When it comes to taking care of our eyes, getting regular eye exams is essential. One common issue that can be detected during an eye exam is astigmatism. Astigmatism is a refractive error that occurs when the cornea or lens of the eye has an irregular shape. This can cause blurry or distorted vision at various distances. To diagnose astigmatism and determine the appropriate treatment, an astigmatism test is conducted by optometrists or ophthalmologists. Let’s take a closer look at what to expect during an astigmatism test.

Discussion about Symptoms and Medical History

During the initial part of the astigmatism test, your eye care professional will begin by having a discussion with you regarding any symptoms you have been experiencing. This includes any issues with blurred vision, eye strain, headaches, or difficulty seeing at certain distances. They will also ask about your medical history, including any previous eye conditions or surgeries, allergies, or medications you may be taking. This information will help the doctor better understand your eye health and potential risk factors for astigmatism.

Visual Acuity Test

The next step in the astigmatism test is the visual acuity test. This is a standard eye exam that determines how well you can see at different distances. You will be asked to read letters or numbers on a chart from a specific distance. This test helps assess the clarity and sharpness of your vision. The results of the visual acuity test can indicate whether or not you may have astigmatism, as well as the severity of the condition.

Refraction Assessment

After the visual acuity test, the optometrist or ophthalmologist will perform a refraction assessment. This test determines your exact eyeglass prescription and helps identify any astigmatism. You will be asked to look through a device called a phoropter, which contains a series of lenses. The eye care professional will ask you to compare the clarity of different images and determine which is clearer. By doing so, they can fine-tune the prescription to correct any astigmatism you may have.

Keratometry Reading

The keratometry reading is another crucial part of the astigmatism test. This test measures the curvature of your cornea, which is essential in diagnosing and evaluating astigmatism. An instrument called a keratometer is used to measure the reflection of light on the cornea’s surface. The readings obtained from this test help determine the specific characteristics of your astigmatism, such as the degree and axis.

Corneal Topography

In some cases, a corneal topography may be conducted during an astigmatism test. This test provides a detailed map of the shape and curvature of your cornea. It is particularly useful if your astigmatism is irregular or if there are concerns about corneal abnormalities. By analyzing the corneal topography, the eye care professional can gain valuable information about the astigmatism’s characteristics and develop an appropriate treatment plan.


During the astigmatism test, the optometrist or ophthalmologist may also perform tonometry. Tonometry is a test that measures the pressure inside your eyes. It is commonly used to screen for glaucoma, a condition that can be associated with astigmatism. By measuring the intraocular pressure, the eye care professional can identify any signs of increased pressure, which may require further investigation or treatment.


When undergoing an astigmatism test, it is essential to provide accurate information about your symptoms and medical history. The tests involved, such as a visual acuity test, refraction assessment, keratometry reading, corneal topography, and tonometry, help diagnose and evaluate astigmatism. By understanding what to expect during an astigmatism test, you can be prepared and confident in discussing your eye health with your optometrist or ophthalmologist. Regular eye exams and early detection of astigmatism are key to maintaining good vision and overall eye health.