Corneal wavefront errors 24 months after deep lamellar endothelial keratoplasty and penetrating keratoplasty.
To evaluate high-order aberrations (HOA) induced by the anterior corneal surface after deep lamellar endothelial keratoplasty (DLEK) and penetrating keratoplasty (PK).
                Prospective, randomized clinical trial.
                Twenty-eight eyes of 25 patients with corneal edema resulting from Fuchs dystrophy underwent DLEK with a 9- to 10-mm incision (n = 13) or PK with double-running sutures (n = 15) at the Cornea Service, Mayo Clinic Department of Ophthalmology, Rochester, Minnesota. The main outcome measures were HOA from the anterior corneal surface calculated from corneal topography and decomposed into Zernike polynomials to the sixth order, high- and low-contrast visual acuity (VA), and contrast sensitivity. Variables after surgery were compared with those before surgery and between treatments by using generalized estimating equation models with Bonferroni adjustment.
                Total HOA through 24 months (0.48 +/- 0.15 microm) after DLEK was similar to total aberration before surgery (0.44 +/- 0.23 microm; P = .10). After PK, total HOA remained elevated through 24 months (1.68 +/- 0.58 microm) compared with that before surgery (0.49 +/- 0.27 microm; P < .005) and compared with that after DLEK (P < .006). At 24 months after PK, corneas with sutures removed had greater total HOAs than corneas with sutures intact (1.90 +/- 0.52 microm vs 1.18 +/- 0.33 microm; P = .001). High- and low-contrast VA and contrast sensitivity at 24 months after PK did not correlate with any HOA.
                HOAs from the anterior corneal surface were higher after PK compared with after DLEK but did not correlate with visual function after PK.
There is no high quality evidence that EK is superior to PKP in the treatment of FED considering the studies that satisfied our primary and secondary outcome measures. One RCT demonstrated that HOAs are lower following EK and some lower quality evidence suggests that endothelial rejection episodes may be less with EK. These findings should be interpreted with caution as they are based on data with risk of biases. Further RCTs of visual and refractive outcomes needs to be performed in this field, comparing EK to PKP, with a larger sample size and at least five years of follow up. To avoid bias due to a surgeon's learning curve, procedures should be performed by experienced surgeons only. Quality of life and vision should also be evaluated. The risk of endothelial rejection will be difficult to address in the context of a RCT because of power considerations but large non-randomised comparative case series and corneal graft registry outcome data will be useful in this regard.