BLOG: DIAMONDS trial: MicroPulse equivalent to continuous-wave laser therapy
Key takeaways:
- A study found subthreshold MicroPulse laser therapy for diabetic macular edema was equivalent to continuous-wave laser therapy.
- The procedure is safe, effective, low cost and easy to teach.
Caesar Luo, MD, FACS, FASRS
Dr. Noemi Lois is a clinical professor at Queen’s University Belfast and a consultant ophthalmologist and vitreoretinal surgeon at the Belfast Health and Social Care Trust in Northern Ireland.
Dr. Lois has been leading a program of research on diabetic retinopathy and its complications for the past 10 years, and she returns here as a guest author to discuss the implications of the recent DIAMONDS clinical trial.
Noemi Lois, MD, PhD, FRCS(Ed), FRCOphth
The Diabetic Macular Oedema and Diode Subthreshold Micropulse Laser (DIAMONDS) clinical trial, which I presented in my previous post, found subthreshold MicroPulse laser therapy (SML) to have equivalent efficacy and cost to continuous-wave laser therapy (CWL)*, suggesting that either treatment could be offered to patients with center-involved diabetic macular edema of less than 400 µm suitable for macular laser. DIAMONDS was powered not only for noninferiority but also for equivalence, and it showed SML is indeed equivalent to CWL.
As I discussed in the post, there had been some skepticism because SML did not leave visible retinal changes. MicroPulse subthreshold laser treatment does not burn the retina. It preserves photoreceptors, retinal pigment epithelium and neurosensory retina.
In my opinion, given the equivalent efficacy of SML and CWL, and the fact that SML does not produce structural alterations in the retina, patients are likely to choose SML. In discussions with people living with diabetes that took place following DIAMONDS, the preservation of retinal tissue was found to be considered very important to patients. People prefer a treatment that would cause no damage. They wanted to preserve the health of their retina over the course of their life.
People living with diabetes also said they preferred fewer visits to the clinic, which is an advantage SML has over anti-VEGF injections. SML is not a painful procedure and does not carry risk of infection. Patients can be dilated with a short-acting drop, and they are not uncomfortable after treatment. They can get right back to normal life.
SML provides an effective means to treat DME early, and such intervention is vital to catch patients before they require costly long-term intravitreal injections.
Meeting a growing need
Studies have shown treating the fovea with SML is even possible with no evidence of damage, which makes the procedure easy and safe to perform. This is a great benefit when treating DME because when treating patients with edema, the center of the macula (fovea) can be difficult to recognize due to the presence of fluid. The lack of damage caused by SML makes patient movement and compliance during treatment less critical.
This lowered treatment risk of SML is an advantage when training health care professionals to perform the procedure. It should make the procedure easier to teach to junior ophthalmologists and general ophthalmologists.
The number of adults with diabetes and clinically significant macular edema is projected to rise from an estimated 18.83 million globally in 2020 to 28.61 million by 2045. As this will further increase the currently already high need for care in the developed and developing world, a procedure that is safe, effective, low cost and easy to teach offers an important opportunity.
* In DIAMONDS, continuous-wave threshold laser therapy (CWL) is referred to as standard laser (SL).
References:
- Lois N, et al. Ophthalmology. 2023;doi:10.1016/j.ophtha.2022.08.012.
- Luttrull JK, et al. Retina. 2014;doi:10.1097/IAE.0000000000000177.
- Varma R, et al. JAMA Ophthalmol. 2014;doi:10.1001/jamaophthalmol.2014.2854.
- Vujosevic S, et al. Retina. 2015;doi:10.1097/IAE.0000000000000521.
- Wells-Gray EM, et al. Ophthalmic Surg Lasers Imaging Retina. 2018;doi:10.3928/23258160-20181203-07.
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