Contact lenses: a look at the risks and recommendations
Thanks to the existence of contact lenses, it can sometimes be impossible to tell if someone has a visual impairment or not. These lenses can make huge differences to the lives of their wearers, providing a certain level of freedom that traditional glasses are unable to.
According to the Centers for Disease Control and Prevention (CDC), around 41 million people in the US wear contact PC lenses.
While they might feel like a relatively modern invention, rigid contact lenses made from plastic were first manufactured in the US between 1938 and 1940. The soft contact lenses currently worn by an estimated 93% of contact lens wearers were first introduced in 1971.
On a personal level, I first started wearing them as a temporary measure when my declining eyesight made playing sports difficult. However, no longer having my vision affected by raindrops and fogging up (along with the boost in self-esteem that came from not wearing glasses) meant that contact lenses quickly became my main method of improving my vision.
But despite their prevalence and the benefits they can provide, many people (myself included) wear contact lenses in a way that can compromise eye health, increasing the risk of damaged corneas and infection from microbes.
This week has marked the second annual Contact Lens Health Week – a week organized by the CDC to increase public awareness and promote healthy wearing and caring of contact lenses. In this Spotlight, we take a brief look at a few of the "do's and don't's" of contact wear. In addition, we will have a look at some of the interesting "can's and can't yet's" of new contact lens innovations.
Healthy habits mean healthy eyes
Although they are similarly effective at improving vision as glasses, contact Pc anti fog lens wearers can be more at risk of eye complications than those who use glasses. If wearers do not follow contact lens care instructions properly, they can put themselves at risk of serious eye infections that can lead to blindness.
The CDC have previously reported that between 40-90% of contact lens wearers do not properly follow their contact lens care instructions, which may explain why serious eye infections affect around 1 in 500 contact lens wearers each year.
Many people compromise their visual health due to bad habits when it comes to wearing contact lenses. While it is easy to manhandle glasses, contact lenses need to be afforded a greater level of care.
This means washing hands with soap and water and drying them comprehensively before ever touching contact lenses. Doing so prevents the transfer of germs from the hands to the lenses and consequently the eyes.
Exposing the lenses to water should be avoided as water can carry bacteria and other microbes that cause infection. With soft contact lenses, water can also alter the shape of the lens and potentially damage the cornea. As a result, contact lens wearers should remove their lenses before showering, swimming or using hot tubs, as tempting as it may be to keep them in.
One particular germ, an ameba called Acanthamoeba, is typically found in tap water as well as other water sources. If it causes infection (Acanthamoeba keratitis), patients can require a year or more of treatment, and possibly a corneal transplant.
Another bad habit that should be avoided where possible – unless prescribed by a doctor – is sleeping in contact PC super blue cut lens. In addition to making the eyes feel uncomfortable, sleeping in any type of lens increases the wearer's risk of a corneal infection known as microbial keratitis by between four and five times.
Fast facts about keratitis
Keratitis is inflammation of the cornea, the clear tissue that covers the pupil and iris
Keratitis can be caused by infectious microbes or by minor injuries to the cornea
In severe cases, keratitis can permanently damage an individual's vision.
This risk extends to the wearers of contact lenses that are designed to be slept in. Recently, the story of a man who went blind in one eye after sleeping in contact lenses for almost a week has come to the media's attention.
"The kind of contacts I have are called 'Night and Day' contacts," Chad Groeschen explained to USA Today, "and it was my impression you could leave them in for 30 days straight. I figured the less I was messing with my eyes, the better."
While people can opt to use disposable lenses that are designed to be worn daily, many choose to wear lenses that last for longer periods and need to be stored properly when not in use. Unsurprisingly, many eye problems arise from bad habits pertaining to the storing of contact lens and associated products.
Contact lenses need to be kept clean if they are going to be used for multiple days. Lenses should be cleaned using a specific contact lens disinfecting solution and never water or saliva, as should the case that the lenses are stored in when not in use.
