Management of DME
Tight treatment schedule yields dividends in diabetic macular oedema
Sobha Sivaprasad FRCOphth.
Although anti-vascular endothelial growth factor (anti-VEGF) drugs remain the first-line agents of choice in the management of diabetic macular oedema (DME), corticosteroids may still play a role in patients where anti-VEGF is contraindicated, unavailable or unaffordable, according to Sobha Sivaprasad FRCOphth.
“We know that the visual outcome will not be as good as anti-VEGF when using steroids when all-comers are considered. As a second-line agent, steroids may potentially be used in combination with an anti-VEGF agent. Although steroid use has been recommended in pseudophakics who are non-responsive to anti-VEGF, the recent evidence from the Protocol U and T studies suggests that switching to combination therapy shows similar visual outcomes to continuing on anti-VEGF in non-responders despite a better macular drying effect with combination,” she told delegates attending the 19th EURETINA Congress in Paris.
In terms of reducing risk factors, Prof Sivaprasad said that it was vital for patients first of all to control their blood sugar, blood pressure and cholesterol levels. They should also carefully monitor their haemoglobin A1c levels, as evidence from the Protocol T and VISTA studies both suggest that high HA1c levels equates to poorer visual outcomes.
In centre-involving DME cases where there is no visual impairment, the best strategy is observation to start with, said Prof Sivaprasad. She advised that any of the approved anti-VEGF agents should be administered on a tight treatment schedule in cases of DME with mild visual impairment. For patients with visual acuity of 20/50 or worse aflibercept performs better in more severe cases.
For non centre-involving DME, the visual acuity in these patients is usually good and observation is normally sufficient, said Dr Sivaprasad. “If the vision is not good in these cases, however, it may be associated with other co-existing pathologies such as macular ischaemia,” she said. She said that based on the ETDRS study of approximately 30 years ago, the recommended approach today in the anti-VEGF era is observation if no clinically significant macular oedema (CSME) was present, with focal or grid laser treatment administered only if circinate CSME was detected.
This approach has evolved somewhat on the basis of the findings of the Protocol V study, noted Dr Sivaprasad.
She explained that this study tried to ascertain whether eyes with centre-involving DME and good visual acuity of 20/25 or better should be initiated using anti-VEGF, laser or observation. Patients in the laser and observation arm could be treated with aflibercept if the visual acuity decreased by 10 letters or more in one visit or five-to-nine letters in two consecutive visits.
“The results over two years showed that the proportion of patients with five letters’ loss or more after two years were very similar for all groups, and that observation did just as well as laser and aflibercept as the initiating option. When it comes to patients with moderate visual impairment due to DME, we know from Protocol T that with any anti VEGF agent we will gain on average about eight letters by the end of two years.
“If the visual acuity impairment is more significant, all three anti-VEGF agents work well, but aflibercept performed best, with a 15-letter gain at the end of one year,” she said.
A very tight treatment schedule needs to be followed for good visual acuity outcomes in DME cases, said Dr Sivaprasad.
“We need to follow the Protocol T treatment schedule, where we repeatedly inject the patients every four weeks until stabilisation is reached, and once stable we resume injections if the visual acuity or OCT worsens. We can apply focal or grid laser after 24 weeks only if persistent DME is not improving after at least two injections,” she said.
For proliferative diabetic retinopathy (PDR), panretinal photocoagulation remains the standard of care in 2019 despite some promising outcomes in the Protocol S and CLARITY studies with anti-VEGF agents, said Dr Sivaprasad.
“Anti-VEGF treatments may offer significant advantages in proliferative diabetic retinopathy but we need a good surveillance programme to be able to provide urgent therapy if there is recurrence or reactivation of new vessels. If we don’t treat this condition promptly, the consequences are disastrous,” she concluded.