Which contact lenses are right for you? Disposable lenses, hard lenses, or soft lenses. See which lenses work for your lifestyle.

Contact lenses are an alternative optical correction to glasses or surgery.  They offer greater freedom for those with active lifestyles.  And let's face it.  Some people just don't like wearing glasses.   Whereas eyeglass lenses sit out in front of the eye, contact lenses rest on the eye, providing more natural vision.  We now have contact lenses which can be worn continuously without removal for up to a month.  This makes contact lenses a more viable alternative to refractive surgery.  And contact lenses can easily be changed to accomodate changes to the eye.  This is not easily achieved with surgery.  Whether you can wear contacts successfully depends on the follow factors: 

1. Need.  The more you need your glasses, the more likely you are to enjoy contact lenses.  

2. Age.  Contact lens wear requires a muture sense of responsibility.  Contact lenses which are not worn responsibly or are not properly maintained can pose a threat to the health of the eye.

3. The nature and degree of refractive error.  Will the contacts be correcting nearsightedness, farsightedness, presbyopia, or a combination of the above?  This question must be answered prior to selecting a suitable type of contact lens.  This also determines the complexity of the fitting procedure and how much it will cost.

4. The overall health of the eye.  Successful contact lens wear requires healthy eyes.  It is the contact lens specialist who, through periodic evaluation of the eyes, insures that contact lenses are being worn safely.  A contact rests on a thin layer of tissue called the cornea.  Like any other part of the body, the cornea requires oxygen and nutrients to remain healthy.  But the cornea does not have blood vessels supplying oxygen.  Instead, the cornea absorbs oxygen directly from the air.  All contact lenses impair oxygen flow to the cornea to some degree. The goal is to select a contact lens and fit it in such a way that the cut off of oxygen is minimized to an acceptable level.  Todays modern contact lenses are safe and effective when worn responsibly.  What follows is an explanation of the types of contact lenses in comman use today.

Any contact lens that has a correction for astigmatism embedded in the lens is called a toric contact.  A toric may be either a firm or soft design.  Astigmatism is the term given when the degree of nearsightedness or farsightedness varies as it is measured through different meridians of the eye.  Ninety percent of astigmatism occurs as a result of the front of the eye being out of round.  The other ten percent is the result of some optical component inside the eye being out of round, probably the lens.  Astigmatism causes light to focus at an infinite number of points instead of one clear point of focus.  The result is blurred distorted vision.  Since a spherical soft contact conforms to the eye, it does nothing to correct astigmatism.  Therefore if a soft lens is used to correct astigmatism, there must be a correction for astigmatism in the lens.  Here is the problem with this approach: A correction for astigmatism must be aligned at a precise axis of rotation to do the job.  If this correction is rotated out of position the result is blurred vision.  Therefore toric lenses are designed to minimize rotation.  The most common technique for this is called prism ballasting, or adding weight or thickness to the bottom of the lens.  But the act of blinking has a rotational effect on contact lenses.  Therefore soft torics may not precicely correct astigmatism.  And because torics are inherently thicker than sperical soft contacts, there is added potential for too much oxygen cut-off to the cornea.  A more direct and precise method for correcting astigmatism is to use a simple spherical firm contact lens.  There is no correction for astigmatism in this lens, so it can rotate all it want's without affecting vision.  What corrects the astigmatism is the tear layer that forms between the lens and the cornea.  So even if the lens rotates, the tear layer remains constant.  The result is consistently clear, precisely corrected vision.  This does not hold true, however, for that ten percent of the the people with astigmatism that have internal astigmatism.  A soft toric is probably the best option for people that fall into this category.