Disorders

REFRACTIVE ERRORS

Refractive Errors cause the light rays entering the eye to NOT focus on the back of the eye, resulting in blurred vision. They can be grouped as follows:

NEARSIGHTED (one sees better close up)

What is myopia?
The term “myopia” comes from a Greek word meaning “closed eyes.” Squinting to see distant objects clearly is one of the main indications of nearsightedness. If you are nearsighted, you can focus well on nearby objects, but you cannot focus as well on objects at a distance.

In the normal eye, light is focused on the retina in the back of the eye. Myopia occurs either because the eyeball is too long, or more rounded shape, or the cornea (front of the eye) has a very steep curvature, all of which cause the light to focus in front of the back of the eye (retina).

Myopia is not a disease, nor does it mean that you have “bad eyes.” There are few perfectly shaped eyes, just as there are few perfectly shaped or aligned teeth. It simply means that you have a normal variation in the shape of your eyeball. The degree of variation determines whether or not you will need corrective eyewear.

How does myopia affect sight?

 
NEARSIGHTED EYE (Focus before back of eye)   NORMAL EYE

To fully understand why myopia causes a disturbance in sight, it is helpful to understand the process by which sight occurs.

If an individual is nearsighted, the unusually long shape of the eyeball causes light rays from a distant point to be focused at a place in front of the retina. Instead of the image being focused into a fine point, it is more like a circle of light. Concave lenses (thicker on the edges) are used to bend the light rays more precisely (to a point) and to focus them exactly on the correct area of the retina.

Who is affected by myopia?
Myopia usually begins between the ages of 8 and 12 years and nearly always before the age of 20. Often the degree of myopia increases as the body grows rapidly, then levels off in adulthood. During the years of rapid growth, frequent changes in the prescription eyewear may be needed to maintain clear vision. It is not very common, but we have seen myopia begin in the mid to late 20s and level off in the early 30s.

This is how someone sees who is moderately nearsighted.

What are the symptoms of myopia?
The inability to see distant objects is the main symptom of myopia. This includes the inability to see road signs, scoreboards, and television screens. It is frequently the teacher who notices that a child is squinting to see the blackboard or is having difficulties seeing distant objects. Headaches are also a common symptom.

How is myopia diagnosed?
As mentioned, myopia is often suspected when a child performs poorly during a routine eye screening at school. Further examination of the child's eyes will reveal the degree of the problem.

A comprehensive eye health examination will detect myopia. Yearly examinations after myopia has been diagnosed are needed to determine if the condition is progressing and whether or not a change in prescriptive eyewear is needed. Eye exams also help to ensure that vision impairments do not interfere with daily activities. With children, in most cases, you can expect the myopia to progress to a point and then level out.

Dr Skowron determining the proper prescription for this nearsighted patient.

How is myopia treated
As with other refractive errors, corrective lenses are prescribed to help focus light more effectively on the retina. Depending on the degree of myopia, glasses may be needed all of the time for clear vision. If the degree of impairment is slight, glasses may be needed only for activities that require distant vision, such as doing board work at school, driving or watching TV. Contact lenses are also an excellent option for myopic patients and should be discussed during your examination.

 


 
Myopia is treated with glasses or contact lenses (LASIK for adults).

The myopic child
It is important to consider the psychological aspects of eye problems in children. The following tips may be helpful:

  • Avoid referring to the child's eyes as "bad eyes." Instead tell the child that they just bend the light differently and corrective lenses are needed to help focus light rays.
  • Letting the child verbalize concerns may also help adjustment to changing vision.
  • Make the occasion of selecting new frames for lenses a fun time.
  • Consider contact lenses (usually between the ages of 12-14) as a viable option for all myopic patients.

A child's maturity is the main factor in selecting contact lenses as an option

  • Do not restrict the child's activities because of poor vision.

FARSIGHTED (one sees better at a distance...the eyes are constantly straining)

Hyperopia, or farsightedness, causes light to focus behind the back of the eye (retina). If you are farsighted, you can focus well on distant objects more easily than you can on nearby objects.

In the normal eye, a fine point of light is focused on just the right position of the retina in the back of the eye. The most common cause of hyperopia is a normal variation in the shape of the eyeball; the length of the eyeball is too short. In other words, the eyeball is shorter from front to back than is normal. In some cases, hyperopia may be caused by the cornea having too flat a curvature.

