In Fuchs' endothelial corneal dystrophy, the pathological hallmark is accumulation of abnormal extracellular matrix ('guttae') composed primarily of:

• A Type IV collagen and laminin deposited anterior to Descemet's membrane
• B Fibronectin and vitronectin deposited within the corneal stroma
• C Amyloid deposits in the corneal epithelium leading to recurrent erosions
• D Wide-spaced collagen (abnormal posterior collagenous layer, PCL) deposited posterior to original Descemet's membrane by dysfunctional endothelium ✓

Explanation

In Fuchs' endothelial dystrophy, dysfunctional corneal endothelial cells secrete a posterior collagenous layer (PCL) — composed of abnormal wide-spaced collagen — which is deposited posterior to the original Descemet's membrane. The guttae are focal nodular excrescences of this PCL and appear as beaten-bronze appearance on specular microscopy. TCF4 gene mutations on chromosome 18q21 are the most common genetic association. Over time, progressive endothelial cell loss leads to corneal edema and bullous keratopathy. DMEK/DSAEK are the preferred surgical treatments.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.