What is astigmatism?
Astigmatism is a condition of the eye in which the cornea is not spherical but oval in shape. The eye aims to bring all light rays to a focus on the retina. So when the cornea is not spherical, its curvature, and therefore its focusing power, is not the same in every axis.
Page contents
- What is astigmatism?
- What are the symptoms of astigmatism?
- How does a person with astigmatism see?
- What are the possible causes of astigmatism?
- How is astigmatism corrected? Is laser treatment necessary?
- What is LASIK?
- How long does LASIK take?
- Is LASIK painful?
- What is PRK?
- Is PRK painful?
- How soon can you see well after PRK?
- How long does PRK take?
- What is our view on the two procedures?
- How much does treatment cost? Are the prices affordable?
- Types of astigmatism
- Degrees of astigmatism: when correction is needed
- How we measure astigmatism
- Astigmatism in children
- Contact lenses for astigmatism
- Astigmatism and cataract: the toric intraocular lens
- Can astigmatism change over the years?
- Tips for everyday life with astigmatism
- Myths about astigmatism
- Astigmatism and screen work
- Frequently Asked Questions about Astigmatism
As a result, light rays do not come together at a single point but along two different axes. The image formed on the retina is therefore blurred at both near and far distances.
There are two types of astigmatism: regular and irregular. Regular astigmatism means that the cornea is oval and can be corrected almost perfectly with glasses, while irregular astigmatism means that the cornea has a shape that does not allow full correction with glasses. One example is a condition called keratoconus, in which the cornea gradually thins and becomes cone-shaped.
What are the symptoms of astigmatism?
The symptoms of astigmatism can vary from case to case. At first you may have blurred vision when trying to focus at a distance. Likewise, your vision at close range may also be affected, for example when reading a book or sitting at the computer. This can lead to more frequent headaches and tiredness. Of course, this depends on the individual case. However, it is a good idea to get advice from a specialist ophthalmologist, who can guide you straight away and talk to you about treatment.
How does a person with astigmatism see?
Because in astigmatism light does not focus at a single point, vision is affected at every distance, not only far or only near. In everyday life this means:
- letters and numbers that look “shadowed” or doubled, so that, for example, an 8 can be confused with a 3,
- lines that look sharp in one direction and blurred in another, such as the grout lines between tiles or the shelves of a bookcase,
- lights at night that spread out into rays or streaks, which makes driving particularly difficult,
- eye strain and headaches after reading, screen use or driving,
- a tendency to squint or tilt the head to see more clearly.
Mild astigmatism often goes unnoticed. Children rarely complain, because they think a blurred image is normal, which is why a children’s eye examination is so valuable. Astigmatism that increases quickly, especially at a young age, needs corneal topography to rule out keratoconus.
What are the possible causes of astigmatism?
Astigmatism is a condition that may be present from birth or may even result from an injury to the eye. For this reason, there is no single cause; it depends on the individual case. In this case the cornea is more steeply curved, rather like a small ball. As mentioned above, this affects vision, which can become even more blurred.
Book an appointment with the doctor
An examination and clear advice on your case at our practice in Neo Psychiko.
How is astigmatism corrected? Is laser treatment necessary?
The most widespread and safest way to correct astigmatism is with glasses. In most cases glasses provide satisfactory vision. A second option is contact lenses for astigmatism, known as toric lenses. Toric lenses are designed to stay still on the axis of the astigmatism, which is often not possible. Constant blinking contributes to this, as do factors related to the shape of the cornea, dryness and so on. This is why many people do not get on well with them, especially with low astigmatism.
The last and permanent way to correct astigmatism is refractive surgery, known to most people as laser surgery for astigmatism.
There are two types of laser surgery for astigmatism: LASIK and PRK.
What is LASIK?
LASIK is a procedure that reshapes the cornea in order to correct astigmatism. It is a completely painless method with immediate improvement in vision and permanent results. Two lasers are used, one called a femtosecond laser and a second called an excimer laser. With the first laser we separate the layers of the cornea in its outer fifth, creating what is called a flap. After the flap is lifted, the second laser is applied to reshape the cornea. The last step is to put the flap back in place, which ensures there is no open wound on the eye and therefore no pain. In addition, vision improves immediately: patients realise straight away that they no longer have astigmatism, although there is some slight haziness, which usually disappears by the next day. The lasers we use are among the most modern and technologically advanced in the world.
How long does LASIK take?
