Abstract
Purpose :
Previously, our contrast-to-noise ratio (CNR) analysis demonstrated that optical coherence tomography (OCT) is more sensitive for detecting diffuse progression in the earlier stages of glaucoma, while standard operated perimetry (SAP) is more sensitive in later stages. Glaucoma commonly involves damage unequally distributed between the superior and inferior hemiretina. Our aim was to test whether the sensitivity of OCT and SAP for detecting glaucoma progression differs between the superior and inferior hemiretina by using the CNR analysis.
Methods :
CNRs for the OCT retinal nerve fiber layer (RNFL) thickness of hemiretinas and for the SAP mean total deviation (MTD) of the corresponding hemifields were calculated from longitudinal data from a prospective study (205 eyes, 123 participants). The glaucoma stage for each hemiretina and corresponding hemifield was based on the hemifield's MTD (Figure 1A). Contrast was defined as the difference of the parameter between two consecutive glaucoma stages, whereas noise was the measurement variability of the parameter in those stages. The higher the CNR, the more sensitive the parameter is to detect progression in the transition between two glaucoma stages.
Results :
The CNRs are shown in Figure 1B. There were no differences between the superior hemiretina and the inferior hemiretina in the first and last transition. However, in the transition of mild to moderate glaucoma, the CNR for the superior hemiretina did not differ between OCT and SAP, while the CNR for the inferior hemiretina was significantly higher for SAP than for OCT. Furthermore, in the transition of moderate to advanced glaucoma the CNR for the superior hemiretina was significantly higher for SAP than OCT, while the CNR for the inferior hemiretina did not differ between OCT and SAP.
Conclusions :
Our results indicate that SAP is more sensitive than OCT for detecting progression from mild to moderate glaucoma in the inferior hemiretina, while they are equally sensitive for detecting progression in the superior hemiretina. In addition, SAP is more sensitive that OCT for detecting progression from moderate to advanced glaucoma in the superior hemiretina, while they are equally sensitive for detecting progression in the inferior hemiretina. The results thereby suggest a different structure-function relationship between the superior hemiretina and inferior hemiretina.
This is a 2020 ARVO Annual Meeting abstract.