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October 26, 2007
Correcting Astigmatism with Contact Lenses
Astigmatism for a long time was an eye problem that could not be fully corrected with contact lenses. Mild astigmatism could be adequately improved with soft contact lenses, but there weren't options for more severe cases. The eye problem itself results from a misshaped cornea - rather than being spherical like a ball, the cornea in people with astigmatism is oblong, shaped more like a football. Because of this shape, light rays can't refract properly against the retina. Instead of focusing the rays on one spot, the odd shape causes light to refract in multiple locations on the retina, causing the blurred vision, regardless of distance, that is symptomatic of astigmatism.
Understanding toric contact lenses
The development of toric contact lenses opened up a whole new world of vision for people with astigmatism. Toric contact lenses don't look any different than other soft or rigid gas permeable contact lenses, but in fact they are very different. The lenses consist of a number of different curvatures in various meridians or sections on the lens. Since astigmatism is a problem involving unbalanced meridian sections (due to the odd shape of the cornea) bringing the meridian sections back into balance is what helps produce clear vision.
Since the positioning of the various curvatures is key to improving vision, toric soft contact lenses cannot rotate - they must be held in a certain position in order to be effective. This is accomplished several ways. One way is to add weight to the bottom of the lens by building up or thickening that section. Another way is to make the top part of the lens lighter, by thinning this section.
Rigid gas permeable lenses are an option
Yet another way to correct astigmatism with contact lenses is to use rigid gas permeable lenses. These lenses are not as flimsy as soft lenses and that enables them to hold onto their shapes, even after blinking. Regular gas permeable lenses work effectively at correcting mild to moderate astigmatism, but in cases where the astigmatism is severe, it's usually necessary to purchase gas permeable toric contact lenses. Toric lenses are custom shaped so that the inside of the lens more closely matches the shape of the astigmatism. Because of the customized fit, toric lenses remain in position and rotation isn't an issue.
And because toric contact lenses involve customization, you'll likely have to pay more for this type of contact lens. You might even find that your eye doctor charges more when fitting you for toric lenses because of the extra work involved in properly measuring each eye.
If you work with an eye doctor you trust, he or she will likely first try to prescribe regular contact lenses to treat your astigmatism. Again, mild and moderate astigmatism can usually be adequately corrected with standard lenses. Only when the astigmatism becomes severe is it necessary to resort to toric style contact lenses. When this happens, you'll find that toric lenses are available as daily wear, extended wear, silicone hydrogel and disposable brands. They even come in an assortment of eye color options!
Posted by Vision at 03:40 PM | Comments (0)
October 25, 2007
Contact Lenses or LASIK Eye Surgery
After years of daily maintenance and spending hundreds on cleaning solutions, replacement lenses and annual eye examinations, those familiar with daily wear contact lenses are ready for change. And the timing couldn't be better. Thirty-day continuous wear contact lenses and LASIK eye surgery are viable alternatives. Which one is right for you? Consider the following:
Benefits of 30-day continuous wear contact lenses
Results are both immediate and guaranteed. The moment you insert the contact lenses, vision is better and if it's not or if the contact lenses feel uncomfortable, then you've somehow ended up with an incorrect prescription, something that's easy to remedy.
Costing less than what you pay for your coffee or other daily habit, these contact lenses are an option that's affordable. Plus, most 30-day contact lens brands are disposable so at the end of the wear cycle, you throw the pair away and put in a new pair. Doing so eliminates the need to constantly spend money replenishing cleaning solutions and other lens maintenance products. You should keep a bottle of cleanser handy but it will last quite a while.
Newer technology is another benefit. Silicone hydrogel contact lenses are more efficient at letting oxygen into the eye, and that keeps eyes healthy and free of irritation.
Should an eye examination reveal the need for a different prescription, such as bifocal lenses, updating to the new prescription is easy.
