Advancing beyond our recent advances in ocular surface disease and corneal surgery

Most people in a given generation can look back and most likely agree that they are better off than the prior generation given new advancements and progress in the world. This is no different in medicine, and in ophthalmology, and as I look at what we have today compared to 25 years ago, I would definitely agree.

Just 25 years ago, patients with dry eye were treated primarily with just artificial tears. It has only been in the last two decades that we have gained a much greater appreciation for and understanding of the pathophysiology of dry eyes (including its various subtypes) and the integral role that inflammation plays. The understanding of this has driven the development of anti-inflammatory therapies for both the ocular surface and the eyelids, to treat dry eye. This special issue of the Taiwan Journal of Ophthalmology opens with a comprehensive review of this topic by Nguyen et al.,[¹] which is relevant to a very large number of our patients. In addition, Chan and Sun show that different concentrations of the same drug can have different effects, with cyclosporin 0.1% being effective for patients with recalcitrant dry eyes after therapy with cyclosporin 0.05%.[²] Equally important to knowing what does work is knowing what does not necessarily work, and an interesting study by Shah et al.[³] describes how conjunctival inflammation and dry eye symptoms at day 100 post-bone marrow transplantation do not predict risk for developing chronic graft versus host disease, an extremely challenging condition to manage.

Similar to the differences in treating dry eye, if a patient walked into an ophthalmologist's office 25 years ago with a corneal disorder that needed a corneal transplant, in almost every circumstance, they would be offered a penetrating keratoplasty. Now, a patient with decompensated Fuchs' endothelial dystrophy would be offered endothelial keratoplasty (Descemet's stripping endothelial keratoplasty [DSEK] or Descemet's membrane endothelial keratoplasty [DMEK]) or even Descemet's stripping only. A patient with keratoconus who could not tolerate a specialty contact lens (which is becoming increasingly rare) could be offered a deep anterior lamellar keratoplasty (DALK). While these are just some of the many surgical advances and innovations that have come around in the last quarter century, advances beyond these new innovations continue. Endothelial keratoplasty is becoming easier and easier to adopt in practice, with eye banks providing very well-prepared tissue for use in the operating room. Surgeons can now order precut DSEK tissue, and even prestripped DMEK tissue which is preloaded and ready to inject into an eye. Juratli et al.[⁴] present their clinical outcomes of prestripped, prestained, and preloaded DMEK tissue (”P3 DMEK”), demonstrating excellent outcomes that are comparable to traditional DMEK preparation techniques. As surgeons have become more comfortable with these newer surgical techniques, the indications for use have become broader, and situations in which early surgeons would avoid for DMEK are now acceptable indications for which to perform the procedure. In this issue, Le et al.[⁵] provide an excellent review of one such scenario: performing DMEK in eyes with glaucoma, including those with previous trabeculectomies and tube shunts. Their review suggests that DMEK can indeed be performed successfully and with very good visual outcomes in these eyes, although some modifications to the surgical technique may need to be used. Even for DALK, new innovations have been developed, and in this issue, Lin and Lee[⁶] present a novel technique to assist in DALK using suture localization of dissection depth by intraoperative OCT.

In addition to clinical trials, one must not forget that basic science and laboratory studies have served as the basis for our current understanding of ocular surface diseases and new surgical techniques, respectively, and studies in these venues need to continue in order to help us continue to advance upon our advancements. As such, Lin et al.'s[⁷] paper on establishing a new dry eye model in rabbits is very relevant and will set the stage for future studies that will advance our understanding of this common condition. Furthermore, continued studies on the in vitro antimicrobial efficacy of riboflavin and ultraviolet radiation on ocular pathogens, as reported by Sharma et al.,[⁸] provide further insights into its appropriateness for use in patients with specific types of infectious conditions of the cornea. The study also suggests to us for which patients we should not use this procedure.

Despite all of these advances in our understanding of corneal diseases and surgery that help in our ability to better treat our patients, we cannot forget that preventative medicine is even more important. Kounser et al.[⁹] performed a cross-sectional study investigating the causes of corneal blindness at a tertiary care center in India. While the causes were diverse, the majority of cases were preventable if addressed appropriately and in a timely fashion, or if preventative measures had been in place. This study certainly highlights the fact that much of the world's corneal blindness is preventable, and that public health measures need to be put in place to help with this.

In addition to these and other studies in this special issue of the Taiwan Journal of Ophthalmology, there are several very interesting case reports that highlight unique medical corneal problems, as well as challenging surgical sequelae. I hope that this compilation of outstanding cornea papers helps to advance the knowledge of our readership beyond the advances that have already been recently made.