A non-invasive and cost-effective laser treatment is beneficial for patients with sight loss as a result of diabetes, a study has found.

The research, funded by the National Institute for Health and Care Research (NIHR) and published in Ophthalmology, found that subthreshold micropulse laser, which does not create a burn on the retina, was effective in maintaining the vision of patients with Diabetic Macular Oedema (DMO). 

DMO is the most common sight-threatening complication of diabetes, affecting more than 29 million adults. It happens when blood vessels in the retina at the back of the eye leak, causing fluid build-up at the macula, which provides central vision. The leakage occurs when high blood sugar levels damage blood vessels. 

The current treatment for people with DMO is either one of two types of laser treatment or eye injections. The type of treatment offered is usually determined by the thickness of the macula.

Patients with more severe DMO (with thickness of 400 microns or more) are treated with injections into the eye of drugs, known as anti-VEGFs.

Those with mild DMO (with thickness of less than 400 microns) can be treated with macular lase, either standard threshold laser or subthreshold micropulse laser. The former produces a burn or scar on the retina. The latter leaves no burn or scar or any type of visible change or mark on the retina. 

Professor Noemi Lois, clinical professor of ophthalmology at Queens University and honorary consultant vitreoretinal surgeon at the Belfast Health and Social Care Trust and lead author on the study, said that the absence of a scar or burn following subthreshold micropulse laser led to some healthcare professionals to doubt its effectiveness compared to the standard threshold laser.

'However, our research addressed this by demonstrating that subthreshold micropulse laser is as good as standard threshold laser for helping people’s vision, reducing macula thickness, allowing people to meet driving standards, and maintaining their quality of life, both in general terms and for vision in particular.'

The research involved 266 patients across 16 NHS hospitals around the UK, with half receiving standard threshold laser and the other half receiving subthreshold micropulse laser. Patients were involved in selecting the outcomes, including how driving standards would be met following treatment. At the end of the two-year trial, both laser treatments were found to offer equivalent benefits. 

Over the two-year period, the cost per patient was just under £900 (£897.83) for patients in the subthreshold micropulse laser arm of the trial compared to £1125.66 for those in the standard laser arm.  

Professor Lois said: 'Some ophthalmologists advise patients with milder forms of DMO to have injections of anti-VEGFs, rather than laser, despite laser being less invasive and requiring less visits to the clinic. Laser treatment costs significantly less than eye-injections of anti-VEGFs. With an average of ten injections required over two years, the total cost of eye injections per patient amounts to approximately £8,500 for the drug alone. This is almost ten times the cost of subthreshold micopulse laser without taking into account additional costings such as staff time. 

She added that prior to the NIHR-funded study, there was no robust evidence comparing the two types of laser treatments, resulting in some healthcare professionals favouring standard laser over subthreshold micropulse laser.

'We now have robust evidence to show that both laser treatments are not only effective in clearing the fluid from the retina and maintaining vision for at least two years, but both are also cost-effective.'

'Armed with this knowledge, it’s likely that patients will opt for micropulse subthreshold laser, which doesn’t burn the retina and is comparable to standard laser.'

The laser treatments were not directly compared to eye injections of anti-VEGFs, but Professor Lois hoped that laser had been shown to be an effective treatment 'while remaining much less invasive to the patient and much less costly to the NHS'.

This comes after data showed earlier this month that more than a tenth of the money spent on prescriptions items in England in 2021/22 was for drugs used in treating diabetes, with diabetes drug prescriptions rising overall.