Femtosecond Laser–Assisted Descemetorhexis: A Novel Technique in Descemet Membrane Endothelial Keratoplasty

Five-Year Safety and Efficacy of Femtosecond Laser-Assisted Descemet Membrane Endothelial Keratoplasty

PURPOSE

The purpose of this study was to evaluate 5-year safety and efficacy outcomes of femtosecond-enabled Descemet membrane endothelial keratoplasty (F-DMEK) in patients with Fuchs' endothelial dystrophy (FED).

METHODS

This was a retrospective study, including patients with FED and cataract who underwent either F-DMEK (16 eyes of 15 patients) or manual DMEK (M-DMEK) (42 eyes of 37 patients) combined with cataract extraction. Outcome measures included visual acuity, graft detachment, graft survival, and endothelial cell loss.

RESULTS

The average follow-up in F-DMEK and M-DMEK was 57.1 ± 12.4 months and 58.5 ± 17.3 months, respectively ( P = 0.757). The rates of primary failure (0% vs. 9.5%, P = 0.567), secondary failure (0% for both), and graft rejection (0% vs. 7.1%, P = 0.533) did not differ significantly between the groups. Improvement in best spectacle-corrected visual acuity was similar in F-DMEK and M-DMEK (0.32 ± 0.27 logarithm of the minimum angle of resolution and 0.35 ± 0.44 logarithm of the minimum angle of resolution, respectively, P = 0.165) and persisted at 2, 3, 4, and 5 years and at the last follow-up. The rates of graft detachment and rebubbling were significantly lower with 6.25% in F-DMEK and 33.3% in M-DMEK ( P = 0.035). Cell-loss rates were lower in F-DMEK compared with M-DMEK throughout the follow-up, significantly so up to 2 years with a difference of 8.6% at 1 year ( P = 0.023), 11.8% at 2 years ( P = 0.021), 7.6% at 3 years ( P = 0.088), 5.8% at 4 years ( P = 0.256), 13.6% at 5 years ( P = 0.169), and 7.1% at the final follow-up ( P = 0.341).

CONCLUSIONS

F-DMEK had an excellent safety and efficacy profile which was maintained over 5 years of follow-up. Lower endothelial cell-loss rates in F-DMEK compared with M-DMEK may help extend the duration of graft survival.

Femtosecond laser-assisted descemetorhexis for Descemet membrane endothelial keratoplasty: a cell- and tissue-based ex-vivo analysis in terms of precision and safety

PURPOSE

To analyze precision and safety of femtosecond laser-assisted descemetorhexis as well as postoperative corneal wound healing in human ex vivo specimens.

SETTING

Department of Ophthalmology, University Hospital, LMU Munich, Munich, Germany.

DESIGN

Experimental ex vivo study.

METHODS

Four donor corneas underwent femtosecond laser-assisted descemetorhexis. The descemetorhexis was performed using the LDV Z8 femtosecond laser followed by live/dead staining, phase contrast microscopy and scanning electron microscopy. The descemetorhexis parameters were set using a modified optical coherence tomography image capturing of 8 segments within a focus of 100 μm at the posterior corneal stroma (reversed capsulotomy program).

RESULTS

Live/dead sample staining analysis demonstrated that the femtosecond laser had minimal impact on the vitality of surrounding endothelial cells. Phase contrast microscopy and scanning electron microscopy evaluation showed that the laser produced precise, clear-cut edges leaving no stromal tissue bridges.

CONCLUSIONS

Femtosecond laser-assisted descemetorhexis could serve as a safe and precise technique with only minimal endothelial cell damage. To minimize stromal damage, further laser energy profile adjustments are necessary to optimize corneal treatment within different stages of corneal tissue swelling.

Laser-assisted corneal transplantation surgery

Corneal transplant surgeries have a broad range of indications with outcomes largely dependent on surgeon experience. Traditional manual techniques have certain limitations pertaining to the preparation of donor tissue and the recipient bed that might affect the predictability of visual outcomes. Use of lasers for keratoplasty procedures not only improves the repeatability and consistency of the technique, but also enables the surgeon to control the thickness and shape of the transplant tissue tailored to the specific condition. Despite the advantages, cost-effectiveness and technical know-how remain the major challenges. We discuss the various techniques of laser-assisted keratoplasties with respect to their methods, precision, and efficacy in various corneal indications.

