A New Method to Detect Visual Field Progression based on Spatial Pattern Analysis

Abstract

Purpose : Current methods for detecting visual field (VF) change only provide global assessments of functional deterioration, while clinician’s judgement of VF progression heavily relies on examination of VF spatial patterns. We aim to develop a new algorithm to detect VF worsening to provide both status outcome and spatial patterns of VF progression.

Methods : In this retrospective cohort study, we selected eyes from multiple sites with at least 5 reliable automated VFs and at least 5 years follow-up using the SITA Standard strategy and 24-2 pattern. The time between each VF was restricted to be at least 6 months. Each VF was decomposed into a weighed sum of 16 VF archetypes (ATs) including 1 normal AT and 15 VF loss ATs (Fig. 1) identified previously [1]. For each eye, linear regressions were applied from follow-up time to the 16 AT weights of VFs. If any of the weights substantially changes for the 15 VF loss ATs (AT slope≥0.01/year and p<0.01) and the normal AT (AT slope≤-0.01/year and p<0.01), the eye is determined to be worsening. Our new algorithm was compared to existing algorithms including MD slope, Advanced Glaucoma Intervention Study (AGIS) scoring, Collaborative Initial Glaucoma Treatment Study (CIGTS) scoring and the permutation of pointwise linear regression (PoPLR). The concordance between those algorithms was evaluated by Kappa coefficient.

Results : 12,217 eyes were selected for analyses. The mean±standard deviation of age, MD and PSD at the first VF were 63.8±12.7 years, -4.1±5.2 dB and 3.9±3.5 dB. The median of follow-up time and number of VFs was 7.1 years and 6. The prevalence of VF progression by AT slope, MD slope, AGIS scoring, CIGTS scoring and PoPLR were 10.3%, 9.3%, 3.9%, 9.4% and 9.2%. The progression detection by AT slope was in fair agreement (Kappa 0.2 to 0.4) with MD slope (0.38), AGIS (0.23), CIGTS (0.25) and PoPLR (0.27). The overall Kappa coefficient between existing algorithms was 0.34. Among the progressed 1,262 eyes determined by AT analysis, 89.6%, 9.8% and 0.6% of the eyes had 1, 2 and 3 ATs progressed, and the 3 most frequent progressed ATs are AT 8 (17.3%), 6 (15.2%) and 3 (8.3%) (Fig. 2).

Conclusions : Our new algorithm based on AT analysis can provide information of spatial pattern of VF progression in addition to status outcome. The spatial patterns of VF progression can be used to assist clinicians to assess progression.

[1] Elze et al., 2015, J. R. Soc. Interface

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Fig. 1

 

Fig. 2