Photographic Reading Center of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT): Methods and Baseline Results

摘要

Purpose.: To describe the methods used by the Photographic Reading Center (PRC) of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) and to report baseline assessments of papilledema severity in participants. Methods.: Stereoscopic digital images centered on the optic disc and the macula were collected using certified personnel and photographic equipment. Certification of the camera system included standardization and calibration using a model eye. Lay readers assessed disc photos of all eyes using the Fris??n grade and performed quantitative measurements of papilledema. Fris??n grades by PRC were compared with site investigator clinical grades. Spearman rank correlations were used to quantify associations among disc features and selected clinical variables. Results.: Fris??n grades according to the PRC and site investigator's grades, matched exactly in 48% of the study eyes and 42% of the fellow eyes and within one grade in 94% of the study eyes and 92% of the fellow eyes. Fris??n grade was strongly correlated (r 0.65, P 0.0001) with quantitative measures of disc area. Cerebrospinal fluid pressure was weakly associated with Fris??n grade and disc area determinations (r a?¤ 0.31). Neither Fris??n grade nor any fundus feature was associated with perimetric mean deviation. Conclusions.: In a prospective clinical trial, lay readers agreed reasonably well with physicians in assessing Fris??n grade. Standardization of camera systems enhanced consistency of photographic quality across study sites. Images were affected more by sensors with poor dynamic range than by poor resolution. Fris??n grade is highly correlated with quantitative assessment of disc area. (ClinicalTrials.gov number, NCT01003639.)