Contact Lenses

If you are over 40 and have difficulty seeing close up, you probably have a common age-related condition called presbyopia which is when the eye’s natural lens loses the ability to focus on close objects. Presbyopia is a natural process as the eye ages and affects the majority of people from age 40 and upward. Individuals with presbyopia are often familiar with the need to hold reading materials such as newspapers an arm’s length away from their eyes in order to see clearly, yet reading glasses with bifocal or multifocal (progressive) lenses can help.

Fortunately for those who don’t like the look, feel or inconvenience of reading glasses, there is another option. Bifocal and multifocal lenses are also available in contact lenses in both soft and Rigid Gas Permeable (RGP) varieties.

Multifocal contact lenses give you added freedom over glasses and they allow you to be able to view any direction – up, down and to the sides – with similar vision. People wearing progressive lenses in glasses on the other hand have to look over their glasses if they want to view upwards or into the distance.

The Difference Between Bifocal and Multifocal Lenses

Just as the name indicates, bifocal lenses are divided into two distinct segments for different vision powers, the first for distance vision and the second for near vision. This enables you to clearly switch your focus from near to far as needed, but your vision will not necessarily be clear in between. The term multifocal lenses can refer to any lenses with multiple powers including bifocals, trifocals or progressive lenses. Non-bifocal multifocal lenses have a range of powers that enable you to constantly adjust your focus to see clearly from up close to far and in between.

Multifocal contact lenses are generally designed in one of two ways, as either simultaneous vision lenses or alternating vision lenses.

Simultaneous Vision Lenses

The most popular version of multifocal contact lenses, simultaneous vision lenses present the distance and near vision zones of the lens at the same time. Typically after a short adjustment period your eyes learn to utilize the segment of the lens that they need to focus on the desired object and essentially ignore the other.

They come in two designs:

• Concentric ring design: In the most basic form these are bifocal lenses that are comprised of a central circular area of one power with a ring around of the alternate power, similar to a bulls-eye. In this design the power of the rings (either near or distance vision is interchangeable). For intermediate viewing (18-24 inches away) extra rings can be added to create a trifocal or multifocal lens. The width of each ring is variable depending on the power that is needed most and the edges of the rings can be blended for a smooth transition of focus, similar to progressive eyeglass lenses.
• Aspheric design: These multifocal lenses attempt to provide a natural vision experience by blending many lens powers across the surface and center of the lens. In this design both distance and near vision power are located in the central visual area and your eyes will adapt to focus on the area needed to view what you are looking at.

Translating or Alternating Vision lenses

Similar to bifocal eyeglass lenses, these contacts are divided into distinct areas or zones and your pupil will move to the desired zone depending on your vision needs. Typically the top of the lens, which is what you look through when looking straight ahead is for distance vision and the bottom area (what you look through when you look down) is for near vision. However, this can be reversed according to unique vision needs.

Since contact lenses sometimes move within your eye, translating lenses are held in place by a ballast which is an area that is thicker than the rest of the lens or by truncating or flattening the bottom to stay in line by the lower lid. These lenses are only available in rigid gas permeable lens material.

An Alternative Option to Multifocal Contact Lenses: Monovision

Monovision is another contact lens alternative for presbyopia particularly if you are having difficulty adapting to multifocal lenses. Monovision splits your distance and near vision between your eyes, using your dominant eye for distance vision and your non-dominant eye for near vision.

Typically you will use single vision lenses in each eye however sometimes the dominant eye will use a single vision lens while a multifocal lens will be used in the other eye for intermediate and near vision. This is called modified monovision. Your eye doctor will perform a test to determine which type of lens is best suited for each eye and optimal vision.

Are Contact Lenses Right for You?

If you have presbyopia, contact lenses may be a great option for you. Many people prefer the look and convenience of contact lenses over traditional reading glasses. Speak to your eye doctor about the options available to you.

Gas Permeable (GP) or Rigid Gas Permeable (RGP) contact lenses are an alternative to soft contact lenses that are made from a hard, oxygen permeable material. GP lenses are currently less popular than soft lenses but offer a number of advantages and are continuing to improve as research and technology advance.

GP contacts are made of a firm plastic material which allows the passage of oxygen through the lens to your cornea and the front surface of your eye – essentially allowing your eye to “breathe”. This increases comfort, health and safety during contact lens wear.

Benefits of GP or RGP Contact Lenses

Because of the strong material and the ability to diffuse oxygen, GP lenses offer a number of advantages over soft contact lenses.

Health and Hygiene Benefits

Unlike soft lenses, GPs don’t contain water which makes them less likely to attract and breed bacteria that can cause eye infections. Further protein deposits won’t build up on the lens, keeping them cleaner and healthier.

