Abstract
Purpose: :
To evaluate the interrelation of mfPhNR and RNFLT in the superior and inferior region in normals and patients with optic nerve lesion.
Methods: :
Ten eyes of ten volunteers with normal vision and six eyes of three patients with optic nerve lesions including normal tension glaucoma (NTG) were tested. The mfPhNR was recorded with the VERIS Science System 5.0.4. The visual stimulus was made up of 37 hexagons in an approximately 40-degree visual field, Pseudo-randomly alternating between black (5cd/m2) and white (200cd/m2) on the CRT monitor. Burian-Allen ERG Electrodes, Adult-bipolar or Pediatric-bipolar, were used for this testing. The recording time was approximately 8 min. with dilated pupils having the best-corrected visual acuity. The band pass filter of the amplifier was set from 1 to 100 Hz. The amplification and stimulus frequency were set to 10000 and 9.41 Hz (8 frames) respectively. Each trace of the mfPhNR found in all the superior and inferior regions was analyzed.RNFLT was measured using Cirrus HD-OCT. The average RNFLT in all superior and inferior quadrants was applied for analysis.
Results: :
There was a correlation between the amplitude of the mfPhNR in the superior region and RNFLT in the inferior quadrant (R=0.7575, P=0.0230) in normals. On the other hand, there was no correlation between the amplitude of the mfPhNR in the inferior region and RNFLT in the superior region in normals. The amplitude of mfPhNR in the eyes with optic nerve lesions decreased not only in the RNFLT decreasing quadrant but also the normal RNFLT quadrant. In unaffected eye of the patient with optic nerve lesion, the amplitude of mfPhNR was within normal range. In more affected eyes and less affected eyes with NTG, the amplitude of mfPhNR decreased in RNFLT decreasing quadrants but also normal RNFLT quadrants.
Conclusions: :
There is a different correlation between the amplitude of the mfPhNR and RNFLT in superior and inferior quadrants in normals. The amplitude of mfPhNR decreased even in patients with normal RNFLT quadrants.
Keywords: neuro-ophthalmology: optic nerve • electroretinography: clinical • nerve fiber layer