Successful Use of Corneal Tissue from LASIK Donors in Descemet-Stripping Automated Endothelial Keratoplasty: A Case Ser

1. The John A. Moran Eye Center Successful Use of Corneal Tissue from LASIK Donors in Descemet-Stripping Automated Endothelial Keratoplasty: A Case Series Mark D. Mifflin, MD Majid Moshirfar, MD Yousuf M. Khalifa, MD JoAnn C. Chang, MD Carlton R. Fenzl, BS

2. Financial Disclosure • This project was supported in part by an unrestricted educational grant from Allergan Inc., Irvine, CA • Research to Prevent Blindness (RPB), New York, NY • Department of Ophthalmology and Visual Sciences at the University of Utah, John A. Moran Eye Center, Salt Lake City, UT

3. Purpose: To report outcomes in Descemet’s stripping automated endothelial keratoplasty (DSAEK) using donor tissue from eyes that have had previous refractive surgery • Methods: Retrospective case series. Preoperative and postoperative data were collected on each patient. Histopathological evaluation of two donor free caps were performed

4. Results • 7 patients underwent DSAEK from donors that had undergone refractive surgery • One patient received PRK donor tissue, had no interface haze • Six patients received LASIK donor tissue (Figure 1) • Donor characterisitics: Table 1 • Donor age ranged from 38 to 57 • Precut pachymetry averaged 509 µm (range 460 to 575 µm) • Residual stromal bed (RSB) measured on average of 146 µm (RSB in one donor was not measurable)

5. Figure 1 Figure 1: Donor corneal button with previous LASIK in the viewing chamber. The black arrows indicate the flap edge. The white arrow is pointed to the hinge site.

6. Table 1: Donor Information Case 2 and 3 received donor tissue from the same donor, and Case 6 and 7 received donor tissue from the same donor. * - ultrasound pachymetry was not able to generate a measurment of the RSB, ECD - endothelial cell density, RSB - residual stromal bed, PRK - photorefractive keratectomy, LASIK - laser in situ keratomileusis

7. Results • Patient characteristics: Table 2 • Preoperative best-corrected visual acuity (BCVA) ranged from 20/40 to light perception • Postoperative BCVA at 3 to 6 months ranged from 20/25 to 20/80 • One patient lost BCVA from 20/40 to 20/80 at 6 months • The patient had visually significant central donor macrofolds • Endothelial cell density (ECD) were available for three patients between 3 to 11 months • The average ECD in the 3 pts with available postoperative ECD was 1890 (SD 284) which represented a decrease of 33.1% (SD 10.5%) from preoperative values

8. Table 2: Patient Information PBK - pseudophakic bullous keratopathy ECD - endothelial cell density BCVA - best corrected visual acuity DME - diabetic macular edema CME - cystoid macular edema RD - retinal detachment CF - count fingers * - Rigid Gas Permeable Contact Lens fitting

9. Results • Histological slides of two donor free caps are shown in Figures 2 and 3. • In the case of one donor, the histologic slide reveals a LASIK flap with uniform adherence to the underlying stroma. • In the case of another donor, microscopic findings revealed that the LASIK flap remained adherent peripherally but showed a central detachment. • We believe an artifact was elicited during the preparation of the microscopic slide since we did not encounter any flap related complications while preparing the endothelial button.

10. Results Figure 2: Light photomicrograph of a donor free cap. The arrows show the adherence of the LASIK flap to the underlying stroma (magnification x100) Figure 3: Light photomicrograph of a donor free cap. The left arrow shows adherence. The middle arrow shows separation of the LASIK flap from the underlying stroma. The right arrow indicates the flap edge (magnification x40)

11. All patients underwent uneventful DSAEK surgery with the exception of case 5 which had severe donor folds at the time of surgery that persisted despite a refloat/ reposition attempt postoperatively. Etiology of folds uncertain. Preparation of the graft was uneventful. The RSB of the donor graft measured186 µm. Intraoperative insertion was atraumatic. Discussion Figure 4: Slit lamp photo of graft visually significant central macrofolds 1 month postoperatively. Note overall clarity and adherence of the donor graft.

12. Our initial findings are similar to previously reported cases of using DSAEK button with corneas that previously underwent LASIK¹·² which noted no significant difference in the preoperative preparation and postoperative results of endothelial keratoplasty using these donors. With the success and popularity of LASIK/PRK today, it will become more common to encounter donors who underwent this procedure. As the pool of LASIK altered eyes increase, it would be of interest if alterations of donor preparation (ie. positioning the flap hinge toward the microkeratome pass) would be necessary Discussion • 1. Armour RL, Ousely PJ, Wall, J. et al. Endothelial Keratoplasty Using Donor Tissue Not Suitable for Full-Thickness Penetrating Keratoplasty. Cornea 2007; 26:515-519. • 2. Phillips PM, Terry MA, Shamie N, et al. Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) Using Corneal Donor Tissue Not Acceptable for Use in Penetrating Keratoplasty as a Result of Anterior Stromal Scars, Pterygia, and Previous Corneal Refractive Surgical Procedures. Cornea 2009; 28:871-876.