Astigmatism is a refractive error that sometimes occurs in combination with myopia (nearsightedness) or hyperopia (farsightedness). When paired with these vision problems, it can lead to discomfort, such as frequent eye strain, squinting, and even headaches.
By recognising these signs of astigmatism and understanding how it affects your vision, you can take steps towards managing symptoms and preserving healthy and comfortable eyesight.
What is Astigmatism?
This eye condition develops when the cornea, the front surface of the eye, or the lens inside the eye has an irregular shape. Instead of a sphere, an astigmatic cornea or lens may be oval-shaped, causing problems in focusing the light entering the eye.
How Does Astigmatism Affect Vision?
Generally, light enters through the cornea, the clear front part of your eye. The cornea bends the light and passes it through the lens, focusing it onto the retina at the back of your eye. The retina turns the light into signals that travel through the optic nerve to your brain. Your brain then turns those signals into images.
If you have astigmatism, the light entering your eye bends unevenly because your cornea or lens isn’t shaped quite right. This makes it hard for light to focus clearly on your retina. As a result, parts of what you’re looking at may appear blurry or wavy.
Types of Astigmatism
There are two main types of astigmatism, depending on where the irregularity occurs:
1. Corneal Astigmatism
This is the most common type and is caused by an irregularly shaped cornea. The distorted cornea bends light unevenly, leading to visual distortion.
2. Lenticular Astigmatism
This is when the lens inside the eye has an irregular shape.
Symptoms of Astigmatism
The common signs of astigmatism include the following:
- Blurred or distorted vision
- Eye strain, especially after screen time or reading
- Frequent headaches, particularly after visual tasks
- Feeling fatigued or needing to squint often
- Difficulty seeing at night
Signs of Astigmatism in Children
In children, astigmatism symptoms may be more subtle. Watch for:
- Having a hard time seeing what’s on the board
- Squinting while reading or watching TV
- Having trouble reading or recognising faces
- Complaints of frequent headaches or tired eyes
- Rubbing their eyes often
If you notice these signs, schedule an eye examination in Singapore to check for possible refractive errors like astigmatism.
Causes of Astigmatism
While the cause of astigmatism is still unknown, there are a few key contributing factors to the condition. These include:
- Genetics: Astigmatism often runs in families and can be inherited from one or both parents.
- Eye Injuries: Trauma to the eye could alter the shape of the cornea, which leads to astigmatism.
- Keratoconus: This progressive eye condition causes a thinning of the cornea, which could cause bulging that changes it into a cone shape. This, in turn, increases the risk of astigmatism.
- Previous Eye Surgery: Certain surgical procedures on the eyes can sometimes result in astigmatism as a side effect.
How is Astigmatism Identified?
An optometrist can identify astigmatism during a comprehensive eye examination. These tests assess how well your eyes focus light and help determine the appropriate prescription for corrective lenses.
Visual Acuity Test
This examines how clearly you can see at a distance. You'll be asked to read letters on a chart, and the results are expressed as a fraction (e.g., 6/12). A result of 6/12 means you must be 6 metres away to see what an individual with normal vision can see from 12 meters. A score of 6/6 is considered normal vision.
Refraction Test
Your optometrist places different lenses in front of your eyes to determine which prescription provides the clearest vision. This is often done alongside a retinoscope or an automated device that measures your eye's focusing ability. Your responses help ensure you get the right prescription for your vision.
Keratometry or Corneal Topography
A keratometer is used to measure the curvature of your cornea by analysing the reflection of light from its surface. This is essential for evaluating astigmatism and fitting contact lenses. Corneal topography creates a detailed map of the cornea’s surface, offering more comprehensive data.
What Level of Astigmatism Requires Glasses?
Astigmatism is measured in diopters (D), and its severity determines whether corrective lenses are necessary:
Mild Astigmatism (Less than 1.00D)
This level is considered normal and is very common. Most people with mild astigmatism experience no noticeable symptoms and typically don’t require corrective lenses or surgery.
Moderate Astigmatism (1.00D to 2.00D)
Moderate astigmatism usually affects vision enough to require correction. While you may be able to function without glasses or contact lenses, symptoms like blurred vision or eye strain are likely. Prescription lenses or refractive surgery can help restore clear vision.
Severe Astigmatism (2.00D to 3.00D)
Severe astigmatism often leads to more significant vision problems, such as persistent blurriness and headaches, which can interfere with daily activities. Corrective measures are typically necessary to maintain visual comfort and quality of life.
Extreme Astigmatism (Greater than 3.00D)
At this level, vision is significantly impaired without intervention. Objects both near and far may appear distorted or blurry, making corrective lenses or surgical options essential for functional vision.
Contact Lenses for Astigmatism
For those who prefer an alternative to wearing glasses, you can also consider contact lenses for astigmatism.
There are two types of contacts to help address astigmatism: toric soft lenses and RGP (rigid gas permeable). Toric soft lenses are typically used for mild to moderate astigmatism, while RGP lenses are used for severe or irregular astigmatism.
Discover Your Options for Addressing Astigmatism
Astigmatism is a common yet manageable vision condition. Although symptoms like blurred vision, eye strain, or headaches may seem minor at first, they can gradually interfere with reading, working, or focusing on daily tasks if left uncorrected.
But with regular eye examinations, optometrists can help identify astigmatism early and allow you to explore suitable ways to address your condition. Depending on the level and type of astigmatism, your optometrist may recommend prescription glasses, contact lenses, or other vision correction methods such as orthokeratology.
At Kacee Eye Care, we provide a wide range of vision care services tailored to both adults and children. Our optometrist conducts comprehensive eye assessments using diagnostic tools to check for refractive errors, eye health conditions, and vision changes over time. If you’re dealing with astigmatism, we’ll work with you to find an appropriate corrective option to address your needs.
Beyond astigmatism, we also help patients manage conditions like myopia, presbyopia, and dry eyes. Our child-friendly eye exams focus on early detection of vision issues, making it easier for young ones to thrive in school and everyday life. For adults, we provide eye screenings for work-related needs, lifestyle changes, or age-related vision concerns.
If you or your child are experiencing ongoing eye discomfort or visual disturbances, getting professional support is the next step. Kacee Eye Care is committed to helping you protect your vision with personalised guidance, trusted care, and long-term solutions for more comfortable sight.