Retina 2007 (page 4)
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Was the imaging & diagnostics sector stagnant in 2007?
When questioned about imaging and diagnostic equipment, Professor Augustin did not feel the sector witnessed any significant breakthrough specifically in 2007, although innovations in imaging equipment have undeniably allowed ophthalmologists to significantly improve their practice and patient outcomes in recent years.
Technological developments are yielding more advanced instruments that provide precise, accurate, and detailed three-dimensional, colour, digital images that can assist in all manner of an ophthalmologist's practice, from diagnosis to intra- and postoperative analysis.
"Without any doubt, I feel that the
most important development,
globally, in retina diagnosis, is the
use of Optical Coherence
Tomography (OCT)"
"Without any doubt, I feel that the most important development, globally, in retina diagnosis, is the use of Optical Coherence Tomography (OCT)," asserted Dr Mauget-Faysse. "Used in combination with visual acuity evaluation, fundus biomicroscopy and, when required, angiographies, OCT provides the most precise features that allow us to easily establish and confirm a diagnosis," she added.
She referred particularly to the newer, high-resolution OCT devices, which are now making their way to the market. "These devices are continuously being developed and improved and they are proving to be an invaluable tool in our everyday practice," Dr Mauget-Faysse said.
Dr Stefansson agreed, "Although it is difficult to say exactly when OCT began to make an impact in my surgery, it has certainly represented a great leap forward in diagnostics in recent years."
Professor Rizzo was particularly impressed by the combined Spectral OCT and Scanning Laser Ophthalmoscope system (OTI Ophthalmic Technologies). "I strongly believe that we need instruments that are able to combine the study of objective parameters, along with functional subjective parameters. In my opinion, this system fulfils these requirements," he said.
Dr Stefansson also referred to a non-invasive device that he is currently using in his clinic, specifically, retinal oximetry, which is a method of analysis that involves the measurement of blood oxygen saturation in the vessels of the retina. "This has been a breakthrough in our clinic. For the first time, we have been able to perform metabolic imaging, rather than being limited solely to structural imaging," he enthused. "It is my hope that more specialists will recognise its benefits and we will see a greater uptake of retinal oximetry moving into 2008," he added.
Diabetics still needlessly going blind
What of progress in the treatment of diabetic ocular disease? Sadly, it did not feel as though we got any closer to a solution in 2007. The product that was showing promise, ruboxistaurin mesylate (Arxxant; Eli Lilly), was rejected by the FDA on the grounds that not enough data was available to warrant its market approval. Having invested a decade of research and development into its diabetic retinopathy candidate, Eli Lilly decided to withdraw its marketing application from the European Medicines Agency (EMEA), where it was undergoing review by the Committee for Medicinal Products for Human Use (CHMP). Although the firm is still evaluating the oral protein kinase C (PKC) beta inhibitor in two trials for diabetic macular oedema (DME), it is currently deciding how to progress with the drug as a treatment for diabetic retinopathy.
Having revolutionized the treatment of AMD, the anti-VEGF class of drugs have also been proving their worth in the treatment of diabetic complications.
Intravitreal bevacizumab therapy, for example, has yielded promising results in a Phase III trial, in which the agent was found to be an effective treatment for DME in the short-term. Meanwhile, results from Phase II continuation studies with Macugen, found that over 33% of DME patients treated with the anti-VEGF agent gained more than 10 letters, as opposed to only 10% of controls, at week 36. Intravitreal Lucentis is also being evaluated for clinical efficacy in the treatment of DME versus focal laser treatment.
Professor Rizzo believes there is a role for anti-VEGF therapy in the treatment of diabetic retinopathy, but in combination with surgery. "I believe that, although anti-VEGF therapies have proven their worth in the treatment of proliferative diabetic retinopathy, they are less evidently effective or recommended for the treatment of DME," said Dr Mauget-Faysse.
"I feel that we still have some way to go with the development of such treatments. Even though a variety of promising new therapies for diabetic retinopathy are under investigation, it will be quite some time before we see any of these in the clinic," she added.
Additional therapies under investigation for the treatment of DME include Retisert (intravitreal fluocinolone acetonide implant), Medidur (next-generation, intravitreal fluocinolone acetonide implant) and Posurdex (intravitreal dexamethasone implant).
"We are faced with challenges when considering continuous drug delivery. On the one hand, longer lasting reservoir implants allow good long-term disease control, but they may have the potential to induce drug or suppressive side effects. On the other hand, shorter acting biodegradable inserts potentially expose the eye to less drug or side effects, but they may control the disease less effectively," said Professor Rizzo. "In my opinion, we must continue to improve our vitrectomy techniques because the complications of diabetic retinopathy are still a challenge for vitreoretinal surgeons," he added.
Dr Stefansson is concerned less with the progress of therapeutics, but more with the utilization of existing tools to reduce the incidence of blindness in diabetics. "We are in the midst of a worldwide diabetes epidemic and diabetic blindness is increasing as a result. Diabetes-induced blindness is preventable with current treatment modalities and public health organization, i.e. screening and preventative laser treatment. We have shown this in Iceland and now England has established a similar, national programme," urged Dr Stefansson. "Diabetics need not go blind," he emphasized.
Dr Stefansson voiced his concerns about the lack of emphasis on public health, "The public expects us to take care of their health, to use preventative approaches and to run an effective medical service for all," he said. "We, as a profession, are too interested in the latest gadget and surgical innovation, and we ignore the public health issues. Nowhere is this more obvious than in diabetic eye disease. We cannot see the forest for the trees," Dr Stefansson insisted.