Comparison of Manual and Femtosecond Laser-Assisted Descemet Membrane Endothelial Keratoplasty for Failed Penetrating Keratoplasty

PURPOSE

To compare outcomes of manual Descemet membrane endothelial keratoplasty (M-DMEK) and femtosecond laser-assisted Descemet membrane endothelial keratoplasty (F-DMEK) in treatment of penetrating keratoplasty (PK) graft failure.

METHODS

Setting: Retrospective, interventional comparative case series. PatientPopulation: Included were all patients with a failed PK graft who underwent either F-DMEK (10 eyes of 10 patients) or M-DMEK (29 eyes of 29 patients) at Toronto Western Hospital and the Kensington Eye Institute between 2014 and 2019, and had 6 months of postoperative follow-up. OutcomeMeasures: Rates of graft detachment, rebubbling, rejection and failure, best spectacle-corrected visual acuity (BSCVA), and endothelial cell (EC) density.

RESULTS

Rate of significant graft detachment (detachment requiring either rebubble or repeat keratoplasty) was 10.0% in F-DMEK and 65.5% in M-DMEK (P = .003). Rebubble rate was 10.0% in F-DMEK and 58.6% in M-DMEK (P = .011). Primary failure rate was 0% in F-DMEK and 27.6% in M-DMEK (P = .086). Rates of rejection and secondary failure did not differ between the groups (P = 1.000 for both). In a multivariable analysis, F-DMEK was found to be the only independent factor significantly associated with reduced postoperative detachment. Postoperative BSCVA at 6 months returned to prefailure levels in both groups, with no significant difference between the groups at any time point. EC loss rates were 43.8% in F-DMEK and 38.0% in M-DMEK at 6 months (P = .453).

CONCLUSIONS

F-DMEK is a safe and effective procedure in failed PK patients, with outcomes comparable to M-DMEK, and with reduced detachment and rebubble rates. A trend towards reduced primary failure should be further studied.

Three-Year Outcome Comparison Between Femtosecond Laser-Assisted and Manual Descemet Membrane Endothelial Keratoplasty

PURPOSE

To evaluate 3-year outcomes of femtosecond laser-assisted Descemet membrane endothelial keratoplasty (F-DMEK) compared with manual Descemet membrane endothelial keratoplasty (M-DMEK) in patients with Fuchs endothelial corneal dystrophy (FECD).

METHODS

A retrospective, interventional study, including eyes with FECD and cataract that underwent either F-DMEK or M-DMEK combined with cataract extraction at either the Toronto Western Hospital or Kensington Eye Institute, and that had at least 18 months' follow-up was conducted.

EXCLUSION CRITERIA

complicated anterior segments, previous vitrectomy, previous keratoplasty, corneal opacity, or any other visually significant ocular comorbidity.

RESULTS

Included were 16 eyes of 15 patients in the F-DMEK group (average follow-up 33.0 ± 9.0 months) and 45 eyes of 40 patients in the M-DMEK group (average follow-up 32.0 ± 7.0 months). There were no issues with the creation of femtosecond descemetorhexis (in the F-DMEK group)-all descemetorhexis cuts were complete. Best spectacle-corrected visual acuity improvement did not differ significantly between the groups at 1, 2, and 3 years (P = 0.849, P = 0.465 and P = 0.936, respectively). Rates of significant detachment in F-DMEK and M-DMEK were 1 of 16 eyes (6.25%) and 16 of 45 eyes (35.6%) (P = 0.027). Rebubbling rates were 1 of 16 eyes (6.25%) and 15 of 45 eyes (33.3%) (P = 0.047). Cell-loss rates following F-DMEK and M-DMEK were 26.8% and 36.5% at 1 year (P = 0.042), 30.5% and 42.3% at 2 years (P = 0.008), 37% and 47.5% at 3 years (P = 0.057), respectively. Graft failure rate was 0% in F-DMEK and 8.9% in M-DMEK (all were primary failures; P = 0.565).

