Structure-Function Relationship in Glaucoma Using the Cirrus Spectral Domain Optical Coherence Tomograph and Standard Automated Perimetry

Abstract

 

Purpose:

 

To evaluate the relationship between glaucomatous structural damage assessed by the Cirrus Spectral Domain OCT (SDOCT) and functional loss as measured by standard automated perimetry (SAP).

 

Methods:

 

Four hundred twenty two eyes (78 healthy, 210 suspects, 134 glaucomatous) of 250 patients were recruited from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). All eyes underwent testing with the Cirrus SDOCT and SAP within a 6-month period. The relationship between parapapillary retinal nerve fiber layer thickness (RNFL) sectors and corresponding topographic SAP locations was evaluated using LOWESS and regression analysis. SAP sensitivity values were evaluated using both linear as well as logarithmic scales. We also tested the fit of a proposed model for structure-function relationship in glaucoma suggested by Hood et al.(Prog Retin Eye Res, 2007).

 

Results:

 

Structure was significantly related to function for all but the nasal thickness sector. The relationship was strongest for superotemporal RNFL thickness and inferonasal sensitivity, both using SAP sensitivity in a linear (R2 = 0.314, P<0.001) and logarithmic scale (R2 = 0.286, P<0.001). The model proposed by Hood et al. fitted the data relatively well with 88% of the eyes inside the 95% confidence interval predicted by the model (Figure 1).

 

Conclusions:

 

RNFL thinning measured by the Cirrus SDOCT was associated with correspondent visual field loss in glaucoma.  

 

Keywords: imaging/image analysis: clinical • nerve fiber layer • visual fields