Astigmatism- What is it, and how to correct it?
Astigmatism is one of the most common vision problems, along with near and farsightedness. If you are diagnosed with astigmatism, you already have an idea what it is, but let's explain it to other people who are trying to find out more about it. In short- astigmatism is the imperfection of your cornea (a transparent cupola that covers your iris and pupil) or your eye’s lens. If one of those two parts is not smooth or correctly curved, it will cause the light rays to be poorly refracted, resulting in blurred vision (refractive error). Your retina (the back part of your eye) will not get a single, proper focus point. Instead, it will have multiple focus points that can be in front of it, behind, or in some cases, both, causing blurred and distorted vision. Depending on if your cornea or lens is out of shape, you could have corneal or lenticular astigmatism.
The main issue of astigmatism is that it impacts your ability to see precisely objects that are both near and far. Like near/farsightedness, astigmatism is not a disease or an eye health problem. It is just a condition, and the result of it is the inability of your eyes to focus light correctly.
Astigmatism is mainly caused by the irregular-shaped cornea. While normal cornea is roundly shaped, if you have astigmatism, your is shaped more like an American football. This shape results in one of your eye meridians being significantly more curved than the other - the steepest meridians of an eye with astigmatism are named principal meridians.
Types of astigmatism
Besides the corneal and lenticular astigmatism, there are also myopic, hyperopic, and mixed astigmatisms.
- Myopic astigmatism- your principal meridians (one or both) are nearsighted
- Hyperopic astigmatism- your principal meridians (one or both) are farsighted.
- Mixed astigmatism- this is a combination of the two types above- one of your principal meridians is farsighted, while the other one is nearsighted.
There are also two types of astigmatism depending on the position of your principal meridians- regular and irregular.
- Regular astigmatism- your principal meridians are perpendicular to each other (90 degrees apart)
- Irregular astigmatism- your principal meridians are not perpendicular. The irregular type is rare and is usually caused by some kind of eye injury, surgery, or disease.
Who suffers from astigmatism?
Astigmatism occurs in children, and some are even born with it. The difficulty with children is that it often goes unnoticed- children don’t know that something is wrong, and they will not alarm their parents about their poor vision. However, parents usually get suspicious when their child starts having problems in school, or on the sports field. To prevent untreated astigmatism (and also any other eye-health issues) from creating more problems, make sure you take your child to an ophthalmologist's office regularly. The sooner your child gets treatment, the better.
Studies show that astigmatism is more common in children of certain ethnicities, mainly Asian and Hispanic, while African-Americans had the least. On average, around 20-50% of all children will have some degree of astigmatism in one or both eyes.
Adults with more severe astigmatism can usually figure out on their own if they have a problem and will visit the doctor’s office.
And no, you won’t get astigmatism if you read at low light, or sit too close to the TV- we got that one debunked. (1)
Testing and Correction options
Your eye doctor will make astigmatism tests using different methods- retinoscopy, automated refraction, and manual refraction. If the test results show you do have a problem, the doctor will recommend one of these solutions- glasses, contact lenses, or even corrective surgery. Glasses are the simplest option, but they will only improve your vision straight in front of you and are not suitable for sports activities. Contact, on the other hand, will fix your peripheral vision too and are better suitable for vigorous activities. Just make sure you keep good hygiene to prevent infections. Surgery is a permanent solution, but it will cost you a lot of money. All things considered, contact lenses are the best solution of all three, at least in our opinion- affordable, comfortable, and suitable for different activities. (2)
Astigmatism requires a special kind of lens to correct the difference between the two principal meridians that cause the problem. These “cylinder” lenses will have different numbering. You will get your “traditional” part of the prescription- the diopter- for example, -2, and you would get the cylinder part, that will describe the additional diopter required to correct the more curved principal meridian -1. The third part will show the location of the flatter meridian, on a 180-degree scale. So, for example, you could get a -2.5, -1.0, 90 prescriptions. Gas permeable contact lenses (GP) and hybrids may or may not require all three numbers, depending n the type of your astigmatism and its intensity. But, for most people, soft toric contact lenses will be the best option.
Toric lenses are special kinds of lenses designed to correct astigmatism. While regular lenses are spherically shaped, toric lenses are not. They are curved differently, and they refract all the light into a single point, correcting the astigmatism problem.
Soft, disposable toric lenses are the best option for most people, since they are the most comfortable, and you don’t have to worry about keeping them clean- you just toss them away after using. RGP contact lenses are also an option, but you will have to be patient with them- getting used to them is a much longer process, and they can be uncomfortable. Your eye doctor will recommend the best option for you, taking into consideration the seriousness of your astigmatism condition. (3)
Astigmatism has a scary name, but it is a simple problem that is easily fixable. Just get a proper pair of contact lenses or glasses, and you are good. If you have a blurry vision, don’t just think it’s because you have been overworked and fatigued, visit the doctor’s office. You don’t want your condition to worsen, the sooner you go, the better. Also, if you have children, regularly take them to get their eyes checked, you don't want their school or sports performance to suffer when the problems are so easily fixable.