Dye from açai fruit safe, effective for use during chromovitrectomy

A dye made from the açai fruit (Euterpe oleracea) is safe for use in human eyes and effective for identifying the posterior hyaloid and internal limiting membrane (ILM) during vitreoretinal surgery, according to phase I preliminary study results. 

After completing an experimental study, Mauricio Maia, MD, PhD, and colleagues conducted a trial to evaluate the efficacy and safety profile of the dye made from anthocyanins from the Brazilian açai fruit. The purple dye was formulated at a concentration of 25% and used to aid visualization of the posterior hyaloid and ILM during pars plana vitrectomy (PPV) in humans.

The dye has a pH of 7.0, an osmolarity of 300 mOSM, and a density of 1.1. Spectophotometric analysis indicated that cyanidine 3-glucoside is the main anthocyanin component, according to Dr. Maia, who is associate professor of ophthalmology, Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil.

Twenty-five patients were included in the clinical trial, and 10 surgeons performed the 25 surgeries. Patients were included who had a diagnosis of idiopathic macular holes of less than 2 years’ duration.

The surgical procedure performed by all surgeons included a 23-gauge, four-port combined phacoemulsification/PPV that was guided by staining the posterior hyaloid and ILM using the açai fruit dye at a 25% concentration.

“The posterior hyaloid detachment was guided by the staining of the membrane and the surgical maneuver was easily performed,” Dr. Maia said. “In addition, another flush of the dye was used to stain the ILM and the ILM peeling was completed using the same dye. This was followed by fluid air exchange, perfluoropropane injection, and 3 days of prone positioning.”

The safety and efficacy investigations included evaluations of the physical and pre-anesthesia evaluations, surgical procedures, ophthalmic examination including measurement of the Snellen best-corrected visual acuity (BCVA), and other evaluations, such as electroretinography (ERG), fundus photography, fluorescein angiography, and optical coherence tomography (OCT) at baseline and 7, 30, 90, and 180 days postoperatively. Sixteen patients completed the 180-day examination, and all 25 patients completed the evaluations at the previous time points.

The 10 surgeons completed a questionnaire immediately after they completed the macular hole surgeries regarding the ability of the dye to adequately stain the membranes. The surgeons graded the dye on a scale of 0 to 10, indicating, respectively, no staining and tissue identification similar to triamcinolone for posterior hyaloid detachment or brilliant blue for ILM identification. The ability of the açai fruit dye to stain the membranes was compared with the experience of each surgeon who used triamcinolone and brilliant blue as part of their current practice.

Dr. Maia demonstrated the staining ability of the dye intraocularly.

“The purple dye is heavy and goes directly to the posterior pole and no flushing of the dye is necessary,” he said. “Importantly, the posterior hyaloid is easily observed when stained in purple, which facilitated its detachment and removal.’

The ILM is restained by the dye and it is easily observed and peeled based on the purple stain, he said.

He also pointed out that 360° of ILM peeling was performed around the macular hole and that the OCT showed residual ILM that was peeled.

Study results

The mean patient age was 68 years and 64% of patients were women; 92% of eyes were phakic.

Analysis of the questionnaire results showed that dye was considered useful in all eyes. On the grading scale of 0 to 10, the mean scores for identification of the posterior hyaloid and ILM were, respectively, 8.88 and 7.84 when compared with the surgeons’ experience with triamcinolone and brilliant blue staining.

“These findings demonstrated the intraoperative efficacy of this new purple dye,” Dr. Maia said.

The baseline minimal macular hole diameter was a mean of 689 ± 397 μm, which likely resulted in the low closure rate of 68%. BCVA improved from 1.18 ± 0.47 to 0.84 ± 0.38 (p < 0.05) logarithm of the minimum angle of resolution.

In addition, Dr. Maia reported that biomicroscopy showed no abnormalities except for one eye 7 days postoperatively that had cells in the anterior chamber that resolved at the 30-day examination.

The baseline IOP was 17.5 ± 4 at baseline, 18 ± 5 at 1 week, 18.5 ± 7 at 30 days, and 17.3 ± 4 at 90 days (p > 0.05).

A retinal detachment developed in one eye at the 30-day examination, and another eye underwent a secondary IOL implantation because of capsular dehiscence. Finally, cells were present temporarily in the anterior chamber.

ERGs showed no difference between the baseline readings and those obtained 30 days postoperatively.

“The preliminary results showed that the new dye based on anthocyanins from the açai fruit at a 25% concentration was safe and useful for identifying the hyaloid and ILM during vitreoretinal surgery in humans at the 3-month follow-up,” Dr. Maia concluded. “Long-term follow-up and additional studies are necessary. However, the initial results suggested that the açai fruit dye may be an alternative dye for use in chromovitrectomy in humans.”

Dr. Maia, who holds a patent on the intraocular use of dye based on anthocyanins from the acai fruit (E. oleracea), reported his results at the 2017 meeting of the American Society of Retina Specialists in Boston.