To establish consensus on definitions and concepts of keratoconus and ectatic corneal diseases by using Delphi approach.

Seventeen Latin American experts on keratoconus and ectatic corneal diseases participated in a 3-round Delphi panel approach. A web-based 12 question survey was answered by panelists in two rounds, followed by life discussion meeting. A two-third majority strategy was defined as a consensus.

Corneal ectatic diseases were defined as progressive thinning conditions without acute stromal inflammation, and were classified as keratoconus, pellucid marginal degeneration (PMD), keratoglobus, and ectasia after trauma or surgery. The pattern of thinning was considered the main aspect for the classification of ectatic diseases, but criteria for staging the disease needs to be improved. Corneal tomography with 3D reconstruction, distinguished from Placido-disk based front surface topography was elected as the diagnostic procedure currently capable of detecting the earliest clinical ectatic changes. Biomechanical alterations were considered to be the first event for ectasia development. Eye rubbing was directly related to the development and progression of ectasia. Inflammation was considered as a possible event on the physiopathology. Keratoconus was considered as a bilateral disease, with often asymmetric presentation, while ectasia may occur unilaterally if there is significant corneal insult, leading to biomechanical failure. No consensus was achieved for the definitions on forme fruste keratoconus (FFKC).

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.

Ambrósio RJr, Belin MW, Perez VL, Abad JC, Gomes JAP. Definitions and Concepts on Keratoconus and Ectatic Corneal Diseases: Panamerican Delphi Consensus — A Pilot for the Global Consensus on Ectasias. Int J Kerat Ect Cor Dis 2014;3(3):99-106.