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Astigmatism is a fairly common condition that affects eyesight due to an irregularity in the shape of the cornea of the eye. To understand what astigmatism is, it’s necessary to have a basic understanding of what the eye does and how it works.

How the Eye Works

Your eyes shape how you see the world; they are a valuable sense organ that reacts to light. Light reflects off objects in your line of sight and enters the eyes through the cornea—the clear, outermost layer of the eye.

From there, the reflected light passes through the iris (the colorful part) and the pupil (the dark circle in the center). The pupils increase and decrease in size to control how much light passes through to the lens, which helps to focus the light on the retina. The retina then converts the light into language your brain can understand and sends it there with optic nerves.

So, as you can see, vision starts with the cornea, which is where the astigmatism irregularity is found when present. You can’t see astigmatism with your naked eye, but you may notice some of its symptoms in the form of blurry vision, nearsightedness, or farsightedness. The condition can only be detected and treated by a doctor of optometry.

Characteristics of Astigmatism

Astigmatism is a refractive error where your cornea is more oval-shaped than circle-shaped. The slightest imperfect bend or curve in the shape of the cornea affects the way the retina receives reflected light. If the cornea is not completely round, the light rays do not reflect evenly and cause distorted vision.

Astigmatism is often paired with nearsightedness (myopia) and farsightedness (hyperopia), resulting in three classifications of the condition: myopic, hyperopic, and mixed (both near- and farsighted, where astigmatism is the primary refractive error).

Astigmatism occurs in varying degrees of severity, sometimes requiring no treatment at all with no noticeable symptoms. Others may need glasses or contacts—or choose a surgical option—to treat the condition. Astigmatism may be present in just one or in both eyes.

How Do Doctors Diagnose Astigmatism?

Checking for astigmatism is a routine part of a comprehensive eye exam, and ophthalmologists use a variety of methods to gain a total picture of your eyes.

Your doctor may use corneal topography to measure the shape and surface of the cornea and provide a detailed map to gauge for astigmatism and any other irregularities. Corneal topography takes measurements to create a computerized, comprehensive topographic map of your cornea.

Visual acuity tests like the Snellen test determine how well you can discern the details of the object you see and can help your doctor diagnose sight problems, including astigmatism. There are no special tools required for this test; you will simply read ever-smaller lines of letters on a chart (usually 20 feet away) until you can’t discern them anymore.

If your doctor detects astigmatism, he or she can assess its severity by measuring the refractive error through the use of retinoscopy. The doctor will shine a beam of light into your eye to see the angle at which it refracts off your retina.

You will also likely need to look through a phoropter, an instrument with a variety of lenses of different strengths. Depending on what looks clear or blurry, the ophthalmologist can determine to what extent the astigmatism affects your vision.

How Common Is Astigmatism?

Astigmatism is a fairly common condition that many are born with. What causes it is unknown; experts suspect it is hereditary. Just because you don’t have astigmatism now doesn’t mean you won’t ever develop it.

Astigmatism can develop after an eye injury or surgery, and its severity can increase and decrease over time. Whether it develops later in life or was with you since birth, astigmatism can be easily treated and should not be extremely worrisome.

Living with Astigmatism

In some cases, astigmatism can cause headaches or eye discomfort. Those with astigmatism may also have trouble seeing at night. In many cases, the most noticeable symptom is blurry, distorted vision at distances both near and far. Your doctor can discuss your options for living with astigmatism based on the degree to which it affects your vision and quality of life.

Glasses can correct astigmatism-affected vision with lenses that incorporate two measurements: cylinder and axis. These indicate the lens power (cylinder) and position of the astigmatism on the cornea (axis). Glasses can typically correct astigmatism to 20/20 vision.

Contact lenses are another option for treating vision affected by astigmatism. They can be soft or rigid, depending on your unique vision correction needs.

You may also elect to correct astigmatism by reshaping the cornea with laser eye surgery (LASIK, or Laser In-Situ Keratomileusis). This outpatient surgery takes less than an hour, but not everyone is a candidate. There are several factors to discuss with your doctor if you are interested in pursuing LASIK corrective surgery, including the stability of your eyesight, age, other health issues and eye conditions, and moisture levels in the eye.

Many times, living with astigmatism is not even noticeable. The error it causes in vision is not enough to call for corrective action as the changes are slight and undetectable. However, when the astigmatism is defined enough to be noticeable, it will cause problems with blurry vision.

Schedule a comprehensive eye exam with your ophthalmologist to check your vision. This is the first step in determining whether you need to take corrective action for your eyesight, whether astigmatism is affecting your sight, and what your options are moving forward to increase your quality of life.

