Change in Visual Acuity of Patients With Fuchs Endothelial Corneal Dystrophy Over 1 Year.

PURPOSE: To determine whether the clinical and paraclinical course of Fuchs endothelial corneal dystrophy (FECD) over 1 year is related to the extent of triplet repetition in the transcription factor 4 (TCF4) gene. METHODS: A prospective study with a 1-year follow-up was conducted. A total of 104 patients (160 eyes) with FECD and an equivalent number of age- and sex-matched control subjects without FECD were included. At inclusion, the corneas were graded using the modified Krachmer grade (KG) and patients were genotyped for the number of trinucleotide repeats (TNRs) in the TCF4 gene by the short tandem repeat assay. Visual acuity, Scheimpflug tomographic features, and the Visual Function and Corneal Health Status using a visual disability instrument were measured on 2 visits at 1-year intervals. RESULTS: KGs ranged from 1 to 6, and 46% of eyes had grades 1 to 4. 71% of the patients harbored TNR expansion (>40) versus 13% in control subjects (P < 0.001). Severity at inclusion was higher in the presence of TNR expansion when considering eyes independently (mean grade ±SD, 4.08 ± 1.42) without TNR expansion and 4.66 ± 1.27 with TNR expansion (P = 0.024). In 1 year, the ETDRS score significantly decreased by -2.97 (95% confidence interval -4.69 to -1.26, P = 0.001) and the ETDRS score with glare by -4.25 (95% confidence interval -6.22 to -2.27, P < 10-5). There was no relationship between the rate of decline and TNR expansion or KG. Central corneal thickness and Visual Function and Corneal Health Status scores did not significantly vary. CONCLUSIONS: It is possible to measure a subtle progression of FECD over a period as short as 1 year. We did not find a relationship between the presence of TNR expansion and the speed of deterioration over 1 year. This work should facilitate the design of future clinical trials on FECD.Trial Registration-URL: ClinicalTrials.gov. Identifier: French Fuchs Follow-up Study (F3S): NCT03974230.

Nanotopography by chromatic confocal microscopy of the endothelium in Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy and healthy corneas.

AIM: To investigate the interest of chromatic confocal microscopy (CCM) to characterise guttae in Fuchs endothelial corneal dystrophy (FECD). METHODS: Descemet's membranes (DM) were obtained during endothelial keratoplasty in patients with FECD and pseudophakic bullous keratopathy (PBK). They were compared with healthy samples obtained from body donation to science. Samples were fixed in 0.5% paraformaldehyde and flat mounted. Surface roughness of DMs was quantified using CCM and the AltiMap software that provided the maximum peak (Sp) and valley (Sv) heights, the mean square roughness (Rq) and the asymmetry coefficient (Ssk). RESULTS: The physiological roughness of healthy samples was characterised by an Rq of 0.12±0.05 µm, which was two times rougher than in PBK (Rq=0.06±0.03 µm), but both were still flat with a symmetrical distribution between peaks and valleys (Ssk close to 0, npeaks=nvalleys), smaller than 1 µm. In FECD, the maximum peak height was 5.10±2.40 µm, up to 5.8 and 8.3 times higher than the control and PBK, respectively. The maximum valley depth was half than the peak (2.28±0.89 µm). The surface with guttae was very rough (Rq=0.45±0.14 µm) and the Ssk=1.84± 0.43 µm, greater than 0, confirms an asymmetric surface with high peaks and low valleys (npeaks>nvalleys). Moreover, the CCM provided quantitative parameters allowing to distinguish different types of guttae from different patients. CONCLUSIONS: CCM is an innovative approach to describe and quantify different morphologies of guttae. It could be useful to analyse the different stages of FECD and define subgroups of patients.

Shotgun proteomics identification of proteins expressed in the Descemet's membrane of patients with Fuchs endothelial corneal dystrophy.

Fuchs endothelial corneal dystrophy (FECD) is a slowly evolving, bilateral disease of the corneal endothelium, characterized by an abnormal accumulation of extracellular matrix (ECM) in the basement membrane (Descemet's membrane, DM). This results in the formation of small round excrescences, called guttae, and a progressive disappearance of endothelial cells. In the intermediate stage, the numerous guttae create significant optical aberrations, and in the late stage, the loss of endothelial function leads to permanent corneal edema. The molecular components of guttae have not been fully elucidated. In the current study, we conducted shotgun proteomics of the DMs, including guttae, obtained from patients with FECD and revealed that 32 proteins were expressed only in the FECD-DMs but not in the DMs of control subjects. Subsequent enrichment analyses identified associations with multiple ECM-related pathways. Immunostaining of flat-mounted DMs confirmed that 4 of the top 5 identified proteins (hemoglobin α, SRPX2, tenascin-C, and hemoglobin γδεß) were expressed in FECD-DMs but not in non-FECD-DMs. Fibrinogen α was strongly expressed in FECD-DMs, but weakly expressed in non-FECD-DMs. We also demonstrated that matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) can display the in situ spatial distribution of biomolecules expressed in the DM, including the guttae.