Abstract
Purpose: :
To evaluate the ability of transient pattern electroretinogram (PERG) parameters to differentiate between healthy eyes and eyes of patients with neuromyelitis optica (NMO) and multiple sclerosis (MS) with or without previous episodes of optic neuritis.
Methods: :
Patients with MS (n=43), NMO (n=20) and healthy controls (n=29) were submitted to ophthalmic examination, including standard automated perimetry (Humphrey 24-2 SITA Standard test) and full field transient PERG, recorded using checkerboard screens with a RETiscan System (Roland Consult, Wiesbaden, Germany, 2006). The stimulus was generated with black-and-white checks (measuring 48 or 14 minutes of visual angle) with a mean luminance of 80 cd/m2 and a contrast of 97% and a reversal rate of 4,03 Hz. Amplitudes and peak times for the P50 and N95 amplitude were measured. Four groups of eyes were compared: MS with (Group 1, n= 27) or without (Group 2, n= 23) previous optic neuritis, NMO (Group 3, n= 30) and controls (Group 4, n= 37). Comparisons were made using Student’s t-test. Receiver operating characteristic (ROC) curves were used to describe the ability of PERG parameters to discriminate the groups.
Results: :
PERG amplitudes values were significantly lower in groups 1, 2 and 3 compared to normal eyes (p<0.05). There were no significant differences in the amplitudes parameters when MS-ON, NMO and Ms without ON eyes were compared to each other. The best area under the ROC curve for discriminating ON MS with ON group of eyes, NMO group of eyes and MS without ON eyes were 0.67, 0.80 and 0.71, respectively. Using the 10th percentile of normals as the lower limit of normal and according to the best discriminating PERG parameter considered abnormal 17 of 27 eyes in the MS-ON group, 18 of 30 eyes with NMO and all 8 of 23 MS eyes without ON. Most abnormalities were observed regarding N95 amplitude wave although the P50 wave also revealed abnormalities in most comparisons with normal eyes. No significant difference was observed between groups regarding PERG peak times for the great majority of comparisons.
Conclusions: :
transient PERG amplitude measurements seems to an important tool to investigate retinal ganglion cell dysfunction from NMO and MS with or without optic neuritis when compared to normals.
Clinical Trial: :
http://www.clinicaltrials.gov NCT01024985
Keywords: electroretinography: clinical • neuro-ophthalmology: optic nerve • optic nerve