Abstract
Purpose: :
To identify the variable with the highest correlation between the magnitude of the relative afferent papillary defect (RAPD) and visual field indices in patients with glaucomatous optic neuropathy (GON).
Methods: :
79 consecutive subjects (41 females, 38 males) with manifest GON, suspected glaucoma or ocular hypertension, aged from 13 to 75 years, were enrolled in this retrospective study. RAPD was assessed with the swinging flashlight test and quantified with a neutral density filter in 0.3 log steps in front of the better eye. Perimetry was performed with the OCTOPUS 101 perimeter (HAAG-STREIT Inc., Koeniz, Switzerland), using the fast thresholding strategy GATE. Both values of the RE and LE of the central differential luminance sensitivity (DLS), of the MD (Mean Defect) and of the "loss volume" (LVOL) of the individually modeled 3D hill of vision - the latter two within the eccentricities of 10°, 20° and 30°, respectively - were entered into a linear multivariable regression model for the magnitude of the RAPD without intercept. The estimates were allowed to differ by the sign of the difference between the values in the right and the left eye. The predicted RAPD values were subsequently correlated with the observed RAPD values according to Pearson’s correlation coefficient (r).
Results: :
An absolute value of RAPD of 0.3 log units or more was present in 20 out of 79 glaucoma subjects (25%). The magnitude of RAPD was most closely correlated with LVOL within 30° eccentricity (r = 0.86), followed by MD-30° (r = 0.81), MD-20° (r = 0.78), LVOL-20° (r = 0.77), LVOL-10° (r = 0.66), MD-10° (r = 0.66) and central DLS (r = 0.18).
Conclusions: :
The magnitude of RAPD in glaucomatous optic neuropathy correlates most closely with "loss volume" within 30° eccentricity and most loosely with central DLS, underscoring the impact of the entire 30°-visual field area on the afferent papillary system.
Keywords: perimetry • visual fields • pupil