Detection of Early Glaucomatous Progression With Octopus Cluster Trend Analysis

Abstract

In PG, Octopus CCTA and CTA are clinically useful to identify early progression and areas suspicious for early progression. However, in some eyes with no glaucomatous visual field damage, vitreous floaters may cause progression artifacts.

Comparison of structure–function relationship between corresponding retinal nerve fibre layer thickness and Octopus visual field cluster defect values determined by normal and tendency-oriented strategies

“…Corrected cluster MD values are corrected for the diffuse defect component of the global visual field. The diffuse defect is defined as the average of the difference between the 20 and 27 percentile values of the cumulative defect curve in relation to the 50 percentile value 1 9. Of the global indices, MS, MD and square LV (sLV) were analysed.…”

“…The G test point pattern follows the nerve fibre bundle distribution and its density is increased around the macula 1 9 10. This is the background for providing information on the central 30° visual field (global indices) and on functionally related test-points (visual field clusters), respectively 9–11.…”

“…This may have a considerable influence on the relationship. Commercial Octopus perimetry offers 10 visual field clusters in contrast to our 16 customised clusters; the information used for clinical purposes is cluster MD (in dB) and not unlogged cluster MS; and since the normal test strategy is time-consuming, in clinical practice mostly tendency-oriented perimetry (TOP) is used, which takes approximately 3–4 min 1 9 12–15. However, with TOP strategy threshold sensitivity is tested only once for each point, the stimulus intensity is adjusted according to the responses at the surrounding points, and in this process the cluster borders are not respected 1 2 16.…”

“…However, with TOP strategy threshold sensitivity is tested only once for each point, the stimulus intensity is adjusted according to the responses at the surrounding points, and in this process the cluster borders are not respected 1 2 16. Finally, the EyeSuite software offers two options for analysing the result: cluster analysis and corrected cluster analysis 9. In cluster analysis, the cluster MD undergoes no correction, and reflects on all effects that influence sensitivity within the cluster (eg, cataract, focal and diffuse glaucomatous deterioration).…”

“…In corrected cluster analysis, the cluster MD is corrected for the global diffuse sensitivity loss,1 to support separation of cataract-related and local, glaucoma-related deteriorations. Corrected cluster trend analysis has been shown to successfully assist the detection of glaucomatous visual field progression 9. In order to clarify if cluster-based structure–function relationship is maintained under the clinically used Octopus perimetry conditions, and in particular using TOP strategy that may change the cluster MD values compared with those determined by normal strategy, in the current investigation we evaluated and compared the visual field cluster–RNFLT sector relationship for the conditions listed above, respectively.…”