Diurnal Variation in Corneal Edema in Fuchs' Endothelial Corneal Dystrophy
- The extent of diurnal variation in corneal edema in Fuchs' dystrophy is unknown. The Prospective cohort study was conducted to measure corneal thickness and posterior profile over the course of the day using Scheimpflug imaging .
- Participants with clinically advanced Fuchs' dystrophy eyes undergoing endothelial keratoplasty and participants with healthy corneas were assessed around noon the day before surgery and late afternoon, and immediately upon eye opening in hospital the morning of surgery.
- Directly upon awakening, mean corneal thickness was 663 μm (interquartile range [IQR], 625-707) in Fuchs' dystrophy (n = 44) and 557 μm (IQR, 527-601) in 11 controls.
- In Fuchs' dystrophy eyes, corneal thickness decreased after awakening but such pattern not seen in control corneas.
- 95% of patients can be expected to have a change in corneal thickness over the first four hours after awakening between -58 μm to -31 μm (95% prediction interval).
- Posterior Q decreased on average by 0.15 (95% confidence interval [CI], 0.07-0.23) and posterior radius of curvature decreased by 0.20 mm (95% CI, 0.14-0.27), indicating that edema resolution steepened the central posterior cornea. Beyond four hours after awakening, corneas no longer changed considerably in Fuchs' dystrophy.
- Impaired hydration control in clinically advanced Fuchs' dystrophy should be considered as it makes measurements of key corneal parameters unreliable directly after eye opening.
- Beyond the first hours after eye opening, corneal thickness measurements are unlikely to vary more in Fuchs' dystrophy eyes than in normal eyes
TAKE-HOME MESSAGE:- In this prospective cohort study, the authors documented the diurnal variation in corneal edema among patients with Fuchs’ dystrophy. They found that the cornea of these patients is thicker in the morning, and the edema typically resolves in 4 hours.
This finding could have an impact on imaging and measurements for endothelial keratoplasty in these patients.
Reference:- Am J Ophthalmol 2019 Aug 12;[EPub Ahead of Print], M Fritz, V Grewing, P Maier, T Lapp, D Böhringer, T Reinhard, K Wacker