Refractive Errors and Vision Correction
- Posted on: Jun 15 2010
A refractive error is the most common eye problem. Refractive errors include nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia (requiring reading glasses with age). All of these problems are are related to the eye not bending (refracting) the light properly. A person would usually notice that he or she can’t focus properly at distance, or at near, or both. If you notice that you are having difficulty focusing you should see an ophthalmologist (eye MD) for a complete eye exam, since refractive error is only one potential cause for blurry vision.
Myopia or Nearsightedness : The person can see well at near but not far. The eye is usually longer, or the cornea is steeper and the images are focused in front of the retina instead of on the retina. “”Minus” lens is usually needed to bring the image into focus.
Hyperopia or Farsightedness : The person can see well far but not near usually, however, with age both near and far vision may become affected. The eye is usually shorter, or the cornea is flatter, and the images are focused behind the retina. “Plus” lens is needed to correct the problem and bring the image into focus.
Astigmatism: The cornea is more curved in one direction that in another, kind of like a football. So as a result patients frequently get distortion of there vision, kind of like looking through a fun house mirror. Both distance and near vision may be blurry. Astigmatism is often accompanied by either nearsightedness or farsightedness, and requires a special lens for correction.
Presbyopia: Decline in near vision that happens with age as the eye stats to loose its ability to “zoom in” at near. Most people with normal vision will notice decline in near vision after the age of 40. You may begin to find that you need to start holding the book further away from your face in order to see properly. This familiar even maybe the first sign presbyopia, which, if not treated on time, may cause eye strain, fatigue, and headaches. Reading or Bifocal glasses may be prescribed.
Refractive Error Correction
There are several ways to correct refractive errors that are available today.
- Glasses – the most common, safe, easy, and simple method of correcting all types of refractive problems. There are significant disadvantages to wearing glasses: discomfort, fogging, inability to do certain activities (swimming etc), cosmetic, and cost.
- Contact lenses – very common method of correction of nearsightedness, less commonly used to correct farsightedness and astigmatism, and rarely used to correct presbyopia. Had cosmetic and comfort advantages over glasses. However, has significant disadvantages: increased risk of infections and allergies especially with long term wear and improper care; risk of corneal scarring and cornea not getting enough oxygen; causes dry eye, eye redness, and irritation; use is commonly limited to 10-15 years, after which time patients usually have to limit wear or stop wearing contacts all together due to all of the above; inability to do certain activities, sa swimming; cost.
- Laser Vision Correction (LASIK, LASEK, and Epi-LASIK) – is becoming more and more popular in US and other developed countries. The cornea is reshaped with the excimer laser correcting nearsightedness, farsightedness, astigmatism, and even presbyopia. With today’s technology, vision resulting after the procedure is sharper, better than with either glasses or contacts. We specialize in cut-free LASEK and Epi-LASIK, in which the cornea does not get cut at all and no flap is created. By using a special gentle solution to prepare the cornea for laser we eliminate the need for all cutting used in traditional LASIK (or I-LASIK), making the procedure 10x safer. I consider this procedure much safer than long term contact lens use, and actually underwent the procedure myself early this year. The advantages of the procedure are better vision, permanent correction, comfort, and safety over contact lenses. Some of the disadvantages include having to undergo a procedure, concerns over safety, and initial cost (not a singificant issue since most patients end up spending more than that in a few years on glasses, contact, solutions etc) Please read more about it on my website www.NYLaserVision.com.
- Intraocular Lens implants or IOLs (ReZoom, ReStor, Technis multifocal) – along with laser vision correction are becoming more and more popular in US for correction of all types of refractive errors. Is usually a preferred method of correction after the age of 50 because these lenses have an advantage of correcting presbyopia and restoring youthful vision to our older patients. To learn more about IOLs please go to our website www.NYLaserVision.com.
- Phakic intraocular lens implants – are usually used in younger patients to correct very high nearsightedness, or farsightedness. Surgical procedure in which the lens gets inserted into the eye and attached to the structures within the eye.
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