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Contact Lenses


The Functional Mechanism of the Contact Lens

A contact lens is used as a substitute when something goes wrong with the real lens inside the human eye. This human lens is quite similar to a contact lens in its functionality. Within the eye, this natural contact lens is covered by the pupil, which in turn is covered by the tissue which is referred to as the cornea. What the lens does is direct the light towards the retina, which then activates the optic nerve. The optic nerve conveys the information of the image to the brain.

When all these parts of the eye work in harmony there is no need for a contact lens. But sometimes the natural contact lens within the eye may get distorted or at other times the cornea or the eyeball might. The result is that the light rays are not directed properly and the image is formed either in front of the retina or at the back of it, or the image could be scattered. It is during such situations that contact lenses become necessary.

When the image is formed in front of the retina, it causes myopia or nearsightedness, when it is difficult to see things further ahead, like a signboard on a road, or things written on the blackboard in a class. Then eye glasses or contact lenses become necessary to correct the vision.

When the image if formed behind the retina, the result is farsightedness or hyperopia, and this is where it is difficult to see things that are nearby. For those with farsightedness, far away things are clear, but reading books or viewing the computer screen may require glasses or contact lenses.

Another situation that makes a contact lens necessary is when the eyeball goes out of shape resulting in the malfunction of the cornea and the lens. In such situations much of the things around may appear blurred. This condition, known as astigmatism, necessitates the wearing of contact lenses. Because of the double problem involved here, it was a bit difficult to treat this situation. Making of contact lenses or doing laser surgery for this condition posed its own problems.

However, there are contact lenses available for the problem now. It is managed by placing another lens between the incoming light rays and the human lens which is supposed to direct it. The result is a camera like action which captures an image by the synchronized action of more than one lens. So, by placing an eye glass of the required power in front of the eye, the problem remains rectified. The eye glasses have been now replaced by contact lenses.

The contact lens, which is inserted into the eyes, is designed to gently glide on a fine layer of moisture atop the cornea. This liquid medium is required to protect the eye as the contact lens would be shaped accurately to fit the eye and remain in place.

The net result of placing the contact lenses or glasses in front of the eyes is that the light gets refracted differently. The light rays get slightly bend when they pass through the contact lens. The rays, which have been refracted by the contact lenses, are further changed by the cornea, the fluid, and the original lens within the eye. The combined effect of contact lenses and the natural mechanism of the eye is that the light rays are directed to form the picture exactly on the retina. So, with the help of the contact lenses, the correct picture is conveyed to the brain.

Choosing Between Laser Surgery and Contact Lenses

Decision making is always a tricky arena, especially when the pros and drawbacks are equal on both sides. And the difficulty is more when it is a health issue with long term ramifications. So when you are forced to make a choice between opting for a laser surgery and wearing contact lenses, you may find the decision difficult, even with a doctor’s guidance. The pros and cons of both options have been weighed in the article below.

A major difference between the contact lens option and laser surgery is its affordability.
Contact lenses are reasonably less expensive. Contact lenses may cost anything between $20 and $100 a pair and it is up to the patient to decide how expensive a contact lens he or she wants. Even after adding the doctor’s bills and the cost of the cleaning solution, the total expenses on a pair of contact lenses would not exceed $200 a year. Your health insurance would generally cover the costs.

Compared to this contact lens expenses, a laser surgery may cost anything between $2000 and $5000 for an eye and the doctor’s visits will be an additional sum between $2500 and $6000. While the surgery is brief and quite safe and reliable, the costs can be an inhibiting factor. Many health insurance programs cover at least part of the cost.

The main plus point with laser surgery is that you will be solving your eye problem once for all. It will be a one time expense for a life long convenience. Even the latest models of contact lenses, whether they are disposable contact lens or not, require cleaning, changing, and replacement after two or three years.

Laser surgery rarely leads to health problems. Some reported negative effects are dryness of the eyes due to lower tear production, and reduced vision. There have also been cases where patients have reported seeing halos while others have reported lack of clarity of vision at night, or during fog. In short, there have been a few reported instances of vision problems after laser surgery.

But the health risks of contact lenses have been found to be more. Even the best models of contact lenses prevent the free flow of oxygen to the eyes, increasing the risks of corneal infection. Compared to older models, RGP or rigid gas permeable contact lenses of today allow five times more oxygen to enter the eyes. Still, even this may not be fully sufficient. Even if a bit of extraneous matter gets trapped between the contact lenses and the eyeball, it could lead to the scarring of sclera, the hard tissue that covers the eyeball.

All these are possible risks but only a very small percentage report these risks. With laser surgery, practically everyone comes out of it with completely enhanced vision and totally repaired eyes. And people go about using disposable contact lens, bifocal contact lenses, cosmetic contact lenses, fashion contact lenses, or blue eye contacts. In short they use a wide variety of contact lenses and sail successfully through their jobs and lives. People get adjusted to the cleaning regimen of the contact lenses pretty fast.

In the end, your doctor’s advice and your budget will be the deciding factor for you to cast your vote in favor of contact lenses or laser surgery.