**4.1 Clinical experience with Femto-DSEK/DLEK**

Another application of the femtosecond laser technology is the new frontier of lamellar surgery: the posterior lamellar keratoplasty (PLK).

The new technique of Descemet Stripping Endothelial Keratoplasty (DSEK)16, 17 assisted by a femtosecond laser has been planned to perform more regular and precise endothelial donor buttons.

We performed this femtosecond-assisted DSEK technique on 12 eyes of 12 patients using the original "taco" technique for endothelial lamella insertion.

## **4.2 Surgical procedure**

The donor lamella is performed on an entire donor cornea delivered by an Italian Corneal Bank using an artificial anterior chamber (Moria, France) and the 60kHz femtosecond laser with a double raster pattern of 9mm diameter at 400 microns of depth. Then, the button is punched with a 8.50mm diameter corneal trephine and the two resulting lamellae are divided with forceps (Figure 13). The receiving bed is prepared in the usual way with endothelium/Descemet layer manual stripping. Then, the donor button is inserted in AC with the "taco" technique and settled in place with air injection.

a b

Fig. 12. Confoscan 4 confocal microscopy analysis of graft rejection of Femto-DALK: a. no

c d

immunological infiltrates of the anterior stroma of donor lamella; d. inflammatory infiltrates

Another application of the femtosecond laser technology is the new frontier of lamellar

The new technique of Descemet Stripping Endothelial Keratoplasty (DSEK)16, 17 assisted by a femtosecond laser has been planned to perform more regular and precise endothelial donor

We performed this femtosecond-assisted DSEK technique on 12 eyes of 12 patients using the

The donor lamella is performed on an entire donor cornea delivered by an Italian Corneal Bank using an artificial anterior chamber (Moria, France) and the 60kHz femtosecond laser with a double raster pattern of 9mm diameter at 400 microns of depth. Then, the button is punched with a 8.50mm diameter corneal trephine and the two resulting lamellae are divided with forceps (Figure 13). The receiving bed is prepared in the usual way with endothelium/Descemet layer manual stripping. Then, the donor button is inserted in AC

recipient endothelium involvement, b. oedema of deep donor lamellar stroma; c.

**4. Posterior Lamellar Keratoplasty Techniques (DSEK/DLEK)** 

and oedema of epithelium of the graft

buttons.

**4.2 Surgical procedure** 

**4.1 Clinical experience with Femto-DSEK/DLEK** 

surgery: the posterior lamellar keratoplasty (PLK).

original "taco" technique for endothelial lamella insertion.

with the "taco" technique and settled in place with air injection.

Fig. 14. Clinical case of Femto-DSEK (with "taco" technique): Preoperative slit lamp examination shows massive corneal oedema (a); One week postoperative shows corneal oedema, endothelial lamella centred with air in AC (b); one month postoperatively the corneal oedema is reduced (c) and three months postoperatively a clear graft is shown (d)

One day postoperatively, the donor lamella resulted in place in 9 cases (Figure 14). In three cases, the donor lamella resulted dislocated (Fig. 15), requiring a second air injection in AC to reposition it back.

One month after surgery the BSCVA resulted not so good (mean BSCVA 0.5 ± 0.15 SD) and increased slowly during the follow-up, resulting a little bit higher six months after surgery ( 0.58 ± 0.23SD).

Femtosecond Laser Assisted Lamellar Keratoplasties 89

a b

c d

Fig. 17. Clinical case of Femto-DSEK (with Busin folder): Preoperative massive corneal oedema with bullous keratopathy (a); one week postoperatively the donor lamella is well adherent but corneal oedema is still present (b); One month postoperatively endothelial lamella is well centred and adherent with light corneal oedema (c); three months

Fig. 18. Femto-DSEK: a. one week after surgery stromal oedema is still present; b. one month postoperatively a clear graft with little oedema well centred and strongly adherent to the

abc

postoperatively there's a clear cornea and the BSCVA results 0.7 (d).

internal surface but with the "step" between donor and recipient (c)

Fig. 15. Donor lamella dislocated downward three days after surgery.

Fig. 16. Optical Coherence Tomography with Visante shows the endothelial lamellar thickness.

