Refractive Corrections

By Rose Susel Lucente, OD

Dunkirk Vision

. http://dunkirkvision.com/

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Refractive Corrections

A refractive error is an optical defect that does not allow light to be brought into sharp focus on your retina, which results in blurred vision. Refractive correction, or vision correction, refers to one of several methods used to improve blurred vision caused by a refractive error.

Spectacles, or more commonly known as eyeglasses, have historically been the only vision correction available. Through the years and improvements in technology, the spectacle frames have become lighter, more flexible and very fashionable. The actual lenses have also become lighter, thinner, and even impact resistant. We can also add digital design to improve on clarity and definition, as well as, sun protection.

Around 1949, contact lenses came on the market and they were generally uncomfortable and thus, new materials were discovered. We now have contact lenses which correct for many types of refractive error, as well as presbyopia, which is the reduction in the ability to focus at near point. Sometimes, an eye care provider will address this condition with monovision; that is where one eye is corrected at distance, while the other is corrected at near. Contact lenses may also be utilized for therapeutic conditions such as keratoconus.

Another option is refractive surgery, of which lasik is the most commonly performed today. Refractive surgery has also experienced many advancements in instruments and techniques. The earliest technique was called radial keratotomy (RK) and involved making corneal incisions in a spoke-like fashion to ultimately reduce refractive error. Over the years, technology has made it possible to have a completely laser driven procedure with incredible results on a patient population between 20-55 years of age.

For those patients with cataracts which is a clouding of our natural lens, a surgical extraction can be performed with a few options as well. Patients can select between a basic intra-ocular lens (IOL) to those which can correct for astigmatism and those which address the focusing at near point. In cases of very high astigmatism, a surgeon can use a technique where laser arcuate incisions (limbal relaxing incisions) are added during the procedure. The final refractive outcome for cataract surgery has changed from matching previous a patient's habitual refractive error to obtaining almost perfect vision at distance. The focusing IOL's can eliminate a patient's need for reading glasses.

Lastly, there has been a renewed interest in a concept called orthokeratology. This procedure is a non-surgical approach to correcting refractive error. The process involves fitting the eye with a progression of sophisticated lens designs to be worn at night-time. It is a very individualized process as it depends on a lot of personal factors.