Abstract
Purpose: :
Visual field index (VFI) has been recently introduced by Heijl to quantify the total visual field damage giving different weigh according to the eccentricity of the area analyzed. This study evaluated the correlation between the VFI and the optic nerve head (ONH) parameters measured by Heidelberg Retina Tomograph (HRT).
Methods: :
This is a cross-sectional study. One hundred and 35 glaucoma patients were recruited for this study. Each patient had an abnormal visual field or /and optic nerve head, an IOP greater than 21 mmHg without treatment and open angle at gonioscopy. All patients recruited underwent visual field and HRT. Each visual field was assessed by Humphrey Field Analyzer (HFA), program SITA standard 30-2 or 24-2 (Carl Zeiss Meditec, Inc., Dublin, CA). Mean Deviation (MD) Pattern Standard Deviation (PSD) and VFI were considered. Each ONH was analyzed by confocal scanning laser ophthalmoscopy HRT (Heidelberg Engineering, Heidelberg, Germany) and the following parameters were considered: rim area (RA), cup area (CA), cup volume (CV), rim volume (RV), cup shape measure (CSM), glaucoma probability score (GPS) and two discriminant analyses: FSM and RB. Correlation was analyzed by using Pearson‘s r coefficient. A linear regression model was used to calculate which was the most predictive HRT parameter of VFI.
Results: :
Significant correlation was found between VFI and RA (r=0.23, p=0.008), CSM (r=-0.23, p=0.007), FSM (0.21, p=0.015) RB (0.39, p=0.000) and GPS (r=-0.176). When a linear regression model was used, RB showed to be the most predictive HRT parameter of the VFI (BETA= 0.757, p<0.001).
Conclusions: :
The new visual field index (VFI) was found to be well correlated with HRT parameter and in particular with RB.
Keywords: imaging/image analysis: clinical • visual fields