Abstract
Purpose :
The analysis of the relationship between structure and function in glaucoma is necessary to understand both the severity and the progression of the disease. In this study, we evaluate the structure-function agreement of the eyes in different stages of glaucoma using the Zeiss Forum® software.
Methods :
Four-hundred and twenty eyes were included in this study. In all cases, the Retinal Nerve Fiber Layer (RNFL) thickness was measured using the Cirrus OCT. On the same day, a SITA-FAST 24-2 Threshold test (Humphrey) was performed to assess the Visual Field (VF). Subsequently, the FORUM® software automatically performed the structure-function analysis. We evaluate the 6 structure-function zones according to the Garway-Heath map, to identify the zones that have the best relationship and the worst relationship. The VF damage is defined as points with values of p<0.1, and an altered RNFL is classified in yellow or red colors. The structure-function relationship was also evaluated by categorizing the cases into stages according to the Glaucoma Staging System (GSS). Non-parametric tests and Venn diagrams were evaluated.
Results :
Eighty-three eyes were classified as Stage 0, 203 eyes as Stage 1, 79 eyes as Stage 2, and 55 eyes as Stages 3-4. The average RNFL color is associated with the Visual Field Index average, the Mean Defect and the Pattern Standard Deviation of the VF (p<0.05). The best structure-function agreement was found in zone 2 (superior temporal of the VF) and in zone 4 (inferior temporal of the VF). The worst structure-function agreement was found in zones 3 and 1 (lower and upper periphery of the VF, respectively). VF damage with normal RNFL thickness was most evident in zone 3 and in GSS Stages 1 and 2. An altered RNFL thickness with normal VF was most visible in zones 2 and 4, but only in GSS Stage 1. The structure-function agreement is higher in GSS Stages 2-4 than in GSS Stages 0-1.
Conclusions :
The results suggest that the global parameters of the RNFL thickness are correlated with the VF parameters. There are more altered points of the VF with normal RNFL in the same zone than altered RNFL with normal VF. The best structure-function agreement is found in the temporal superior and temporal inferior zones. In addition, the agreement is better in advanced glaucoma than in early glaucoma stages. The Zeiss Forum® is an automatic software that is useful for analyzing structure-function agreement.
This is a 2020 ARVO Annual Meeting abstract.