To assess the precision, safety and reproducibility of femtosecond laser cut we studied the donor lamellae with a Spectral Domain Optical Coherent Tomography analysis (Visante, Carl Zeiss Meditec, Jena, Germany). The planned donor lamellar thickness of 198m ± 25.45SD (range 190-210), resulted 177m ± 34.50SD (range 150-200) three months after surgery (Fig. 16). These results probably were related to the deswelling of the donor lamella during the follow-up.

Nevertheless, the greatest problem using the "taco" technique was the high surgical endothelial cell loss. In fact, with Confoscan 4 confocal microscopy analysis we found that endothelial cell loss was around 49% three months after surgery (preoperative mean ECD: 2389 ± 368 cell/mm2 (range: 2150-2580; postoperative mean ECD: 1028 ± 582 cell/mm2 (range 787-1550), with respect to the 22% of PK procedures. These higher rate resulted in a high graft failure percentage (around 55%).

For this reason, we began to utilize the "pull in technique" with the Busin folder. Utilizing this new device to insert the donor lamella, we performed the Femto-DSEK in 12 eyes of 10 patients with endothelial pathologies. With this technique, intraoperative endothelial cell loss resulted around 30%, with better postoperative results (Figure17). During the followup, two cases required endothelial lamella replacing and two cases required a penetrating keratoplasty after the DSEK failure for vision recovery.

Fig. 16. Optical Coherence Tomography with Visante shows the endothelial lamellar thickness. To assess the precision, safety and reproducibility of femtosecond laser cut we studied the donor lamellae with a Spectral Domain Optical Coherent Tomography analysis (Visante, Carl Zeiss Meditec, Jena, Germany). The planned donor lamellar thickness of 198m ± 25.45SD (range 190-210), resulted 177m ± 34.50SD (range 150-200) three months after surgery (Fig. 16). These results probably were related to the deswelling of the donor lamella

Nevertheless, the greatest problem using the "taco" technique was the high surgical endothelial cell loss. In fact, with Confoscan 4 confocal microscopy analysis we found that endothelial cell loss was around 49% three months after surgery (preoperative mean ECD: 2389 ± 368 cell/mm2 (range: 2150-2580; postoperative mean ECD: 1028 ± 582 cell/mm2 (range 787-1550), with respect to the 22% of PK procedures. These higher rate resulted in a

For this reason, we began to utilize the "pull in technique" with the Busin folder. Utilizing this new device to insert the donor lamella, we performed the Femto-DSEK in 12 eyes of 10 patients with endothelial pathologies. With this technique, intraoperative endothelial cell loss resulted around 30%, with better postoperative results (Figure17). During the followup, two cases required endothelial lamella replacing and two cases required a penetrating

Fig. 15. Donor lamella dislocated downward three days after surgery.

during the follow-up.

high graft failure percentage (around 55%).

keratoplasty after the DSEK failure for vision recovery.

Fig. 17. Clinical case of Femto-DSEK (with Busin folder): Preoperative massive corneal oedema with bullous keratopathy (a); one week postoperatively the donor lamella is well adherent but corneal oedema is still present (b); One month postoperatively endothelial lamella is well centred and adherent with light corneal oedema (c); three months postoperatively there's a clear cornea and the BSCVA results 0.7 (d).

Fig. 18. Femto-DSEK: a. one week after surgery stromal oedema is still present; b. one month postoperatively a clear graft with little oedema well centred and strongly adherent to the internal surface but with the "step" between donor and recipient (c)

Femtosecond Laser Assisted Lamellar Keratoplasties 91

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Fig. 19. Optical Coherent Tomography (on the left) of Femto-DLEK shows perfect "matching" of donor lamella like an "insert" into the recipient bed.

To avoid the problems of the endothelial lamellar dislocation (Figure 15) and the presence of the "step" between donor and recipient (Figure 18), we tried to perform a Femto-DLEK technique (basing on the Melles' manual DLEK technique) using the femtosecond laser to perform the endothelial lamellar cut both in the donor cornea and the recipient one 18. In this way we tried to realize a perfect "match" between donor and recipient cornea with the donor lamella "inserted" in the recipient bed (Figure. 19), but the stroma-stroma interface resulted in a hard scarring showing low visual results (0.3 or little more) with patient dissatisfaction that required a PK and we abandoned this technique.
