The use of the argon laser photocoagulator in retinal surgery

Helen Jordan, RN

In 1967, research began on an instm- ment to retard and prevent the blind- ing side effects of diabetes, sickle cell anemia and other diseases affecting the eyes. In 1969, the research was completed and the first patients were treated with the argon laser photo- coagulator a t the Palo Alto Medical Clinic, Palo Alto, California, in Octo- ber of 1969.

In June 1972, the first argon laser photocoagulator in Arizona was in- stalled at St Luke’s Hospital Medical Center. The equipment is one of about 300 in the world.

Helen Jordan, RN, i s a graduate of Jewish Hos- pital School of Nursing, St Louis, Mo. She is a staff nurse in the recovery room at St Luke’s Hospital Med- ical Center, Phoenix, Ariz. Ms Jordan expresses her gratitude to the hospital’s community relations depart- ment for their assistance in writing the article.

The laser is used to treat retinal tears and holes, plus most blood ves- sel irregularities on the retina, in- cluding side effects of diabetes, sickle cell anemia and congenital and trau- matic abnormalities.

The principle of laser function is absorption of light by tissue, in this case, absorption of the intense green light of the laser by red blood vessels. This process of absorption, known as photocoagulation, allows bloodless,. essentially painless surgery.

Equipment includes a slit lamp or binocular optical viewing instrument that keeps a beam of light in accur- ate focus and controls the spot size. The laser’s intense energy is focused on a carefully selected part of the inner eye. The light energy changes to heat upon contact with the retina. The heat, in turn, causes sealing of the blood vessels, thus stopping leak- age of fluid or blood. The argon laser is also used to seal retinal tears to prevent retinal detachment. The

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growth of abnormal blood vessels on the retina and into the vitreous body, the main cavity of the eye filled with a clear, semi-solid fluid, can be treated with the instrument. The pro- liferation of vessels, a side effect of diabetes, causes the growth of scar tissue which pulls on the retina, caus- ing traction in the eye. If left un- treated, the vessels and scars can develop to the point that they liter- ally tug at the retina. It is then that the retina detaches.

The argon laser offers a number of major advances over its predecessors. First is its efficiency. It is so precise its green beam of light can be focused on an area only six times the size of a red blood cell. The argon laser also allows for more precision in treating specific areas and permits more ac- curate control of the power in each retinal exposure. Since less power is introduced into the eye with the argon laser than with other instru- ments, exposure and damage to sur- rounding tissues is minimized. The slit-lamp microscope delivery system provides higher magnification than other instruments and permits the physician to see the eye in three di- mension, again giving more precision. Another advance of the argon laser is patient-oriented. Treatment with the argon laser is essentially painless and can be performed on an out- patient basis. Treatment takes ap- proximately 30 minutes and the patient is usually free to leave the hospital after that time.

The most important advance of the argon laser is that i t is the only means of treatment for blood vessels which are on the retina and extend out in front of the retina into the vitreous. Although this condition re- gresses naturally in some cases,

many persons whose eyes have been affected by blood vessel leakage in the vitreous cavity have suffered eventual blindness. Treatment with the argon laser photocoagulator is the only known preventive or re- tardant for blindness for some per- sons with this condition.

At St Luke’s Hospital the argon laser is located in surgery in a room adjacent to the recovery room. Re- covery room nurses assist ophthal- mologists with the procedure.

Most patients having a laser treat- ment are out-patients. When the pa- tient arrives the nurse determines if the eye to be treated has been di- lated. If not, drops are given to dilate the eye. At the time of admis- sion, the nurse also has the patient sign the consent for the procedure to be done. Water, which circulates through the laser, is turned on prior to arrival by the physician. Various lenses and medications he may want to use are placed in a convenient place on the laser. The lubricant used for the lens contains methylcellulose and phenylmercuric borate. Proparacaine hydrochloride drops are used to anesthetize the cornea. When the ophthalmologist is ready to begin the treatment, the nurse positions the pa- tient behind the slit-lamp. She places a few drops of the anesthetic in the eye to be treated so the patient will not feel the lens being placed in the eye.

The ophthalmologist decides the spot size, power and length of ex- posure he will use to begin the treat- ment. These settings will be changed, sometimes frequently throughout the procedure. The physician adjusts a knob on the slit-lamp to determine spot size. The nurse, directed by the

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physician adjusts exposure time and power settings located on a control box on top of the laser. One tenth second and two tenths second are the exposure times most often used. The power may vary from 25 milliwatts to 1000 milliwatts with 150 to 500 milliwatts most frequently used. The ophthalmologist starts with what he thinks is the required power to treat the lesion. He usually has to make changes until he finds the proper set- tings. As he moves to other areas of the retina he will probably have to again change settings.

At St Luke’s Hospital we have a form to record the various settings used throughout the treatment. If the patient requires further treatment, the physician can check to see what

was satisfactory on previous treat- ments. The number of exposures varies according to the lesion to be treated. We have had treatments with as few as seven exposures and some with as many as twenty-three hun- dred exposures. Patients with dia- betic retinopathy usually require more exposures than other condi- tions.

The patient usually experiences no discomfort during the treatment. Oc- casionally, if the lesion is in the periphery of the eye the patient may feel some applications.

When the treatment is finished the patient can immediately leave the hospital to be followed by the physi- cian in his office. 17

HEW uwurds child abuse s+udy The Office of Child Development of HEW has awarded two grants as o first step in coordinating all departmental efforts on child abuse. The grants were awarded to the Children’s Division, American Humane Association, Denver, Colo, and to the Mershon Center, Ohio State University, Columbus.

The American Humane Association will establish a clearinghouse for gathering data on the nature and characteristics of child abuse and neglect, and will collect information on reporting procedures and action taken by receiving agencies as well as the impact of these actions on the children, The group will disseminate periodic reports and analyses of trends and the national status of the problem, and will encourage the growth of child protective services along with other services needed to safeguard the physical and men- tal health and welfare of abused and neglected children. It will also design a uniform reporting system for voluntary use by the states. Data gathered could be used for mobil- izing local, state and national resources for the most effective and coordinated preventive and treatment services, for designing better public education programs on child abuse, and for the enactment of local, state or national legislation.

The Mershon Center will survey individual local program models already in ex- istence. The three-step survey will sample existing programs, conduct the survey, and analyze the results in order to recommend demonstration efforts. The survey will also identify the strengths in individual local programs which could be used on a wider scale. Similarly, where limitation of services is discovered, possible remedies will be recommended.

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