Changes of oscillatory potentials and photopic negative response in patients with early diabetic retinopathy.
OBJECTIVE
To investigate the clinical significance of the oscillatory potentials (OPs) and photopic negative response (PhNR) of the electroretinogram (ERG) in patients with early diabetic retinopathy.


METHODS
One hundred two diabetic patients with diabetic retinopathy at different stages were examined. Thirty-two age-matched normal controls were also studied. Full-field maximal and photopic cone ERGs were recorded. The amplitudes and implicit times of the OPs, cone b wave, and PhNR were compared at the different stages of diabetic retinopathy.


RESULTS
The a and b wave amplitudes of the maximal scotopic ERGs remained unchanged despite advancing stages of retinopathy, but the OP amplitudes were significantly attenuated even at an early stage of diabetic retinopathy. The amplitudes of both the PhNR and cone b wave were reduced at an early stage of diabetic retinopathy. Analysis of the receiver operating characteristic curves demonstrated that the amplitudes and implicit times of the OPs were more sensitive and specific than those of the PhNR in detecting changes of retinal function in the early stages of diabetic retinopathy.


CONCLUSIONS
The amplitudes of the OPs and PhNR progressively decrease with the progression of diabetic retinopathy. The PhNR amplitudes were reduced along with the cone b wave, indicating that earlier change of the PhNR in diabetic patients reflects reduced input to the retinal ganglion cell from the distal retina. The amplitudes and implicit times of the OPs are better indicators than those of the PhNR in detecting functional decreases in patients with early diabetic retinopathy.
Kizawa
Junya
J
Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan.
Machida
Shigeki
S
Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan. smachida@iwate-med.ac.jp.
Kobayashi
Takaki
T
Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan.
Gotoh
Yasutaka
Y
Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan.
Kurosaka
Daijiro
D
Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan.
D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D018450:Disease Progression; D004596:Electroretinography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012372:ROC Curve; D012189:Retrospective Studies