Prophylactic scleral buckle for prevention of retinal detachment following vitrectomy for macular hole
- Dr Kuhn
Editor,—Chang et al 1 deserve credit for calling attention to one of the most serious complications following macular hole surgery—retinal detachment.
Occurring in typically 4% to 7% (1–18%) of such eyes, retinal detachment usually results in a final visual acuity significantly lower than in eyes without such complication,2 3 even if surgery to reattach the retina is successful. Prophylaxis of retinal detachment is therefore of great importance.
Certain precautions such as careful peeling of the still attached posterior hyaloid face and careful inspection of the retinal periphery with scleral indentation before fluid-air exchange are useful in reducing the rate of postoperative retinal detachment. Having been alerted to the unexpected frequency of this complication, however, such precautions are already observed by most surgeons performing macular hole repair. Additional preventive measures are warranted for those continuing to experience retinal detachment despite careful techniques.
Prophylactic scleral buckling has been found by some authors to reduce the incidence of retinal detachment in trauma,4 while others have not identified it as effective or necessary.5An encircling band is useful in reducing traction at the vitreous base, but perhaps less effective in preventing retinal detachment in the presence of a retinal break created by a partial vitreous detachment as in case of macular hole surgery. Indeed, the authors' incidence of retinal detachment in eyes despite placing a prophylactic buckle was still 5.9%, a figure most surgeons would consider rather high. In addition, an encircling band has certain morbidity that cannot be ignored.6
Since 1995 we have elected to reduce the incidence of retinal detachment in our macular hole surgeries using a different strategy. Following fluid-air exchange, we perform indirect ophthalmoscopic (IDO) laser cerclage in a moderately tight PRP pattern (800–1200 spots) from the ora serrata to the equator, sparing the horizontal meridians. The postoperative peripheral visual fields compared with the those of the fellow eye have not been significantly reduced, and no complication of IDO laser retinopexy was seen in over 200 eyes. We have followed 94 consecutive eyes for over 6 months after surgery with no case of retinal detachment.7 This contrasts with our other series in which the surgical technique was identical except that no laser cerclage was performed. In this series of 47 consecutive eyes, four (7%) developed retinal detachment (Mester and Kuhn, submitted for publication).
References
Reply
Editor,—We would like to thank Morriset al for bringing to light some of the important issues regarding macular hole surgery that we discussed in our article. One of the fundamental points that remain regarding this subject is a determination of the actual retinal detachment rate for this procedure. In a multicentred randomised clinical trial for macular hole surgery the retinal detachment rate was noted to be as high as 14%. Several retrospective series have noted a considerably lower rate although this may reflect a “reporting bias”. That is to say, retrospective series with lower than expected success rates or higher than expected complication rate often are not submitted for publication review.
If we assume that the detachment rate may be higher for patients undergoing macular hole surgery, it then behoves us to identify methods of lowering this incidence. Morris and colleagues have describe a novel technique of prophylactic laser cerclage that likely would have lower ocular morbidity. Prospective evaluation of this and other methods would be helpful in investigating the optimum approach to this problem.
