Purpose:
To evaluate the strength and pattern of the relationship between Frequency Doubling Technology (FDT) and optic nerve head morphometric parameters by Heidelberg Retina Tomograph (HRT).
Methods:
One hundred and two eyes of primary open angle glaucoma patients were included in this cross sectional study. Glaucomatous patients were classified when they had an abnormal visual field and / or optic disc. Each patient was imaged with a Confocal Scanning Laser Ophtalmoscope. Visual field was assessed by Humphrey Field Analyzer 24-2, full threshold SITA standard and by FDT N30. From HRT cup shape measure (CSM), retinal nerve fiber layer thickness (RNFLt) and rim volume (RV) were considered. From the visual field print-out mean deviation (MD) and pattern standard deviation (PSD) were considered in the dB (log) and in the 1\Lambert (unlog) scales.Relationship between structure and function was assessed by Pearson’s r correlation coefficient and then linear regression model was used to evaluate which index (log vs unlog) was more predictive of HRT parameters.
Results:
A significant (p<0.001) correlation was found between HRT parameters and both log and unlog FDT indices. When a linear regression model was used, no difference was found between log and unlog indices. The scattergrams showed a curvilinear relationship between MD (dB) and HRT parameters, while linear relationship was found for unlog MD. The scattergrams showed a curvilinear relationship between HRT parameters and both log and unlog PSD.
Conclusions:
A significant (p<0.001) correlation was found between HRT parameters and FDT indices. The relationship was curvilinear with the decibel scale and linear with the 1\Lambert scale for the MD, however for the PSD the relationship was curvilinear when both the decibel scale and the 1\Lambert scale were used.
Keywords: optic disc • visual fields • imaging/image analysis: clinical