Post-DSAEK Optical Changes: A Comprehensive Prospective Analysis on the Role of Ocular Wavefront Aberrations, Haze, and Corneal Thickness
ABSTRACT The aim was to assess the visual impact of ocular wavefront aberrations, corneal thickness, and corneal light scatter prospectively after performing a Descemet stripping automated endothelial keratoplasty (DSAEK) in humans.
Data were obtained prospectively from 20 eyes preoperatively and at 1, 3, 6, and 12 months post-DSAEK. At each visit, the best spectacle-corrected visual acuity and visual acuity with glare (brightness acuity testing) were recorded, and ocular wavefront measurements and corneal optical coherence tomography (OCT) were performed. The magnitude and the sign of individual Zernike terms [higher-order aberrations (HOAs)] were determined. Epithelial, host stromal, donor stromal, and total corneal thicknesses were quantified. The brightness and intensity profiles of OCT images were generated to quantify light scatter in the whole cornea, subepithelial region, anterior and posterior host stroma, interface, and donor stroma.
The mean best spectacle-corrected visual acuity and glare disability at low light levels improved from 1 to 12 months post-DSAEK. All corneal thicknesses and ocular lower-order aberrations and HOAs were found to be stable from 1 to 12 months, whereas total corneal, host stromal, and interface brightness intensities decreased significantly over the same period. A repeated measures analysis of variance performed across the follow-up period revealed that the change in scatter, but not the change in the HOAs, could account for the variability occurring in the acuity from 1 to 12 months post-DSAEK.
Although ocular HOAs and scatter are both elevated over normal values post-DSAEK, our results demonstrate that the improvements in visual performance occurring over the first year post-DSAEK are associated with decreasing light scatter. In contrast, there were no significant changes in the ocular HOAs during this time. Because corneal light scatter decreased between 1 and 12 months despite there being stable corneal thicknesses over the same period, we conclude that factors that induced light scatter, other than tissue thickness or swelling (corneal edema), significantly impacted the visual improvements that occurred over time post-DSAEK. A better understanding of the cellular and extracellular matrix changes of the subepithelial region and interface, incurred by the surgical creation of a lamellar host-graft interface, and the subsequent healing of these tissues, is warranted.
- SourceAvailable from: PubMed Central[Show abstract] [Hide abstract]
ABSTRACT: To evaluate myofibroblast differentiation as an etiology of haze at the graft-host interface in a cat model of Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK). DSAEK was performed on 10 eyes of 5 adult domestic short-hair cats. In vivo corneal imaging with slit lamp, confocal, and optical coherence tomography (OCT) were performed twice weekly. Cats were sacrificed and corneas harvested 4 hours, and 2, 4, 6, and 9 days post-DSAEK. Corneal sections were stained with the TUNEL method and immunohistochemistry was performed for α-smooth muscle actin (α-SMA) and fibronectin with DAPI counterstain. At all in vivo imaging time-points, corneal OCT revealed an increase in backscatter of light and confocal imaging revealed an acellular zone at the graft-host interface. At all post-mortem time-points, immunohistochemistry revealed a complete absence of α-SMA staining at the graft-host interface. At 4 hours, extracellular fibronectin staining was identified along the graft-host interface and both fibronectin and TUNEL assay were positive within adjacent cells extending into the host stroma. By day 2, fibronectin and TUNEL staining diminished and a distinct acellular zone was present in the region of previously TUNEL-positive cells. OCT imaging consistently showed increased reflectivity at the graft-host interface in cat corneas in the days post-DSAEK. This was not associated with myofibroblast differentiation at the graft-host interface, but rather with apoptosis and the development of a subsequent acellular zone. The roles of extracellular matrix changes and keratocyte cell death and repopulation should be investigated further as potential contributors to the interface optical changes.PLoS ONE 09/2013; 8(9):e75623. DOI:10.1371/journal.pone.0075623
- [Show abstract] [Hide abstract]
ABSTRACT: Penetrating keratoplasty is being replaced by posterior lamellar techniques like Descemet stripping automated endothelial keratoplasty or Descemet membrane endothelial keratoplasty (DMEK) for the surgical treatment of patients with endothelial insufficiency. Although DMEK leads to the best visual results, Descemet stripping automated endothelial keratoplasty is still the standard procedure for many surgeons because it is technically more standardized. Here, we investigated how donor characteristics may influence DMEK surgery. After in vitro preparation of DMEK grafts (n = 28), we measured the width of the graft roll, which we correlated to various donor characteristics. In 31 DMEK cases, we measured the intraoperative time from implantation to attachment of the graft, which we correlated to the respective donor characteristics and endothelial cell loss. We used Pearson's method and a multifactorial linear model for the statistical assessments. We found a statistically significant correlation between donor age (P < 0.001) and endothelial cell density (P < 0.05), and the width of the DMEK rolls. That is, older donors and grafts with higher endothelial cell densities formed broader graft rolls. Donor age also showed a trend to directly influence the unfolding time that took longer using younger grafts. Furthermore, the relative endothelial cell loss increased with longer unfolding times. We found that donor age and endothelial cell density influence the properties of DMEK grafts, and thereby the duration of the surgical procedure. Increased unfolding times result in higher endothelial cell loss. Therefore, it seems reasonable to accept preferably older donors with high endothelial cell densities for DMEK, which may be particularly true for inexperienced surgeons or complex clinical situations.Cornea 03/2014; DOI:10.1097/ICO.0000000000000106
- [Show abstract] [Hide abstract]
ABSTRACT: Descemet stripping automated endothelial keratoplasty (DSAEK) has become worldwide the procedure of choice for the replacement of diseased corneal endothelium. More recently, ultrathin DSAEK (UT-DSAEK) has been introduced to guarantee better visual outcomes preserving good donor graft manipulation.Current Opinion in Ophthalmology 05/2014; DOI:10.1097/ICU.0000000000000071