Another view of neodymium:YAG capsulotomy

Abstract

The article by Buehl et al.1 regarding the effect of intraocular lens (IOL) design on posterior capsule opacification (PCO) is 1 of many that focus on the negative implications of neodymium:YAG (Nd:YAG) posterior capsulotomy, both economic and clinical.2–5 I have serious concerns regarding some of the main assumptions in these articles. Buehl et al., in their introduction, state that Nd:YAG posterior capsulotomy increases the rate of retinal detachment (RD) and increases the cost of cataract treatment. However, they fail to point out the positives, such as increased clarity of vision and increased reimbursement. Let's look more closely at some of their assumptions. First, in my experience, the rate of RD is not increased after Nd:YAG posterior capsulotomy—a radical statement, to say the least. During the past 20 years, I have tracked almost 10 000 procedures (Table 1) that I performed using the same phacoemulsification machine, the same 6 to 7 mm incision, the same poly(methyl methacrylate) (PMMA) IOL. I live in a small rural community and function as its sole ophthalmologist. Any postoperative problems would have found their way to my office. Surveys of our computerized medical record system and statistical analysis of these data show no statistically significant difference between patients who did and did not have Nd:YAG posterior capsulotomy (Table 1). The YAG laser population lags about 1 to 2 years behind the non-YAG population because the mean time from YAG to RD is 1.3 years. A correction of 1 RD was added to the actual occurrence of RD after Nd:YAG posterior capsulotomy to make the 2 populations as similar as possible (Table 1). For both populations to be statistically significantly different, the RD rate would have to be 22, more than 50% greater than that observed. This view is shared by others given recent responses on the American Society of Cataract and Refractive Surgery (ASCRS) Web site about this issue (J. Weston, online posting June 27, 2005; L. Loewenthal, online posting June 24, 2005; S. Safran, online posting June 23, 2005; available at: http://www.ascrs.org/lists/ascrs.htm).Table 1: Summary of 20-year experience.With respect to cost, we spend much more for lenses and various materials used to prevent PCO than for Nd:YAG posterior capsulotomy itself. The mean cost of the phacoemulsification surgery cited earlier (by T.P. Werblin) is $125 per case at our hospital. The mean cost of surgery across the United States is about $350,6,7 a difference of $225 per case. Given that over 2 million cataract procedures are being done annually in the United States, the $200,000,000 cost of Nd:YAG posterior capsulotomy ($250/case, 47% of cases; our incidence of Nd:YAG posterior capsulotomy is somewhat higher than that generally cited in the literature) is dwarfed by the $500,000,000 cost of doing more “sophisticated” surgery. By the way, the loss of YAG laser procedures further cuts reimbursements. Also it seems strange that we (MDs) are suddenly so concerned about decreasing the cost of medicine in light of how much medicine seems to devalue our services, without regard to clinical safety or effectiveness. Finally, it would seem that one has to assume that even minimally clouded intact capsules are without clinical significance. Several years ago Trevor Woodhams, MD, posted this message on the ASCRS Eye-Mail, which states that PCO is a problem even in its “subclinical” state: “His complaints [a patient's] were that there was a ‘film’ over the right eye that was worse at night—this from day one post op. I finally (in desperation) performed a YAG at 3 months… Bingo! Pt very happy now. My suspicion, growing over the years is that the ICCE boys were right after all…the quality of vision in an eye without a posterior capsule is superior to even the cleanest capsule.” More recently, technology has been developed to quantify this phenomenon.8 By the way, I am not advocating a return of PMMA, although I personally have no problem using that technology. But for those readers radical enough to consider this, the main clinical drawback to a 6 to 7 mm incision for a PMMA lens is the 0.75 D of induced, against-the-rule astigmatism, assuming a 12-o'clock incision site. However, if the incision is moved temporally, no induced astigmatism ensues (J. Schultz, “POCOman Program Found Effective for Measuring PCO,” Ocular Surgery News, February 2005, page 9). In conclusion, Nd:YAG posterior capsulotomy does not significantly increase morbidity but does increase the clinical effectiveness of cataract surgery. Economically, we would save the system much more money by looking at the supplies and IOLs we use rather than by picking on Nd:YAG posterior capsulotomy, which, by the way, slightly mitigates against our devalued services.