Katrin Wacker

Effect of Graft Thickness on Visual Acuity After Descemet Stripping Endothelial Keratoplasty: A Systematic Review and Meta-Analysis

PURPOSE To assess the relationship between graft thickness and best-corrected visual acuity (BCVA) after Descemet stripping endothelial keratoplasty (DSEK). DESIGN Systematic review and meta-analysis. METHODS PubMed, EMBASE, Web of Science, and conference abstracts were searched for studies published up to October 2015 with standard systematic review methodology. Eligibility criteria included studies evaluating graft thickness in primary DSEK and visual outcomes. There were no restrictions to study design, study population, or language. Correlation coefficients were pooled using random-effects models. RESULTS Of 480 articles and conference abstracts, 31 met inclusion criteria (2214 eyes) after full-text review. Twenty-three studies assessed correlations between BCVA and graft thickness, and 8 studies used different statistical methods. All associations were reported dimensionless. Studies generally had small sample sizes and were heterogeneous, especially with respect to data and analysis quality (P = .02). Most studies did not measure BCVA in a standardized manner. The pooled correlation coefficient for graft thickness vs BCVA was 0.20 (95% CI, 0.14-0.26) for 17 studies without data concerns; this did not include 7 studies (815 eyes) that used different statistical methods and did not find significant associations. CONCLUSIONS There is insufficient evidence that graft thickness is clinically important with respect to BCVA after DSEK, with meta-analysis suggesting a weak relationship. Although well-designed longitudinal studies with standardized measurements of visual acuity and graft thickness are necessary to better characterize this relationship, current evidence suggests that graft thickness is not important for surgical planning.

Medical and Semi-surgical Treatments for Fuchs Endothelial Corneal Dystrophy

Unraveling the genetic mechanisms of Fuchs endothelial corneal dystrophy has opened new possibilities for future targeted medical therapy of the disease. Until these possibilities mature, regenerative semi-surgical approaches by cell injection or cell sheet transfer could help expand the donor pool, and possibly enable autologous transplantation. Descemet membrane stripping alone and acellular Descemet membrane transfer are more immediate surgical approaches that could be temporary treatments in some patients, though there is a lack of understanding of the factors that predict success for these procedures. Regardless of approach, clinical trials will be necessary, and clinicians should therefore try to standardize their methods of assessing disease severity and the outcomes of intervention.

Optical and Anatomic Changes in Fuchs Endothelial Dystrophy Corneas

The advent of endothelial keratoplasty and improvements in corneal imaging have advanced our understanding of the optical and anatomic properties of corneas with Fuchs endothelial dystrophy before and after keratoplasty. Corneal changes appear earlier in the course of Fuchs endothelial dystrophy than previously considered, indicating disease chronicity, probably in response to a state of long-term subclinical corneal edema. These early changes increase optical aberrations and light scatter that decrease visual acuity and increase disability glare, respectively. Because many of the structural changes that contribute to aberrations and scatter originate in the anterior cornea, they persist in the host cornea after endothelial keratoplasty and even after corneal edema has resolved. These factors that originate early in the disease process probably determine the visual outcomes of endothelial keratoplasty for Fuchs endothelial dystrophy.