Evaluation of relationship between retinal nerve fiber layer thickness progression and visual field progression in patients with glaucoma

Purpose

To evaluate the capability of optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thickness, and visual field (VF) measurements in glaucoma progression detection.

Methods

The study examined 62 eyes of 37 glaucoma patients observed over a 3-year period. All eyes underwent at least four serial RNFL measurements performed by Cirrus OCT, with the first and last measurements separated by at least 3 years. VF testing was performed by using the Swedish interactive threshold algorithm (SITA) Standard 30-2 program of the Humphrey field analyzer (HFA) on the same day as the RNFL imaging. Both serial RNFL thicknesses and VF progression were assessed by the guided progression analysis (GPA) software program. RNFL thickness progression was evaluated by event analysis. Total deviation (TD) in the superior or inferior hemifield was also examined.

Results

A total of 295 OCT scans and 295 VFs were analyzed. Five eyes exhibited progression by OCT only and 8 eyes exhibited progression by VF GPA only. When the analysis was based on the combined measurement findings, progression was noted in 6 eyes. The average of the progressive hemifield TD at baseline for combined RNFL and VF progression was ?3.21 ± 1.38 dB, while it was ?2.17 ± 1.14 dB for RNFL progression and ?9.12 ± 3.75 dB for VF progression. The average of the progressive hemifield TD indicated a significant advancement of VF progression as compared to RNFL progression (P = 0.002).

Conclusions

When a mild VF defect is present, OCT RNFL thickness measurements are important in helping discern glaucoma progression.