Advantages of the DUCK Scoring System for Determining Keratoconus Progression
JAMA Ophthalmology, June 2019
Defining keratoconus progression is crucial for treatment decisions, but consensus is lacking as to which parameters are best suited for this purpose. Wisse et al. compared two methods for determining keratoconus progression and found that the Dutch Crosslinking for Keratoconus (DUCK) score was superior to conventional methodology (e.g., change in maximum keratometry).
The comparative prospective study was conducted at two academic treatment centers (one for discovery and the other for validation). The discovery and validation cohorts were comparable with respect to demographics and maximum keratometry. Eligible patients had keratoconus and were referred from January 2010 through June 2014. The study goal was to assess whether the DUCK scoring system could identify patients who require corneal cross-linking (CXL).
The DUCK system includes five parameters that are assessed routinely: age, visual acuity, refraction error, keratometry, and the patient’s subjective experience. Each item is scored on a three-point scale (0-2). For instance, patient-reported quality of vision is scored as 0 (no complaints), 1 (complaints mildly affecting quality of life), or 2 (complaints severely affecting quality of life). The overall DUCK score range is 0 to 10 points, with 10 indicating the highest rate of disease progression. In addition, a score ≥6 indicates the need for CXL.
The authors compared DUCK scoring with the conventional criterion of 1.0-D increase in maximum keratometry during the preceding 12 months and conducted sensitivity analyses. Main outcomes were the overall rate of treatment reduction and the rate of duly withheld treatment.
Among the 504 eyes (388 patients) that qualified for analysis, the DUCK score proved superior to maximum keratometry for recognizing progressive keratoconus. The overall treatment rate was reduced by 23% without increasing the risk of disease progression. The DUCK score also was more sensitive in identifying eyes for which treatment was correctly withheld.
Improving patient selection for CXL would avoid unnecessary treatment risks for patients who don’t require this procedure, the authors said.
The original article can be found here.