Structure-Function Relationship of Changes in Visual Field Indices with Quadrant and Average Retinal Nerve Fiber Layer Thickness in the Eyes with Exfoliation

Abstract

The progressive nature of glaucoma suggests it should be possible to detect structural changes such as retinal nerve fiber layer (RNFL) thickness loss before the condition becomes clinically apparent with visual field (VF) impairment. Therefore, the aim was to analyze RNFL thickness and VF changes in study groups with unilateral exfoliation syndrome (XFS), bilateral XFS and bilateral exfoliative glaucoma (XFG), and compare it with controls. The study included 114 subjects (228 eyes) divided into 4 groups according to the presence of exfoliation: 30 subjects with unilateral XFS (30 with clinically visible XFS and 30 fellow eyes), 24 subjects (48 eyes) with bilateral XFS, 28 (56 eyes) subjects with bilateral XFG, and control group (32 subjects). All subjects underwent VF and RNFL measurements after ophthalmologic examination. Both eyes of unilateral XFS (clinically ­visible and fellow eye) showed positive correlation between Mean Defect (MD) and square root of Loss of Variance (sLV) and between MD and inferior quadrant RNFL thickness. In bilateral XFS and XFG, there was negative correlation between MD and inferior quadrant RNFL thickness. Inferior, superior and nasal quadrant RNFL thickness was lower in XFG group than in other groups. In bilateral XFS group, the inferior quadrant RNFL thickness was lower as compared with unilateral XFS group (in both eyes). The mean RNFL thickness negatively correlated with MD in bilateral XFS and XFG groups. In conclusion, structural changes before VF impairment have an important role in early detection of glaucoma in subjects at risk.

Keywords

• Glaucoma
• Nerve fibers
• Visual fields
• Exfoliation syndrome
• Croatia