RETINOPATHY

[caption id='attachment_5287' align='alignright' width='200'] Anat Loewenstein MD[/caption]

Although new pharmacologic approaches have undoubtedly improved the treatment of diabetic retinopathy, there is still a need for surgery in diabetic retinopathy, Anat Loewenstein MD, told the 12th EURETINA congress. Dr Loewenstein, chairman of the Department of Ophthalmology, Tel Aviv Sourasky Medical Center, listed eight clearcut indications for vitrectomy. These were primarily related to vitreous haemorrhage, retinal detachment and fibrovascular proliferation.

Despite the encouraging results of the RISE, RIDE and BOLT trials, which support the use of anti-VEGFs for diabetic macular oedema, there are still many situations in which surgery remains the primary treatment modality, said Dr Loewenstein. “This is because of the limitations of anti-VEGF treatment. Macular hypoxia is not alleviated with anti-VEGF and treatment requires multiple injections over extended periods.†In contrast, the theoretical benefits of vitrectomy on diabetic macular oedema include relief of vitreomacular traction and retinal vasoconstriction associated with increased oxygen supply from the ciliary body.

Dr Loewenstein also highlighted the role of posterior vitreous detachment (PVD). She cited considerable research showing that diabetic patients with PVD are less likely to develop macular oedema. Spontaneous resolution of the oedema was seen in 55 per cent of eyes with vitreomacular separation compared with 25 per cent of eyes with vitreomacular adhesion. Thus, Dr Loewenstein argued that there is still an important role for diabetic vitrectomy, especially considering the ongoing advances in vitreoretinal surgical instrumentation and technique. She made the case for vitrectomy in cases of DME that are unresponsive to pharmacological treatment. This applied even in cases with no vitreomacular traction present.

“Some patients are unwilling or unable to undergo multiple anti-VEGF or steroid injections,†she added. An interesting question was raised by a delegate. “What about the problem of persisting macular oedema even after vitrectomy? Without a vitreous to slow clearance of drugs out of the posterior chamber, aren’t we then left with no options besides laser?†Dr Loewenstein replied that a slowrelease steroid such as Ozurdex (Allergan) or Illuvien (Alimera Sciences) might be useful in such a situation. In a related presentation Ramin Tadayoni MD, Lariboisiere University Hospital, Paris, discussed the border between pharmacology and surgery in the treatment of diabetic retinopathy. “This is a highly indistinct border. For example, slow-release drugs implanted in the vitreous: is this surgery or pharmacology? And pre-surgery treatment with anti-VEGF: does this represent two different modalities, or is the pre-treatment actually part of the operation?â€

Experience of surgeon

Dr Tadayoni also cited the example of microplasmin, which is a drug that is used to achieve a surgical result, namely the separation of the vitreous from the retina. In the end, the main dividing line is the skills-based difference between pharmacology and surgery. The success of surgery is highly dependent on the skills and experience of the surgeon, said Dr Tadayoni, whereas prescribing and injecting anti-VEGF is relatively straightforward. “But,†Dr Tadayoni added, “with the introduction of more and more ‘surgical drugs’ like r-tPA, enzymatic vitreolytics and anti-PVR antibodies, the dividing line between surgery and pharmacology will continue to blur.â€Â