Spatial Relationship Between Structural and Functional Glaucoma Progression in Extended Long-Term Cohort

Abstract

 

Purpose

 

To evaluate the spatial relationship between structural and functional progression as measured by optical coherence tomography (OCT) and visual field (VF).

 

Methods

 

211 eyes of 120 glaucomatous, glaucoma suspect and healthy subjects were followed at 6-month intervals for a median of 9.4 years (range: 3.9-18.2). OCT retinal nerve fiber layer (RNFL) thickness measurements performed by multiple generations of the OCT technology were standardized by applying calibration equations. Superior and inferior quadrants RNFL thickness and VF mean sensitivities in the corresponding locations were used for analysis. Eyes were defined as progressing when two consecutive visits had significantly negative linear regression slopes with either or both OCT and VF measurements.

 

Results

 

53 eyes (32 superior, 28 inferior, 7 Both) showed RNFL progression in the superior and/or inferior quadrants. Of this subset, 12 eyes (9 superior, 5 inferior, and 2 both) showed VF progression (Table 1). Progressing eyes with spatial agreement (n=7) and eyes with spatial disagreement (n=6) had similar baseline age and RNFL, time to progression by OCT and VF, and length of follow-up after progression was detected (Table 2). Baseline VF, and VF at progression tended to be worse in eyes with agreement than in eyes with disagreement.

 

Conclusions

 

Spatial agreement between structural and functional progression as measured by VF and OCT is poor. While there was no difference in any of the tested indicators in eyes with spatial agreement and disagreement, the markedly worse VF deficit in the spatial agreement eyes probably indicate worsening of pre-existing structural and functional deficits.

 

 

Table 1. Number of Progressors by Quadrant

 

 

Table 2. Progressor Characteristics

 

Keywords: 610 nerve fiber layer • 758 visual fields • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)