For more information about astigmatism and other eye conditions, visit eyesurgeryclinics.org.

How does it affect me? 

UV light, or also known as ultraviolet light is a type of electromagnetic radiation that is given off from the sun and allows life to thrive naturally and correctly. Although UV rays sound great, they also come with some unwanted side effects if someone experiences too much exposure. A minor inconvenience could be a sunburn or a dark tan, but too much UV rays can lead to the damage of living tissues. Most people do understand the dangers that they risk when they experience large amounts of exposure to the Sun’s UV rays when it comes to the skin, although not nearly as much people worry about their eyes.   

Although people know that it is important to wear sunscreen to prevent skin damage or reduce the risk of skin cancer, not enough think about the eyes which are very vulnerable and can be damaged easily if not taken care of. For instance, if your eyes ever feel a slight burn on them after being exposed to UV radiation for an extended period, then your eyes are most likely feeling photokeratitis. Photokeratitis can be painful and feels like a sunburn on the eye. The damage and burning will depend on the levels of UV light experienced.  

What different types of UV rays are there? 

UV rays aren’t as simple as they seem as there are 3 different types of ultraviolet all ranging in strength and danger.   

UVC rays 

These rays are most likely the most dangerous rays there is as they can easily damage your eyes and skin and other living tissues. Although long amounts of exposure can damage your eyesight, thankfully the ozone layer protects us from most of these strong rays. But our dependency on the Ozone layer could mean that if it is depleted or weakened at some point that the number of injuries or conditions caused by UVC rays could rise. The number of conditions could arise as a result of our protection from UVC being removed from us, leaving us vulnerable. 

UVB rays 

UVB rays have wavelengths that are slightly longer than UVC rays at around 285-315 nanometers but have somewhat lower energy than the stronger but shorter UVC rays. These rays are weaker than UVC rays but are only partially obstructed by the ozone layer and quite a bit of UVB rays still reach our surface. In lower amounts of exposure, UVB rays stimulate the production of melanin. Increased amounts of melanin can lead to tanning and sunburns. Although in high amounts, UVB rays can cause extreme sunburns or increase the risk of skin cancer. These rays can also cause skin discolorations, wrinkles, and other types of premature aging in the skin. UVB can cause eye-related issues such as photokeratitis, pinguecula, and pterygium. Thankfully, the cornea is known to absorb 100% of all UVB rays, so they are unable to cause conditions such as cataracts and macular degeneration.   

UVA rays 

UVA rays are the last of the three types and have lower energy than both UVB and UVC but can reach past the cornea and enter the retina. When comparing the different types of UV, a pattern shows itself. The pattern seems to represent that the less powerful the ray, the longer its range. Since UVA rays can reach past the cornea and enter both the lens and the retina, elongated periods of exposure to UVA rays are thought to cause different issues. These issues can be quite serious and examples of these complications are cataracts and macular degeneration.   

THE RISKS OF UV 

Anybody that exposes themselves to UV rays does risk damage to their eyes but UV damage does have a list of factors that can contribute to the risk your eyes have to take when they come in contact with UV. The amount and level of exposure that someone encounters when they go outside depend on several conditions.  

Geographic Location 

The level of UV exposure from rays depends on your distance from the equator as the equator is one of the closest points to the sun on earth. The closer to the equator you are the more powerful the UV rays are.  

Altitude 

Along with geographic location, your altitude also matters when it comes to the strength of the UV light around you. The higher you are and the closer you are to the sun, then the stronger the UV radiation will be.  

Time of Day 

The radiation of the sun is at its strongest in the very middle of the day. This is when the sun is at its full strength and when the sun covers the surface the most. The middle of the day is between 10 a.m and 2 p.m.   

Setting 

The setting also matters as being in a wide-open area gives much more space for UV rays to shine down on rather than being in a closed-off shaded area. As said before, being in wide-open areas can make it hard to attempt to avoid UV rays and highly reflective surfaces can just concentrate the harsh sunlight, which produces more and more UV radiation. UV rays can even reflect off of surfaces such as sand or snow. Since urban areas have much more tall buildings and shady trees, living in urban areas will most likely mean that you will come across UV rays much less often than someone that lives in a rural area with plenty of sunlight.  

Medication  

Certain medications can increase your sensitivity to UV light such as tetracycline, sulfa drugs, birth control medications, diuretics, and tranquilizers.  

