The Columbia Thyroid Eye Disease-Compressive Optic Neuropathy Formula

Purpose: Diagnosing thyroid eye disease–compressive optic neuropathy (TED–CON) is challenging, particularly in cases lacking a relative afferent pupillary defect. Large case series of TED–CON patients and accessible diagnostic tools are lacking in the current literature. This study aims to create a mathematical formula that accurately predicts the presence or absence of CON based on the most salient clinical measures of optic neuropathy. Methods: A retrospective case series compares 108 patients (216 orbits) with either unilateral or bilateral TED–CON and 41 age-matched patients (82 orbits) with noncompressive TED. Utilizing clinical variables assessing optic nerve function and/or risk of compressive disease, and with the aid of generalized linear regression modeling, the authors create a mathematical formula that weighs the relative contribution of each clinical variable in the overall prediction of CON. Results: Data from 213 orbits in 110 patients derived the formula: y = −0.69 + 2.58 × (afferent pupillary defect) − 0.31 × (summed limitation of ductions) − 0.2 × (mean deviation on Humphrey visual field testing) − 0.02 × (% color plates). This accurately predicted the presence of CON (y > 0) versus non-CON (y