Mathematical and optimal clustering of test points of the central 30-degree visual field of glaucoma

Purpose: To determine a mathematically optimal sector pattern of the central 30 degrees visual field for the follow-up of glaucomatous visual field change based on a large number of actual visual field test data of patients with glaucoma. Methods: Visual field test data obtained from 1,039 eyes of 1,039 patients with open-angle glaucoma (OAG) using the 30-2 program of the Humphrey Field Analyzer were used for sectorization of the central 30 degrees visual field. Of the 1,039 visual field data, 698 (modeling data) were used for determining the sector pattern and 341 (testing data) for checking the sector pattern. The modeling data were further divided into three groups according to the mean deviation (MD) (MD greater than or equal to -10 dB, -20 less than or equal to MD < -10 dB, and MD < -20 dB), and the sector pattern was constructed from visual field data of each group using a clustering procedure called VARCLUS. The testing data were used for determining the optimal sector pattern. In a separate set of repeated visual field data of 303 patients with GAG, the fluctuation of MD, sector values of each sector determined, and total deviation of each test point were calculated and compared. Results: The sector pattern constructed from visual field data of MD greater than or equal to -10 dB summarized the visual field performance most effectively. The fluctuation of the sector value of each sector was roughly 1.5 times smaller than the total deviation of each test point. Conclusion: The sector pattern determined may be useful in analyses of the visual field data of patients with glaucoma.