St. John's Surgery Center
St. John's Surgery Center

A Patients Guide to Lasers in Modern Eye Care

Lasers use a complex system of crystals, gases, lenses, mirrors, and mechanisms for focusing and cooling to produce an extremely intense, uniform beam of light of a single color or wavelength. The energy of this beam can be focused very precisely on diseased eye tissue.

Because some colors of laser light have more effect on certain eye tissue than others, different lasers are used to treat different eye problems.

Lasers used at St.John’s Surgery Center include:

  • The SLT laser, used in treatment of open-angle glaucoma
  • The YAG laser, used for treatment of the lens capsule following cataract surgery and diseases of the vitreous.

Precise Control

Modern lasers are miracles of control. The laser beam can be focused on a spot as small as one-millionth of a meter, the power controlled to one-thousandth of a watt, and the exposure time set to one-billionth of a second.

The laser has replaced conventional surgical techniques for many procedures because laser surgery can often be performed with little or no pain, without anesthesia or hospitalization, and at a lower cost.

Because lasers eliminate the need to make a physical incision in the eye, the incidence of infection and other complications after surgery is greatly reduced.

Lasers and Cataracts

Cataracts are a gradual clouding of the eye’s natural lens. Although lasers are not used in the removal of cataracts themselves, they can be an important tool in treating a condition related to cataract surgery.

In modern eye surgery techniques, the cloudy cataract is removed from the eye’s lens capsule, leaving the lens capsule membrane in place to hold the new artificial lens implant.

In some patients, the remaining lens capsule membrane can become cloudy a short time after the cataract surgery and vision is blurred once again. In these cases, a YAG laser is used to open this membrane. After a YAG laser treatment, vision is usually restored almost immediately.

Lasers and Glaucoma

Glaucoma is an abnormally high fluid pressure within the eye. As pressure builds, it can “pinch” both the optic nerve and the blood vessels which nourish the retina. The result is usually a slow loss of peripheral, or side vision, and eventual blindness.

Chronic glaucoma has no symptoms in its early stages. Detected by a simple test in our office, it is the leading preventable cause of blindness in the U.S. today.

In most cases, the traditional treatment for glaucoma includes eyedrops and tablets, both of which must be taken in precise amounts on a regular schedule to control fluid pressure. If this fails, treatment using the SLT laser may be tried before resorting to conventional surgery to open drainage channels within the eye. During SLT laser treatment, specific cells in the eye are stimulated to activate increased fluid drainage thereby reducing pressure inside the eye.

Lasers and Acute Glaucoma

In the relatively rare instances of acute glaucoma, immediate treatment is required. Argon lasers will often be used to open a fluid channel directly in the iris to reduce pressure and avoid more extensive surgery.

Lasers and Retinal Tears

The retina is at the back of the eye, virtually inaccessible to conventional surgery. In some people, the retina can tear and become partially detached from the back wall of the eye.

Although retinal detachment in advanced stages usually requires major surgery, doctors using an Argon laser can fuse smaller tears in place and help prevent further detachment.

Lasers and Diabetes

It is not uncommon for a diabetic to have blood vessels under the retina which begin to leak. The Argon laser is often used to seal them closed.

Lasers and Macular Degeneration

As the body ages, weak blood vessels may leak and scar the central retina. Called macular degeneration, this condition prevents the patient from seeing objects straight ahead, leaving him or her with only peripheral vision.

Eight in ten patients suffer from a slow-progressing form of the disease which cannot be treated by lasers. If detected in time, however, the other 20 percent with fast-progressing macular degeneration may benefit from laser therapy.

Laser Surgery and Laser Therapy

Some laser procedures may correctly be called surgery; a one-time treatment of a specific condition. Other procedures are more like therapy and may require repeated sessions to accomplish a particular goal. If you have questions, your doctor at St.John’s Surgery Center will be more than happy to answer them.

What to Expect

Unlike conventional surgery, for a laser treatment you will be seated in an upright position, leaning slightly forward with your chin and forehead resting on a chin-rest. You’ll be asked to hold your head steady and try not to blink. Anesthesia, if required, will probably be in the form of eyedrops.

Although the laser generally produces little or no pain, you may experience discomfort similar to looking at the headlights of an oncoming car at night.

After surgery, your eyes may be somewhat scratchy or sensitive to light, but these symptoms seldom last more than a day or two.


Lasers have been one of the most revolutionary medical tools in history. With them, surgeons may operate on diseased eye tissue without disturbing neighboring healthy cells. The eye is left untouched except by a beam of energy.

Once a science fiction miracle, today lasers at St John’s Surgery Center are a practical tool used in the effort to maintain and restore good vision.