Application of subthreshold laser therapy in retinal diseases: a review

ABSTRACT

Introduction: Laser photocoagulation has been a valuable tool in the ophthalmologist’s armamentarium for decades. Conventional laser photocoagulation relies on visible retinal burns as a treatment end point, which is thought to result in photocoagulative necrosis of retinal tissue. Recent studies have suggested that using subthreshold (ST) laser, which does not cause detectable damage to the retina, may also have therapeutic effects in a variety of retinal diseases.Areas covered: We review the proposed biological mechanisms mediating the therapeutic effects of ST laser on the retina, followed by the evidence for ST laser efficacy in retinal diseases such as diabetic macular edema (DME), central serous chorioretinopathy, age-related macular degeneration, and retinal vein occlusion.

Expert commentary: Multiple clinical studies demonstrate that ST laser does not cause structural damage to the retina based on multimodal imaging. Evidence suggests that there is a therapeutic effect on decreasing DME and subretinal fluid in chronic central serous retinopathy; however, the effect may be relatively modest and is not as efficacious as first-line treatments for these diseases. Given the repeatability and lack of damage to the retina by this treatment, ST laser deserves further study to determine its place in the retina specialist’s armamentarium.

KEYWORDS:

• subthreshold laser
• micropulse laser
• nanosecond laser
• duty cycle
• heat shock proteins
• diabetic macular edema
• photocoagulation

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

A reviewer on this manuscript has disclosed that they are a paid consultant for Iridex.

Additional information

Funding

Funding has been received in the form of a grant from the National Eye Institute [1K12EY024225-01A1].