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Increasing evidence shows value, reliability and benefits of OCT angiography
Patients may be more willing to undergo frequent monitoring with OCTA rather than fluorescein angiography.
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As a noninvasive substitute for fluorescein angiography, OCT angiography will improve patient compliance, monitoring of disease progression and treatment outcomes.
Increasingly, OCTA is establishing itself as a reliable, easy-to-perform, noninvasive tool for the evaluation of disease progression and treatment-related improvement in retinal diseases such as age-related macular degeneration, diabetic retinopathy and retinal vein occlusion.
“There has been a lot of debate in the last few years on the reliability of the new method as compared with the gold standard fluorescein angiography. There was debate about truth or artifacts, about possibilities of errors and non-visibility of the new vessels. Moreover, we all know and accept FA and structural OCT as the gold standard because we have so many years of experience with them. The new method needed further investigation and more data,” Gabriel Coscas, MD, said in an interview with Ocular Surgery News at the Euretina meeting.
Two studies, one published by Coscas’ group and one by David Sarraf’s group, recently demonstrated that the information and results provided by OCTA and fluorescein angiography are nearly the same.
“This is a very important achievement because we have proved that we can trust the method,” Coscas said.
In addition, in a series of 54 patients with RVO, he found that OCTA could go further than fluorescein angiography in detecting abnormalities in the deeper layers.
“For the first time we have an imaging technique that enables evaluation of the deep capillary plexus, which appears to be more severely affected than the superficial plexus in RVO,” Coscas said.
Improved reliability, compliance
Studies have also focused on better understanding of OCTA and overcoming its pitfalls. Fluorescein angiography also has pitfalls and a risk of errors, but specialists have been trained to deal with them.
“In a relatively short time, we have learned quite a lot on OCTA, too,” Coscas said.
The first lesson learned was that automatic segmentation must be avoided, at least in difficult cases, in favor of manual segmentation. The second lesson was that thin sections of no more than 30 µm are necessary to clearly visualize, and not confuse, the different vascular layers.
“The third conclusion we reached now is that this technique will improve patient compliance with frequent visits because it is noninvasive and comfortable. This will allow us to treat the patients at the early stage of any recurrence and not when the recurrence has progressed to loss of vision, which is always partially irreversible,” Coscas said.
It makes a difference for patients to come for an easy, quick 5-minute photograph rather than for an intravenous injection of a dye, he said. Patients are willing to come more frequently, and because it has been shown that best results are obtained with monthly monitoring — “not monthly injections, but monthly monitoring,” Coscas noted — the overall management of vascular diseases is likely to improve.
“Patients may not come 12 times in a year, but certainly six at least, and this will give us much better control. We can monitor the efficacy of treatment, work out a personalized schedule and have a clearer prognosis of future results,” he said.
OCTA has shed new light not only on AMD and RVO, but also on diabetes.
“We have nowadays the possibility to better understand the way diabetes affects the eye and to better monitor and predict the results of the treatment. We know now that the disease is not only edema but has an ischemic component, which can be analyzed very precisely with OCTA,” Coscas said.
Newly developed software allows detection and quantitative evaluation of ischemic retinopathy changes and a closer follow-up of the patients who are progressing to ischemia.
“We can treat promptly and more intensely these patients, thus saving vision. Too often diabetic patients are treated too late, when vision loss is irreversible,” Coscas said. – by Michela Cimberle
- References:
- Coscas F, et al. Am J Ophthalmol. 2016;doi:10.1016/j.ajo.2015.10.008.
- Inoue M, et al. Invest Ophthalmol Vis Sci. 2016;doi:10.1167/iovs.15-18900.
- For more information:
- Gabriel Coscas, MD, can be reached at Centre Hospitalier Intercommunal de Créteil, 40, Avenue de Verdun, 94010 Créteil, France; email: gabriel.coscas@gmail.com.
Disclosure: Coscas reports he is a member of the advisory board of Allergan, Novartis, Bayer and Heidelberg Engineering.