Lasers in ophthalmology have recently celebrated their golden anniversary — and despite advancements in surgical techniques and intravitreal agents, lasers still firmly hold their seats at the table. So, how did laser manage to remain part of standard care for so long? The short answer: It is effective.
It can be difficult to narrow down the coolest part about being a retina specialist. Preventing blindness is, of course, the best, and having a toolbox that includes an array of surgical options and multiple avenues for drug delivery is awesome, too. Not to mention, “Oh, by the way, I use lasers!” is actually also a pretty impressive dinner party conversation starter.
Ophthalmologists have been using lasers for more than half a century now. And as our understanding of laser technology and the pathophysiology of retinopathies grows, laser is now less of a ‘turn and burn’ and more focused on safer, less intense stimulation of cells to restore function.
Laser applications have advanced and evolved over the decades to address the collateral damage to surrounding retinal anatomy and other side effects. Changes have included shorter wavelength lasers, smaller spot sizes, shorter (micro) pulse duration and intensity, and the option of focal versus grid pattern technology.
The evolution of laser technology
We had the opportunity to ask two prominent retina specialists to weigh in on how they have seen laser technology and its application evolve throughout their careers.
Dr. Jay Chhablani is a professor of ophthalmology and a vitreoretinal specialist at the University of Pittsburgh Eye Center, Pittsburgh, USA. Meanwhile, Dr. Igor Kozak is a vitreoretinal specialist and chief of retina service at Moorfields UAE in Abu Dhabi.
“There has been a tremendous amount of evolution in retinal laser technology — most importantly, the experimental and clinical work on sublethal and non-damaging approaches that include both subthreshold and micropulse laser techniques,” shared Dr. Kozak.
These approaches address the collateral damage of older laser versions and apply our greater understanding of retinal diseases. “These provide therapeutic effects without causing tissue damage, which is characteristic of the classic threshold approach. In those, a thermal scar is produced in the tissue, and that was believed to convey a therapeutic effect. We know now that this may not be true even though the pathophysiology of many retinal diseases is not fully understood,” he noted. “Another evolvement includes retinal laser delivery, which encompasses splitting and thus shortening of the laser beam in pattern treatments and eye-tracking in retinal navigation technology.”
Dr. Chhablani couldn’t agree more, as he has witnessed similar progression and significant changes in retinal laser applications since his fellowship in 2007.
“It has gone from a single spot to multi-spot laser, and the newer systems with features such as eye tracking, computer-based laser planning, and visualization systems. Damage to the retina has been significantly reduced,” he enthused. “Now we are using very efficient peripheral laser and subthreshold laser.”
The benefits of laser therapy
We also asked our experts to explain the benefits of laser therapy in the management of current retinal disorders. Dr. Kozak noted that he no longer uses a classic threshold laser photocoagulation, especially when treating the posterior pole disease due to its untoward effects.
“Instead, for the last decade, I have been using both retinal subthreshold pattern and micropulse treatments, which are much safer,” he shared. “The idea with these is to stimulate retinal pigment epithelial cells to resume their function, the lack of which is many times the cause of retinovascular diseases resulting in macular edema. The treatment effect may take longer and is more difficult to measure objectively. Traditionally, physicians look at optical coherence tomography (OCT) fluid and use it as a measure of treatment outcome. With sublethal techniques, the fluid resolution may take longer. But it has been observed that the retinal function restores much quicker. This can be measured by visual acuity, color vision, or contrast sensitivity — the latter are not routinely used in clinical practice,” Dr. Kozak explained.
Although color vision or contrast sensitivity may be less commonly assessed in the day-to-day clinic, when combined with improvement in visual acuity, these are the outcomes that are noticeable and valuable to patients.
Where do lasers fit in the treatment paradigm?
For decades, lasers dominated the standard of care for many retinal disorders, but as intravitreal agents were introduced, they were soon adopted as the standard and a more conservative management strategy.
“Lasers are still very useful in many diseases,” shared Dr. Chhablani. “For example, for central serous chorioretinopathy — for which we are doing subthreshold laser — quite often.”
He added that laser is useful for treating diabetic retina, particularly in the non-responder cases of DME. “As for peripheral laser, panretinal photocoagulation (PRP) still holds a very good position in the management strategy, as well as for proliferative retinopathy, such as neovascularization associated with branch retinal vein occlusion (BRVO), neovascular glaucoma, and sickle cell retinopathy. There are many conditions where we continue to use laser,” he added.
However, despite the cool factor of using laser and its decade-long reputation as the workhorse of the retina, the popularity of intravitreal injection therapy cannot be denied — perhaps fueled by well-funded marketing teams and a media frenzy that now surrounds reported clinical trial data.
The truth behind the shift of attention away from laser therapy
We wanted to know how the role of laser is currently acknowledged in clinical practice. Dr. Kozak doesn’t think we should be counting out laser anytime soon and shared his insights.
“The shift of attention away from laser to drug therapy has had a great impact on both basic research and clinical practice,” he said. “The lack of research funding and support for laser treatment has created the impression that retinal laser treatment is therapeutically inferior and is thus no longer relevant in the drug era — despite ample evidence to the contrary. Such evidence gets little attention because retinal laser treatment does not produce revenue for the companies that sponsor over 95% of all clinical trials in medicine and ophthalmology alike and support numerous practitioner investigators via clinical trials, all major ophthalmic journals, and professional societies,” he affirmed.