Because they are made with a strong durable material, GP lenses won’t tear and are easy to clean and disinfect. RGPs maintain their firm shape and will not dehydrate. Further GPs last longer than soft lenses – when cared for properly, a pair can last a year or more.

Comfort

GP contact lenses are custom made for each patient based on the eye’s individual curvature, size, corneal shape. Their ability to transmit oxygen reduces eye problems such as dry eyes caused by reduced oxygen that are common in many brands of soft lenses or hard (non-GP) lenses.

GP lenses have a smaller diameter than soft contacts, meaning that they cover less of the surface of your eye. While this may take some time getting used to initially, ultimately many find that they are just as if not more comfortable than soft contacts.

Better Vision

Due to the rigid material, GPs have a smooth surface and maintain their shape, moving along with the eye to hold their place. This provides sharp and stable vision. Further they do not dehydrate, which is often a cause for reduced vision with other lenses.

Cost

Because they last so long, GPs are much more cost effective than soft lenses, especially disposable lenses that require a constant supply. Because they are made to order, there is an initial cost investment and they will take up to a week to manufacture if you do need a replacement pair.

GPs for Astigmatism

GP lenses are ideal for individuals with astigmatism that may have been told that they cannot wear soft contacts. Because of the rigid nature of the lens, they hold their shape on the eye allowing for more clear and stable vision correction.

Adapting to GP lenses

One of the downsides of GP contact lenses is that they require an adaptation period, particularly if you are used to soft lenses with a larger diameter. One of the major differences is an experience of “lens awareness” in which you feel the edge of the lens when you blink. It could take up to a few weeks to get used to the lenses but many people report that after this initial period they find that GP lenses are just as if not more comfortable than soft lens varieties.

GP Lenses for Myopia Control and Ortho-K

Research shows that gas permeable lenses might be effective in slowing the progression or worsening of myopia or nearsightedness, particularly in children. They are also used in Orthokeratology (ortho-k), a vision correcting procedure in which you wear the lenses at night to reshape your cornea for improved vision during the day.

It is not uncommon for patients to have difficulty wearing contact lenses for a number of reasons. Due to the individual eye shape, certain conditions or impairments or the aftermath of surgery, some patients are considered to be “hard to fit” as contact lens wearers.

For hard to fit patients that prefer to wear contact lenses however, there are options available that can provide comfortable and effective contact lens wear. This will require a specialized fitting with an eye doctor that is an expert that knows your condition and the various products available to find the right match for your specific condition. You may be considered a hard to fit contact lens candidate if you have one of the following conditions:

• Dry Eyes
• Astigmatism
• Giant Papillary Conjunctivitis (GPC)
• Keratoconus
• Pellucid Marginal Degeneration
• Post-LASIK or other refractive surgery
• Presbyopia (reduced near vision common in individuals aged 40 and over)
• Corneal Scarring

Benefits of GP or RGP Contact Lenses

Dry Eye Syndrome causes your eyes to feel dry, gritty, burning, red, and irritated. Dry Eye Syndrome can also cause blurred vision. Often these symptoms can sometimes worsen by the use of contacts. In fact, many people who do not normally suffer from chronic dry eyes, will experience some of these symptoms as a result of contact lens wear.

First of all, if you have chronic dry eyes, you should see your eye doctor for treatment and relief before you think about contact lenses. Once your dry eyes are treated, it is safe to try contacts and there are a number of options that can be considered.

Many brands of soft contacts and products such as disinfectant and cleansing solutions are made with ingredients that are designed to be more comfortable for individuals with dry eyes. Your eye doctor will be able to recommend some of these brands and products to you. Alternatively, gas permeable (GP) or rigid gas permeable (RGP) lenses are made with a hard material that in some cases does not dry out like soft lenses and they are able to hold a certain amount of moisture beneath the lens to keep the eye from drying out. Gas permeable lenses are a very good option and can be quite comfortable for individuals with dry eyes.

Additionally, your doctor might recommend a specific wearing schedule such as limiting the time you wear your contacts throughout the day or replacing your contacts on a more frequent basis.

Toric Lenses for Astigmatism

Astigmatism is a condition that causes blurred vision (in some cases double vision) because rather than being round, the front of the eye (the cornea) has two curves instead of one, therefore, having two focal points instead of one. This makes it hard for traditional contact lenses to fit and therefore requires specialized contact lenses such as toric lenses or rigid gas permeable lenses (RGPs).

Toric contact lenses are designed to correct astigmatism and custom made to fit the eye of the patient. Most are made of soft material designed to stay in place on the eye, however in some cases, when the rotation of the lens (due to blinking and eye movement) can’t be stopped, gas permeable lenses might be tried. Due to the customization and more complicated fitting process required for these lenses, they are more expensive and take more time for the contact lens laboratory to make than traditional lenses.

