Risks of Treatment

There are two decades of combined experience with the laser vitreolysis procedure. It has proven itself to be a low risk procedure and an attractive alternative to 1.) doing nothing, and 2) the invasive and much riskier surgical vitrectomy. Using our experience combined with the others in the US performing this technique, there have been some short term complications, but no major or devastating vision threatening complications such as retinal detachment.

Every activity has some risk. The only way to have no risk is to do nothing. We believe that for most patients, the potential benefits WELL outweigh the potential risks of the laser procedure.

Here is a listing and explanation of the major real and theoretical risks of using the laser for eye floaters:

• Inaccessible Floaters/Inability to Treat Successfully: Not so much a risk, but still an important consideration and possibility. The optics of the treating laser are designed more for use toward the front of the eye and in the central visual axis rather than the periphery of the eye. The further back the floaters are, the treatment increases in difficulty and inefficiency. The laser energy can be blocked by small pupils, small lens implants, and made more difficult in “long” eyeballs as is typical in the nearsighted eye. Floaters in the periphery of the eye are very difficult to treat and even though we may see them quite clearly, the laser energy may be so diminished that nothing happens when the laser is activated. Some of this challenge can be compensated for by rapid, vigorous eye movements and gyrations which may allow the floater to move into a more central and treatable position. And sometimes not. Fortunately, peripheral floaters, if untreatable, tend not to be as bothersome as centrally located floaters.
• Recurrence of Floaters: The floater material that is directly hit by the laser should be permanently vaporized. That small mass of material should never come back. Immediately adjacent to the laser focal spot, the long collagen molecules may be fractured and broken into small, microscopic fragments. We theorize that one of two things may happen to this material: 1. Some of it is liberated into the fluid portion of the eye and flows out with the natural fluid drainage of the eye (trabecular meshwork), and 2). The fractured collagen molecules become “sticky” and may regroup or clump up to form a newly shaped floater. These “reformed” floaters are usually quite treatable with subsequent, follow up laser treatments. Because of this tendency, it is rare to be able to treat someone in just one treatment session. Most people will need a second and 3rd (and sometimes more) treatments to achieve a satisfactory outcome. This expectation of the need for re-treatments is logistically easier for those that live in the Southern California area. Those that travel longer distances may need to allow for longer stays, or leave open the possibility to return at some future date.
• Inability to Treat Some Floaters: The treatment of eye floaters is highly individualized and dynamic. It impossible to predict exactly how the floaters will behave. That unpredictability is more so in younger patients. There exists the distinct possibility that despite our best, most dedicated and meticulous effort, there may be some residual material that simply cannot be safely treated, or remains inaccessible.
• Retinal Detachment: There has never been a published or unpublished report of a retinal detachment from this procedure that we are aware of. A theoretical risk. It is much more likely that a person will experience a retinal tear or hole from the original event causing the floaters (posterior vitreous detachment). If fact, your lifetime greatest risk for retinal detachment is when the vitreous is in the process of separating from the back wall. When the vitreous separates completely, then your lifetime risk of retinal detachment drops to its lowest point. The laser does not create traction or tugging on the retina during or after treatment, and so the laser rocedure for floaters should not be able to cause a retinal detachment.
• Eye Pressure: This is the most common side effect or complication of treatment. We have had several patients that experienced significant elevations of eye pressure within 24 hours of (usually the first) procedure. Now with several patients having experienced this problem, we have a better understanding of the potential pre-existing conditions that might place someone at risk for post-treatment pressure spikes. We believe the broken fragments of vitreous material (microscopic fragments of collagen molecules) will sometimes overwhelm the eye’s own natural drainage system (the trabecular meshwork). It may may take days (or even months) for the eye to clear that material out. We estimate the incidence to be 3-5 episodes per 1000 treatments based on cumulative reported and anecdotal conversations with other providers. There does not appear to be a direct correlation between the amount of treatment (number of shots or total energy used) and the elevation in pressure for the typical patient. There may be some predictive risk factors such as the following:
  • pre-existing elevated eye pressures
  • previous cataract surgery
  • large, dense floaters in the front one-third of the eye
  • aggressive treatment

  If a potential patient exhibits some of these or other characteristics we think may put them at higher risk, we may modify the treatment strategy or choose not to treat at all. One modified approach is to treat at much lower energy levels at the first treatment session to assess how the eye responds. We have observed that if the patient does not respond with a pressure elevation after the first treatment, then it is very unlikely they will have a problem with subsequent treatments regardless of how aggressive. There is the possibility that the eye pressure may not come down with treatment which could require long term use of eye pressure medications or possibly the need for further surgery.

• Cataract: A cataract is a change in the clarity of the crystalline lens in the eye. There always exists the potential for the creation of a (traumatic) cataract by the laser, but it would essentially take a direct hit to the lens to do so. There are very few reports of cataract being caused by the laser procedure. If the laser breaks the outer lens capsule, the cataract that develops could be a rapid-onset traumatic cataract and may develop quickly as in days or weeks. A cataract may require surgical treatment. This risk is almost 100% avoidable by staying an adequate distance away from the lens when treating.
• Retina Injury: If the laser is aimed and fired directly at the retina, it is possible to directly damage retinal nerve cells. The laser’s focused spot size is approximately 4-8 /1000′s of a millimeter, so the area affected would be quite small, and possibly without any symptoms. We do not believe that even a direct hit to the retina can cause a retinal detachment. We have experienced minor complications to the retina via laser “shock-wave” when we chose to work in close proximity. This has occurred when attempting to get “that one” bothersome floater. It is a judgment call as to whether to fire the laser, and it would never be done in the central part of the vision, only peripheral. The shock wave can cause some temporary edema or swelling of the retinal nerve fiber layer or a small sub-retinal (beneath the retina) hemorrhage. Both conditions are about 0.5mm in size. When these have occurred, most of the time they are without any symptoms. When the patient was aware of anything, they might describe a faint, bluish, after-image seen when they quickly close and squeeze their eyes. This is self-limited and may only last a few weeks to a couple months. There have been a couple of instances where the patient described persistent symptoms, and because of that we have compensated by no longer treating small floaters close to the retina as before. The results of this less aggressive posture have been a near elimination of this problem. We believe it is a better policy overall.

Because many patients come to our office from out of town, we believe it is a good idea to have a local eye care provider that can provide follow up care if needed. For instance, to be able to check your eye pressure, should you experience any unusual symptoms after your procedure and after returing home.

The in-person and personalized discussion of risks for any medical procedure is part of the informed consent process and occurs with Dr. Johnson prior to any treatment. We try to present a fair representation of the risks and potential risks of this procedure. Fortunately, virtually all risks listed above can be avoided by the experienced physician being aware of the focus of the laser at all times. Doctor Johnson is one of the most experienced ophthalmologists in this particular procedure with over 1.5 million laser bursts aimed at these sometimes elusive eye floaters. He has enjoyed a very high success rate because of the careful, conscientious, diligent, and unhurried approach to each treatment.

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