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Fluorescent OVD safely simplifies surgery
Without sacrificing transparency, a small amount of fluorescein makes the OVD visible at the stage of removal.
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A colored but transparent ophthalmic viscosurgical device makes cataract surgery easier and safer, ensuring that no residuals of the substance are left in the eye at the end of the procedure, according to one surgeon.
Complete removal of the OVD is necessary but not easy to accomplish with the standard transparent OVDs currently used.
“You have a transparent OVD inside a transparent medium, and even if you do your irrigation and aspiration diligently, you never know if you have left residuals inside the eye. This easily happens in the angle, clogging up drainage into the trabecular meshwork and potentially causing an IOP increase in the hours following the procedure,” Alain Telandro, MD, told Ocular Surgery News.
Another zone where residuals of OVD are easily trapped is between the bag and the lens. This obstructs the natural aqueous humor flow, prolonging the residence time of bacteria and ultimately leading to infection.
Telandro learned to overcome this problem by coloring the OVD with a tiny amount of preservative-free fluorescein.
“In these very small quantities, fluorescein does not alter the transparency of the substance but still reacts to blue light. When the lens is in the bag, I change the filter in the operating microscope and then I can see the OVD and be sure I remove it completely. This also means that the washing of the anterior chamber lasts for exactly the time that’s needed because I see precisely when even the smallest residuals have gone and stop at that point,” he said.
Safe in the eye
Compared with the concentration of fluorescein used intravenously for angiography, which is normally between 10% and 25%, the concentration used for this purpose is negligible, approximately 0.005%. It is fully absorbed by the OVD and therefore thoroughly removed with the OVD.
“It does not stain the eye tissues or the [balanced salt solution] because the fluorescein molecules are fixed to the OVD. Nothing remains in the eye after OVD removal,” Telandro said.
For the same reason, this amount of dye is safe. In 6 years, with approximately 3,000 cataract patients operated using this method, no side effects were reported. In addition, fluorescein is not a pharmaceutical agent and has no chemical effect on the tissues.
“When I insert the blue filter, I slightly increase light intensity to compensate for the loss of brightness. The fluorescence is so evident that you see exactly what is happening. It is very clear also on the video, and you have full control of your maneuvers,” Telandro said.
There is no learning curve for this technique, and from the first procedure surgeons can observe the advantages of better visualization.
“I use it also with femtosecond laser-assisted surgery, which I perform with the Victus platform (Bausch + Lomb). Colleagues who have come to visit me to learn the femtosecond procedure showed to be more interested in the fluorescence technique than in the rest of the surgery,” he said.
Significant benefits
There are significant benefits for the eye in performing a procedure with complete and efficient removal of the OVD. Telandro performs cataract surgery bilaterally in the same session, and in a series of patients, for study purposes, he used the fluorescein-stained OVD only in one eye. Both eyes were operated by the same surgeon, using the same technique and a new set of single-use instruments.
“A significantly lesser increase in intraocular pressure after surgery was observed in the eye operated with the fluorescent OVD, as well as less inflammation and less edema. You can greatly reduce the classical complications of cataract surgery,” Telandro said.
Endothelial cell count was also higher in those eyes because of better controlled maneuvers and reduced trauma.
“If you enter the eye knowing exactly what you are doing rather than flying blind, you reduce the time and reduce the trauma. This means that the patient’s recovery is faster. We have a lot of patients who have simultaneous bilateral surgery, and 70% to 80% of them can read without glasses and drive already when they come for their day 1 visit. I operated on my brother, and 4 hours after surgery he was able to send emails on his mobile phone,” Telandro said.
Soon on the market
Telandro said that the use of fluorescein has taught him a lot. It has shown how difficult it is to remove OVDs completely when there is no way to see them. Fluorescence enabled him to see OVD remnants trapped behind the IOL optic, behind the iris and in the angle, and stuck to the base of the angle even after that area had been specifically addressed.
To explore the potential of fluorescent liquids, he performed several cataract surgery procedures with two drops of preservative-free fluorescein in the 2 cc balanced salt solution syringe he used for hydrodissection to enhance visualization and fluid control during these maneuvers.
“I discovered in this way that even with a perfectly intact capsule, the liquid filters through the capsular bag into the vitreous almost immediately. The dye was quite revealing of how easily and fast infections can spread within the eye,” he said.
Fluorescent OVDs will soon be available on the market with the brand name of Fluon, produced by British company OVD Development.
“Fluon products should obtain the CE mark and be launched on the market before the end of 2018,” Telandro said. “Meanwhile, distribution network will shortly after cover Europe, Middle East, South America and Southeast Asia. FDA clearance will be the next step.”
There are five types of Fluon OVD in the pipeline, cohesive and dispersive, with different molecular weights in prefilled syringes.
“Fluorescent OVDs are a simple solution that works, and I believe they will be largely adopted by cataract surgeons,” Telandro said. “They will be particularly useful in femtosecond-assisted procedures, where a very stable OVD is needed and, for this characteristic, is also very difficult to remove.” – by Michela Cimberle
- For more information:
- Alain Telandro, MD, can be reached at 69-71 Avenue Roi Albert, Résidence Saint Michel Valetta, 06400 Cannes, France; email: alain@telandro.fr.
Disclosure: Telandro reports he is a final beneficiary of the company OVD Development Ltd.