What to do if you have vision challenges

Human eyes can differentiate between several thousand colors, assess the speed of a flying tennis ball and recognize letters as well as images in a fraction of a second. However, all of this works perfectly only if your eyes are absolutely healthy. Millions of people suffer from visual impairments for which they wear eyeglasses. A vision test performed by your optometrist or ophthalmologist will tell you whether you are nearsighted, farsighted or whether you are suffering from any age-related vision impairments.

Myopia, hyperopia or presbyopia - eye experts use plenty of Latin vocabulary to describe visual challenges. As a patient, do not let the language confuse you, because all of these medical terms simply refer to common vision impairments.

In plain English, myopia is called nearsightedness, hyperopia farsightedness and presbyopia refers to age-related vision impairments. More than half of the population struggles with one or the other.  A vision test determines the actual condition instantly. As a result, appropriate eyeglass lenses can be prescribed to restore perfect vision.

 

The most common types of vision problems

Nearsightedness (myopia)

Nearsightedness occurs when images form in front of the retina, rather than on it. Objects in the distance cannot be recognized clearly.

We recommend visiting your optometrist or ophthalmologist once a year for a brief vision exam. If you are one of the many people who go through life without needing glasses and suddenly find it difficult to make out road signs while driving, you should definitely make an appointment for an eye exam.

How does myopia develop?

In most cases, an excessively long eye is the cause of myopia. Even a discrepancy as minute as one millimeter can result in significant nearsightedness. Given that the human eye accommodative ability can only move the focus closer, not farther away, the eye cannot compensate for nearsightedness without a visual aid.

The root causes of myopia remain a mystery. The only fact that has been established to date is that genetic factors do play a pertinent role. This is one of the reasons why a higher percentage of people of Chinese heritage suffer from myopia than people with a European background. Genetic myopia starts in school age children and usually varies from -2 to -4 diopters. The process usually comes to a slow halt during puberty or young adulthood.

How do ophthalmologists and optometrists perform eye exams?

Optometrists or ophthalmologists check the acuity or sharpness of your vision. They may use a measuring device, into which they insert a variety of lenses' or an instrument called a phoropter.

In just a few simple steps, the examiner can test an array of lenses placed in front of the patient’s eyes. The patient can easily determine which of these lenses improves his or her vision and which ones do not. Computerized measuring processes are now also available.

How eyeglass lenses correct myopia

Restoring perfect long-range vision in myopia patents requires a lens that diffuses light (minus lens) in such a manner that the light rays meet on the retina, making it possible for the eye to generate a sharp image on the retina.

Farsightedness (hyperopia)

In eyes affected by this condition, incoming light rays come to a point behind the retina and create a distorted image. The farsighted eye is too short to allow images to come to a proper focus on the retina. This condition can cause the following problems:

• Close-range activities such as sewing can be very difficult and cause headaches.
• It takes quite a while for the eye to adapt from long - range to short - range vision and vice versa

Make an appointment for an exam with your optometrist or ophthalmologist if you have repeated headaches after reading or doing close-up work, for instance on a computer. Younger eyes can actually compensate for hyperopia with the assistance of the eye lens’s accommodation strength. Many younger people affected by hyperopia do not even notice it until they are older. However, if you notice any such symptoms, take them seriously and have your eyes checked.

How does hyperopia develop?

The eyes of a patient suffering from hyperopia are either too short or the refraction rate of the eyes lens is insufficient.  As a result, light rays come to a point of focus behind the retina, rather than on it.

The refraction rate of the eye’s lens has to be increased in farsighted eyes to provide sharp close- range vision. This can be achieved only if the ciliary muscle is tightened, which causes the lens to bend more. This added muscle tension can cause the symptoms described above. Many people do not even complain when this added strain causes migraines, which is why many of them continue to suffer until their hyperopia is finally diagnosed.

How eyeglass lenses correct hyperopia

After a vision test (see details above) at the optometrist or ophthalmologist, eyeglasses with convex lenses are prescribed to ensure that the light beams coming from objects in the distance come to a focus on the retina without the eye having to struggle to compensate for this vision problem through its accommodation strength. 

Age-related vision problems (presbyopia)

As the lenses of our eyes change with age, we may eventually find ourselves confronted with an age-related vision problem. Starting at around age 45 the lens begins to lose its capacity to adjust to the close-up vision tasks it is required to handle. This is evident in the following symptoms:

• Reading seems to be harder and the patient holds a book or newspaper further and further away to be able to make out the text.
• Longer reading sessions fatigue the eyes very quickly and may cause headaches.
• The patient has problems with his or her close-up visions when light conditions are not ideal.
• Zooming in on objects from near to far and vice versa becomes more and more difficult.

See your optometrist or ophthalmologist as soon as you notice your first vision problems, for instance if you suddenly find reading very tiring.

How does presbyopia develop?

As we age, the content of water in the eye’s lens diminishes, while the insoluble protein content increases. As a result, the lens becomes stiffer and loses its elasticity. Consequently, it can no longer bend as much as it needs to for the human eye to be able to see clearly up close.

Presbyopia begins to develop around the age of 45. In the early stages, only minimal corrections are required. As the years pass, the eye’s ability to accommodate shorter focal distances continues to decline. The process is usually complete after the age of 60 and the impairment remains at the same level.

How eyeglass lenses correct presbyopia

Once the patient’s visual acuity has been determined, this visual impairment can be compensated with a variety of lens options. Patients who were previously blessed with normal vision will need reading glasses with concave lenses. Depending on the strength of the prescription, these glasses may have to be taken off during some close-up work, for instance while working on a computer.

The situation of people who were previously nearsighted or farsighted is a little more complicated. Nearsighted patients need reading glasses with weaker diffusion lenses. Farsighted patients are prescribed stronger concave lenses and reading glasses. Because most users do not like having to constantly switch between spectacles, most people who are farsighted will opt for progressive lenses.

In addition to covering both long and short range vision issues, progressive lenses also have a corrective zone that allows users to comfortably see at medium range distances. Progressive lenses emulate our natural vision patterns by providing a seamless change of focus from close to far. Modern progressive lenses are so easy to get used to that the adaptation time is very brief for most people.

Astigmatism

This visual impairment is caused by an irregular curvature of the cornea and in rare cases, irregularities in the lens. Those affected by this condition see distorted and blurred images. Almost all people have very mild forms of astigmatism.

Astigmatism results from the surface of the eye having a slightly elliptical shape. As a result, the refraction of the incoming light is increased. Objects are seen in blurry and distorted patterns and a dot-shaped light source looks like a line.

In most cases, astigmatism occurs in conjunction with myopia or hyperopia. Experts distinguish between two types of astigmatism: patients with regular astigmatism have only two different refraction levels. Those suffering from irregular astigmatism have corneas that are shaped so irregularly that the incoming light comes to multiple points rather than a single point.

How eyeglass lenses correct these conditions

To correct for the elliptical shape of the eye’s surface, patients who have regular astigmatism are prescribed lenses containing a cylindrical curve. Prescriptions for patients with this condition not only stipulate details about the patient’s myopia or hyperopia, but also the degree levels for the cylinder lens.

Important information: Children who have these vision problems should start wearing eyeglasses made for their specific needs as early as possible.  Otherwise, they may suffer from headaches, double vision or distorted vision.

The only correction for irregular astigmatism is available in the form of special contact lenses. They allow the tear film between the cornea and the contact lens to compensate for the irregularities.