Assessment of Corneal Graft Attachment in Patients With Fuchs Endothelial Corneal Dystrophy Following DMEK Using Ultra-high Resolution OCT

Assessment of Corneal Graft Attachment in Patients With Fuchs Endothelial Corneal Dystrophy Following DMEK Using Ultra-high Resolution OCT

Assessment of Corneal Graft Attachment in Patients With Fuchs Endothelial Corneal Dystrophy Following Descemet's Membrane Endothelial Keratoplasty Using Ultra-high Resolution Optical Coherence Tomography

Fuchs endothelial corneal dystrophy (FECD) is a progressive disease characterized by the loss of endothelial cells, thickening of Descemet's membrane and deposition of extracellular matrix in the form of guttae. This result in failure of the endothelium to support corneal deturgescence leading to corneal edema. Affected patients complain about blurred vision at early stages of the disease which can progress to blindness. The pathophysiology of the disease is still unclear, but several studies point towards a genetic susceptibility. Additional risk factors that have been identified are female sex, smoking and older age. While for a long time penetrating keratoplasty (PKP) was the only therapy available for affected patients, in the recent years less invasive methods such as descemet's membrane endothelial keratoplasty (DMEK) have been developed. In DMEK, only the Descemet's membrane and the endothelium is removed and replaced with the corresponding parts from a donor's cornea. For FECD, this brings the advantage that only the diseased part of the cornea is replaced. Graft detachment has been identified as the main complication following DMEK. In the investigators' study, an ultra high resolution OCT system will be used to detect graft detachment in patients with FECD after DMEK. With this technique, even small detachments can be visualized. The area of graft detachment will be evaluated at predefined time points after surgery and correlated to visual acuity. A follow-up of one year will be performed in order to investigate the predictive value of graft adherence status at several time points for visual outcome.

The area of graft detachment will be measured by a customized ultra high-resolution OCT for the cornea. A spectrometer based ultrahigh resolution Spectral Domain OCT (SDOCT) system operating at 800 nm for the anterior chamber will be employed in the present study. The spectrum of the Ti:Sapphire laser light source is centered at 800 nm. With a full width at half maximum bandwidth of 170 nm, the axial resolution is 1.3 μm in the cornea. The transverse resolution of the employed OCT system is 21 μm at the front surface of the cornea. For measurement, patients will place their head in a modified slit lamp head rest. During the measurement period, patients will be asked to look straight forward onto an internal fixation target and to avoid blinking. Different scattering patterns, e.g. raster, circular and spiral scans will be employed.

Change in best corrected visual acuity at 12 months compared to baseline using a standardized protocol with the Early Treatment Diabetic Retinopathy (ETDRS) charts (4 meters).

Visual acuity will be measured using a standardized protocol with the Early Treatment Diabetic Retinopathy (ETDRS) charts (4 meters).

Best corrected visual acuity at 6 months using a standardized protocol with the Early Treatment Diabetic Retinopathy (ETDRS) charts (4 meters).

Visual acuity will be measured using a standardized protocol with the Early Treatment Diabetic Retinopathy (ETDRS) charts (4 meters).

Inclusion Criteria: Men and women aged over 18 years scheduled for primary DMEK because of Fuchs' Endothelial Dystrophy Exclusion Criteria: Any disease inhibiting OCT acquisition; such as blepharospasm, severe tremor or immobility Any previous intraocular surgery other than cataract extraction Previous clinically significant ocular trauma in the study eye, as judged by the investigator Pregnancy, planed pregnancy, or lactating Appointment of a custodian Progressive retinal disease History or presence of glaucoma