Safety of Vitrectomy for Floaters – How Safe is Safe?

Contemporary vitreous surgical techniques established by Machemer and associates are now approximately 40 years old. Prior to 1956, no manuscripts regarding vitreous surgery were published in the United States, and between 1968 and 1974 only 68 such papers appeared in the literature. However, the year 1975 witnessed a 1600% increase in the number of publications, and the topic of vitrectomy has since become commonplace in both the lay and academic press.

As vitrectomy equipment and surgeon experience have improved, the indications for surgery have also profoundly expanded. Removal of vitreous opacities, the oldest of surgical indications, was initially limited to eyes with massive vitreous hemorrhage with or without intraocular foreign bodies. Vitrectomy for repair of retinal detachments was originally limited to cases that could not be repaired with conventional scleral buckling, but the former operation is now gradually replacing the latter in many instances, especially in pseudophakic cases. In addition, macular holes, endophthalmitis, retinal vascular disorders, and a variety of maculopathies have become both new and common indications for vitreous surgery.

The expanded numbers of entities undergoing vitrectomy and the increased enthusiasm of vitreous surgeons for the procedures have significantly modified the risk/benefit equation. Informed consent for vitreous surgery for cases in which it provided the only hope for vision is vastly different than that for a purely elective vitrectomy in which surgical alternatives and/or “watchful waiting” are viable strategies.

In this issue of the Journal , Tan and associates describe their experiences in performing vitrectomies upon eyes with vitreous floaters that had caused persistent troublesome symptoms in spite of relatively modest losses of visual acuity. The authors clearly acknowledge that vitrectomy for such eyes may be “primarily patient driven” and that it remains controversial among vitreoretinal surgeons. They express hope that their data will establish a more meaningful risk profile for the operation in this context.

Regarding surgical outcomes, the 2 major “take-away points” from this article are similar to previous publications on the subject: patient satisfaction regarding visual outcomes is in general very high, and significant and potentially blinding complications do occur. In fact, the incidence of iatrogenic retinal tears and rhegmatogenous retinal detachment (RRD) was considerably higher than previously reported. It is impossible to determine the location or the morphology (persistent vs relieved vitreous traction) of the iatrogenic tears, but it is likely that the RRD rate would have been higher if the authors were not diligent in their intraoperative searches for these lesions. In addition, the follow-up times were relatively short, and another cited report demonstrated that RRD continues to occur in these cases long after surgery. The visual outcomes are confounded a bit by the inclusion of 26 cases that had phacoemulsification performed at the time of vitrectomy, although literal improvement in visual acuity was greatest in these cases.

Tan and associates divided 116 cases into “primary floaters” (86), in which no associated ocular disorders other than posterior vitreous detachment (PVD) were present, and “secondary floaters” (30), in which a variety of other problems were present. At surgery, a PVD had to be induced in 26 (30%) of the 86 primary cases but in only 4 (16%) of the 30 secondary eyes. Importantly, iatrogenic retinal breaks were observed in over 30% of the cases requiring PVD induction and in less than 12% of those in which this maneuver was not performed, and these differences were statistically significant. These data are consistent with prior reports demonstrating that a history of prior PVD without problems is associated with a significantly reduced risk of later retinal tears or RRD, and this should be remembered in all discussions of RRD as a surgical complication as well as those regarding prophylactic therapy of RRD. In addition, it remains clear that significant cataracts will develop relatively rapidly in phakic eyes undergoing vitrectomy for any reason. The data presented in this manuscript are important, and the outcomes should be included in the informed consent process regarding vitreous surgery for the indication of “vitreous floaters.” The operation is clearly associated with major risks that were fortunately rarely responsible for a permanent reduction in vision.

Vitreous opacities can be a legitimate source of major frustration and reduced visual function in some individuals, and one group of authors proposed that “some personality traits” may be associated with an increased awareness and perceived morbidity associated with the floaters as well as with an increased desire to have them removed. And it must be admitted that visual and anatomical outcomes as expressed in quality-of-life documents and by personal experience are excellent. Still, the patient and his/her prospective surgeon must ultimately confront the question of “how safe is safe?” or “does the frequency of complications of vitrectomy for vitreous floaters indicate acceptable risk?” The informed consent process is more than a piece of paper; it is the surgeon’s responsibility to provide information and to obtain consent only after all options and alternatives have been provided. The process includes the basic principles of biomedical ethics—patient autonomy, non-malfeasance, beneficence, and justice—and these must be presented in a “truth-telling” manner. The determination of “acceptable risk” is a complex task that involves a consideration of many issues. The usual solution is to determine the best combination of advantages and disadvantages among alternatives. In this instance, this would mean comparing the outcomes and complications of surgery for a typically nonprogressive condition vs doing nothing and “living with the symptoms.” Acceptable risk does not mean that the patient is pleased regarding the known risk of complications. It does indicate that if surgery is chosen, the level of risk is associated with what is considered to be the best of available alternatives.

Tan and associates have performed a service in providing the reader with a realistic overview of the risks associated with vitrectomy for vitreous floaters. Uncomplicated operations will result in excellent visual outcomes, but problems will occur in a significant percentage of patients. The data in the manuscript will be of benefit in enhancing the informed consent dialogue between patients and their surgeons.

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Jan 16, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Safety of Vitrectomy for Floaters – How Safe is Safe?

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