Looking at the real-world data, Dr. Kozak added: “Data for retinal laser treatment since the 1980s has relied on small clinical trials, retrospective studies, and real-world data studies that can be done at a far lower cost than large, randomized trials. The neglect of laser treatment is not because it is not useful or of no further scientific interest. Studies show that even conventional retinal photocoagulation remains indispensable even in the drug era and thus in wide use,” he continued.
Another key example has been shown in the treatment of retinopathy of prematurity, where laser photocoagulation has been a mainstay of treatment for decades, with a recent shift toward intravitreal anti-VEGF agents.
Although visual outcomes have been promising and intravitreal treatment is more easily accessible in some regions, some studies have shown that the number of treatments and recurrence rates are higher with anti-VEGF therapies. Additionally, laser therapy in these infants does not incur the same concerns associated with antiangiogenic therapy in a developing infant.
Where laser therapy steps in
Dr. Chhablani shares a similar perspective: “The rise in popularity of so many intravitreal therapies has definitely attempted to push laser to the back seat. However, I still feel that laser plays an important role — particularly for things like central serous chorioretinopathy, where we can deliver subthreshold laser without causing any damage, especially when PDT is not available,” he said.
Dr. Chhablani noted that intravitreal therapy cannot be used for all retinal diseases, and many patients remain inadequate or non-responder. “Subthreshold laser is playing a very important role in CSC and other diseases where we cannot do intravitreal therapy or when intravitreal therapy alone is not sufficient,” he enthused.
As an example, he continued: “Many advanced proliferative, diabetic retinopathy patients and other proliferative retinal diseases benefit from laser therapy. It also plays a valuable role for the treatment of diabetic macular edema and macular edema associated with venous occlusions. For many conditions, we tend to use laser as an adjunct therapy — so laser is not going anywhere. It will remain there, along with intravitreal injections.”
A trusted, long-lasting treatment
As Dr. Kozak noted, meetings and journals are filled with presentations of drug-centered trial data, enticing clinicians with the promise of improved outcomes.
Dr. Kozak recognizes the lure of new treatments but does not forget our old faithfuls. “The treatment indications for laser therapy are clear, however, it is always tempting to try novel therapies and approaches,” he shared. “For that reason, the armamentarium is wide and includes intravitreal pharmacotherapy, systemic treatment, or even topical/local treatments for some. Many of these have failed due to not reaching sufficient therapeutic levels in the target tissue and thus the practitioners have returned to laser treatments to treat such conditions. Another classical example is non-compliance with new medications and returns to laser being a trusted, long-lasting treatment.”
Dr. Chhablani shared similar circumstances where laser remains the best treatment of choice, despite the approval of intravitreal therapy. “There are patients who are not compliant with regular intravitreal therapy for many reasons. They may simply do not remember their appointments, there may also be insurance coverage challenges, or those that cannot manage the financial burden,” he explained. “As well, many of these patients also have systemic diseases, which means multiple specialist appointments, and transportation or arranging for family members to bring them is difficult. When we recognize these challenges in our patients, where intravitreal therapies cannot be provided on a monthly basis, consistently, we tend to offer more long-term treatment options, such as laser.”
He shared other common examples: “Proliferative diabetic retinopathy and diabetic macular edema, as well as venous occlusions.”
Often the first-line therapy
Finally, we wanted to know where laser fits in the vitreoretinal toolbox today. As Dr. Chhablani previously noted, “For central serous chorioretinopathy, laser is certainly the first-line treatment. We do focal, conventional laser treatment, as well as subthreshold laser and PDT.”
Laser also has a stronghold in the management of the diabetic retina, as Dr. Chhablani shared: “For me, if I see an eye with proliferative diabetic retinopathy, first-line treatment is still a laser, panretinal photocoagulation. As well, if I see any neovascularization or other proliferative diseases, I would do laser as first-line.”
Similarly, Dr. Kozak shared that laser is still very much part of his treatment toolbox, often in a synergistic way. “While the first-line therapy for the majority of central retinovascular diseases is anti-angiogenic therapy, a large portion of primary non-responders will have laser supplementation,” he said. “This is done exclusively using sublethal approaches even if they need to be repeated. Such approaches are non-damaging and often act synergistically with other therapies. I then carefully assess functional outcome, which influences my follow-up and retreatment if needed.”
“Where the injections are not doing a great job, or we cannot afford to give injections or we are not able to do injections every month — in those situations, laser fits into a second line and as a combination of treatments,” shared Dr. Chhablani. “As well, for treatment-resistant retinal conditions, we tend to use laser as part of combination therapy, including peripheral ischemia for venous occlusions or even peripheral ischemia for diabetic macular edema.”
Dr. Kozak described the value of threshold laser for peripheral retinal diseases: “Such as sealing retinal breaks or holes or ablating ischemic areas of the retina that would produce secondary damage to the eye. Similarly, during retinal surgery, I use endolaser to address the pathology leading to conditions such as retinal detachment or severe diabetic retinopathy,” he concluded.
Editor’s Note: A version of this article was first published in PIE Magazine Issue 26.