HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Boden, C. Articles by Goldbaum, M. H. Search for Related Content PubMed PubMed Citation Articles by Boden, C. Articles by Goldbaum, M. H.

Assessing Visual Field Clustering Schemes Using Machine Learning Classifiers in Standard Perimetry

¹From the Hamilton Glaucoma Center and Visual Function Laboratory, Department of Ophthalmology, and the ²Institute for Neural Computation, University of California at San Diego, La Jolla, California; and the ³Computational Neurobiology Laboratories, Salk Institute, La Jolla, California.

PURPOSE. To compare machine learning classifiers trained on three clustering schemes to determine whether distinguishing healthy eyes from those with glaucomatous optic neuropathy (GON) can be optimized by training with clustered data.

METHODS. Two machine learning classifiers—quadratic discriminant analysis (QDA) and support vector machines with Gaussian kernel (SVMg)—were trained separately using standard perimetry data from the Diagnostic Innovations in Glaucoma Study (DIGS), clustered using three clustering schemes on a training data set (123 eyes/123 glaucoma patients with GON; 135 eyes/135 normal control subjects). Trained classifiers were then applied to an independent data set containing 69 eyes of 69 glaucoma patients with early visual field loss and 83 eyes of 83 normal control subjects. Two control conditions were included: unclustered data and a random assignment of locations to clusters.

RESULTS. Areas under the receiver operating characteristic (ROC) curve ranged from 0.85 (SVMg, thresholds clustered by Glaucoma Hemifield Test sectors) to 0.92 (QDA, thresholds clustered by Garway-Heath mapping) for the training data set. Use of clustered data showed no significant optimization of sensitivity over use of unclustered data, and no single clustering method resulted in significantly higher performance in the independent data set. Sensitivities tended to be higher with QDA than with SVMg, regardless of specificity cutoff and clustering method.

CONCLUSIONS. QDA performed better with the early glaucoma data set than did the SVMg. Clustering may be advantageous when data-dimension reduction is needed—for example, when combining field results with other high-dimensional data (e.g., structural imaging data)—but it is not necessary for visual field data alone.