Abstract
Purpose: :
To evaluate the relationship between pattern electroretinogram (PERG) amplitude, Fourier-domain optical coherence tomography (FD-OCT) macular and retinal nerve fiber layer (RNFL) thickness and visual field (VF) loss on standard automated perimetry (SAP) in 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=29), NMO (n=19) and healthy controls (n=25) were submitted to ophthalmic examination, including SAP (Humphrey 24-2 SITA Standard test), full field PERG and to FD-OCT RNFL and macular thickness measurements, using a FD-OCT equipment (3DOCT-1000; Topcon, Inc). Full-field stimulation transient PERG were recorded using checkerboard screens, according to the ISCEV with the RETiscan System (Roland Consult, Wiesbaden, Germany, 2006). The stimulus was generated with black-and-white checks (measuring 48 or 14 minutes of arc) 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= 29) and controls (Group 4, n= 28). Comparisons were made using Student’s t-test. Correlation between PERG, FD-OCT and VF findings was investigated.
Results: :
PERG amplitude and OCT measurements were significantly lower in eyes of Groups 1, 2 and 3 compared to normals (group 4). A significant correlation was found between N95 PERG amplitude and OCT RNFL or OCT macula thickness parameters in the Group 1 (r= 0.58 and r=0.47, respectively). No significant correlation was observed between VF sensitivity loss (mean deviation in dB) and OCT parameters, except for RNFL thickness measurements in the Group 2 (r=0.65). Likewise no significant correlation was observed between PERG parameters and VF sensitivity loss.
Conclusions: :
Although the amplitudes of the PERG and OCT measures were lower in patients with MS and NMO, only in eyes with previous optic neuritis significant correlation between the PERG and OCT parameters was observed. Our study suggests that PERG and OCT quantify neural loss differently, but both technologies are useful in understanding structure and function relationship in patients with multiple sclerosis and neuromyelitis optica.
Keywords: neuro-ophthalmology: diagnosis • neuro-ophthalmology: optic nerve