Giant Papillary Conjunctivitis (GPC) and Contact Lenses

GPC is a type of conjunctivitis in which the inner surface of the eyelid becomes swollen. The condition can be caused or worsened by a buildup of protein deposits on contact lenses. Your eye doctor may either recommend daily disposable lenses or RGP lenses (which are not water based) and therefore do not have a tendency for protein buildup. Your doctor may also prescribe medicated eye drops and require you to stop the use of contact lenses until the symptoms improve.

Rigid Gas Permeable (RGP) or Gas Permeable (GP) Lenses

Rigid Gas Permeable (RGP) also known as Gas Permeable (GP) lenses are effective for many hard to fit patients. The hard, oxygen permeable material lets the eye breathe and significantly reduces the chance of infection due to protein deposits which tend to harbor bacteria on soft lenses. RGPs also hold moisture under the lens to keep eyes from drying out.

Rigid Gas Permeable (RGP) Lenses for Keratoconus

Keratoconus is a condition in which the cornea thins and bulges forward into a cone shape. Traditional contact lenses may cause some discomfort in these patients and the vision may still be blurry therefore RGPs are often used for treatment for mild, moderate, and some severe cases. Rigid gas permeable lenses may help to slow down the cone shape from worsening in some cases. Further, RGPs are able to assist in vision correction for keratoconus which is often not possible with soft contacts or even eyeglasses.

Post-LASIK or Vision Correction (Refractive) Surgery

While LASIK surgery has a very high success rate, there are vision complications and symptoms that sometimes remain. Night vision after LASIK, in particular, can sometimes give you side effects such as glare or halos around lights. RGPs are often effective in helping with these side effects and restoring clear vision.

Bifocal and Multifocal Contact Lenses for Presbyopia

Presbyopia is a common condition in those people usually over 40 years old iin which the eyes’ ability to focus on close objects is impaired. Many people keep a pair of bifocal or multifocal glasses on hand for times when they have to read menus, newspapers, books, and other objects that require near vision. For those that prefer contact lenses over eyeglasses, bifocal and multifocal contact lenses are an option.

For some patients that have presbyopia and need correction for distance vision as well, one option is monovision. Monovision is a contact lens fitting process in which you wear a contact lens in one eye for distance vision and the other contact lens of your other eye for near vision. Another option is multifocal contact lenses. In this contact lens fitting process, both eyes are usually fit for distance vision and both eyes are used for near at the same time. Both contact lens fitting options usually take about one week for the brain and the eyes to adjust.

If you have one of these conditions or find contact lens wear difficult for another reason, speak to your eye doctor. As technology improves there are more and more options for hard to fit contact lens patients to benefit from the comfort and convenience of contact lens use.

Astigmatism is a condition that is caused by an irregular shape of the cornea – the clear part of the eye that covers the iris and the pupil. The cornea is usually smooth, round, and spherical but in an astigmatic eye, the cornea turns into a shape that is not spherical and develops a second curve. One of the primary duties of the cornea is to focus light onto the retina which enables you to see clearly. When the cornea is out of shape and develops two curves, this created two focal points therefore causing blurred vision.

The irregular shape of the eye makes it hard for traditional contact lenses to fit and provide clear vision and therefore requires specialized contact lenses such as toric lenses or rigid gas permeable lenses (RGPs).

Benefits of GP or RGP Contact Lenses

Toric contact lenses are designed to correct astigmatism and custom made to fit the eye of the patient. Rather than having a perfectly spherical surface like standard contact lenses, toric lenses have a more oblong shape made to accommodate the shape of the astigmatic eye. Toric lenses can be made of either soft or rigid gas permeable (RGP or GP) lens material, however the soft toric lenses are more common.

Toric contact lenses are also designed in such a way that the lenses stay in place on the eye to maintain proper vision. Sometimes as the eye moves or blinks the lens can rotate considerably on the eye. If this rotation continues with a soft toric lens, a rigid gas permeable lens might be more effective. Rigid gas permeable lenses have a longer initial adjustment time, but once this has passed they are usually just as comfortable as soft contact lenses and they are often easier to care for.

Toric lenses are available in every wearing schedule from daily disposable to long-term wear. In some cases you may even find colored toric contact lenses. Due to the customization required, toric lenses tend to be more expensive and may take more laboratory time to make than traditional lenses.

If you have astigmatism, finding the right fit for your contact lenses is essential. Speak to your eye doctor today for a full assessment to determine which type of toric lenses will work best for you to help you see and feel your best.