CONCLUSIONS

F-DMEK showed good efficacy with reduced detachment, rebubble, and cell-loss rates, compared with M-DMEK.

Exploring the precision of femtosecond laser-assisted descemetorhexis in Descemet membrane endothelial keratoplasty

Objective

Descemet membrane endothelial keratoplasty (DMEK) remains a challenging technique. We compare the precision of femtosecond laser-assisted DMEK to manual DMEK.

Methods and Analysis

A manual descemetorhexis (DR) of 8 mm diameter was compared with a femtosecond laser-assisted DR of the same diameter (femto-DR) in 22 pseudophakic patients requiring DMEK. We used OCT images with a centred xy-diagram to measure the postoperative precision of the DR and the amount of endothelial denuded area. Endothelial cell loss (ECL) and best corrected visual acuity were measured 3 months after surgery.

Results

In the manual group, the median error of the DR was 7% (range 3%–16%) in the x-diameter and 8% (range 2%–17%) in the y-diameter. In the femto group, the median error in the respective x and y-diameters was 1% (range 0.4%–3%) and 1% (range 0.006%–2.5%), smaller than in the manual group (p=0.001). Endothelial denuded areas were larger in the manual group (11.6 mm², range 7.6–18 mm²) than in the femto group (2.5 mm², range 1.2–5.9 mm²) (p<0.001). The ECL was 21% (range 5%–78%) in the manual DR and 17% (range 6%–38%) in the femto-DR group (p=0.351). The median visual acuity increased from 0.4 logMAR (range 0.6–0.4 logMAR) in both groups to 0.1 logMAR (range 0.4–0 logMAR) in the manual group and to 0.1 logMAR (range 0.3–0 logMAR) in the femto group (p=0.461). Three rebubblings were required in the manual group, whereas the femto group required only one.

Conclusion

The higher precision of the femto-DR bears the potential to improve DMEK surgery.

Comparison of Femtosecond Laser-Enabled Descemetorhexis and Manual Descemetorhexis in Descemet Membrane Endothelial Keratoplasty

PURPOSE

To introduce a novel method to perform descemetorhexis in Descemet membrane endothelial keratoplasty (DMEK) using the femtosecond laser and to compare it with Descemet membrane endothelial keratoplasty performed with manual descemetorhexis (M-DMEK).

METHODS

A retrospective medical chart review of 2 groups of patients who underwent DMEK surgery combined with cataract surgery secondary to Fuchs corneal endothelial dystrophy and cataract: 17 patients underwent femtosecond laser-enabled descemetorhexis Descemet membrane endothelial keratoplasty (FE-DMEK) and 89 patients underwent DMEK surgery with M-DMEK. Best spectacle-corrected visual acuity, endothelial cell density (ECD), graft detachment rate, and complications were compared.

RESULTS

Average age of the 106 patients (64 women and 42 men) was 68 ± 11 years. Postoperative best spectacle-corrected visual acuity was 0.19 ± 0.13 logarithm of the minimum angle of resolution in the FE-DMEK group and 0.35 ± 0.48 logarithm of the minimum angle of resolution in the M-DMEK group (P = 0.218). One day after surgery, there were no significant graft detachments in the FE-DMEK group, compared with 20% graft detachment rate in the M-DMEK group (P = 0.041). Rebubbling was performed in 17% of eyes in the M-DMEK group compared with none in the FE-DMEK group (P = 0.066). The mean endothelial cell count in the FE-DMEK and M-DMEK groups at 6 months after surgery were 2105 ± 285 cells per square millimeter (24% cells loss) and 1990 ± 600 cells per square millimeter (29% cells loss), respectively (P = 0.579).

CONCLUSIONS

FE-DMEK shows efficacy similar to that of M-DMEK with apparently less graft detachment and reduced need for rebubbling.