HERE IS A BRIEF VIDEO INTRODUCTION TO THE LASER AND TREATMENT DETAILS:
EXAMPLE 1, A SIMPLE WEISS RING FLOATER
We have created a model to better understand how the YAG laser interacts with the collagen of the vitreous fluid. We use cooked noodles on a cross-section cartoon of the eye.
The normally clear vitreous fluid is 99.9% water with the remaining material mostly collagen. Collagen is a non-cellular, long-stranded, polymer structure. It is normally dispersed throughout the vitreous, and it is invisible.
Around the optic nerve head is a particular thickening that may become obvious when it pulls away and separates which is typical of a posterior vitreous detachment (PVD). There is a naturally occurring outer thickened layer of the vitreous shown here as a shiny and reflective food wrap sheet. It is the material that is adherent to the retina and often collapses into semi-transparent fold or wrinkled sheets after the collapse of the vitreous and separation.
The Weiss ring type of floater is our favorite type of floater to treat. They are usually easily seen, they correlate very well with the patient’s description of the moving shadows and they are typically tethered fairly stably in the central part of the eye.
EXAMPLE 2, MORE COMPLEX
This next example illustrates a much more complex situation with a mixture of various types of vitreous thickening and densities. There may be a mixture of strands, and dense clouds, and thicker fibrous material.
These small residual fragments of collagen have the opportunity to do one of two things: 1) Now that they are liberated from the original tangled mass of vitreous condensation, they can break free and work their way into the eye’s own drainage system. There is a naturally occurring recirculating pump and drainage of fluid in the front part of the eye. It occurs where the cornea meets the iris which drains fluid (trabecular meshwork). The small fragments of collagen may find their way into the eyes drainage system and exit the eye as a secondary manner. 2) Unfortunately, some of this fragmented collagen has a strong attraction towards itself and may re-form. The reformed clumps typically form as long, soft and fuzzy strands as illustrated here.
The situation described above is not that unusual and is in fact quite common when there is a large, three-dimensional, cloud-like floater mass to begin with. This regression of treatment is not a treatment failure, but a not-uncommon treatment challenge. Typically, these long fuzzy strands are quite treatable even though a bit resistant to the laser energy. Further treatments are usually necessary to break it down and reduce the mass and volume of the residual floater material. This may take to or three or sometimes more treatments to get to the desired effect.
We think it is important and beneficial to understand these concepts prior to treatment as it is all about setting appropriate expectations for the patient. If our patients have these large, three-dimensional, thick masses of floaters we want them to understand that it will take more than 1 to 2 treatments to get a stable improvement. It is better to describe this in advance as it better prepares the patient for the treatment series.
What happens to the vaporized collagen? It is converted directly to gas bubbles. You can see the bubbles float away in the videos. They go to the roof of the eye (seen here using a mirrored lens way out in the periphery of the retina). Here is one larger bubble and approximately 60-80 very small micro-bubbles. They will only last about 10-30 minutes where they will dissolve into the surrounding fluid.
So what can you expect for a treatment or treatment series. The answer is that it is very difficult to know in advance of the initial consultation and evaluation with Dr. Johnson. It is often difficult to know after the evaluation or even after the first treatment. Each eye is different and each eye behaves and responds differently. Some floater types are more likely to regress or reform than others. It is one of the weaknesses of the laser procedure, this difficulty in predicting its behavior. We strongly believe it is better to educate and prepare the potential patient prior to treatment rather than proffer excuses and explanations after their 1st or 2nd treatment. We look forward to your thoughts and comments.