Retinal Nerve Fiber Layer Measurements by Scanning Laser Polarimetry With Enhanced Corneal Compensation in Healthy Subjects

Abstract

Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

Atypical birefringence pattern and the diagnostic ability of scanning laser polarimetry with enhanced corneal compensation in glaucoma

“…Previous studies have reported this using the VCC protocol of SLP (Bagga et al 2005;Da Pozzo et al 2006). We have also reported the same previously using the ECC protocol of SLP in normal subjects even when the TSS values were within the acceptable limits (Rao et al 2013). We had found that the TSNIT average measurements were significantly higher at low TSS values.…”

“…We also ran the entire analysis using a control group consisting of eyes with no suspicious findings for glaucoma. The characteristics of this control group have been detailed earlier (Rao et al 2013). The results of the ROC regression analysis remained similar with TSS significantly affecting the AUCs of TSNIT average (coefficient: 0.08, p value: 0.001) and inferior average parameters (0.06, 0.007) but not NFI (0.02, 0.39) and superior average parameters (0.01, 0.71).…”

“…However, in a previous study, to evaluate the effect of TSS on the RNFL measurements with the ECC protocol of SLP in healthy subjects, we found that the TSS affected the overall average RNFL measurement even when it was over 80. Lower TSS values were associated with significantly thicker overall average RNFL measurements (Rao et al 2013).…”

“…The general principles of SLP and the algorithm used for ECC have been described in detail elsewhere (Weinreb et al 1995;Reus et al 2006;Medeiros et al 2007). The procedure followed in our study has been described previously (Rao et al 2013). The parameters generated on the printout and used in this study were superior average (superior 120 degree), inferior average (inferior 120 degree), TSNIT (temporalsuperior-nasal-inferior-temporal) average and nerve fibre indicator (NFI).…”

Diagnostic Abilities of Variable and Enhanced Corneal Compensation Algorithms of GDx in Different Severities of Glaucoma

“…6,8,12 Our procedure of SLP imaging has also been reported earlier. 13 In brief, a corneal scan was obtained first to measure the corneal birefringence. RNFL was imaged later using a single-scan protocol.…”