Contact Lenses and Dry Eye
What causes dry eyes from contact lenses?
Dry Eye Syndrome Symptoms
Persistent dryness, scratching and burning in your eyes are signs of dry eye syndrome. These symptoms alone may prompt your eye doctor to diagnose dry eye syndrome.
But sometimes your eye doctor may want to measure the amount of tears in your eyes. A thin strip of filter paper placed under the lower eyelid, called a Schirmer test, is one way to measure tear production.
Another symptom of dry eyes is a “foreign body sensation”, the feeling that something is in the eye. And it may seem odd, but sometimes watery eyes can result from dry eye syndrome, because the excessive dryness works to overstimulate production of the watery component of your eye’s tears.
According to the Schepens Eye Research Institute in Boston, approximately 10 million people in the United States suffer from Dry Eyes. One risk factor for dry eyes that might be surprising is that wearing contact lenses can actually cause Dry Eyes. Why is it that contact lenses can cause Dry Eyes? Simply stated, Dry Eyes can occur if you either don’t have a sufficient quantity of tears or if the composition of the tears you do have is not correct.
Ohio State University researchers have ruled out contact lens solutions as a possible underlying cause of dry eye that may occur among contact lens wearers.
In an analysis of 360 contact lens wearers involved in a major Contact Lens and Dry Eye Study, researchers identified several factors that appear associated with development of dry eye. Factors contributing to dry eye included high water content in contact lens materials and individual problems such as greater eye discomfort even when contact lenses are not worn.
People wearing contact lenses also were likely to have dry eye when they reported inability to wear contact lenses for desired time periods and complained of dissatisfaction with contact lenses in general.
Dry Eyes and Soft Contact Lenses
Contact lenses are manufactured from one of two types of polymeric materials. Soft contact lenses are made from hydrophilic plastics that contain water. In fact they may contain anywhere from 30-75% water depending on what type of wearing schedule they are designed for. In general, the more water a soft contact lens contains, the more prone it is to dehydration and losing its water. This is not a desirable attribute because as water evaporates from the front surface of the lens while being worn, it reacts by absorbing water from your natural tear film, causing you to have symptoms of Dry Eyes. While in most situations dehydration is usually not a problem, common environmental conditions and activities can cause the dehydration to occur with resulting Dry Eyes. Conditions that may cause dryness, such as the heat being on in a room, using a hair drier, someone smoking or being exposed to smoke from any source, exposure to wind while running or even bike riding can cause soft contact lenses to produce Dry Eyes. Fortunately, dry eye symptoms from contact lenses is usually temporary and can often be minimized or eliminated by changing lens materials and or water content of the soft contact lenses. However, for patients who have been wearing their lenses for many years, there may be another cause. The continual rubbing of the lens across the surface of the cornea, may result in sloughing off of the microscopic hairlike structures that exist on the outermost layer of the cornea to assist in keeping the tear film stable. Years and years of gently chaffing these fine structures can result in poor tear film stability resulting in Dry Eyes. This can occur even if you are totally comfortable with you contact lenses and wear them successfully for most waking hours.
Rigid Gas Permeable Lenses and Dry Eyes
Rigid Gas Permeable Lenses are manufactured from polymeric materials that do not contain any water all. One would think that this is preferred to having the possibility of water evaporating from the lens and causing dry eye symptoms. However, the very nature of the Rigid Gas Permeable Contact Lens polymer is that is “hydrophobic” and tends to repel water and thus the tear film. Rigid Gas Permeable Contact Lenses must be specially formulated to enhance their wetting characteristics so that they are compatible with the tear film. Even with these formulations, their surfaces are more prone to drying and creating dry eye symptoms. The problem of mechanically chaffing the fine structures that attract the tear film and make it stable is even greater with Rigid Gas Permeable Lenses because of the stiffness of the lens…it is rigid.
Contact lenses can provide a great improvement over eyeglasses for people who are bothered by the cosmetic appearance of eyeglasses or the limitation to activities that they pose. To have a comfortable and successful contact lens wearing experience you should always be under the care of an eye care practitioner to be sure that the lens fit and lens materials you currently have are the best possible choice for you.
There are ways for contact lens wearers to combat dry eyes and feel comfortable in their lenses for longer periods of wearing time. Possible remedies of contact lens related dryness include:
- Switching to a different lens material: There are lens brands designed specifically to provide more comfort for those who have problems with dryness. Some examples areProclear Compatibles and Acuvue Oasys. The newer, more oxygen permeable silicone hydrogel materials such as Focus Night & Day, Ciba O2 Optix, and Acuvue Advance have proven to be more comfortable for patients with moderate dry eye issues.
- Contact lens rewetting drops: This is usually a temporary solution but does offer some relief. Some examples are Refresh Contacts, Clerz Plus, or Clear Eyes Contact Lens Relief. For those with sensitive eyes, it is best to use a preservative-free drop.
- Prescription eye drops: Restasis is an anti-inflammatory eye drop prescribed for moderate to severe dry eyes and has proven to be very effective in cases where inflammation is the underlying cause of the dryness symptoms. Contact lenses should be removed before using these drops.
- Take good care of lenses: Inserting fresh new lenses as often as prescribed, as well as cleaning lenses properly, greatly contributes to contact lens comfort. Protein deposits and other types of buildup on the lens surface contribute to increased lens dryness. Sometimes switching to a more disposable lens or switching to a different or stronger lens cleaning system also helps.
- Re-soak lenses during the day: People who have dryness symptoms after a few hours of wearing time often experience much relief by removing and soaking their lenses for a few minutes. Upon reinsertion, most are able to wear their lenses comfortably for many more hours.
- More complete and frequent blinking: Blinking completely and often is necessary to rewet the lenses and maintain comfort. It is often the case that when a person is concentrating, they do not blink as often as they should. This is why computer users often complain of lens dryness. It is important to consciously be aware of blinking frequently and completely under these circumstances.
Source: eyecaresource.com, aclens.com