An Automated Method for Assessing Topographical Structure–Function Agreement in Abnormal Glaucomatous Regions

PURPOSE: To develop an automated/objective method for topographically comparing abnormal regions on optical coherence tomography (OCT) and visual field (VF) tests of eyes with early glaucoma. METHODS: A custom R program was developed that allows for both visualization and automatic assessment of the topographical agreement between functional (24-2 and/or 10-2 VF) and structural (widefield OCT retinal nerve fiber layer and/or retinal ganglion cell layer) deviation/probability maps. It was optimized using information from 98 eyes: 53 diagnosed as “definitely glaucoma” (DG) and 45 recruited as healthy (H) controls. Different pairs of abnormal VF (P <1%, <2%, <5%) and abnormal OCT (P <5%, <10%, <15%) criteria were evaluated. The percentages of abnormal structure–abnormal function (aS-aF) agreement found in DG eyes and nonagreement found in H eyes were used to define the optimal criteria and number of aS-aF locations for the detection of aS-aF agreement. RESULTS: A criterion of two aS-aF locations with “OCT <10% and VF <5%” on VF pattern deviation (PD) probability and OCT deviation/probability maps yielded high overall agreement (92%) with high aS-aF agreement for the DG eyes (89%) and high aS-aF nonagreement for the H eyes (95%). Total deviation probability maps achieved slightly lower performance than PD maps. CONCLUSIONS: The method described here can automatically and objectively evaluate aS-aF agreement with a direct comparison of abnormal regions of function and structure. TRANSLATIONAL RELEVANCE: As glaucoma diagnosis often involves assessing structure–function agreement, this technique can overcome subjectivity in this assessment.