The exact cause of this eyeball shape variation is not known, but the tendency for farsightedness is inherited: Some people are more prone to developing this condition than others. It may also be caused by factors other than heredity but to a lesser degree.

Hyperopia is not a disease, nor does it mean that you have "bad eyes." It simply means that you have a normal variation in the shape of your eyeball. There are few perfectly shaped eyeballs, just as most sets of teeth are not perfectly shaped or aligned. There are many individual variations. The degree of variation from the ideal determines whether or not you will need corrective lenses.

If your eyeball is a good deal shorter than normal, light refraction may be impaired to the degree that corrective lenses are needed to help focus light rays better. If variation is slight, you may focus well enough without corrective lenses.

HOW DOES HYPEROPIA AFFECT SIGHT?

 
FARSIGHTED EYE (Focus behind the eye)   NORMAL EYE

To fully understand why hyperopia causes a disturbance in sight, it is helpful to understand the process by which sight occurs. For clear vision to occur, the lens of the eye directs light rays toward the retina, and the light rays must come together in a fine point and must strike the retina in exactly the right place. If the eyeball is too short, the "point of light" focuses on a location behind the retina, instead of its correct position, right on the retina. So at the point on the retina where a fine point of light should be, instead, there is a disk-shaped area of light. Convex lenses (thicker in the center) are prescribed to bend light rays more sharply (as close to a point as possible) on the retina.

Reading is strained for someone who is farsighted.

WHAT ARE THE SYMPTOMS?

A person who is farsighted may have trouble concentrating or focusing on objects close up such as a book or a newspaper. After viewing nearby objects for a long period of time, blurred vision, nervousness, tension, and irritability can occur. A person simply may not enjoy reading, or if the person is a child, poor reading ability (skills) may be the result.

Hyperopia causes the eyes to exert extra effort to see objects nearby and causes the eyes to strain in order to see. Younger people can overcome this by providing additional focusing. But as they get older and there is more visual demand on the eyes, additional focusing effort can cause tension, fatigue, and eyestrain. If the lens of the eye cannot bring objects into focus after the additional expended effort, blurred vision is the result.                                                     

Dr Skowron looking for areas of eyestrain for someone who is farsighted.

HOW IS IT DIAGNOSED?

Unlike some eye problems, hyperopia is seldom diagnosed in school eye-screening tests. Screening tests usually involve reading objects at a distance, but farsighted children can see distant objects very well. Focusing on nearby objects presents a problem. Hyperopia must be diagnosed during a comprehensive eye health examination when both near and far vision is checked.





HOW IS HYPEROPIA TREATED?

Glasses can eliminate any eyestrain when reading for someone who is farsighted.
  • GLASSES
  • CONTACT LENSES
  • LASIK (Limited cases)

Corrective eyewear (eyeglasses or contact lenses) are usually prescribed to treat hyperopia. (Click here for more information about rigid gas permeable contact lenses; click here for soft disposable contact lenses.) If you do not have other vision problems, such as astigmatism, you may need only to wear glasses for reading or other tasks done at close range.

The best option for you depends on your individual lifestyle and needs. During your examination we will ask you a number of questions to help determine the best course of treatment. You may be asked to describe your usual lifestyle or daily activities. If your occupation involves reading fine print for most of the day, correction of the problem might involve different options than might be considered for a person who is not as dependent on near vision. Your lifestyle, occupation, types of recreational activities, and your general health status will give us clues about the lenses that will best suit you. A comprehensive eye examination at the recommended intervals ensures that minor changes in vision can be diagnosed and treated so that your vision will remain as clear and comfortable as possible.

ASTIGMATISM (vision can blur at both far and near distances)
Astigmatism occurs when the eye is oval shaped instead of spherical. This causes the light rays to split into two beams as they enter the eye. Astigmatism usually is present when the front surface of the eye, the cornea, has two different curvatures. Normally, the cornea should be smooth and equally curved in all directions. With astigmatism the front surface of the cornea is shaped more like a football than a basketball. This abnormality may result in vision that is much like looking into a distorted, wavy mirror. The distortion results because of an inability to focus light rays to a point.

Astigmatism is not a disease, nor does it mean that you have "bad eyes." It simply means that you have a variation or disturbance in the shape of your cornea. Not all corneas are perfectly curved, just as sets of teeth are seldom perfectly aligned. There are many variations that might occur in the corneal surface. The degree of variation determines whether or not you will need corrective eyewear.

