1. Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy Findings in Femtosecond Laser- Assisted Keratoplasty Kurt H. Kelley, MD; Roni M. Shtein, MD; Jessica Knowlton, BS; David C. Musch, PhD; Leslie M. Niziol, MS; Alan Sugar, MD; Shahzad I. Mian, MD Kellogg Eye Center, Department of Ophthalmology and Visual Sciences University of Michigan, Ann Arbor, Michigan The authors have no financial interest in the subject matter of this poster.

2. Abstract Purpose: To describe anterior segment OCT and in vivo confocal microscopy findings in patients after femtosecond laser-assisted keratoplasty (FLAK), and to determine if there are any associations between specific findings and visual outcomes over time. Methods: Prospective, consecutive case series of patients undergoing FLAK with anterior segment optical coherence tomography (OCT) and in vivo confocal microscopy performed preoperatively and at 1 week, and 1, 3, 6, 12, and 18 months postoperatively. Inclusion criteria included age ≥18 years, corneal opacification, and BCVA ≤20/40 in the affected eye. Results: 18 eyes of 18 patients were included with a mean follow-up of 10.6 months. Anterior segment OCT showed a decrease in graft-host junction interface and malapposition over time. Malapposition was associated with decreased BCVA (P=0.003). In vivo confocal microscopy showed increased keratocyte activation and dendritic cells at the first postoperative visit followed by a decrease over time. Stromal and subbasal reinnervation were seen beginning at 1 and 3 months, respectively. Needle-like opacities were present on almost all scans, and microdots were variably present. Conclusions: Graft-host junction interface and malapposition after FLAK decrease over time, and malapposition is significantly associated with decreased BCVA. There is an initial increase then decrease in keratocyte activation and dendritic cells over time. Corneal reinnervation is seen as early as 1 month postoperatively. Other in vivo confocal microscopy findings are variably seen and are presumed to be indicators of corneal inflammation and healing.

3. Background Femtosecond laser-assisted keratoplasty (FLAK) results in faster healing times and visual recovery, less astigmatism and endothelial cell loss, and better wound strength than standard PK. 1-3 Anterior segment optical coherence tomography (OCT) and in vivo confocal microscopy are not well described for FLAK, and may provide some insight into healing and improvement in visual acuity. 1. Bahar I, et al. Femtosecond laser versus manual dissection for top hat penetrating keratoplasty. Br J Ophthalmol. 2009 Jan;93(1):73-8. 2. Malta JB, et al. Femtosecond laser-assisted keratoplasty: laboratory studies in eye bank eyes. Curr Eye Res. 2009 Jan;34(1):18-25. 3. Farid M, et al. Comparison of penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional blade trephination. Ophthalmology. 2009 Sep;116(9):1638-43.

4. Purpose To describe anterior segment OCT and in vivo confocal microscopy findings after FLAK, and to determine if there are any associations between specific findings and visual outcomes over time.

5. Methods Prospective, consecutive case series of 18 eyes of 18 patients undergoing mushroom-shaped FLAK with mean follow-up of 10.6 months. Inclusion criteria: age ≥18 yrs, corneal opacification, and BCVA ≤20/40 in the affected eye. Anterior segment OCT* and in vivo confocal microscopy** performed at 1 week, and 1, 3, 6, 12, and 18 months postoperatively. *Visante® OCT, Carl Zeiss Meditec, Dublin, CA **HRT II Rostock Cornea Module, Heidelberg Engineering, Heidelberg, Germany

6. Figure 1. Examples of anterior segment OCT images in two patients after FLAK showing measurement of graft-host junction interface and malapposition. Malapposition Interface OCT

7. 0 3 10 2 Figure 2. In vivo confocal microscopy standards used for grading keratocyte activation. Activated keratocytes were characterized by the presence of hyperreflective nuclei and/or visible cytoplasmic processes. Grade 0=0-25% activation; grade 1=25-50% activation; grade 2=50-75% activation, grade 3=75-100% activation. Confocal Microscopy

8. 12 3 Figure 3. In vivo confocal microscopy standards used for grading dendritic cells. Grade 0 (not shown)=no cells; grade 1=1-5 cells; grade 2=6-20 cells; grade 3=>20 cells. Figure 4. In vivo confocal microscopy standards used for determining the (A) presence of microdots, (B) needle-like opacities and (C) corneal reinnervation. CB A Confocal Microscopy

9. Results Figures 5-7. Distribution plots showing graft-host junction interface and malapposition (top) and BCVA (bottom) over time. Mean values are listed. Malapposition was significantly associated with decreased BCVA (P=0.003).

10. Figures 8-9. Mean values from in vivo confocal microscopy grading showing increased keratocyte activation and dendritic cells from 0 months (preoperative) to 1 month, followed by a decrease in these two features over time on both central and peripheral scans. - central - peripheral Results - central - peripheral

11. Preoperative1 month3 months6 months12 months18 months Corneal nerves (% present) Central Subbasal87.5% (14/16)6.7% (1/15)0% (0/14)0% (0/11)45.5% (5/11)33.3% (1/3) Stromal88.9% (16/18)20% (3/15)40% (6/15)36.4% (4/11)40% (4/10)33.3% (1/3) Peripheral Subbasal87.5% (14/16)0% (0/12)27.3% (3/11)9.1% (1/11)30% (3/10)0% (0/3) Stromal88.9% (16/18)42.9% (6/14)40% (6/15)45.5% (5/11)40% (4/10)33.3% (1/3) Needle-like opacities (% present) Central88.9% (16/18)87.5% (14/16)100% (16/16)81.8% (9/11)90.9% (10/11)100% (3/3) Peripheral100% (17/17)85.7% (12/14)86.7% (13/15)100% (11/11)100% (10/10)66.7% (2/3) Microdots (% present) Central50% (9/18)68.8% (11/16)53.3% (8/15)72.7% (8/11)90.9% (10/11)100% (3/3) Peripheral62.5% (10/16)78.6% (11/14)60% (9/15)72.7% (8/11)70% (7/10)66.7% (2/3) Table 1. Data from pre- and postoperative in vivo confocal microscopy scans. Stromal and subbasal reinnervation after FLAK were seen in multiple patients beginning at 1 and 3 months, respectively. Needle-like opacities were present on almost all central and peripheral scans. Microdots increased over time on central scans and were variably present over time on peripheral scans. Results

12. Conclusions Graft-host junction interface and malapposition after FLAK decrease over time, and malapposition is significantly associated with decreased BCVA. In vivo confocal microscopy shows an initial increase in keratocyte activation and dendritic cells after FLAK that decreases over time. Corneal reinnervation is seen as early as 1 month postoperatively. Further study is needed to better characterize FLAK imaging findings and to compare with standard PK wound healing.