This small, retrospective study shows that patients treated with a single injection of ocriplasmin experienced transient changes in the outer retina that are possibly due to disruption of photoreceptors. The authors write that this is the first study to quantify the extent of outer retinal changes seen in patients receiving ocriplasmin.
Because original studies used only time domain optical coherence tomography, the authors sought to evaluate spectral domain optical coherence tomography images to provide additional insight into structural changes to the retina following treatment.
The authors evaluated anatomical and visual outcomes in 17 patients treated with a single intravitreal injection of 0.125 mg ocriplasmin for symptomatic vitreomacular adhesion, including vitreomacular traction syndrome and macular holes.
Imaging showed that almost all patients who responded to treatment exhibited changes in the outer photoreceptor segments (OS) and the disruption occurred in the ellipsoid zone. These patients also experienced a transient acute reduction in vision and demonstrated subretinal fluid during the release process with almost the exact time course as the loss of the OS ellipsoid zone.
The authors write that this finding may suggest a “transient toxicity of ocriplasmin at the level of the outer retina and RPE possibly due to disruption of the photoreceptors. If this transient affect occurs for both rods and cones, it may explain the dyschromatopsia, contrast sensitivity changes, dark adaptation issues and ERG changes seen in the ocriplasmin clinical trials.”
All patients experienced a gradual return of the OS ellipsoid zone and resolution of the subretinal fluid. They conclude that larger clinical studies are necessary to validate these initial findings.
Despite the transient changes noted, this study found a higher success rate than was reported from phase 3 trials, with an adhesion release rate of 47.1 percent. The authors attribute the higher response rate to a smaller patient sample, better patient selection, and use of SD-OCT to monitor vitreomacular separation.