If the corneal surface has a high degree of variation in its curvature, light refraction may be impaired to the degree that corrective lenses are needed to help focus light rays better. The exact reason for differences in corneal shape remains unknown, but the tendency to develop astigmatism is inherited (runs in the family). For that reason, some people are simply more prone to develop astigmatism than others.

 
ASTIGMATIC EYE (Notice 2 points of focus)   NORMAL EYE

 

HOW DOES ASTIGMATISM AFFECT SIGHT?

To fully understand why astigmatism causes a disturbance in sight, it is helpful to understand the process of sight. The crystal clear cornea is situated at the very front surface of the eye and enables light to enter the eyeball. At that point of entry, the cornea accomplishes about four-fifths of the refractive work needed for clear vision, bending light rays toward one another into a point. The lens further refines the refractive work begun by the cornea and directs that point of light towards a precise location on the retina (the fovea). If light is not focused into that fine point, the image that reaches the retina cannot be clearly transmitted to the brain.

When astigmatism is present, the surface of the cornea, instead of being spherical, is distorted. Therefore, light rays entering the eye are not focused into the fine point needed for clear vision. Rather, light is focused on two distinct points, neither of which may be on the retina, resulting in a blurred image.

This is what reading may look like for a person who has an astigmatism. Notice the shadows on the letters.

WHO DEVELOPS ASTIGMATISM?

Astigmatism is a very common problem. Some experts agree that almost all persons have some degree of astigmatism, often present at birth. The degree of astigmatism may remain the same throughout life.

WHAT ARE THE SYMPTOMS OF ASTIGMATISM?

The symptoms of astigmatism include a distorting or blurring of images at all distances, nearby as well as distant. Even though vision may be fairly sharp, slight degrees of astigmatism may cause headache, fatigue, squinting, and eye discomfort or irritation. Of interest to parents and those who work with children, astigmatism may contribute to poor schoolwork but is often not detected during routine eye screening in schools.

HOW IS ASTIGMATISM DIAGNOSED?

Astigmatism is diagnosed through the process of a comprehensive eye health examination that checks for near vision, distant vision, and clarity of vision.

Reading is strained for someone who is farsighted

HOW IS ASTIGMATISM TREATED?

  • GLASSES
  • CONTACT LENSES
  • LASIK

We will recommend corrective eyewear to help direct light in a more effective manner. If the degree of astigmatism is slight and no other problems of refraction are present, corrective lenses may not be needed. If the degree of astigmatism is great enough to cause eyestrain, headache, or distortion of vision, prescription lenses will be needed for clear and comfortable vision. Astigmatism often occurs with other refractive conditions such as nearsightedness or farsightedness.

The corrective lenses needed when astigmatism is present are called cylinders and have better light bending power in one area of the lens than in the others. The doctors and staff at Skowron Eye Care will perform precise tests during your comprehensive eye health care examination to determine precisely the ideal prescription to give you maximum clarity.

Astigmatism is treated with glasses, contacts, or Lasik (adults)

PRESBYOPIA (loss of focusing ability at near, due to age 40+)

WHAT IS PRESBYOPIA?

Presbyopia is a condition of vision in which the normally flexible lens of the eye gradually loses elasticity, affecting the refractive ability of the eye. It is usually first noticed when you have difficulty reading close up. The eye loses its ability to focus up close usually around 40 years of age.

Normally, the cornea, lens, and eyeball all work together to focus light into a precise point on the retina. The lens can bend or flatten out to focus light rays. With presbyopia, the lens is not as flexible, making it more difficult for the eye to focus.


Reading is strained for someone who has presbyopia
.

WHAT CAUSES PRESBYOPIA?

As we age, body tissues normally lose their elasticity. A familiar sign of that process is wrinkled skin. Our eyes are not immune to that type of change. Likes wrinkles, changes in the eye do not occur overnight but take place gradually over a period of years.

When you experience a change in vision, you may feel as though it happened suddenly. A condition such as presbyopia actually develops slowly; it just had not impaired your vision to such a degree that it was noticed.

Presbyopia is caused by a loss of elasticity in the LENS of the eye.


HOW DOES THE LOSS OF ELASTICITY AFFECT SIGHT?