From the moment the patient enters the treatment room, the procedure usually takes around 10 minutes. Most of this time is spent preparing the procedure and the patient, since the time each laser actually needs is just a few seconds (10 on average).
Is LASIK painful?
Not at all! As mentioned earlier, anaesthetic drops alone are enough to ensure the patient feels no pain at all. After the procedure there is usually no discomfort, although occasionally there may be a feeling of something in the eye, which has gone by the following morning.
Book an appointment with the doctor
An examination and clear advice on your case at our practice in Neo Psychiko.
What is PRK?
PRK is a procedure for removing refractive errors such as myopia, in which the most superficial layer of the cornea, called the epithelium, is removed first. This can be done with a laser, in a technique called PTK, or with drops that soften the epithelium so that it can be removed. The next stage is performed with the excimer laser, which sculpts the cornea to remove the refractive error. As with LASIK, the laser we use is among the most modern and technologically advanced in the world.
Is PRK painful?
With PRK, mainly on the first day, there may be anything from mild discomfort to pain, which can however be managed with simple painkillers. From the second day the symptoms begin to improve and they usually subside completely after the third day. By this stage the epithelium has fully healed.
How soon can you see well after PRK?
With PRK, vision is improved during the first three days but, because the epithelium is missing, it is not perfect. There is a significant improvement after the first three days, once the epithelium has healed, and from that point vision improves gradually until it is fully sharp. The final result usually appears after the first week, but in some patients it may take up to a month. This depends on the person’s healing ability, whether they have dry eye and other factors.
How long does PRK take?
From the moment the patient lies down, the procedure takes no more than 10 minutes. If the PTK technique is chosen, it can be even shorter.
What is our view on the two procedures?
Both methods, LASIK and PRK, are very good ways of correcting astigmatism as well as myopia or hyperopia. In fact, that is why both are still performed and neither has replaced the other. The doctor’s choice is based on the thickness of the cornea and a test called topography. The third method, which as mentioned is called SMILE, is promising but is still evolving. At the first eye examination, with the results of these tests available, we discuss the two methods in detail, answer all your questions and recommend the method we consider best for you.
How much does treatment cost? Are the prices affordable?
For information about the cost and prices of the procedure, please contact the ophthalmologist.
Types of astigmatism
Astigmatism is not a single condition. Depending on the shape of the cornea and how it combines with other refractive errors, we classify it into different categories. The category has a direct effect on the choice of correction.
Regular and irregular astigmatism
In regular astigmatism the cornea is shaped more like a rugby ball than a football: it has two main axes with different curvature, at right angles to each other. This is the usual type and it is corrected very well with glasses, contact lenses or laser.
In irregular astigmatism the surface of the cornea is uneven, as happens in keratoconus, after injury, infection or previous surgery. In this case glasses often do not give clear vision, and special contact lenses or other treatments are needed.
By the position of the axis
- With-the-rule: the vertical axis is steeper. It is more common in young people.
- Against-the-rule: the horizontal axis is steeper. It becomes more common with age.
- Oblique astigmatism: the axes are slanted. It often causes more discomfort for the same degree.
Combined with myopia or hyperopia
Astigmatism rarely occurs on its own. We speak of myopic astigmatism when it is combined with myopia, hyperopic astigmatism when it is combined with hyperopia, and mixed astigmatism when one axis is myopic and the other hyperopic.
Degrees of astigmatism: when correction is needed
A small amount of astigmatism, up to about 0.50 dioptres, is very common and usually does not need correcting. From 0.75 to 1.00 dioptre and above, many people experience eye strain, headaches or blurring, especially when reading, using screens and driving at night. Above 2.00 dioptres, vision is affected at all distances. What matters is not only the number but also each person’s symptoms and needs.
How we measure astigmatism
Diagnosis begins with measuring visual acuity and refraction. For a complete picture, however, corneal topography is also needed: a painless test that “maps” the surface of the cornea point by point. Topography distinguishes regular from irregular astigmatism, reveals early signs of keratoconus and is essential before any laser procedure. In children, the measurement is taken with cycloplegic drops so that it is not affected by the eye’s focusing.
Blurred or doubled vision and headaches?
A full examination with corneal topography shows the type and degree of your astigmatism. Book an appointment in Neo Psychiko.
Astigmatism in children
Many babies have astigmatism that decreases during the first years of life. However, when it remains high or differs a lot between the two eyes, the brain does not receive a clear image and amblyopia may develop. Children rarely complain, because they assume everyone sees this way. Signs such as tilting the head, squinting, holding a book very close or difficulty seeing the board need assessment by a paediatric ophthalmologist. At this age, glasses are not just an aid but a treatment that allows vision to develop properly.
