The word "laser" is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. A LASER is a beam of light energy that has very special properties. It is said to be "coherent." This means that all of the light waves or particles are traveling in the same rhythm. In addition, all of the light waves from a particular LASER are of the same wavelength, or color. Because of these special properties, laser light is much more powerful than regular light. LASERS are used in surgery because their power can be harnessed to cut, burn, vaporize or destroy different tissues.
LASERS have been used in eye surgery for more than thirty years. There are distinct advantages to laser eye surgery over conventional surgery. Because the laser light can pass through the cornea to be concentrated inside the eye, a surgical opening does not need to be made in the eyeball. This greatly decreases the risk of infection and bleeding. Because of this decreased risk, laser procedures usually do not need to be performed in an operating room. Recovery time is reduced and people do not need to restrict their activities after surgery.
LASER surgery is indicated in the treatment of many eye diseases. Lasers are used to treat the ocular complications of diabetes. For glaucoma patients, lasers help to control the pressure inside the eye when medications, alone do not succeed. Lasers are used to seal holes in the retina, and prevent or treat retinal detachments. Macular degeneration is another condition where laser can sometimes help prevent vision loss. Finally, laser is also used after cataract surgery to improve upon vision if necessary. Different wavelengths of LASER are used in different settings. In general, Argon and Krypton lasers are used for most retinal conditions. The YAG laser is used for membranes after cataract surgery.
LASER surgery is the most effective way to prevent loss of vision in diabetes. DIABETES causes specific changes in blood vessels inside the eye. At first, blood vessel walls become leaky. Fluid escapes from the blood vessels and into the layers of the retina, causing it to swell. This retinal swelling causes significant visual loss. In this setting, the laser is used as a welding-type tool to seal the leaking blood vessels and prevent further swelling. Later in the course of diabetes, blood vessels begin to close off and circulation is lost. Abnormal new blood vessels start to grow. This is called proliferative diabetic retinopathy. These abnormal blood vessels do little to restore the lost circulation, and do cause a great deal of damage to the eye. Severe loss of vision can result from the bleeding and scarring that come from these abnormal blood vessels. Extensive LASER surgery, called PANRETINAL PHOTOCOAGULATION causes these abnormal blood vessels to shrink away and disappear.
When GLAUCOMA cannot be controlled with medication, LASER is a very effective tool used to lower the pressure inside the eye. Small burns are applied to the trabecular meshwork, the area where fluid drains from the eye. These burns stretch open the drainage channels and allow more fluid to escape the eye. By doing so, the pressure is reduced. In acute angle closure glaucoma, the laser is used to make a hole in the iris. This redirects the flow of fluid in the eye, opening the angle and allowing the pressure to return to normal.
RETINAL HOLES, if left untreated, can lead to retinal detachment. The LASER can be used to seal the retinal hole before a retinal detachment occurs. If a retinal detachment does occur, laser alone, cannot repair it. A retinal reattachment operation is performed to bring the retina back in contact with the inner wall of the eye. LASER can then be applied to secure it in place.
Macular Degeneration is a disease in which abnormal blood vessels beneath the retina can lead to bleeding, swelling and scarring in the center of vision. In some individuals, LASER can be used to destroy these abnormal blood vessels before they have a chance to damage vision.
When a CATARACT is removed, it is common practice to try to keep a membrane called the posterior capsule intact within the eye. This membrane serves to support the lens implant that is placed in the eye at surgery. It also serves as a barrier separating the front and back parts of the eye. In as many as 30% of people, this membrane will lose some of its clarity in the months and years after a cataract operation. In such a setting, the YAG LASER is used to create an opening in the center of the membrane to restore quality vision.
Although the risks of LASER surgery are usually less than that of conventional surgery, these procedures are not without risk. Severe, permanent vision loss can result from laser procedures if they are not administered correctly. Sometimes, the LASER is not adequate to control the underlying condition. Loss of vision might occur despite adequate treatment. Conventional surgery might be contemplated in such a case.
PLEASE NOTE: The information contained on this system is not intended to supplant individual professional consultation, but is offered as a community education service. Advice on individual problems should be obtained directly from a professional.
Copyright, 1994. Richard E. Gans, M.D.
Last Modified: August 23, 1996