Reply: Safety and effectiveness comparison of a new cohesive ophthalmic viscosurgical device

Abstract

Comment on: Safety and effectiveness comparison of a new cohesive ophthalmic viscosurgical deviceWe have read with great interest the article by Packer et al. and would like to offer critical commentary on the use and analysis of StableVisc OVD (Bausch & Lomb, Inc.). 1 We hope that these perspectives may provide insight into areas that may require further research on the topic and improve subsequent research design.First, there is a discussion of how a surgeon's technique and preferences influence their selection of an ophthalmic viscosurgical device (OVD) and further that this selection may affect the surgery success, postoperative outcome, and patient satisfaction. Then later in the Discussion section, it is noted that the surgeons were only permitted to use a cohesive OVD. We believe this presents a potentially confounding variable. That is, a surgeon's familiarity with cohesive OVDs, without being randomized across groups, could have potentially skewed the data on postoperative outcomes.In addition, the authors report that 77.7% of the patients were White and that 62% were women. This confounding demographic selection could have affected the outcomes of the treatments. According to other studies, there is a potential relationship between race or sex and cataract or refractive surgery outcomes. Two such studies found that women consistently had poorer outcomes and were less satisfied with their vision. 2,3 Another study found that people of different ethnicities had statistically significant variations in the dimensions and position of their lens and capsular bag. 4 As such, the generalizability of the results of Packer et al. could potentially be decreased.Finally, in the "Surgical Procedure and Follow-up" subsection, the authors state that only 1 eye from each patient was used in the study. However, it is not stated how each eye was chosen on each patient and whether the patients had 1 or both eyes operated on using the StableVisc cohesive OVD. This brings into question the internal validity of findings, although this may have just been a mistaken omission.Overall, we applaud the researchers for their interesting new study on a brand new surgical tool. We look forward to seeing this future publication and the effect it could have for the development of new and improved surgical technology and medicine. We believe that with some of these potentially confounding variables addressed, this study could provide great benefit to physicians and their patients. Further highquality studies should be conducted exploring this potentially beneficial cohesive OVD medical tool to further that goal.