Definitions and Concepts of Keratoconus and Ectatic Corneal Diseases: Pan-American Delphi Consensus
Narrative Responses:
Purpose
To establish consensus on definitions and concepts of keratoconus and ectatic corneal diseases by using Delphi approach.
Methods
Seventeen Latin American experts on keratoconus and ectatic corneal diseases participated in a 3-round Delphi panel approach. A web-based twelve questions survey was answered by panelists in two rounds, followed by life discussion meeting. A two-thirds majority strategy was defined as consensus.
Results
Ectatic diseases, defined as progressive thinning conditions without acute stromal inflammation, were classified as keratoconus, pellucid marginal degeneration (PMD), keratoglobus, and ectasia after trauma/surgery. Thinning pattern was the main aspect for classification, but criteria for staging needs to be improved. Corneal tomography (3-D reconstruction), distinguished from Placido-disk topography, was elected as the most sensitive diagnostic procedure. Eye rubbing was related to the development and progression of ectasia. Keratoconus was considered as a bilateral disease, with often asymmetry, while ectasia may occur unilaterally if significant corneal insult leads to biomechanical failure. No consensus was achieved for defining forme fruste keratoconus (FFKC).
Conclusion
Consensus was achieved on definitions of corneal ectatic diseases. Disease staging, including criteria for FFKC or subclinical ectasia remains controversial. A larger consensus including experts from different groups around the world is needed.