AUG 15, 2012
Cataract/Anterior Segment, Cornea/External Disease
The authors of this study in the April issue of the Archives of Ophthalmology investigated the relationship between Fuchs' dystrophy and central corneal thickness (CCT), and found that CCT is proportional to the progression of Fuchs'. This relationship remained even at lower grades of dystrophy without clinically observable edema. The authors conclude that CCT may be useful as a quantitative factor in following progression of Fuchs' dystrophy and guiding decisions about treatment including surgery.
They examined 1,610 eyes from a subset of index cases, family members and unrelated control subjects with normal corneas from the Fuchs' Endothelial Corneal Dystrophy Genetics Multi-Center Study. To estimate the association between severity grade (7-point severity scale based on guttae confluence) and CCT measured by ultrasonographic pachymetry, they used a multivariable model that adjusted for eye, age, race, sex, history of glaucoma or ocular hypertension, diabetes mellitus, contact lens wear, IOP and familial relationship to the index case.
Average CCT was thicker in index cases for all severity grades compared with unaffected controls (P ≤ 0.003) and in affected family members with a grade of 4 or greater compared with unaffected family members (P ≤ 0.04). Similar results were observed for subjects without edema. Average CCT of index cases was greater than that of affected family members with grades 4, 5 and 6 (P ≤ 0.02). IOP was also associated with CCT (P = 0.01).
The authors note that subjects with as few as 1 to 2 mm of confluent guttae may begin to develop central corneal thickening, pointing to a gradual process of endothelial dysfunction rather than an acute "tipping point" of endothelial decompensation as a likely mechanism of corneal edema in Fuchs' dystrophy.