Correlation of localized glaucomatous visual field defects and spectral domain optical coherence tomography retinal nerve fiber layer thinning using a modified structure–function map for OCT

Abstract

Purpose To study the correlation between glaucomatous visual field (VF) defects assessed by standard automated perimetry (SAP) and peripapillary retinal nerve fiber layer (RNFL) thinning measured by spectral domain optical coherence tomography (OCT) using a modified OCT-based peripapillary RNFL structure-function map. Patients and methods Perimetric glaucoma patients and age-matched normal control subjects were recruited from a university hospital clinic. All eyes underwent testing with the Spectralis spectral domain OCT and SAP on the same day. An OCT-based correspondence map, which correlated VF areas with peripapillary RNFL sectors was created to evaluate the relationship between glaucomatous RNFL thinning and VF loss in six nerve fiber layer bundle areas. Correlations of RNFL thinning with corresponding VF defects were examined using Spearman rankorder correlations. To demonstrate the association between localized VF defects and RNFL thickness, the theoretical curves were made according to an established log-linear model. The measured RNFL thickness values and VF defects were presented in the same scatterplot for each sector. Results Fifty-six glaucoma patients and 85 normal subjects were included in the study.Significant association between localized VF loss and RNFL thinning was found in corresponding areas. Data from the current study fit well with established log-linear models, which compare RNFL thickness values with VF defects. Conclusion Analysis of RNFL thinning in eyes with localized glaucomatous VF defects showed good structure-function correlation in a new OCT-based structure-function correspondence map.

Discriminant Function of Optical Coherence Tomography Angiography to Determine Disease Severity in Glaucoma

“…However, all these were global correlations. Previous studies 22,23,30 have already established regional correlations between RNFL loss, GCC loss, and VF deficits. This study looked at sectoral vascular changes with corresponding regional VF defects.…”

“…Linear regressions of global vascular parameters and vessel density inside disc were performed with C/D ratio, RNFL average thickness (lm), GCC average thickness (lm), FLV (%), GLV (%), VF MD (dB), and PSD (dB) for glaucomatous eyes. From a previously established relationship between regional RNFL and GCC loss with VF defects, [21][22][23] linear regressions of vascular parameters in T, ST, IT, N, SN, and IN sectors were performed with corresponding regional pattern deviation loss in the VF map (Fig. 3).…”

Structure versus function in high myopia using optical coherence tomography and automated perimetry

“…Visual field sensitivity was assessed from 17 central test locations, in decibels (dB) (red dashed square on the right side of Figure ), roughly the equivalent of the area tested by optical coherence tomography in the macular scan. Each visual field test location provided in dB was converted to anti‐logged 1/Lambert (1/L) units by dividing the dB value by 10 and anti‐logging the quotient . This conversion is based upon the assumption that the relationship between the structure and function is linear when visual field measures are expressed in a linear scale .…”

“…Additionally, patients were further classified as having abnormal visual field based on their mean deviation (MD) from the instrument ‘normal’ across the whole field as follows: mild (−6 dB < MD ≤ −2 dB), moderate (−12 dB < MD ≤ −6 dB), or severe (MD ≤ −12 dB) …”

“…The correlations between macular retinal layer thicknesses (6 mm diameter disc) and visual field sensitivity were assessed in four matched quadrants (Figure ) . For correlation with peripapillary retinal nerve fibre layer thickness, the visual field positions were grouped into six areas according to the modified structure–function correspondence map of Wu et al (Figure ).…”