Abstract
Purpose :
To date, the structure–function relationship in advanced glaucoma has been investigated in insufficient detail. Although several previous studies reported a strong relationship between macular structure and central visual function in advanced glaucoma, whether this association is also applicable after the circumpapillary retinal nerve fiber layer (cpRNFL) thickness reaches the measurement floor has not been reported. The present study aims to investigate the relationship between the central VF and macular parameters obtained from SD-OCT in patients with end-stage glaucoma in whom the cpRNFL thickness reaches the measurement floor and to determine whether SD-OCT is useful for estimating functional status in these patients.
Methods :
A total of 68 eyes from 68 patients with end-stage glaucoma were included. Only eyes with an average cpRNFL of 57 μm or less that reached the measurement floor were enrolled in this study. Macular imaging using Cirrus SD-OCT and 10-2 Humphrey VF were performed. The VF mean deviation (MD) was converted to a linear scale using unlogged 1/Lambert values. The relationships between the central VF and various macular parameters were determined using Spearman correlation analysis. Subgroup analysis in the NTG and POAG groups were also performed.
Results :
Patients had a mean VF MD of -20.69 dB and average cpRNFL of 51.76 ± 3.61 μm. Correlations between the central VF and all cpRNFL thickness parameters were not significant. Significant correlations were found between the central VF and superonasal mGCIPL thickness (r = 0.377, P = 0.002), inner nasal macular thickness (r = 0.305, P = 0.011), and outer nasal macular thickness (r = 0.314, P = 0.009). Interestingly, the association between central visual function and SD-OCT parameters slightly differed depending on the glaucoma subtype. In the NTG group, central visual function was significantly associated with inner and outer nasal macular thickness (r = 0.695, P = 0.003 and r = 0.666, P = 0.005, respectively). Meanwhile, in the POAG group, superonasal mGCIPL thickness showed a significant association with central visual function (r = 0.318, P = 0.022).
Conclusions :
Although the cpRNFL had reached the measurement floor, several macular parameters showed a strong structure–function relationship. In particular, the nasal macular region is important for assessing central visual function in end-stage glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.