Farsightedness (Hyperopia)

Hyperopia or farsightedness is very common, affecting up to 62% of people over the age of 40. Hyperopia occurs when the eyeball is too short or the cornea is too flat. When rays of light enter a hyperopic (short) eyeball, they are focused behind the retina instead of directly on the retina where light must be directed for normal vision. Because of this, the focusing apparatus in the eye must work constantly to make up for the problem and focus images. Symptoms of farsightedness can include eyestrain, blurred vision, or headache (especially when reading or at the end of the day). Symptoms can increase over time.

Young people with hyperopia (30 to 45 years) may not have any problems seeing things in the distance, but may strain their eyes unnecessarily to maintain focus on close-up objects. This ability to see things "far away," but not near, is how the term "farsightedness" came into being.

Middle-aged hyperopes (45 to 55 years) also may not have any problems seeing things in the distance, but may require reading glasses at an earlier age because their eyes can no longer compensate or strain to maintain near focus. Finally, older hyperopes (55 years and up) often cannot see things in the distance nor close up, which is why they need bifocals. Because hyperopia or farsightedness seems to get worse with age, it is often confused with presbyopia.

Correcting Hyperopia

Hyperopia or farsightedness requires a convex corrective lens (glasses or contact lenses), which is written as a "plus" number in your prescription. Surgically, hyperopia is corrected by steepening the central cornea.

Nearsightedness (Myopia)

Myopia or nearsightedness is very common, affecting 26% of the non-Asian population. (Myopia occurs at a much higher rate in the Asian population.) It is a condition in which people have difficulties seeing objects in the distance, but may have no problems focusing on objects that are up close. This ability to see "near" but not far is why this condition is more commonly called "nearsightedness."

Myopia occurs when the eyeball is too long or the cornea is too steep. When rays of light enter a myopic (long) eyeball, they are focused in front of the retina instead of directly on the retina where light must be directed for normal vision. Symptoms of nearsightedness can include eyestrain, blurred vision or headaches.

Correcting Myopia

Myopia or nearsightedness requires a concave corrective lens (glasses or contact lenses), which is written as a "negative number" in your prescription. Surgically, nearsightedness is corrected by flattening the central cornea or implanting a contact lens (ICL) or intraocular lens (IOL).

Astigmatism

Astigmatism occurs in nearly 30% of the non-Asian population. In an eye with astigmatism, the front of the cornea is not equally curved; it is slightly oval in shape, like a football. Light rays entering the eye bend unequally, resulting in a distorted image. Astigmatism usually occurs in conjunction with myopia (nearsightedness) or hyperopia (farsightedness), and is a complicating factor for refractive surgery.

Correcting Astigmatism

Astigmatism can be corrected with eyeglasses, contact lenses or refractive surgery.

Presbyopia

People often confuse farsightedness with another condition called presbyopia, which occurs as a normal result of aging. Presbyopia affects most of those over the age of 40 and all over the age of 51, as the aging process affects the eyes' natural ability to bring near objects into focus.

Presbyopia occurs when the lens inside the eye loses flexibility, preventing accurate focusing on objects that are up close. People with this condition may experience eye fatigue when reading in poor lighting or at the end of the day, trouble changing the focus from distance to near, or the need to constantly reposition reading material in an attempt to find the right focus.

This condition affects people with good vision or myopia (nearsightedness), but is more problematic for those who are hyperopic (farsighted). Prior to becoming presbyopic, hyperopes were able to naturally accommodate to bring things into focus at any distance. Suddenly, after 40 years of living without needing vision correction, hyperopes often lose both distance and near vision at the same time because their eyes can't compensate any longer.

Options for Presbyopes

Presbyopia has been traditionally treated with reading glasses, bifocals, or contact lenses. But now there is NearVision CK (Conductive Keratoplasty), a minimally invasive procedure developed specifically for presbyopic patients who need near vision improvement.

Monovision

One of the best ways to define monovision, in the context of contemplating refractive surgery, is that you can aim to have each eye corrected to a natural focus at any distance you choose. How well it will see at other distances depends upon how old you are. In those under 40 we typically correct both eyes for excellent distance vision and you will have good vision at almost any distance because the eye will be able to accommodate (adjust focus) from far to near. If, on the other hand, you are past your mid-40's and we correct both eyes for distance vision, you will not see well at a typical reading distance and will need glasses for near tasks. This loss of ability to change your focusing distance will occur whether or not you have refractive surgery during your 40's.

At any age, if you have the vision in an eye corrected to a natural focus for near things such as reading, you will not see clearly with it farther away as the ability to change focus only goes from far to near. By correcting one eye to focus in the distance and one eye to focus for near, the part of our brain that controls vision tends to suppress or filter out the image from the eye that is not in clear focus at any given moment. This use of one eye for distance and one eye for near vision is referred to as monovision and is one of the options to consider as part of your refractive surgery decision. Monovision has been used for longer than 20 years with contact lens correction and with various types of refractive surgery.

In our experience, most people over the age of 40 to 45 who try monovision and take a few months to become accustomed to it, like it and find it very useful. Those who have monovision will be able to generally see well enough both at distance and near to do most things at any age without corrective lenses. Some people with specific distance tasks such as automobile racers and professional baseball players would not want to have monovision as it could disturb their depth perception.

It is probably helpful to realize that without a specific cure for Presbyopia, once you are past the 40 year age range, all refractive corrections involve compromise. If you have both eyes corrected for good distance vision, you will need glasses for close vision. If you choose monovision, although your vision may work quite well for most purposes, you might feel it is less than perfect. Many people with monovision correction have a pair of bifocal glasses that they use for rare occasions such as night-time driving or extended reading of small print.

We know of no perfect way to help you make this choice. We would most likely suggest that if significant doubt remains in your mind, that you aim to have your vision corrected for monovision. If you are uncomfortable with monovision after trying it for a few months, it is usually possible to correct the near vision eye for distance vision and use eyeglasses for near when necessary.