Lasers and the Treatment of Glaucoma
Blog vol 5.36. Lasers and the Treatment of Glaucoma.
For the next two months, I will be mainly preoccupied with lasers and glaucoma. I am in the throes of a course from Waterloo on this topic. I must keep quiet about the course material so this information is only what is publicly available online in industry journals and websites (signed a nondisclosure, sorry). These are the latest trends in the field.
The latest in selective laser trabeculoplasty (SLT) comes from Alcon. They have purchased the rights to a new way to apply the laser, called Direct SLT. The unit delivering the laser is called the Voyager. In July 2024, Alcon purchased Belkin Vision, a glaucoma surgery company from Israel, and in the fall of this past year introduced the Voyager at the American Academy of Ophthalmology annual meetings.
The Voyager is a Q-switched (pulsed), 532 nanometre-wavelength, frequency-doubled. neodymium-doped yttrium aluminum garnet (Nd:YAG) laser device. Try saying that ten times quickly! The neodymium ions act as a laser gain medium and the ions are “pumped” into excitation from an external source. The pulsing increases in energy and allows great control with phasing, generating 250 megawatts of energy at a pulse duration of 10-to 25 nanoseconds. A lot of controlled energy in a very short burst. Usually the wavelength is at 1064 nanometres but the frequency doubling halves it to 532 nm. LOTS of energy, PRECISELY directed, for NANOSECONDS.
This type of laser has been used for many surgical procedures in the eye, the mouth, and throughout the body. So nothing new here. We know from the Light I and Light II studies that conventional SLT is the new recommended first treatment in primary open angle glaucoma. This is still in its early stages. It takes time to make changes. To perform SLT with the current technology, you need to be an ophthalmologist who is skilled with the mirrored gonisoscopy lens and with a slit lamp. It requires skill and time. The Voyager is Direct SLT and will change that, as it requires no physical contact with the patient, no gonioscopy lens, and the device has an eye tracker that lines up the eye and keeps it lined up during movements to apply the focused energy through the cornea to the trabeculae. Much less skill required. This device needs to be approved for use in Canada as a first step.
From the patient’s point of view, the use of SLT early on in glaucoma should prevent the need for regular eye drops, the standard treatment currently. The prognosis is similar, the treatment much less cumbersome. If SLT could be done with the new machine, i.e. Direct SLT, it could be made more readily available as it would not need to be done by an ophthalmologist.
Once again, exciting times in the Eye Care industry (right up there with an excited Neodymium ion),
The good doctor
