Primary Descemet’s Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy versus Bullous Keratopathy: Histopathology and Clinical Results

<p><b>Purpose</b>: To investigate functional and anatomical results up to 12 months after Descemet’s membrane endothelial keratoplasty (DMEK) for Fuchs’ endothelial dystrophy (FED) versus bullous keratopathy (BK) in consideration of morphologic characteristics on host’s endothelium-Descemet’s membranes (EDM).</p> <p><b>Methods</b>: In a prospective consecutive case series, 119 eyes underwent a primary DMEK for FED or BK. Intraoperatively obtained EDM were investigated immunohistologically. Clinical and morphological parameters were compared between FED and BK.</p> <p><b>Results</b>: Overall, the 12-months best-corrected visual acuity (BCVA) was 0.14 logMAR, and 0.10 logMAR in eyes without vision-limiting comorbidities; thereby no differences were revealed between eyes with FED and BK up to 12 months postoperative (<i>p</i> = 0.186 and <i>p</i> = 0.095, respectively). Correspondingly, the mean central corneal thickness (CCT) measured 520 vs. 529 µm and the mean endothelial cell density (ECD) was 1743 vs. 1457 cells/mm² for FED and BK, 12 months postoperative. Regarding CCT and ECD, no differences were observed between the groups (<i>p</i> = 0.181 and <i>p</i> = 0.112, respectively). The overall detachment rate was 40% (48/119). Comparing FED and BK the detachment rates did not differ, which were 41% vs. 39% and 43% vs. 35%, in pseudophakic eyes (<i>p</i> = 0.554 and <i>p</i> = 0.601, respectively). Yet, the distribution of recurring graft detachments differed between FED and BK; secondary re-detachments were more frequent in the FED group (7 cases). Regarding histologic investigations, a lower ECD was found in specimens with BK, no differences were revealed for EDM and anterior banded layer thicknesses. Immunohistologically, differences in the distribution of fibronectin and cytokeratin were observed. A rarification of matrix proteins was found in EDM complexes with FED.</p> <p><b>Conclusions</b>: DMEK produces similar results for FED and BK. However, the postoperative course may differ with regard to the recurrence of secondary graft detachments that may be associated by histopathologic particularities.</p

Segmentation of retinal layers.

<p>(A) Sample ring scan with additional layer segmentation. Layers from top: Nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor layer (PRL) and retinal pigment epithelium (RPE). (B) Comparison of the mean thickness of the additional retinal layers between healthy controls (in blue) and SCA1 patients (in red).</p

Single case reports of SCA1 patients.

<p>Single case reports of SCA1 patients.</p

Differences of RNFLT between SCA1 and HC.

<p>(A) Average RNFLT (in µm) of the total ring scan (G) and in the different sectors (nasal-superior (NS), nasal (N), nasal-inferior (NI), temporal-inferior (TI), temporal (T) and temporal-superior (TS)). Error bars indicate standard deviation. Significance levels (*** for p<0.001, ** for p<0.01 and * for p<0.05) were calculated by GEE. (B) Mean RNFLT profile of both study groups in µm. (C) Both eyes (OD = right, OS = left) of a sample patient (upper line) with typical RNFLT sectors in comparison with matched healthy control (bottom line). The colors of the sectors are related to the comparison with the Spectralis normative database. Green indicates thickness values within the 95%-percentile of the database, while sectors in yellow were thinner than the 5%-percentile of the normative database and sectors in red were within the lowest 1%.</p

OCT examination results.

<p>RNFLT results were obtained from 9 SCA1 and compared to 9 age/sex matched healthy controls (HC). 2 eyes of SCA1 patients had to be excluded, one left eye due to blindness and one right eye because of errors in the OCT image. In total, 11 eyes of SCA1 patients fulfilled quality criteria for the TMV scan and were compared to the corresponding eyes of the matching healthy controls.</p

Demographic information and clinical of the patient cohort (SCA1) and the matched healthy controls group (HC).

<p>Results for the VEP examination were available for 6 SCA1 patients and of 5 of the matching healthy controls. For 1 SCA1 patients repeat length of the diseased allele were missing and 2 patients lack values for the healthy allele and 1 patient had no examination of the visual acuity.</p

Correlation of clinical parameters with RNFLT.

<p>(A) Dependency of disease duration to SARA score. RNFLT with respect to SARA score (B), disease duration (C) and visual acuity (D) for SCA1 patients (red) and healthy controls (blue).</p

Comparison of RNFLT results to the Spectralis normative Database.

<p>Comparison of RNFLT results to the Spectralis normative Database.</p