Combined Use of Frequency Doubling Perimetry and Polarimetric Measurements of Retinal Nerve Fiber Layer in Glaucoma Detection FOLKERT K. HORN, PHD, NHUNG X. NGUYEN, MD, CHRISTIAN Y. MARDIN, MD, AND ANSELM G. JU ¨ NEMANN, MD ● PURPOSE: The aim of this study was to evaluate the diagnostic usefulness of the combined use of frequency- doubling technology (FDT) perimetry and polarimetry of the retinal nerve fiber layer. ● DESIGN: Cross-sectional study. ● METHODS: Seventy ocular hypertensive patients (nor- mal optic disk and standard perimetry, elevated intra- ocular pressure [>21 mm Hg]), 59 patients with “preperimetric” open-angle glaucoma (glaucomatous op- tic disk atrophy, elevated intraocular pressure [>21 mm Hg], no visual field defect in standard perimetry), 105 patients with “perimetric” open-angle glaucoma (glau- comatous optic disk atrophy and clearly marked visual field defect), and 73 control subjects had FDT screen- ing (protocol: C-20-5) and polarimetric measurements (GDx). Criteria for exclusion: optic disks larger than 4 mm 2 , media opacities, patients younger than 33 years or older than 66 years. None of the subjects had earlier FDT perimetry. One eye of each patient and control subject entered the statistical evaluation. Database and statistical software were used for case-wise recalculation of all missed localized probability levels to create a FDT screening score. ● RESULTS: At a predefined specificity of 94.5% in control eyes, discrimination between “perimetric” glau- coma and normal subjects is superior using the FDT perimetry (sensitivity  84.8%) in comparison to pola- rimetry (sensitivity  63.8%), whereas sensitivity is similar with both methods in “preperimetric” patients (GDx, FDT: 25.4%). In several cases, patients classified as glaucomatous by the GDx are not the same patients as identified by the FDT perimetry. Therefore, a two- dimensional discrimination analysis can increase correct positive classification. Using a linear combination of the present FDT screening score and polarimetry (“the number”), 92.4% of “perimetric” glaucoma eyes and 44.1% of “preperimetric” glaucoma eyes have been classified as glaucomatous. ● CONCLUSION: Joint usage of polarimetry and FDT perimetry indicate that a combination of different tech- niques which can uncover different glaucoma properties, might be helpful in early glaucoma detection. (Am J Ophthalmol 2003;135:160 –168. © 2003 by Elsevier Science Inc. All rights reserved.) E ARLY DETECTION OF GLAUCOMATOUS OPTIC NERVE atrophy is crucial for prognosis of the disease and prevention of an irreversible restriction of the visual field. New devices have been developed that might be able to detect early signs of glaucoma. Such devices should fulfill several specifications such as rapid assessment, cost, and performance by a trained nongraduate. Early glaucoma detection can focus on analyses of abnormalities of the optic disk and the nerve fiber layer as well as on psycho- physical methods, which might be more sensitive than conventional white-on-white perimetry. In the present study, both strategies have been applied to the same cohort of patients utilizing two modern methods: analyses of the retinal nerve fiber layer thickness with a polarimeter device, and a new perimetric screening strategy with frequency-doubling technology (FDT). The present scan- ning laser polarimeter (GDx) is not a specialized screening instrument, but can be easily mastered, providing quanti- tative and objective information and was reported to have potential value in the detection of advanced and early glaucoma and even of ocular hypertension. 1–3 In addition to morphometric evaluation of the ocular fundus, perimetry using the frequency-doubling technique has been described as a new tool for glaucoma determina- tions. 4 –12 In FDT perimetry, localized defects in the visual field, as well as malfunctions of temporal transfer proper- ties, may contribute to the results. The usefulness in Accepted for publication Aug 27, 2002. From the Department of Ophthalmology and University Eye Hospital, Friedrich-Alexander University Erlangen-Nu ¨rnberg at Erlangen, Erlan- gen, Germany. This work was supported by Deutsche Forschungsgemeinschaft, Bonn, Germany (SFB 539). Inquiries to Folkert K. Horn, PhD, Universita ¨ts-Augenklinik, Schwabachanlage 6, D-91054 Erlangen, Germany; fax: (+49) 9131- 8534-415; e-mail: folkert.horn@augen.imed.uni-erlangen.de © 2003 BY ELSEVIER SCIENCE INC.ALL RIGHTS RESERVED. 160 0002-9394/03/$30.00 PII S0002-9394(02)01926-8