1A Optimizing corneal transplantation techniques for two common cornea disorders.

Fuchs endothelial dystrophy (FED) and keratoconus (KC) are common indications for corneal transplantations. Keratoplasy techniques have evolved dramatically during the last decade with few comparative studies on clinical outcome of distinctive operative procedures[1]. In addition, some techniques may enable the reduction of operating theatre (OT) time, thereby reducing costs. In this project, surgical techniques for two corneal disorders are evaluated for their clinical efficacy and the potential to reduce OT time. KC is a common corneal disorder leading to reduced visual acuity (VA) in young patients. It is progressive in a minority of patients who subsequently need a penetrating corneal transplant (around 100 yearly in the Netherlands). Several new surgical techniques for the treatment of KC have been developed, including deep anterior lamellar (DALK) and penetrating mushroom techniques. An example of the latter is a technique designed by Busin with a large anterior lamella and a smaller posterior lamella floating against the anterior lamella. Alternatively, a mushroom shape of the donor cornea can be prepared with a femtosecond laser (FL), potentially reducing operation theatre (OT) time by 60% if donor and recipient preparation takes place outside the OT. FED is a fairly common corneal disorder leading to reduced VA and contrast sensitivity (CS) in patients over 50 years. In 2013 in the Netherlands 407 patients with FED underwent a corneal transplantation. There is a debate whether Ultrathin Descemet Stripping Automated Endothelial Keratoplasty (UTDSAEK) or Descemet Membrane Endothelial Keratoplasty (DMEK) is the procedure of choice in FED. At this moment, donor preparation of the posterior cornea lamella is mostly performed in the OT, while cornea banks are developing techniques to deliver prepared tissue, potentially reducing OT time and enabling better use of donor tissue. Objectives: 1.To compare the effect on visual rehabilitation of 2 surgical techniques for mushroom shaped donor preparation (Busin and FS) in corneal transplantations for KC. 2.To reduce operation theatre (OT) time by 75 minutes by preparation of donor material and recipient trephination with FS laser. 3.To compare the effect on visual rehabilitation of 2 surgical techniques for posterior corneal transplantation (UTDSAEK and DMEK) in FED patients. 4.To reduce OT time by 45 minutes by preparation of donor material in the cornea bank. Hypothesis: -FL shaping of the donor- and recipient cornea leads to a reduced astigmatism as opposed to the MALK technique. -DMEK leads to a better VA than UTDSAEK in Fuchs’ dystrophy patients. Study Design: Two randomized studies. Study population: -patients with advanced KC needing a keratoplasty to restore vision -Fuchs’endothelial dystrophy patients eligible for posterior lamellar surgery for visual rehabilitation. Interventions: -[KC] femtosecond laser assisted mushroom shaped keratoplasty or keratoplasty performed with MALK -[FED] UTDSAEK or DMEK Outcome measures: Primary outcome:KC] Astigmatism after 3, 6 and 12 months -FED] LogMAR Best Corrected Visual Acuity (BCVA) at 1, 3, 6, 12 months. Selected secondary outcomes: -logMAR visual acuity (uncorrected, spectacle corrected) at 1, 3, 6, 12 months -Rate of LogMAR BSCVA recovery in both groups (RMANOVA) -Contrast sensitivity and stray light at 1, 3, 6, 12 months -Quality of vision questionnaire at 1, 3, 6, 12 months -Endothelial cell density of the grafts before transplantation and at 6 and 12 months -Number of patients who need hard contact lens wear after surgery to achieve a VA > 0.5 at 12 months -Graft survival at 12 months in both groups -RMS (root mean square of Zernike polynomials) of total high order aberrations -Number of graft detachments and failures in both groups -OT time and costs Sample size: [KC] 40 patients (20 in each treatment group) based on 0.2 difference in VA at 24 months [FED] 80 eyes (40 in each study group) based on a difference between the DSAEK and DMEK group of 10 letters of logMAR VA at 1 year. Data analysis: [KC] Crude- and vector analysis of astigmatism at 6 and 12 months will be compared ((RM)ANOVA). Visual acuity, contrast sensitivity, stray light, quality of vision and endothelial cell density data will be compared ((RM)ANOVA). Number of graft failures and number of patients in need of contact lens wear will be compared (Fishers’ exact test and/or chi square test) [FED] BSCVA results will be compared (RMANOVA). Contrast sensitivity, stray light and quality of vision questionnaire results will be compared (RMANOVA). Numbers of graft detachments and failures will be analyzed (chi-square test). Collaboration/connection: measurements, database design and filling and statistical analysis will be performed in close collaboration with the Rotterdam Ophthalmic Institute. Time schedule: inclusion 1.5 year, follow-up 2 years (total 3.5 years)