do I have astigmatism and is it causing my headache?

What is astigmatism anyway?

To understand this, let’s discuss some parts of the eye. There is a white part and the colored part. The colored part, or iris, is covered by a transparent layer, the cornea. Further inside the eye behind the iris is another structure, the lens. Both the cornea and the lens are normally smooth and curved evenly. When light enters the eye, these two structures focus the light toward the other parts of the eye (the retina) so that we see clear images. However, some patients’ corneas or lenses are irregularly shaped and this is what we call astigmatism. Light, which should enter as a straight line, becomes bent or mismatched due to astigmatism, blurring the images we see.

Astigmatism can occur on top of a refractive error such as myopia (nearsightedness) or hyperopia (farsightedness), or it can occur on its own. How do we know we have it? The usual symptoms are blurring of vision, headaches, eye strain, feeling of tiredness around the eyes, squinting to see clearer, or having eye discomfort. Frequent squinting to improve image clarity can overwork the muscles of the eye and the brows which can cause the headache. Yet these symptoms may not necessarily mean you have astigmatism, so a visit to an ophthalmologist should be your next step.

At the eye clinic, a complete eye evaluation includes visual acuity test. If the vision is not 20/20 or if the patient has to squint to achieve this, it will prompt the doctor to check your refraction to reveal the presence of astigmatism or an error of refraction. The doctor will give you a prescription — the SPH (sphere) indicates if you are near or farsighted, while the CYL (cylinder) is the measurement of your astigmatism and the axis. Measured in degrees, it refers to where the astigmatism is on the cornea.

How do we treat this condition? Regular eye check ups are advised for all patients so that any undiagnosed eye problem can be addressed. Especially for kids who would not be as vocal about discussing their concerns, a yearly eye check up is best so that their vision is optimized. If found to have astigmatism, eye glasses or contact lenses are often prescribed. Sometimes, the astigmatism or even the refractive grade of the eye can change over time, either decreasing or increasing. This prompts the need for regular check ups to update glasses to realize your full visual capacity.

If you have any questions about your eyes, consult your eye doctor today.