The CDC report that fewer than half of contact lens wearers report always cleaning their contact PC blue cut lens cases, and the number of moderate to severe lens-related infection could be halved if case cleaning practices were improved. Contact lens cases should also be replaced at least once every 3 months.
Contact lenses are stored in a purpose-built solution that is recommended by an eye care specialist. Contact lens wearers should stick to the recommended solution as the recommendation will be based upon the wearer's eyes and medical history. Water should never be used, again due to the fact that it can increase the risk of infection.
Old solution in a lens case should never be "topped off" with new solution – instead, only fresh solution should be used. Solution can become contaminated with microbes that cause infections, and simply adding fresh solution to old solution reduces how effective it is at eradicating germs.
According to the results of a recent CDC study, these bad behaviors are incredibly prevalent. The Contact Lens Risk Survey was completed by approximately 1,000 contact lens wearers, and around 99% of respondents reported at least one behavior associated with an increased risk of eye infections.
"Good vision contributes to overall wellbeing and independence for people of all ages, so it's important not to cut corners on healthy contact lens wear and care," reports CDC Medical Epidemiologist Dr. Jennifer Cope. "We are finding that many wearers are unclear about how to properly wear and care for contact lenses."
The following figures illustrate how prevalent some risky behaviors were among survey respondents:
Napping while wearing contact lenses – 87.1%
Showering while wearing contact lenses – 84.9%
Not replacing contact lens cases as frequently as recommended – 82.3%
Swimming while wearing contact lenses – 61.0%
"Topping off" contact lens solution – 55.1%
Sleeping in contact lenses overnight – 50.2%.
"Nearly one third of all wearers reported ever having experienced a contact lens-related red or painful eye that required a doctor's visit," the researchers write.
Considering how common contact lenses have become, the figures produced by the CDC's study are significant, illustrating just how important it is that people become more aware of how contact lenses should be used and the impact bad practice can have on health.
The health problems that can be caused by risky contact lens behaviors may be enough to put some people off wearing them. However, there are a number of other benefits that specific types of contact lenses can provide that no other devices are able to.
Contact lens designs have become more sophisticated over time. While original products may have only been able to correct nearsightedness (myopia) and longsightedness, newer models of lens can be used to treat and monitor additional conditions that affect the eyes.
Orthokeratology, also known as Ortho-K, is a PC clear lens fitting procedure that offers a temporary degree of vision correction by changing the curvature of the cornea to improve its ability to focus on objects.
Altering the cornea's curvature is achieved through the use of specially designed rigid contact lenses that are typically worn overnight. Ortho-K lenses are most commonly used to correct myopia.
Some people wear multifocal glasses because they have a condition known as presbyopia, whereby the eye's ability to focus on nearby objects is lost. However, the condition can also be treated with multifocal contact lenses.
There are two main designs for these types of lenses. Alternating vision lenses have two distinct areas for short- and long-distance prescriptions. The pupil alternates between the two different prescriptions as the wearer's gaze shifts up or down.
Simultaneous vision lenses involve the pupil looking through short- and long-distance prescriptions simultaneously. The two prescriptions can either be laid out in alternating concentric rings or blended together across the lens.
Presbyopia is one condition that a "smart lens" being developed by Google and Novartis should hopefully address. Last year, Novartis suggested that the use of technology such as noninvasive sensors and microchips contained within the lens could "provide accommodative vision correction" to restore the eye's ability to focus.
Their smart lens might also provide benefit outside of visual health. Novartis stated that such a lens could provide a continuous measurement of glucose levels in diabetic patients and deliver this information to a mobile device using a wireless connection.
"We are looking forward to working with Google to bring together their advanced technology and our extensive knowledge of biology to meet unmet medical needs," announced Novartis CEO Joseph Jimenez. "This is a key step for us to go beyond the confines of traditional disease management, starting with the eye."
