Approximately six months ago my mother-in-law developed a severe vitreous hemorrhage. Though it took several months to clear, it did so without intervention and her best corrected visual acuity has returned to 20/25. That said, she notices significant metamorphopsia in her view. OCT imaging of her macula reveals significant distortion of her foveal contour from vitreomacular traction. As her other eye has some amblyopia, the retinal specialists she has seen have wisely abstained from surgical intervention. Nevertheless, she is disappointed her metamorphopsia cannot be helped. Vitreomacular Adhesion (VMA), sometimes referred to as vitreomacular traction (VMT), can cause significant distortion of vision for some patients. Because this may not always degrade snellen acuity, many surgeons are conservative in offering pars plana vitrectomy/membrane peeling for this condition. Additionally, PPV/MP does have its share of potential complications that could certainly make vision worse.
Ocriplasmin (Thrombogenics) has recently been recommended for approval to the FDA by the FDA Dermatologic and Ophthalmic Drugs Advisory Committee. A truncated form of the human serine protease plasmin, it is believed to retain its enzymatic properties against fibronectin, laminin, and type IV collagen fibers that adhere the vitreous to the retina.
In a multicenter, randomized, double-blind, phase 3 clinical trial patients with symptomatic vitreomacular adhesion received either a single intravitreal injection of ocriplasmin (125 ug) or placebo. The authors found that VMA resolved in 26.5% of ocriplasmin injected eyes and 10.1% of placebo injected eyes. Nonsurgical closure of macular holes was achieved in 40.6% of ocriplasmin-injected eyes, as compared with 10.6% of placebo-injected eyes. BCVA was also more likely to improve by a gain of at least three lines on the eye chart with ocriplasmin than placebo. The majority of adverse events were similar to what one would expect with any intravitreal injection: eg floaters, conjunctival hemorrhage, photopsias, etc.
While not all patients had resolution with a single injection, many were greatly helped, and by a method much less invasive than pars plana vitrectomy surgery. While not looked at in the study (as this would certainly be off-label), it would be interesting to know if those patients whose VMA was not resolved with the injection would have success with a second or larger injection of medication. Certainly these and other off-label studies will need to be conducted, as the potential for this medication is tremendous. By inducing a posterior vitreous detachment, this may become a pre-injection regimen to facilitate and make safer pars plana vitrectomy surgery for patients with non-VMA retinal pathology. Additionally, visual acuity outcomes may be better in these patients as the ocriplasmin will likely create a cleaner separation of the posterior vitreous and the internal limiting membrane. Cataract patients desiring multifocal lenses with vitreomacular traction with distortion of foveal contour could undergo treatment to restore normal retinal architecture and enable them candidates for the multifocal lenses.
Ultimately, this medication will unlikely be able to cure all patients with symptomatic vitreomacular adhesion. That said, because of its relative ease of use and minimal risk of side effects, ocriplasmin may very well become first line therapy for all of these patients upon initial presentation. For patients like my mother in law, this may very well be the therapy she has been hoping for.