I have been involved at every stage in the development of the Neusidl Corneal Inserter (NCI), from the moment that a talented ophthalmologist and innovative engineer, William Neusidl, showed me his initial drawings, through laboratory testing and revisions of several prototypes, to the clinical testing of the final product. Many surgeons who are uncomfortable with forceps or other insertion techniques have embraced the NCI, and it has allowed them to do safe Descemet stripping automated endothelial keratoplasty (DSAEK) surgery. It is a welcome contribution to this field.

Drs. Belin and Hannush have highlighted page 6 of our publication, where we discuss the reasoning behind our decision not to use viscoelastic for the NCI-placed tissue, and they state that not using viscoelastic is atypical and not “standard practice.” The implication is that if we had used viscoelastic for the NCI tissue in this study, we would have had less cell loss for this randomized arm of the study.

Standard practice with the NCI: The company that manufactures the NCI, Fischer Surgical (St. Louis, Missouri, USA) sponsored a breakfast meeting to talk about the product on October 20, 2010, during the meeting of the American Academy of Ophthalmology. At that meeting, which was moderated by Dr. Belin, a speaker, Dr. Anthony Lubniewski of Washington University (St. Louis, Missouri, USA), emphasized that one of the benefits of the NCI was that viscoelastic did not need to be used at all, so the cost savings resulting from omitting viscoelastic would offset the added expense of the device (confirmed by personal communication, August 26, 2013). In addition, the majority of surgeons using the NCI here on the West Coast also did not use viscoelastic at the time of our study. Therefore, not using viscoelastic would appear to be the preferred practice. However, just like Drs. Belin and Hannush, I do not have a scientific, broad-based survey of surgeons to produce the data that would demonstrate what is the “standard practice.”

Endothelial protection with viscoelastic: Would a viscoelastic coating have improved our endothelial cell loss with the NCI? Not necessarily. The platform Endoserter device is very similar to the NCI and although Endoserter investigators used viscoelastic, their endothelial cell loss was 28%. Similarly, the Endoglide insertion device uses viscoelastic, and the cell loss has been reported at 26%. With the NCI’s internal fluid flow directly under the donor endothelium, any cohesive viscoelastic placed would likely be washed off during the extension of the platform for delivery of the tissue, eliminating any protective effect of the viscoelastic. Nonetheless, whether or not there is improved endothelial survival if viscoelastic is used to coat the donor tissue when using the NCI remains an unanswered question that calls for hard data. Until investigators perform a prospective, randomized, masked study of this question, the data from our highly controlled study stands.

The NCI device and other insertion devices, for that matter, despite all of their other user benefits, have not been proven with prospective data to provide better endothelial cell survival than a well-established forceps insertion technique. Marketing the devices to the contrary contradicts the best available data.