A morning myopic shift and glare issues may contribute to visual impairment in advanced Fuchs’ endothelial corneal dystrophy (FECD) patients in their first waking hours, a team of German researchers suggest. Their study, published in the American Journal of Ophthalmology, also found the early morning visual acuity problems seemed to mirror a temporary increase in corneal thickness. 

Since impaired subjective morning visual acuity with improved symptoms later in the day can be common in advanced FECD cases, investigators analyzed the daily fluctuations in corneal thickness, refraction and visual acuity in these patients.

Their study enrolled 29 advanced FEDC subjects and 22 patients with normal corneas. Testing included slit lamp exam, funduscopy, macular OCT, corneal Scheimpflug tomography, refraction, corrected distance visual acuity and glare-corrected distance visual acuity at 4pm and again the following day at 8am.

The study noted the following variations in the afternoon and morning readings of both groups:

• An approximate corneal thickness change of 41.45±34.1μm in the FECD group compared with just 5.5±6.72μm in the healthy corneas.
• A spherical equivalent change of -0.64±0.6dpt in the FECD patients vs. -0.01±0.50dpt in the controls.
• A total corneal refractive power change of 0.60±0.83dpt in the FECD group compared with -0.01±0.49dpt in the controls.
• A corrected distance visual acuity variation of 0.15±0.18LogMAR in the FECD group compared with 0.02±0.04LogMAR in the controls.
• A change in corrected distance visual acuity glare of 0.34±0.25LogMAR in the advanced Fuchs’ patients vs. 0.05±0.11LogMAR in the healthy eyes.

The investigators suggested clinicians take these findings into account during assessments and when making surgical decisions for FECD patients.