Differences in Guttae Ultramorphology in Relation to Visual Function in Fuchs Endothelial Corneal Dystrophy

Area of Science:

• Ophthalmology
• Corneal Science
• Histopathology

Background:

• Fuchs endothelial corneal dystrophy (FECD) is a progressive condition affecting the cornea's inner lining.
• Guttae are characteristic deposits in FECD, but their precise role in visual impairment is debated.
• Understanding guttae ultramorphology may offer insights into FECD pathogenesis and visual dysfunction.

Purpose of the Study:

• To investigate the ultramorphological differences of guttae in FECD.
• To determine the relationship between guttae morphology and visual function in FECD patients.
• To identify potential ultramorphological markers for disease severity in FECD.

Main Methods:

• Corneal morphology and visual function (visual acuity, contrast sensitivity) were assessed in 30 FECD eyes using Scheimpflug tomography and standard visual tests.
• Surgically removed Descemet membranes were examined using light and transmission electron microscopy.
• Corneal edema was evaluated using Scheimpflug tomography and clinical assessment.

Main Results:

• All eyes exhibited subclinical corneal edema; 40% showed clinically visible edema.
• Guttae buried within a posterior fibrillar zone (PFZ) were exclusively found in eyes with clinically visible edema.
• No significant correlation was found between guttae morphology (PFZ presence, guttae protrusion) and visual function parameters or tomography measurements.

Conclusions:

• Guttae morphology and density are not directly correlated with visual functional parameters in FECD.
• Guttae embedded within the PFZ serve as an ultramorphological indicator of advanced FECD with clinically manifest edema.
• Subclinical edema, present in all studied eyes, may have a greater impact on visual quality than guttae ultramorphology.