Changes in Corneal Parameters after DMEK Surgery: A Swept-Source Imaging Analysis at 12-Month Follow-Up Time

Abstract

Purpose. To assess the time course changes in corneal topographic parameters during the one-year follow-up after Descemet membrane endothelial keratoplasty (DMEK) surgery. Materials and Methods. Twenty-one patients (24 eyes) who underwent DMEK surgery were evaluated. Best corrected visual acuity (BCVA), endothelial cell count (ECC), central corneal thickness (CCT), mean keratometry (MK), mean astigmatism (MA), astigmatism asymmetry (AA), and higher-order aberration (HOA) were assessed at baseline and 1, 3, 6 and 12 months after the surgery using CASIA2 anterior segment swept-source OCT (Tomey, Japan). Results. In patients who underwent DMEK surgery, BCVA improved gradually at the subsequent visits during the 12-month follow-up. A significant reduction in ECC and CCT at the 1st month was noted, which remained stable until the 6th month postoperatively. Anterior and total MK values remained unchanged, whereas changes in posterior keratometry were noticeable until the 6th month after surgery. A significant reduction in the anterior, posterior, and total astigmatism magnitude as well as astigmatism asymmetry was observed during the first 6 months after surgery. A gradual anterior, posterior, and total HOA decrease was documented until the 12th month after surgery. Negative correlations between baseline values of CCT, MK, MA, AA, and HOA and postoperative variations in those parameters at consecutive follow-up time points were observed. Accordingly, negative correlations between baseline CCT and postoperative changes in corneal topographic parameters after surgery were found. Conclusion. The stabilization of most corneal topographic parameters takes place within 6 months after the procedure, whereas HOA reduction and BCVA improvement gradually occur during the first year after surgery. Preoperative values of corneal topographic parameters strongly determine their changes detected after DMEK surgery, which may suggest that early therapeutic intervention results in better visual outcomes.

Postoperative, but not preoperative, central corneal thickness correlates with the postoperative visual outcomes of Descemet membrane endothelial keratoplasty

“…Our failure to find a correlation between preoperative CCT and post-DMEK BSCVA has also been observed by three other studies, including two with large cohorts (n = 160 and 1084) [14,15,21]. However, a study by Peraza-Nieves et al on 393 DMEK eyes found with multivariate analysis that 1-μm higher preoperative CCT predicted 0.0008 higher logMAR BSCVA at 24 months [6].…”

“…Thus, it is possible that this CCT threshold could help determine when to conduct DMEK, with the aim of achieving the best possible postoperative visual acuity. However, four other studies have to our knowledge examined the relationship between preoperative CCT and final BSCVA after DMEK, and three failed to find a relationship [6,14,15,21] (Table 1). To address this issue further, we performed the present study assessing the influence of preoperative CCT on the postoperative BSCVA of eyes that underwent DMEK.…”

“…Due to concerns about surgery, patients often prefer to delay DMEK as long as possible. However, because FECD eventually generates scarring and a toxic inflamed ocular environment that is hostile to the graft endothelium, the visual success of grafting drops the longer surgery is postoponed [11][12][13][14]. Therefore, it would be useful to determine a clinical point that could signal to both surgeons and patients when DMEK should be conducted, thereby preserving optimal outcomes.…”

Comparative Analysis of Corneal Parameters in Swept-Source Imaging between DMEK and UT-DSAEK Eyes

“…The preparation of the DMEK graft and surgery was performed following the ‘no-touch’ technique, as described previously [ 13 ].…”

Deformable Biomechanics of DMEK Tissue Scrolls Traveling Through Narrow Lumens: The Inverse Relationships Between Fluid Velocity, Scroll Width, and Wall Contact and Their Clinical Implications for Preloading

“…In recent years, several DMEK tissue injectors have been introduced with narrower tips as surgeons continue their pursuit of more optimal astigmatism outcomes, but surgeons' adoption of narrower DMEK injectors has been mixed. 3,4 One concern is that DMEK tissue will incur greater endothelial cell loss (ECL) in injectors with narrower lumens because the corneal endothelium, which resides on the outside of the scroll, may have more contact with the lumen wall. This contact may especially be greater when the cross-sectional diameter of tissue scroll (ie, scroll width) is greater than the injector lumen diameter.…”