Contact lenses for astigmatism
For regular astigmatism there are soft toric contact lenses, designed to settle in a specific position on the eye. For irregular astigmatism, rigid gas permeable or scleral lenses are used, which create a new, smooth optical surface in front of the cornea. Proper fitting and regular check-ups are essential for the health of the eye.
Astigmatism and cataract: the toric intraocular lens
For people who need cataract surgery and have significant astigmatism, a toric intraocular lens can be implanted. This lens corrects the cataract and the astigmatism at the same time, so that after surgery the need for distance glasses is much lower. The calculation is based on precise measurements of the cornea before the operation.
Can astigmatism change over the years?
Regular astigmatism in adults usually remains stable for many years, while with age its axis tends to change slowly. Astigmatism that increases quickly in a teenager or young adult is a warning sign, because it may be caused by early keratoconus. In this case early diagnosis makes all the difference, as there are treatments that stop the condition from progressing. A chalazion or swelling of the eyelid can also cause temporary astigmatism, which settles once the cause is treated.
Tips for everyday life with astigmatism
- Wear your glasses when driving, especially at night, when astigmatism causes “stars” and streaks around lights.
- If your glasses make you feel dizzy for the first few days, give yourself time to adjust. If the discomfort lasts more than a week, ask for your prescription and the centring of the lenses to be checked.
- Avoid rubbing your eyes hard, as this habit is linked to worsening in vulnerable corneas.
- Have a check-up every one to two years, or sooner if you notice a change in your vision.
Dr. Vasileios Skouteris examines and treats astigmatism in children and adults at his practice in Neo Psychiko, Athens. To book an appointment, call +30 210 677 0007.
Myths about astigmatism
- “Astigmatism is an eye disease.” Regular astigmatism is simply a refractive error, like myopia. It does not mean the eye is diseased.
- “Reading in poor light causes astigmatism.” Poor light tires the eyes, but it does not change the shape of the cornea.
- “If I have astigmatism, I can’t wear contact lenses.” Today there are toric and specialist lenses for almost every degree of astigmatism.
- “Laser can’t be done for high astigmatism.” Many cases of high astigmatism can be corrected with laser, provided the cornea is thick enough and has normal topography. Suitability is always assessed after a full pre-operative examination.
- “Glasses will make astigmatism worse.” Glasses do not change the degree. They simply give the eye the clear image it needs.
If you have questions about your own astigmatism, an examination at the clinic is the most reliable way to find out which solution suits you.
Astigmatism and screen work
Even a small amount of astigmatism that causes no trouble in everyday life can become noticeable after many hours in front of a computer. The eye keeps trying to focus, leading to fatigue, stinging and headaches by the end of the day. In these cases, a pair of computer glasses with the right astigmatism correction greatly improves comfort. Regular breaks, the right distance from the screen (about an arm’s length) and glare-free lighting also help.
If symptoms persist despite the correct prescription, the surface of the eye should also be checked, because dry eye causes similar discomfort and often coexists.
Frequently Asked Questions about Astigmatism
How does a person with astigmatism see in everyday life?
With astigmatism the image is blurred or distorted at all distances. Letters and numbers may look shadowed or doubled, lights at night spread out into rays, and lines in one direction look sharper than others. It is often accompanied by eye strain and headaches after reading or screen use.
What is myopic astigmatism?
Myopic astigmatism is the combination of myopia and astigmatism in the same eye. The patient sees distant objects blurred because of the myopia, while the astigmatism adds distortion and blurring at all distances. It is very common and is corrected with glasses, toric contact lenses or laser surgery, which corrects both errors at the same time.
Can astigmatism be corrected with laser?
Yes. LASIK, PRK and TransPRK correct astigmatism up to a certain degree, often together with myopia or hyperopia. Before the procedure, corneal topography is performed to rule out keratoconus, in which conventional laser treatment is not suitable. For higher degrees, alternatives such as toric intraocular lenses are considered.
Does astigmatism increase over the years?
Astigmatism is usually stable in adults, with small changes in its axis with age. Astigmatism that increases quickly, especially in teenagers and young people, can be a sign of keratoconus and needs corneal topography. Astigmatism can also be caused by a pterygium, a chalazion or previous eye surgery.
Medically reviewed by: Dr. Vasileios Skouteris MD, FEBO