ISSN 2706-9354

Abstract:

Background: Primary open-angle glaucoma is a chronic optic neuropathy whose diagnosis and monitoring are carried out by functional and structural examinations, so the identification of structure-function relationship is essential for the choice of the therapeutic strategy.

Aim: To evaluate the correlation between tomographic (optic nerve head (ONH) / ganglion cell complex (GCC) / retinal nerve fiber layer (RNFL)) and functional parameters in normal, perimetric and manifest glaucoma.

Methods: A retrospective analytical study, involving 275 eyes of 152 subjects. Participants were divided into 3 groups:  33 normal subjects, 32 patients with preperimetric glaucoma and 87 patients with manifest glaucoma.  All subjects underwent a complete ophthalmologic examination, a visual field and spectral-domain optical coherence tomography (SD-OCT).

Results: Correlations between functional and tomographic parameters were absent or very weak in the group of normal or preperimetric glaucoma subjects. In contrast, in manifest glaucoma group, mean deviation (MD) was significantly correlated with all tomographic parameters (p<0.001). The correlation of loss variance (LV) with tomographic parameters in manifest glaucoma group was significant with most tomographic parameters assessing RNFL and GCC.

The regression studies of (MD with RNFL /GCC) and (LV with GCC) were better explained with nonlinear models (p <0.001). Linear models described the relationship between LV and average RNFL as well as the polynomial models (p=0,275).

Conclusions: No structure-function correlation was observed at the preperimetric stage. However, MD correlated better with tomographic parameters than LV in manifest glaucoma group. A curvilinear function is the suitable model to describe the structure-function relationship.

Key-words: Optical coherence tomography, correlation, regression, primary open-angle glaucoma, retinal ganglion cells, retinal nerve fiber.