An Alternative Remedy for VMT
BY LEO SEMES, OD, FAAO
How many of your patients complain of floaters? It is certainly not uncommon among myopes. What we know about vitreous degeneration, which produces the symptom of floaters, is that it is more common among myopic patients and that the likelihood increases with advancing age. Up to now, for those who were significantly symptomatic the only remedy was vitrectomy, a procedure not undertaken lightly. It was recommended not only in cases of significant symptoms but when vitreo-macular traction (VMT) threatened to reduce vision secondary to macular hole (MH) formation, for example.
Study and Results
A recent study conducted in Belgium demonstrated the efficacy of intravitreal injection of ocriplasmin for enzymatic vitreolysis (Stalmans et al, 2012). Investigators reported significant VMT relief and, as a secondary endpoint, closure of MH in just over 25 percent of cases. What promise this holds for patients in the United States remains to be seen, as the U.S. Food and Drug Administration just approved ocriplasmin in October.
The primary purpose of the Belgian study was to determine whether a single intravitreal injection of 125μg of this recombinant protease, with activity against fibronectin and laminin, compared to a placebo injection procedure resulted in resolution of VMT at a 28-day time point. Secondary endpoints of importance included induction of complete posterior vitreous detachment, visual acuity improvement, and nonsurgical closure of MH.
The results are impressive. While 26.2 percent of the treated eyes (n=464) had VMT resolution, so did 10.1 percent of the 181 eyes in the placebo group. The numbers were not appreciably increased at the six-month point. The significance is that some will enjoy spontaneous VMT resolution, and it suggests that observation for a month may prove useful. The guidance that these results suggest is that following those patients who have good visual acuity using optical coherence tomography at close intervals in a small percentage of instances will avoid both surgical vitrectomy and nonsurgical intervention of intravitreal injection.
The data also suggest that within the first 28 days following presentation, only about 4 percent of patients will have spontaneous posterior vitreous detachment (PVD), while nearly three times that number will have PVD with treatment. Again, the implication is to observe patients who have stable VA before rushing to a surgical recommendation.
Let’s look at the impressive results of MH closure at the study’s conclusion, six months from baseline. In about 10 percent of patients (n=47), the hole closed spontaneously. In contrast, 40 percent of macular holes closed in the treated cohort (n=106). Again, the implication is that observation for a short period is valuable. It is important to note that patients were seen at days 7, 14, 28, 90, and 180 following baseline/randomization.
Perhaps most important to practitioners are the data on visual performance. At the six-month time point, the criterion of at least three lines of visual acuity improvement was reported. In the placebo group, 12 of 188 eyes (6.4 percent) met this endpoint while 57 of 464 treated eyes (12.3 percent) achieved this level of improvement. While these numbers are small, there was a statistically significant difference (<0.02).
Although vitreous floaters, photopsia, or injection-related eye pain—all self-reported—occurred in 68.4 percent of ocriplasmin-injected eyes and in 53.5 percent of placebo eyes (P<0.001), look for implementation of this procedure to reach the frequency of intravitreal injection of antivascular endothelial growth factor agents. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #205.
Dr. Semes is a professor of optometry at the UAB School of Optometry. He is a Speakers’ Bureau, Advisor or Consultant to Alcon, Allergan, ArcticDx, B&L, MedOp, Merck, OptoVue, and Zeiss.