Reading is strained for someone who is farsighted

To understand presbyopia, it is helpful to have a basic understanding of the process of sight. Our ability to see starts when light enters the eye through the cornea. The shape of the cornea, lens, and the eyeball help bend (refract) light rays in such a manner that light is focused into a point precisely on the retina. When any one of the participating structures of the eye is changed, sight will be affected. The greater the abnormality, the more likely that vision will be impaired.

The lens, an important partner in the process of sight, is responsible for focusing light on the retina. In youth, the lens is flexible; with the help of tiny ciliary muscles, it accommodates for both near and distant objects by bending or flattening out when needed to help focus light rays.

With age and the accompanying loss of lens flexibility, it becomes more difficult for the lens to bend to a greater degree. In addition to a loss in ability to bend, the lens responds more slowly with age. Therefore, it not only becomes difficult for the eye to focus on near objects, which require a greater degree of flexibility; but the eye also does not adjust well to rapid changes in focus.

WHEN DOES IT OCCUR?
The flexibility of the lens actually begins to decrease in youth. The age at which presbyopia is first noticed varies, but it usually begins to interfere with near vision in the late 30s and early 40s. It affects everyone, and there is no known prevention for the problem.

WHAT ARE THE SYMPTOMS OF PRESBYOPIA?

 
On the left, what a crossword puzzle may look like to someone for whom presbyopia is beginning and needs reading glasses.

A common symptom of presbyopia is holding reading material further away because the eye has difficulty focusing on very near objects. Other common symptoms include eye fatigue or headaches when doing close work.

Difficulties with near vision may be noticed when reading printed materials such as newspapers, books, or restaurant menus at close range. You may also notice problems during activities that require a clear focus on nearby objects such as sewing, knotting, or painting. Some complain that the newspapers are using lower quality ink or they are making the print smaller.

HOW IS THE PROBLEM DIAGNOSED?

The usual treatment for presbyopia is prescription eyeglasses to help the eye accommodate close-up work. Prescription lenses (reading glasses) help refract light rays more effectively to compensate for the loss of vision in the natural lens of the eye.

If you do not have other vision problems, such as nearsightedness or astigmatism, you may only need to wear glasses for reading or doing other tasks done at a close range. If you do have other refractive problems, bifocal or progressive addition lenses are often prescribed. Contact lenses are also a preferred option for many people, either bifocals or monovision. With monovision one eye is corrected for distance viewing, and the non-dominant eye is corrected for close work. This works well for many people, and some patients can't tolerate it at all. We can determine that during your examination.

HOW IS PRESBYOPIA TREATED?

  • READING GLASSES
  • CONTACT LENSES

The usual treatment for presbyopia is prescription eyeglasses to help the eye accommodate close-up work. Prescription lenses (reading glasses) help refract light rays more effectively to compensate for the loss of vision in the natural lens of the eye.

If you do not have other vision problems, such as nearsightedness or astigmatism, you may only need to wear glasses for reading or doing other tasks done at a close range. If you do have other refractive problems, bifocal or progressive addition lenses are often prescribed. Contact lenses are also a preferred option for many people, either bifocals or monovision. With monovision one eye is corrected for distance viewing, and the non-dominant eye is corrected for close work. This works well for many people, and some patients can't tolerate it at all. We can determine that during your examination.

THE BEST OPTION FOR YOU DEPENDS ON YOUR INDIVIDUAL CHARACTERISTICS…Our staff and eye doctors may ask you a number of questions to help determine the best avenue of treatment. You can assist in the process by answering all questions thoughtfully. You may be asked to describe your usual lifestyle or daily activities. For instance, you may be asked whether or not you frequently need near vision. If your occupation involves reading fine print for most of the day, correction of the problem might involve different options than might be considered for a person who is not as dependent on near vision. So, your occupation, types of recreational activities, and your general health status will give us the clues about the lenses that would best fit your lifestyle.

Although it is aggravating to acknowledge that we are growing older and will continue to have various decreases in some physical capacities, remember that most of those changes are gradual and should not cause major disruptions in our lifestyles. A comprehensive eye health examination at the recommended intervals ensures minor changes in vision can be treated so that your vision will remain as clear and comfortable as possible.

Questions or Comments?
We encourage you to contact us whenever you have an interest about our services.

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Elmhurst, IL 60126