Morning Myopic Shift and Glare in Patients with Advanced Fuchs Endothelial Corneal Dystrophy
A newly published study by a German team analyzes the morning and afternoon differences in various parameters in patients with Fuchs endothelial corneal dystrophy to determine which of them contribute to subjective visual difficulties in the morning.
Study Objectives
Subjective decrease in visual acuity in the morning with gradual improvement during the day is a pathognomonic symptom of corneal endothelial dysfunction. The aim of this work was to analyze the fluctuations in central corneal thickness, refraction, and visual acuity throughout the day in advanced stages of Fuchs endothelial corneal dystrophy.
Methods and Course
Patients with corneal dystrophy (29 eyes) and a control group of individuals with normal corneas (22 eyes) were included in a prospective cohort study. Routine clinical examination included biomicroscopy and optical coherence tomography of the macula. Further examination at 16:00 in the evening and at 8:00 the next morning included Pentacam testing, refraction determination, and best corrected visual acuity (BCVA) under standard conditions and using an optotype with lateral glare illumination.
Findings
The differences between afternoon and morning central corneal thickness values were significant between both groups, with patients with Fuchs dystrophy averaging 41.45 ± 34.1 µm (SD) (p < 0.001), compared to the control group's 5.5 ± 6.72 µm (SD) (p = 0.001).
Values measured in patients with Fuchs endothelial corneal dystrophy for spherical equivalent (−0.64 ± 0.6; p < 0.001) and total corneal refractive power (0.60 ± 0.83 D; p = 0.001) also showed significant diurnal changes compared to controls.
The same applied to visual acuity. In individuals with Fuchs dystrophy, the differences between BCVA measurements were 0.15 ± 0.18 logMAR (p < 0.001) and for BCVA with glare 0.34 ± 0.25 logMAR (p < 0.001).
Conclusion
The study demonstrated that patients with Fuchs endothelial corneal dystrophy experience a myopic shift, increased glare, and corneal thickening in the morning, which can particularly contribute to subjective visual difficulties during the first hours upon waking. These findings should be considered when assessing the patient's condition and deciding on potential surgical interventions.
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Source: Loreck N., Adler W., Siebelmann S. et al. Morning myopic shift and glare in advanced Fuchs endothelial corneal dystrophy. Am J Ophthalmol 2020 May; 213: 69−75, doi: 10.1016/j.ajo.2020.01.011.
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