How to protect yourself against UV rays 

The most popular, and easiest way to protect yourself from harmful UV rays is to wear sunglasses when you plan to go outside for longer than just a few moments. If possible, it is best to look for sunglasses of good quality that claim to block out 100% of all UV rays. If you feel necessary it can be helpful to ask and consult your optician on what is the best kind of pair for you. Depending on your hobbies it is also possible to search for athletic glasses or performance glasses, but normal pairs should either be wraparound kinds of glasses with large lenses to cover the eye and the skin around it. The type doesn’t matter nor does the color of the lenses, it is just important that the lenses work well and fully cover the eyes.  

Conclusion and Sources 

Although skin can be damaged and should also be taken care of, eyes can receive a myriad of side effects from a lack of proper care for the eye.  

What is it? 

Nearsightedness or myopia as it’s known medically is a condition in the eyes where nearby objects seem clear, but objects that are a little farther away may seem to be blurry and can be hard to focus on. This may result in some difficulties in school or driving, as it could be hard to pinpoint details on whiteboards, screens, or traffic lights. This condition occurs when the cornea or the front clear cover of the eye is too curved or the entire eyeball itself is too long. Myopia is incredibly common with almost a third of the U.S population (30%) being diagnosed with it. Although the cause of the eyeball being too long, or the cornea curving too much isn’t exactly known and sort of a mystery, it is believed to mostly be inherited. Most of the time myopia seems to be inherited from family members who already have it and passed down. If a parent or both have either farsightedness or nearsightedness, then there is a fair chance that their child may receive it at some point in their childhood. Additionally, people that engage in close work such as computer work, reading, or graphic design may be more likely to inherit myopia. 

Myopia’s Health Conditions 

Myopia usually becomes noticeable in young children and develops until someone’s early 20’s. Although for it to develop in young children is very common and normal, people can develop myopia as adults from stress on the eye or serious health conditions such as diabetes. 

 Strangely, myopia can also factor in environmental problems. One of these environmental problems is known as “night myopia” where far away objects become blurry but only at night. An explanation for this may be that the increased size of the pupils during the night allows for more unfocused rays of light to enter the eye.  

 Another strange form of myopia is a type of fake/”pseudo” myopia. This type of myopia occurs when someone constantly takes part in near visual work. This can create visual stress and for a short while and tires the eyes out. While the eyes are tired out, they are unable to properly and accurately focus on objects farther away until the eyes rest. 

 Symptoms in myopia may be a result of rising blood sugar levels, which are common in diabetics. This is why people with diabetes have a fair chance of having nearsightedness. Another cause for symptoms of myopia may be a forming cataract.  

Diagnosis and Treatment 

Several tests are needed to conclude the state of someone’s vision and discover how well their ability to focus is. Different tests are conducted to see if there is a problem, and if so, which kind is it. A very popular form of testing is known as the distance chart. A distance chart has different levels of letters that get smaller and smaller with every level. The results for this test are usually used as a fraction with 20/20 being perfect for both eyes. This test is meant to be tested for visual acuity and uses 20/20 to describe the number of feet someone has to be to clearly see something. For instance, if someone had 20/20 vision, then they would be able to see something 20 feet away from 20 feet away. But if someone had 10/20 vision, that would mean that they would have to be 10 feet from an object that someone with correct vision would be able to see from 20 feet.[Text Wrapping Break]Doctors also conduct many tests on a phoropter, which is a complicated device with many lenses that are used to measure how the eyes focus light. 

The phoropter measures how the eyes focus light by using a retinoscope. The doctor will then ask a series of questions which in turn allows them to discover which lenses provide the clearest vision. An optometrist usually looks to find lenses that will allow your eyes to see in perfect clarity. 

Most of the time, a doctor will recommend prescribed eyeglasses that are specially made to fit your eyes, as they are easy to make, and aren’t very complicated. Although this is the main way to fix your eyesight, there are also a variety of different ways to help from contact lenses to surgery.   

• For many, contact lenses are preferred as it provides better clarity and field of view for some even though it does take some amount of precision and care to insert them into your eyes correctly and safely 

• Ortho-K is a type of corneal therapy aimed to eventually reshape the cornea through rigid contact lenses. The lenses apply pressure to the cornea to flatten it which then allows it to reshape, however for the user’s safety it can only be worn for limited periods of time. 
• Laser procedures and surgeries are also popular. These procedures entail precise lasers to be used to help any refractive errors in the eye. 

Myopia is an incredibly common eye condition with more than 3 million cases occurring every single year. Myopia or nearsightedness has many different types of treatment such as contacts, glasses, and surgeries. Myopia is the medical term of nearsightedness and it’s a more popular form of treatment is eyeglasses for their simplicity and availability.