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All About Vision

Orthokeratology (CRT & VST)

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Orthokeratology, commonly called ortho-k, is a method used to correct myopia (nearsightedness) by wearing rigid gas permeable contact lenses overnight, so that no vision correction is needed during daytime hours.

Gas permeable (GP) lenses specialized for ortho-k are inserted at bedtime and worn as you sleep. Throughout the night, the lenses reshape your cornea gently so that your vision becomes clear on the following morning. The correction is temporary, and ideally no eyeglasses or contact lenses will be needed on the next day or two. In order to maintain sharp visual acuity on a daily basis, you need to wear the ortho-k reshaping lenses every night.

At present, two brands of ortho-k contact lenses are approved for use by the FDA. Paragon Vision Sciences produces “Corneal Refractive Therapy” (CRT), and Bausch and Lomb manufactures “Vision Shaping Treatment” (VST).

Candidates for Ortho-K

Ortho-k is very suitable for nearsighted people who are not appropriate candidates for vision correction surgery, such as children. Individuals of all ages with healthy eyes can try ortho-k, namely because it can be discontinued at any point without permanent effects to the eyes.

People who require vision correction and engage regularly in sports or work in extremely dusty, dirty environments will also appreciate the convenience of ortho-k.

Vision Results from Ortho-k

Success rates for ortho-k are generally higher for more mild vision prescriptions. The ideal goal is to provide 20/20 vision without any need for eyeglasses or contacts during the day.

According to FDA trials conducted on both CRT and VST lenses, more than 65% of ortho-k patients were provided with 20/20 visual acuity. A whopping number of more than 90% of ortho-k patients achieved 20/40 vision or better (this is the legal requirement for driving without vision correction in most states). Consult with your eye doctor to find out if your vision prescription is within range for successful ortho-k treatment.

Note that although improvement in vision is generally reported within a day or two of wearing ortho-k overnight, the full effects may not be experienced until the lenses are worn for a few weeks. During this transition period, your vision will probably not be as crisp as it was with regular contacts or eyeglasses, and glare or halos around lights may be visible. Until ortho-k works fully, a temporary pair of eyeglasses may be required for specific actions, such as driving at night.

How Does Ortho-k Feel?

Although some people have trouble wearing regular gas permeable contact lenses during the day, ortho-k GP lenses are worn while sleeping – so discomfort and awareness of the lenses in your eyes is generally not an issue.

Is Ortho-k expensive?

Professional fitting for ortho-k requires a series of visits to your eye doctor. A number of pairs of contact lenses are also generally needed. GP lenses that are special for ortho-k are more costly than standard contacts. In sum, the fees for ortho-k add up to a higher total than regular contact lenses.

LASIK after Ortho-k

Refractive surgeries, such as LASIK, are possible after treatment with ortho-k lenses. Yet because ortho-k works to reshape your cornea, you are required to stop wearing the lenses for approximately several months before undergoing LASIK. This allows your eyes to return to their original shape.

It’s important to inform your LASIK surgeon if you’ve been wearing ortho-k lenses, and you will be advised as to how long of a wait is necessary before having the laser procedure.

Low Vision

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Low vision is significant vision impairment that usually results from serious eye disease or an injury. The vision loss, which is characterized by either reduced visual acuity (to 20/70 or worse) or reduced field of view, can’t be fully corrected with glasses, contact lenses, medication or surgery.

Low vision can affect both children and adults, but is more common in the elderly, who are at greater risk of eye diseases such as glaucoma, macular degeneration and cataracts, which are some of the most common causes of the condition.

Patients with low vision may have complete central or peripheral vision loss, blurry vision, poor low-light vision, loss of light sensitivity and/or loss of contrast, making daily activities such as writing, watching TV, driving or reading difficult or impossible. Since the vision loss can’t be corrected, low vision requires significant adjustments to daily life and the help of techniques and specialized low vision aids to help you maximize your remaining vision to increase independence and quality of life.

What are causes of low vision?

  • Eye diseases such as: glaucoma, macular degeneration, cataracts, diabetic retinopathy, and retinitis pigmentosa
  • Eye injury or brain injury
  • Heredity

How does low vision affect eyesight?

Low vision is partial vision loss which varies from person to person. Depending on the severity and type of vision impairment, the patient may have some useful vision. Typically the impairment includes a significant reduction in visual acuity to worse than 20/70, hazy, blurred vision, blind spots or significant visual field loss and tunnel vision. Sometimes the extent of vision loss is considered to be legal blindness (20/200 or less visual acuity in the better eye) or almost total blindness.

How does low vision affect daily life?

With significant vision loss it can become challenging to complete common daily tasks including reading, writing, cooking and housework, watching television, driving or even recognizing people.

When low vision is diagnosed it can come as a shock. Initially, it is an adjustment to learn how to function with impaired vision but the good news is there are numerous resources and products available to assist. Because low vision often results in one’s inability to work, function independently, drive and resume normal life, many patients feel isolated and depressed.

Visual Rehabilitation and Visual Aids

Low vision means that a minimal amount of sight remains intact. There are millions of people who suffer from the condition and manage to function with the remaining vision available to them through the use of visual rehabilitation or visual aids.

What are visual aids?

These are devices that help people with low vision function by maximizing remaining eyesight. This often involves the use of magnifiers (handheld, mounted or stand-alone), telescopes and other tools to enlarge the images of objects to make them more visible. Some visual aids reduce glare and enhance contrast which makes it easier to see. Other low vision aids act as guides to help the person focus on non-visual cues, such as sound or feel. Finding the right visual aid is a matter of consulting with a professional and experimenting with what works for you and your daily needs.

How to make life with low vision easier

  1. Ensure that you have adequate lighting in your home. This may require some trial and error with different lights and voltages to determine what works best for you.
  1. Use a magnifier. There is a vast selection of magnifiers available, ranging from hand-held to stand magnifiers. Binoculars and spectacle mounted magnifiers are also an option.
  1. Your optometrist or low vision specialist can recommend specialized lens tints for certain conditions such as retinitis pigmentosa or cataracts, which enhance vision or reduce light sensitivity.
  1. Use large print books for reading. Alternatively, try digital recordings or mp3s.
  1. Make use of high contrast for writing. Try writing in large letters with a broad black pen on a white piece of paper or board.
  1. Adding a high-contrast stripe on steps (bright color on dark staircase, or black stripe on light stairs) can prevent falls in people with low vision, and may enable them to remain independent in their home.
  1. Find out what other technology is available to help make your life simpler.

If you or a loved one has low vision, don’t despair. Be sure to consult with your eye doctor about the best course of action to take to simplify life with low vision.

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