Purpose: To evaluate the strength and pattern of the relationship between visual field (VF) sensitivity and retinal nerve fiber layer (RNFL) thickness measurements by scanning laser polarimetry (SLP).
Methods: Fifty-four eyes of 54 normal subjects (age, 42 +/- 15 years; VF mean deviation [MD], -0.69 +/- 1.01 dB) and 51 eyes of 51 glaucoma patients (age, 66 +/- 14 years; VF MD, -6.92 +/- 5.43 dB) were imaged with an SLP using fixed corneal compensation (FCC) and variable corneal compensation (VCC). VF sensitivity was recorded in the dB and the 1/L scales. Linear and logarithmic relationships were sought globally and in six VF sectors. Relationships of VF and RNFL thickness with age were sought in normal subjects.
Results: Both VF sensitivity and RNFL thickness declined with age (as determined by the regression slope): -0.13% (P = 0.0005) and -0.64% (P = 0.0001) per year for dB and 1/L VF sensitivity, respectively, and -0.25% (P = 0.003) per year for VCC RNFL thickness. FCC RNFL thickness was not statistically significantly related to age. The relationship of VF sensitivity to VCC global (R(2) = 0.49) and sectoral (R(2) = 0.00-0.47) RNFL thickness was greater than for FCC global (R(2) = 0.12) and sectoral (R(2) = 0.00-0.21) RNFL thickness. Relationships were curvilinear with the dB scale, with logarithmic regression of dB VF sensitivity against RNFL thickness being significantly better than linear regression. Logarithmic regression of 1/L VF sensitivity against RNFL thickness was no better than linear regression for all sectors. There was no relationship between VF sensitivity and RNFL thickness in the temporal peripapillary RNFL sector.
Conclusions: The strength of the structure/function relationships compare well with previous reports in the literature. The relationships were curvilinear with the dB scale and linear with the 1/L scale, and were much stronger with VCC than with FCC RNFL thickness measurements.