Towards Patient-Tailored Perimetry: Automated Perimetry Can Be Improved by Seeding Procedures With Patient-Specific Structural Information

Abstract

Purpose: To explore the performance of patient-specific prior information, for example, from structural imaging, in improving perimetric procedures. Methods:Computer simulation was used to determine the error distribution and presentation count for Structure-Zippy Estimation by Sequential Testing (ZEST), a Bayesian procedure with prior distribution centered on a threshold prediction from structure. Structure-ZEST (SZEST) was trialled for single locations with combinations of true and predicted thresholds between 1 to 35 dB, and compared with a standard procedure with variability similar to Swedish Interactive Thresholding Algorithm (SITA) (Full-Threshold, FT). Clinical tests of glaucomatous visual fields (n ¼ 163, median mean deviation À1.8 dB, 90% range þ2.1 to À22.6 dB) were also compared between techniques.Results: For single locations, SZEST typically outperformed FT when structural predictions were within 6 9 dB of true sensitivity, depending on response errors. In damaged locations, mean absolute error was 0.5 to 1.8 dB lower, SD of threshold estimates was 1.2 to 1.5 dB lower, and 2 to 4 (29%-41%) fewer presentations were made for SZEST. Gains were smaller across whole visual fields (SZEST, mean absolute error: 0.5 to 1.2 dB lower, threshold estimate SD: 0.3 to 0.8 dB lower, 1 [17%] fewer presentation). The 90% retest limits of SZEST were median 1 to 3 dB narrower and more consistent (interquartile range 2-8 dB narrower) across the dynamic range than those for FT. Conclusion:Seeding Bayesian perimetric procedures with structural measurements can reduce test variability of perimetry in glaucoma, despite imprecise structural predictions of threshold.Translational Relevance: Structural data can reduce the variability of current perimetric techniques. A strong structure-function relationship is not necessary, however, structure must predict function within 69 dB for gains to be realized.

Clinical Evaluation of Swedish Interactive Thresholding Algorithm–Faster Compared With Swedish Interactive Thresholding Algorithm–Standard in Normal Subjects, Glaucoma Suspects, and Patients With Glaucoma

“…26,27 However, the implementation of recommendations for increased frequency of testing has been challenging, with issues of timing and availability of resources being cited as barriers, despite long-term cost savings. 28 Alternative approaches, such as the use of previous sensitivity information, 29 adaptation to regions of interest, such as scotomata, 30 censoring of unreliable test points to reduce the number of stimulus presentations, 31 and the use of structural information for targeting specific regions of the visual field 32,33 remain theoretical at present and have not yet been widely implemented in practice.…”

Relating optical coherence tomography to visual fields in glaucoma: structure–function mapping, limitations and future applications

“…This can be achieved by making predictions of sensitivity at each visual field location based on OCT measurements as mentioned, and then using these predictions as a starting point for testing the visual field. Denniss et al took this approach, using a modified Zippy Estimation by Sequential Testing procedure with Gaussian prior probability mass function centred on hypothetical predictions from structural data to investigate the possibility of improving visual field sensitivity measurements in this way. The study showed that the procedure seeded by predictions from structural measures could deliver benefits over existing procedures when the structure‐derived predictions of visual field sensitivity were accurate to within ±9 dB .…”

“…Denniss et al took this approach, using a modified Zippy Estimation by Sequential Testing procedure with Gaussian prior probability mass function centred on hypothetical predictions from structural data to investigate the possibility of improving visual field sensitivity measurements in this way. The study showed that the procedure seeded by predictions from structural measures could deliver benefits over existing procedures when the structure‐derived predictions of visual field sensitivity were accurate to within ±9 dB . Similar advantages over existing visual field test procedures were demonstrated by Ganeshrao et al, who incorporated structure‐based predictions of visual field sensitivity into a combined suprathreshold‐threshold procedure.…”

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives

“…In clinical practice, the reliability of SAP results is affected by a range of factors, including those that are patient‐related. Modern thresholding algorithms have been developed to increase test efficiency and reduce patient fatigue (see McKendrick for a full review and select recent papers for newer algorithms). The reliability of the visual field results can be assessed using four primary indices or some variation thereof: fixation losses, false positives, false negatives and the results of gaze tracking.…”

“…52 In clinical practice, the reliability of SAP results is affected by a range of factors, including those that are patient-related. Modern thresholding algorithms have been developed to increase test efficiency and reduce patient fatigue (see McKendrick 53 for a full review and select recent papers for newer algorithms [54][55][56] A key for the greyscale levels of probability of normality is shown as an inset. (A) The right eye findings of a 54-year-old Asian man with moderate normal-tension glaucoma.…”