One of the most frequently repeated recommendations concerning contact lenses is that wearers should always follow the advice of their eye care providers. Unlike glasses, contact lenses are in direct contact with an opening into the human body, and as such there are far more things that could go wrong from a health perspective.
When used correctly, contact lenses can have a transformative effect on the wearer's quality of life. The same can be said for when they are used incorrectly, only for wholly different and more unpleasant reasons.
It does not take much time to wash hands before handling lenses, to remove them before showering or to clean out a storage case properly, and yet by skipping these simple steps, thousands of contact lens wearers are putting their vision at risk. Follow the advice of eye care providers and vision can be protected for years to come.
Previously, Medical News Today reported on a study that suggested wearing contact lenses may alter the microbiome of the eye.
Once an optometrist has confirmed a diagnosis of myopia, several treatments are available. Speaking to an optometrist can help a person decide on the best option for them.
The sections below will discuss some of these treatment options in more detail.
Glasses and contact lenses
Glasses and contact lenses are the most common treatment options for myopia. An optometrist will order custom lenses that have the right prescription for that person. These will fit into the frame of the glasses and correct any nearsightedness.
Contact lenses are clear discs that sit on the surface of the eye. Like glasses, contact lenses are also customizable for different prescriptions.
Many people who do not like the look or feel of glasses will choose to have contact lenses, as they are a lot smaller and harder to notice. However, it is necessary to change and clean them regularly.
People with mild forms of myopia may benefit from a nonsurgical process called orthokeratology, or corneal refractive therapy. This treatment involves wearing a series of rigid contact lenses to reshape the cornea.
These lenses put pressure on the cornea to flatten it. This, in turn, changes how light focuses as it enters the eye. People tend to wear these contact lenses while sleeping.
This process can help people experience clear vision temporarily. However, it also carries a risk of eye infections.
There are a couple of different types of surgery available to people who would rather not wear glasses, who want a more permanent solution, or who have severe forms of myopia.
One form of surgery is laser surgery, wherein an eye doctor will use a powerful beam of light to change the shape of the cornea.
Laser surgery adjusts how the eye focuses light, meaning that images that were once blurry should now be clear.
The surgery takes around 10 minutes per eye. This option can be expensive, but it is usually painless. Vision should return to normal within a day or so of the surgery.
However, it is normal to have occasional blurred vision or dry eyes for weeks or months afterward. Attending follow-up appointments after this procedure is important to make sure that the eyes are healing properly.
Other forms of surgery can involve placing a PC photochromic blue cut lens inside the eye, either in front of the person's lens or in place of it. Eye doctors tend to recommend this form of surgery for more severe forms of myopia.
Given that myopia has genetic links, it can be hard to prevent in people who have a history of nearsightedness in their family.
Spending time outside, in the daylight, could help lower the progression of myopia. Making sure not to spend too much time doing up-close work, such as reading or working on a computer, can also help.
In most cases, myopia does not cause any further health problems. There are a range of treatments available that allow people to experience no symptoms of the condition in their daily lives.
For those who have more severe forms of myopia, it is important that they tell their optometrist about any changes in their vision. Without treatment, they could be at risk of developing additional eye problems, or even vision loss.
There is evidence that both genes and environmental factors, such as spending less time outdoors and more time indoors reading and using computers, can increase the risk of myopia. Before this study, however, it was not clear what the underlying molecular mechanisms were.
One way to observe the biological development of myopia or hyperopia is by altering the focal length of the eye in laboratory animals. Specialists can do this by placing a lens in front of the eye for several weeks.
Depending on the type of lens, the exposure causes the eye to develop to a length that is either too long or too short.
The scientists used this method in marmosets to study the development of myopia and hyperopia. They placed a PC photochromic lens in front of only one eye for up to 5 weeks and let the other eye develop normally for comparison.
- ایجاد شده: 21/10/11
- آخرین ورود: 21/10/11