Abstract
Purpose: :
To correlate RAPD with RNFLT, Humphery visual field (HVF) and multifocal visual evoked potential (mfVEP) measurements in patients with multiple sclerosis (MS) and ON.
Methods: :
28 MS patients (age 23-56, mean 40±9.6) with a history of ON in one (16 patients) or both eyes (12 patients) and at least 6 months recovery from the most recent ON attack were included. RAPD was quantified by performing the swing flashlight test with log-scaled neutral density filters placed over the less affected eye. The RNFLT was measured with ocular coherence tomography (OCT Stratus 3000: Fast RNFL protocol). On HVF, a mean unlogged deviation for each eye was calculated from the total deviation plot by dividing each location’s deviation value (dB) by 10 then unlogging it, which was then averaged across the 24-2 test locations. Monocular mfVEPs were recorded with a multi-channel technique using 60 sector pattern-reversal dartboard stimuli (VERIS). Data analysis used customized software to calculate the interocular response amplitude ratio and interocular latency differences at each sector.1,2 A median or mean value from 60 sectors was used to represent an individual’s overall interocular response amplitude ratios or latency differences.
Results: :
RAPD ranged from 0 to 1.2 log units. Regression analysis revealed a good linear relationship between RAPD and interocular RNFLT ratios or differences (R2=0.73 and 0.68 respectively, p<0.0001 for both), interocular mean unlogged deviation differences (R2=0.68, p<0.0001), and the median interocular mfVEP response amplitude ratios (in log scale) (R2=0.66, p<0.0001). A weaker linear relationship was found between RAPD and 1) HVF interocular mean deviation (MD in dB) differences: R2=0.45 (p=0.0001); 2) mfVEP mean or median interocular latency differences: R2=0.24, p=0.01 for both.
Conclusions: :
Persistent RAPD defects in ON were correlated with retinal nerve fiber loss and functional deficits measured by HVF and mfVEP response amplitudes.1. Hood & Greenstein 2003; 2. Hood et al. 2004.
Keywords: pupillary reflex • neuro-ophthalmology: optic nerve • electrophysiology: clinical