The evaluation of retinal nerve fiber layer in pigment dispersion syndrome and pigmentary glaucoma using scanning laser polarimetry

PURPOSE. To measure the retinal nerve fiber layer thickness in patients with pigment dispersion syndrome (PDS) using scanning laser polarimetry and to compare these measurements with those of normal subjects and patients with pigmentary glaucoma (PG). METHODS. Age-, sex-, and refractive error-matched subjects - 18 patients with PDS, 18 patients with PG, and 20 healthy subjects - were evaluated by scanning laser polarimetry (Nerve Fiber Analyzer [NFA] GDx). The NFA did not have a compensator for corneal polarization. One randomly selected eye from each patient was included in the statistical analysis. The NFA measurements of patients with PDS and PG and healthy subjects were compared statistically using analysis of variance, Tukey multiple comparisons, chi-square, and independent t-tests. RESULTS. The mean values for average thickness, superior and inferior maximum, superior and inferior average, ellipse average thickness, and superior integral were found to be lower in the patients with PDS (p<0.02) and PG (p<0.005) compared to the normal subjects. The mean values for maximum modulation, superior ratio, inferior ratio, and superior/nasal ratio in PDS were in between those of the PG and control groups (p>0.05). The ellipse modulation was significantly lower in the PG group when compared to the other two groups (p<0.03). CONCLUSIONS. Retinal nerve fiber loss is present to some extent in patients with PDS and this loss is not age or sex dependent. Parameters of modulation might be more representative of significant damage of the nerve fiber layer.