Abstract
Purpose:
Fuchs Corneal Dystrophy (FCD) is a progressive, hereditary corneal disorder marked by central corneal edema and the presence of guttae, excrescences of Descemet membrane. Traditional grading of severity is based on slit-lamp biomicroscopy and subjective clinical assessment of the distribution of guttae and presence of corneal edema; however, we have previously shown that retroillumination photography analysis (RPA) can objectively and reliably assess progression of disease and distribution of guttae, which accelerate in their development over time. Here, we explore the correlation between two methods and implications for high levels of severity.
Methods:
Retroillumination photography was conducted in 54 individuals affected with FCD; all subjects provided written informed consent. The number of guttae were summated manually. Exclusion criteria included history of intraocular surgery or inflammation. Clinical grading using the Krachmer scale measuring 1 to 5 was documented for each eye at the time of examination. Regression analyses were performed to identify the best-fit model between the two methods. Ranges of guttae were assessed at each stage of clinical grading.
Results:
A total of 96 retroillumination photographs passed exclusion criteria and were analyzed. Krachmer score ranged in severity from 1 to 5, with mean score of 2.625. The mean number of guttae in corneas at each clinical level of severity (Krachmer grading in parentheses) were 289 (1+), 999 (2+), 2669 (3+), 5474 (4+), and 7133 (5+). Higher levels of clinical grading were associated with larger ranges of guttae (p<0.02), with corneas identified as 5+ demonstrating 7227 guttae between the maximum and minimum affected. A power model resulted in a strong and greater fit between RPA and Krachmer score (r2=0.78) than a linear model (r2=0.62).
Conclusions:
In this largest study of RPA data and comparison with subjective clinical grading of FCD severity, RPA correlates well and demonstrates better resolution of severity at advanced stages of disease. This method provides objective levels of severity and may benefit clinicians and researchers who seek to track detailed rates of progression over time.