Calcarine Cortex Volume is Reduced in Glaucoma Patients

Abstract

Purpose: : The purpose of this study is to evaluate the difference on calcarine cortex volume between glaucoma patients and a control group and the association between standard automated perimetry (SAP) mean deviation (MD) and calcarine cortex volume.

Methods: : Patients and controls were submitted to a complete ophthalmic examination, including Humphrey standard automated perimetry (SAP) 24-2. A 3.0 Tesla MRI was performed, and an automated segmentation of pericalcarine area was made by FreeSurfer software. This program uses a dataset and complex maths to separate and calculate cortical areas. Using the standard model, the pericalcarine area was segmented in superior and inferior. Having each subject registered in this model, the segmentation was projected for all. To compare both groups regarding anatomical and functional examinations, generalized estimating equation (GEE) models were performed to account for the dependence between eyes and cortical segment of the same patient.

Results: : 20 individuals performed the exams, 14 with glaucoma and 6 controls. Mean age was 59.3 ± 14.8 years for control group and 61.7 ± 10.5 years for glaucoma group. There was no significant association between SAP MD and calcarine cortex volume (Wald Chi-Square p=0.127) but a statistically significant difference between glaucoma and control group regarding calcarine cortex volume: estimated marginal means and standard error of 914.96 ± 46.89 mm3 for the control group and 847.36 ±31.61 mm3 for the glaucoma group (Wald Chi-Square p=0.006).

Conclusions: : Calcarine cortex volume was reduced in glaucoma patients. No significant association between SAP MD and calcarine cortex volume was found.

Keywords: clinical (human) or epidemiologic studies: natural history • imaging/image analysis: clinical