1. The authors have no conflicting interest in the subject matter of this poster. In Vivo Evaluation of DSAEK Interface with Scanning- Laser Confocal Microscopy C. Macaluso ٭, E. Delfini ٭, G. Ferrari* § ٭ University Hospital, Dept. of Ophthalmology, Parma, Italy * G.B. Bietti Eye Foundation, IRCCS, Rome, Italy §Schepens Eye Research Institute, Harvard Medical School, Boston

2. INTRODUCTION Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) has gained popularity among ophthalmologists as a less invasive alternative to penetrating keratoplasty in diseases affecting corneal endothelium. Visual outcome tends to be good with DSAEK, but long term improvement has been observed. Differently from penetrating keratoplasty, DSAEK creates an interface between the receiving and the donor tissue, which influences the visual outcome. Laser confocal microscopy allows visualization of corneal anatomy in vivo at a cellular level. The purpose of our study is to evaluate corneal morphology at the donor-graft inerface with confocal microscopy in DSAEK patients

3. METHODS Patients. 33 patients who had undergone DSAEK surgery (1 month to 2 years follow-up), were examined in the operated eye and their BCVA was measured. Confocal microscopy was performed with the Heidelberg Retina Tomograph II (Rostock Cornea Module). Imaging. The interface between recipient and donor cornea was examined for reflectivity and particles. Measurement of interface haze was obtained by grading from 1 to 4, with 1 meaning low reflectivity (hence good quality interface), as proposed by Kobayashi et al, 2008. Little amorphous particles were found at the interface (previously described as necrotic tissue, metal particles, and dust), and they were counted as number of particles per square mm, using the Heidelberg Retina Tomograph II Rostock Cornea Module software for cell counting.

4. Reflectivity grading scale ( from Kobayashi et al.) Minimal reflectivity Maximal reflectivity

5. RESULTS Interface reflectivity grading in DSAEK grafts resulted significantly correlated with BCVA, with a Spearman correlation coefficient of 0.79 (p<0.001). Interface reflectivity grading was significantly correlated with time after surgery in months (Spearman correlation coefficient 0.87, p<0.001). The number of particles detected at the interface level was not correlated with BCVA(Spearman correlation coefficient 0.064). Figure 1. In vivo confocal microscopy picture of corneal stroma taken at the DSAEK interface (A) and from a healthy, control eye, at the same depth (B). (A): Note the absence of keratocytes, the fine folds (arrow) and particles. A B

6. In vivo corneal confocal microscopy is a non invasive exam amenable to study corneal interface in DSAEK patients. A smooth and optically perfect interface area is considered crucial for the successful outcome of DSAEK. We show here that a low reflectivity (i.e. good quality) interface is related to a better visual outcome. As time after surgery passes, the interface becomes less reflective, and BCVA progressively improves after surgery. Finally, we have shown that, even if often evident and aesthetically disturbing upon slit-lamp examination and confocal microscopy imaging, interface particles do not appear to significantly affect visual outcome. CONCLUSIONS

7. REFERENCES References Kobayashi A, Mawatari Y, Yokogawa H, Sugiyama K. In vivo laser confocal microscopy after descemet stripping with automated endothelial keratoplasty. Am J Ophthalmol. 2008 Jun;145(6):977-985. Cursiefen C, Kruse FE. Descemet's stripping with automated endothelial keratoplasty (DSAEK). Ophthalmologe.2008 Feb;105(2):183-90, 192. Review. CONTACT: claudio.macaluso@unipr.it giulio.ferrari@schepens.harvard.edu