Cons of 30-day continuous wear contact lenses
Even with the new technology, many people find it difficult to sleep with their contact lenses on. That for many is the determining factor for or against 30-day contact lenses.
The chances of developing an infection increase when contacts remain in place while sleeping.
Annual eye examinations are still required to keep the prescription valid.
Pros of LASIK eye surgery
Technology, training and experience have improved the success rates of LASIK eye surgery so those who undergo the procedure generally end up with eyesight that's even better than 20/20 with long-lasting results.
Customized LASIK surgery, which involves creating a multi-dimensional map of the cornea and then feeding the customized data into the laser, offers even higher rates of success.
Results are immediate with LASIK eye surgery and most patients see well enough to drive home from the procedure.
Cons of LASIK eye surgery
Cost is a big factor. With rates running approximately $2,000 per eye, LASIK eye surgery is a huge investment that's unaffordable for many, even though many surgeons offer financing.
Another consideration with LASIK eye surgery is that the outcome cannot be guaranteed. Any type of surgical procedure has risks and eye surgery is no different. There have been instances in which vision is not improved after surgery. Potential side effects include nighttime dry eyes, glare, seeing spots and the appearance of halos surrounding objects.
Some people are not good candidates for LASIK eye surgery. Eyes must be healthy and individuals should be in good overall health.
Eyeglasses may still be needed later in life, when presbyopia becomes an issue.
Regular eye examinations are still needed.
Posted by Vision at 03:04 PM | Comments (0)
October 20, 2007
Are Your Contacts Uncomfortable?
Wearing contact lenses should be painless. There should be not even the slightest feeling that there is something in or on the eye. When you can go through your day forgetting that you're wearing corrective lenses, you know you're wearing the right pair.
What's causing that pain?
But what happens when that invisible feeling starts becoming more noticeable? What happens when it feels as though there is indescribable pressure on one of your eyes? Or worse, what happens when you feel sharp, gritty or localized pain in your eye? More often than not, the culprit is a piece of dirt or other type of debris that somehow has become lodged between the inside surface of your contact lens and the surface of your eye.
When this is the case, relief is easy. Since it's not a good idea to touch contact lenses unnecessarily, start by adding a few drops of your contact lens solution or lubricant into the eye. Hopefully the debris will rinse away and the uncomfortable feeling will be gone. If it's not, then remove the lens and take a closer look. You might find protein deposits accumulating on the lens surface. If that's the case, it's time to pay more attention to your cleaning routine. If you're using disposable lenses, it's probably time to replace one or perhaps even both lenses.
And you should feel fortunate that you have such an early warning device. A build up of protein deposits left untreated can turn into something far more serious than an uncomfortable feeling.
If you've checked the lens surface and done a bit of lens maintenance, yet still, wearing your contact lenses feels uncomfortable, there's the possibility that the lens has developed a tear. Remove the lens, place it on your fingertip and hold it up towards a light source. Look around the edges for what appears to be a tiny fiber. If one is found, investigate further. It may be just that - a tiny piece of something on the surface. If it won't come off, it's probably a tear and there's nothing you can do to repair it.
What else could be wrong?
Other reasons contact lenses are uncomfortable include wearing the wrong prescription, a problem with dry eyes, allergies or other medical problems including eyes that aren't healthy and eye strain. These types of problems should be discussed with your eye doctor. Testing and a medical history evaluation can help rule out or pinpoint the cause of the pain and once it's been identified, proper corrective measures can be put into place.
That might include a new, properly-fitting contact lens prescription or possibly a different brand of contact lens, one that allows more oxygen to flow to the cornea. The eye doctor might recommend using lubricants and/or artificial tear drops when dry eyes are causing the uncomfortable feelings. Other medical treatments might also be prescribed depending on what's causing the discomfort. Hormonal and thyroid problems can impact a person's ability to wear corrective contact lenses as can some prescription and over-the-counter medications.
Posted by Vision at 03:08 PM | Comments (0)
