Clinical studies have shown Laser Floater Treatment (LFT) to be an effective treatment approach for vitreous strands and opacities. It also offers a high degree of patient satisfaction. When performed with a YAG laser designed specifically for use in both the posterior and anterior segment, reported side effects and complications associated are rare. As an added benefit, if LFT is not effective, or if the floaters return, surgical intervention is still an option.
John Karickhoff, MD, USA has performed the procedure more than 5,000 times and reports a success rate of 90%. In a Dutch study by Cees van der Windt, MD, and colleagues, 100 eyes with PVD-related floaters persisting for more than nine months were treated with laser floater treatment (n=65) or pars plana vitrectomy (n=35). After all eyes were treated, both the YAG and vitrectomy groups reported an improvement in vision at 80% and 90% respectively. Furthermore, over a follow-up period of eight years, no complications were observed among patients treated with laser floater treatment. These findings echo those of two small-scale studies carried out by Tsai, et al, and Toczolowski, et al, in the 1990s. In both studies, a near 100% rate of floater removal was achieved with laser floater removal and no intra- or post-operative complications occurred in any patient.
Despite these advantages, Laser Floater Treatment is generally not taught, nor endorsed, by medical schools. This is due, in part, to the belief that floaters are benign and do not require treatment. Indeed, many ophthalmologists consider floater treatment to be unnecessary. Furthermore, the technical constraints of conventional YAG laser technology, which offers a limited view of the vitreous, can make it difficult to visualize the vitreous strands and opacities and to perform the procedure. These conventional YAG lasers also require the use of high levels of energy, which poses a significant risk of damage to surrounding ocular tissue, as well as of side effects such as cataract and intraocular pressure (IOP) spike. As a result, Laser Floater Treatment is not widely practiced and is performed only by a small number of specialists.
The following guidelines have been provided to help ophthalmologists new to Laser Floater Treatment better understand the procedure and are provided for information purposes only. It is the operating physician’s responsibility to familiarize themselves with the latest recommended techniques.
- Laser Floater Treatment is well suited to the Weiss-ring type of vitreous strand/opacity caused by a PVD. Because these vitreous strands/opacities are fibrous, they absorb the laser energy well and can be vaporized more efficiently. In addition, they are usually located safely away from the crystalline lens and the retina.
- Do not attempt to treat the diffuse, cloud-like syneresis type of vitreous strand/opacity, which is much more difficult to visualize and to treat effectively. Treatment of these strands/opacities should be undertaken only once sufficient experience with Laser Floater Treatment has been gained.
- Because the laser energy used in Laser Floater Treatment has to pass through more optical media than during capsulotomy treatment, more energy will typically be required to perform the procedure as compared to standard YAG laser procedures. Regardless, always start with a lower level of energy and titrate upwards until there is adequate optical breakdown and vaporization of the vitreous collagen.
- Commence treatment with a single pulse per shot. Set energy at the minimum level required to create the optical breakdown in the vitreous cavity (typically 3-4 mJ). Most treatments can be performed at approx. 5 mJ per shot. It is not uncommon, however, for surgeons to use higher energy levels of approx. 8-10 mJ. It is important to note that you should titrate the power up, however, rather than starting at the higher energy levels. More energy will be required if the floater is located deep in the posterior vitreous. For example, the same floater may be vaporized at 4 mJ in the anterior vitreous, at 5 mJ in the mid-vitreous and 6 mJ in the posterior vitreous.
- The number of shots required will vary depending on the type of floater to be treated. For physicians new to the technique, it is recommended to limit the number of shots per treatment session to a maximum of 300-400 shots, single pulse (Note: refer to pulse counter on laser remote display). You can always bring the patient back for a follow-up treatment session.
- There is no limit to the maximum energy or number of shots, but most physicians limit each procedure to a maximum of 1000 shots. This is largely due to the fact that, after a significant number of shots, gas bubbles can build up and make visualization more difficult.
- It is important to note that there is a non-linear relationship between the increased dispersion of energy in the eye and energy setting on the laser. In other words, increasing the energy from 5 mJ to 10 mJ does not double the amount of dispersed energy; instead, it represents an approx. 40% increase. This non-liner relationship is what allows for increased energy settings to be used during Laser Floater Treatment.
- It is important to maintain an adequate distance of more than 3-4mm from the lens and more than 3-4 mm from the retina. This is referred to as the 'safe zone'. (Note: When starting out, consider observing a wider margin of safety and treat only in the central third of the vitreous and always avoid the direction of the macula.)
- If the aiming beam is not clearly in focus, avoid firing. If in doubt, focus on the vitreous strand/opacity and pull back the joystick slightly: this will enable you to clearly visualize the two aiming beams before refocusing them to one spot.
- When the system is in on-axis mode, the red glow of the fundus can make it difficult to visualize the aiming beams. If you are confident that you are not near any structures i.e. retina is not in focus, it is ok to fire on the floater after you have gained more experience. You can also place the system in off-axis mode to reduce the amount of the red glow to allow for increased contrast, which can help to visualize the aiming beams and the floaters.
- The vitreous strand/opacity may be seen to move or become mobile during Laser Floater Treatment due to the shock wave introduced with each shot fired. When firing directly at a mobile floater, always wait for it to settle into position before continuing with treatment. This avoids unnecessary energy delivery into the eye.
- In the presence of multiple floaters, commence treatment anteriorly and proceed inwards. This will enable you to first remove those vitreous floaters that may impede your vision of the posterior structures. Likewise, try and treat from the top down as gas bubbles may impede vision of higher floaters if the lower ones are treated first. Although, it is important to treat the floaters that are easiest to see first.
- If the floater is over the macula and the retina is also in focus, do not fire. If you are not sure of the distance between the floater and retina, move the eye up and down to try and move the floater to a different position.
- Moving the eye up and down, or left and right, can also be a very useful tool to help move hard to reach floaters into a more easily treatable position. If the floater is too far in the periphery of the contact lens, the laser energy will not achieve the necessary therapeutic effect.
- Singh MidVitreous Lens (Volk)
- Ocular Karickhoff 21mm Vitreous Lens (Ocular Instruments)
- Ocular Karickhoff Off-Axis Vitreous Lens (Ocular Instruments)
- Ocular Peyman Wide Gield YAG Laser Lens (Ocular Instruments)
- CGVL Vitrectomy Contact Lens (Haag Streit)
- CGPL Capsulotmy Contact Lens (Haag Streit)