The third annual FloRetina meeting took place in Florence, Italy from June 6-9th, 2019 at the Palazzo dei Congressi. The program covered medical retina topics, surgical panels, and live surgery performed at multiple sites across the world. Here is an overview of some of the many interesting presentations from the meeting.
The Dark Halo Around Choroidal Neovascularization In Age Related Macular Degeneration
Maria Cristina Savastano presented her theory and data on why patients have a dark halo of fluorescein angiography around choroidal neovascularization in age related macular degeneration. The authors observed and quantified choriocapillaris vascular density changes before and after anti-vascular endothelium growth factor (VEGF) injections by optical coherence tomography angiography (OCTA).
Within her study, all the patients were evaluated by a spectral-domain OCT system. The scans were registered at baseline before injection, between 6 days and 14 days after injection, and monthly thereafter. The dark halo was automated assessed by Image J software. Dr. Savastano’s theory is that there is vascular shunting around the choroidal neovascular membrane which leads to a relative deficit around the lesion thus leading to a dark halo on oct angiography. Following anti-VEGF treatment, the dark halo size was reduced but not cured.
Take home point: We now know what the dark halo is from but the clinical relevance of the dark halo in anti-VEGF re-treatment or outcomes is now being studied further.
Results of Anti-VEGF treatment outcomes in Ischemic Vein Occlusions
Dr. Anat Loewstein presented an overview of treatment options for macular edema secondary to retinal vein occlusions. The most recent study results from the BRIGHTER and CRYSTAL studies evaluated the treatment outcomes in patients with ischemic versus non-ischemic vein occlusions. Both studies treated patients with Ranibizumab for macular edema retinal vein occlusion. In the BRIGHTER study, patients with branch retinal vein occlusions were classified into ischemic and non-ischemic vein occlusions. Those with ischemia gained +15.9 versus +14.5 for non-ischemic vein branch vein occlusions. The ischemic patients received on average 3 injections more than the non-ischemic patients. In the CRYSTAL study, patients with ischemic central retinal vein occlusions had similar visual gains to those without ischemia.
The LEAVO study recently compared the outcomes of patients treated with Bevacizumab, Ranibizumab, and Aflibercept for non-ischemic vein occlusions. This non-inferiority trial enrolled 463 patients and randomized them to four initial injections with each drug and then PRN therapy thereafter. The study findings demonstrated that Bevacizumab was equivalent to Ranibizumab at year 1 but by year 2 was inferior to Ranibizumab. The study also found that bevacizumab was inferior to aflibercept at year 1 and year 2. Overall, Ranibizumab and Aflibercept were equivalent with regards to visual gains at year 1 and year 2 though aflibercept had a slight anatomical benefit or Ranibizumab.
Take home point: All anti-VEGFS are effective in treatment of macular edema in retinal vein occlusions even in the presence of ischemia. However, both Ranibizumab and Aflibercept are superior to Bevacizumab for this condition.
Pneumatic Retinopexy leads to less retinal vessel displacement and less visual distortion over vitrectomy for primary retinal detachment.
The most recent study on pneumatic retinopexy (PIVOT study) demonstrated superior visual outcomes in those patients who underwent pneumatic retinopexy versus primary vitrectomy for primary retinal detachment repair. But why? In a study recently, using the technique of retinal vessels printing seen on fundus autofluorescence, Sabatino and colleagues followed patients following primary vitrectomy versus pneumatic retinopexy to determine whether their visual outcomes were due to inadvertent retinal displacement. Sabatino reported less mean displacement within the pneumatic retinopexy group in comparison to the primary vitrectomy group. The majority of the displacement seen was an inferior displacement especially in the primary vitrectomy group.
Take Home Point: Pneumatic Retinopexy leads to less retinal displacement than vitrectomy with drainage. However, the authors never studied whether utilizing PFO would have changed this outcome. Nonetheless, Pneumatic Retinopexy offers a cost effective and potentially lower side effect treatment when selecting the right patient.
Subthreshold laser for diabetic macular edema. How it really works.
Eduardo Midena presented his findings on patients treated with subthreshold laser for diabetic macular edema. Subthreshold laser, or sub visible laser photocoagulation, encompasses all types of laser treatment that show no visible signs of damage to the eye of the examiner. The actual damage may range from significant cell damage and subsequent mild scarring (but no visible damage at the time of application) to no cell death whatsoever. This treatment method is currently most commonly used in cases of retinal vascular diseases with macular edema, such as diabetic macular edema (DME), central serous (CSR), and macular edema secondary to branch retinal vein occlusion (BRVO).
In Dr. Midena’s study, patients were treated with subthreshold laser and aqueous taps were performed every three months. Patients were treated with yellow subthreshold laser with multiple and confluent spots at baseline. The fluid was analyzed for Mueller cell markers, inflammatory markers, and RPE markers which included EPO and PEDF. While the study showed a significant reduction in the OCT thickness, there was no change in the visual acuity. Remarkably, the aqueous sample over a 1-year period of demonstrated a return to levels seen in control patients including VEGF, the inflammatory markers, and RPE markers.
Take home point: While we have a lot to learn about sub-threshold laser, aqueous sampling appears to show that it does have an effect on the biomarkers seen in DME.