Repeated low-level red light therapy in the clinic: Q&A with Song Chow, Jagrut Lallu and Simon Rose

Song Chow: I describe repeated low-level red light (RLRL) therapy as an innovative myopia control technique, complementing established methods such as peripheral defocus spectacles, contact lenses, atropine, and orthokeratology. This user-friendly approach involves a straightforward at-home device, necessitating brief 3-minute sessions twice a day with a minimum 4-hour gap, totaling 5 sessions per week.¹ Centered around the use of harmless long-wavelength red light, this regimen aims to fortify the retina, mitigating potential complications associated with uncontrolled elongation of the eyeball. Its simplicity promotes easy adherence, making it an accessible and promising addition to the array of myopic control strategies. This proactive approach offers a convenient means of safeguarding eye health for both patients and their parents.

Jagrut Lallu: As of now, we have a total of 25 patients either currently enrolled or in progress with RLRL treatment. Thus far, treatment tolerance has not posed any challenges, and the safety profile appears robust. Notably, we have not encountered any side effects, and all patients have demonstrated excellent tolerance to the RLRL device.

An intriguing observation is the apparent thickening of the choroid and a notable reduction in axial length, also noted in previous research. Approximately one-third of this is explained by the choroidal thickness change.^1-3 We utilize measurement devices such as the Nidek AL scan and Zeiss IOL Master for length measurements, and retinal scans are performed using the Heidelberg Spectralis.

 To further ensure safety, patients are instructed to promptly report any instances where an afterimage lasts longer than 5 minutes. I am pleased to note that, to date, there have been no occurrences of prolonged afterimages.

 It's worth mentioning that the patients prescribed RLRL treatment represent diverse ethnic backgrounds, including Caucasian, Indian, and Chinese. This diversity adds an extra layer to our understanding of the treatment's effectiveness across different demographics.

SImon Rose: Absolutely. When discussing with parents regarding the RLRL treatment protocol, I consistently find three key concerns they often ask:

• How does it work? In addressing this query, I clarify that the red light employed in the treatment stimulates increased blood flow in the back of the eye, specifically in the choroid region. This stimulation promotes an augmentation in the thickness of the choroidal tissue, leading to a strengthening effect on the sclera, the outer part of the eye.
• What happens when we (the patient) go on holiday? In response to this question, I reassure parents that there's no need for undue concern, as long as the holiday period does not exceed four weeks. Additionally, I recommend taking the machine along if the trip extends beyond this duration.
• How long will we have to use the machine in total? Addressing this concern, I delve into a discussion about the child's age, current prescription, axial length, and the likely point at which progress may slow down, allowing for discontinuation. I consistently emphasize a minimum usage duration of two years as a general guideline - this is the extent of current research.⁴

Song Chow: In prescribing Red Light Retinal Therapy (RLRL), rigorous selection criteria are employed for optimal patient safety and efficacy. Ideal candidates fall within the age range of 7 to 16 years, exhibiting rapid myopic progression and axial elongation. RLRL is particularly considered for those who have allergies to traditional myopic control drugs or contact lens solutions, and for individuals experiencing uncontrolled progression with other myopic control methods. However, caution is exercised in cases of pre-existing macular conditions, glaucoma, cataracts, congenital pigmentary diseases, and color vision defects, where RLRL is contraindicated due to potential complications. Additionally, young patients who may not fully comprehend the effects of afterimages may be excluded from RLRL therapy. These stringent criteria ensure that RLRL is administered with precision, addressing specific patient needs while prioritizing safety and treatment efficacy in the context of myopic control.

Jagrut Lallu: When deciding on monotherapy or combination therapy, we take into account various factors that guide our decision-making process. These factors include:

• Axial length based on age and ethnicity: If there is a growth of greater than 0.1mm in twelve months or a significant increase in a shorter period, we consider the option of combination therapy.
• Myopia level for age: In cases where axial length information is not available, we assess the myopia level for age to inform our decision.
• Our goal as a clinic: Our clinic's objective has evolved from merely slowing down myopia progression to achieving full control. We aim for minimal change, ideally less than 0.1mm per year. This brings eye growth in a myopic child at least in line with that which would be observed for an emmetropic child.⁵ 

At the moment, we have prescribed the RLRL device to various patient groups, employing both monotherapy and combination therapy approaches. As a monotherapy, that would look like RLRL and single vision distance lenses to correct vision – although our approach is not to prescribe single vision to progressing myopes, this was how it was prescribed in the studies.^1-3 Since we have myopia controlling spectacle lens designs available, we preference prescribing of these. Combinations we have used have been with MiYOSMART, orthokeratology and MiSight 1 day along with RLRL. 

Simon Rose: At follow-up appointments for patients prescribed RLRL, I adhere to the established clinical protocols outlined in the training manual. The follow-up process I adhere to is:

• Baseline Assessment: This would include visual acuity, baseline axial length measurements, and high-resolution optical coherence tomography (OCT) macula scans, including Auto Angio.
• One-month follow-up: I would reassess VA, OCT. This time, an especially noteworthy  consideration is afterimage recovery duration, as prolonged recovery can be a negative indicator of potential side effects. A meticulous check of compliance is also conducted, involving both the parent and child. This includes ensuring stability during the examination and verifying that the platform is accessible to the parent. Additionally, a push notification system is employed to remind parents and ensure ongoing compliance.
• Six-month follow-up: Similar to the one-month check, I reassess VAs, OCT images and afterimage duration. Additionally, I perform refraction check, and axial length plotting is conducted via Tiedman Curves.
• Subsequent six-monthly follow-ups: consistent with the six-month evaluation (as above), with continued monitoring of key parameters.

This comprehensive follow-up approach ensures thorough assessments and ongoing compliance monitoring throughout the treatment process.