An interview with Dr. Johnson

Dr. James Johnson is an Irvine, California based ophthalmologist who includes laser vitreolysis as a treatment for floaters in his practice. He is a diplomate with the American Board of Ophthamology.
Compiled by Kelly Garrison. Updated 2010

What exactly happens to floaters that are lasered?

The YAG laser emits the beam in a cone-shaped pattern. At the apex (or tip) of the cone, there is a concentration of energy. Using focusing lights, this apex is directed onto the front surface of the floater material.

The laser "shot" lasts 20 to 30 nanoseconds (0.000000030 seconds), and at that moment the concentrated laser light creates a small plasma bubble.

Plasma is the fourth state of matter, the first three being solids, liquids and gas. Matter that has been converted to plasma has the electrons pulled away from their usual location and creates a high-energy state of the matter. This process actually converts the floater material to a micro-gas bubble that floats away.

It is important to understand that the laser does not break the floater into small pieces, but actually changes it to a gas. The gas is reabsorbed into the bloodstream over the coarse of several hours.

What determines how many floaters can be removed during the procedure?

Time, location, and total energy. For longer treatments, I am working against the clock. After 30 to 45 minutes, I'll notice that the laser shots are becoming less effective, probably in part due to a little swelling (or edema) of the cornea. In addition, floaters that are too close to the retina or lens may not safely be treated.

During the treatment, I monitor the energy of each shot, as well as the total energy used during the treatment and keep it within a certain range.

How do you prevent the patient from moving his/her head during surgery?

There is a head strap on the laser that snugly holds the head in place. In addition, a hand-held contact lens stabilizes the eye quite well. The combination allows me to focus on objects that are very small with great accuracy. Sedatives are available to patients who think they may not feel comfortable sitting still for a prolonged period of time.

What short and long term complications or side effects is the patient at risk for? What are the odds of these complications?

Short Term: dilation of pupil, corneal swelling, occasional discomfort (mild to moderate) from the corneas being a little scuffed up from the contact lens. I have not witnessed any rise in eye pressure but that is a potential problem.

I continually monitor and remain aware of the location of my treatment, and avoid aiming near the lens or retina. A misfired shot could conceivably cause a cataract formation or injury such as bleeding from the retina or damage to the receptors. There have not been any documented cases of loss of vision, but we must state that possibility.

How should a patient prepare for laser surgery of floaters? What type of exam(s) are needed in advance?

A complete eye examination should be completed prior to any laser treatment. Most people come to us already with the diagnosis of floaters after an exam that includes a dilating the retina to ensure that there is no retinal detachment or area at risk for same. I also perform or repeat this exam prior to any laser treatment.

Are there cures for all of these potential complications? Which, if any, would have no remedy?

If a cataract were to develop, the patient might need cataract surgery. If the retina were hit in the periphery, it would not likely be noticed, but if it were hit in the center of the vision (in the macula) there could conceivably be a decrease in visual acuity. None of these have been reported yet.

Can an ophthalmologist train to become a specialist in vitreous issues? Are there resources available to obtain credentials for this type of expertise?

Currently, there is no official or unofficial training or courses for Laser Vitreolysis techniques and applications. There is, though, a Vitreo/Retinal subspecialty of ophthalmology. These specialists perform vitrectomy procedures.

In our residency training, there is a supervised training and certification on the YAG laser. General ophthalmologists may use this laser hundreds of times in the course of a year.

Usually the laser is used for anterior segment procedures, namely, Capsulotomies and Iridectomies. The use of the laser in the vitreous is an adaptation of a laser we are already familiar with.

What are a patient's odds of seeing significant improvement? No improvement?

I went back to look at the interview you reference here. First understand that that interview with Kelley Garrison took place about two years ago. Much of the information is technical and stands up to scrutiny, but a lot of floaters have passed through the crosshairs since then and if I were asked the same question I would answer it differently. Here again is the original.

What are a patient's odds of seeing significant improvement? No improvement?

It depends on a number of factors. The age of the patients, the type and volume and distribution of floaters present, and other optical characteristics that may make the procedure more difficult, less efficient, and challenging. The well defined, distinct, large Weiss-ring type floaters associated with a posterior vitreous detachment are the most successfully treated. With that type, it is not uncommon for the patient to perceive a 70-95 percent reduction in the bothersome floaters in the first treatment. Older patients with diffuse, cloudy and hazy syneresis type floaters are much more unpredictable and generally will benefit from more treatments spaced out in time if feasible. This type of floater mass has the most tendency to "backslide" and reform some strings and strands and part of its 3-4 steps forwards, 1-2 steps backwards campaign. Young people in their 20-30's are more difficult to predict. they typically have much less floater mass with the tendency to form thin cobweb-like strands intersperse with otherwise clear vitreous that has not seperated or diffusely degenerated. These floaters tend to be small, dense and fibrous, posteriorly located and quite mobile. Their shadows also tends to be quite distinct and bothersome. It these can be treated successfully, these patients are elated, and if you can't treatment them successfully they are often the most despondent and depressed over their condition.

All in all it is impossible to get 100% of the floaters. The endpoint of treatment and treatment success is indeed hard to define sometimes as floaters are seen and interpreted somewhat by the personality type of the floater sufferer. The numbers don't always tell an accurate story either. For instance, a 95% percent "patient-perceived" reduction in floater mass and volume is great, unless there is even a small residual fine strand moving across the central vision that is still bothersome. I think a better definition of success is a functional one: The goal of a treatment series is to return the patient to activities of daily living (reading, driving, sports, etc.,) where they are not constantly aware and reminded of the presence of distracting moving shadows across their vision and the ultimate goal of improving the quality of vision and the quality of life. Only the patient can fully assess the success or failure of that goal. Objective measurements (e.g. photos, ultrasounds) can not do that.

How does your procedure compare to that of floater treatment specialists, Dr. Geller (Florida) and Dr. Karickhoff (Virginia)?

The procedure and experience should be very similar with all three. We do have different lasers, but that is just a technical difference and personal preference.

What is your hope for the future of floater treatment? How can the doctors, the public and floaters sufferers best help the cause?

Eye care professionals can be collectively blamed for not listening to patients and taking the floaters seriously. If we did, there would be. We have always considered it adequate to pronounce the eye as healthy, and send the patients on their way. I am more attuned to how people suffer these floaters - usually suffering in silence because no one wants to take them seriously.

I am looking into better ways of locating and documenting the floaters, possibly with B-scan ultrasound or better yet, Ocular Coherent TomographyThe optics of lasers were designed for working on the anterior portion of the eye, and it is difficult to deliver the laser to the periphery of the eye. Maybe someday there will be a nontoxic way of enzymatically removing the floaters. Until then, Laser Vitreolysis is an attractive, noninvasive alternative to a much more aggressive Vitrectomy procedure.

It is really exciting to be on the cutting edge of a newer treatment. I do want to thank doctors Geller and Karickhoff for being the true pioneers and establishing the credibility and success for this procedure. It is incredibly rewarding to help these patients, in some ways even more so than our LASIK patients since some of our floater patients are on the border of functional disability. I am promoting this part of my practice slowly and cautiously so as to maintain it's credibility. The biggest obstacle will be convincing other eye care specialist that it is a legitimate treatment so they can help refer their long suffering floater patients.