Supernormal Flicker ERGs in Eyes With Central Retinal Vein Occlusion: Clinical Characteristics, Prognosis, and Effects of Anti-VEGF Agent

Abstract

PURPOSE. To determine the clinical characteristics, prognosis, and effect of anti-vascular endothelial growth factor (VEGF) agents on eyes with a central retinal vein occlusion (CRVO) with and without supernormal flicker ERG amplitudes. METHODS. Forty-eight eyes of 48 patients with a CRVO were studied. Flicker ERGs were recorded from fully dilated eyes with the RETeval system. The amplitudes and implicit times of the fundamental component were analyzed. ''Supernormal flicker ERGs'' were defined as those whose amplitudes were ‡117% of the unaffected fellow eyes. RESULTS. Ten of the 48 eyes (20.8%) with a CRVO showed supernormal flicker ERGs before the treatment. The difference in the implicit times of these 10 CRVO eyes and those of normal fellow eyes was <4 millisecond. There was a significant correlation between the implicit time delay and the relative amplitude in the 48 CRVO eyes. All 10 CRVO eyes with supernormal flicker ERGs had the nonischemic type of CRVO and tended to have better visual acuities than did the 28 nonischemic CRVO eyes without supernormal flicker ERGs at 12 months after the treatment (P ¼ 0.058). The CRVO eyes with supernormal flicker ERGs had a significant amplitude reduction after a single injection of an anti-VEGF agent. CONCLUSIONS. These results indicated that the supernormal flicker ERGs can be a sign of a mild degree of ischemia, and these eyes have a better prognosis. The results also suggest that the supernormal flicker ERG may be caused by changes in the electrical activities of retinal cells following a mild increase in the VEGF levels in eyes with CRVO.

ROCK inhibition reduces morphological and functional damage to rod synapses after retinal injury

“…One surprising finding was the larger than baseline b-wave amplitudes at 2 days, termed "supernormal ERGs" in the earliest observations of large scotopic b-waves 37,51 , primarily in the ROCK-inhibitortreated eyes. Although increase in ERG amplitudes is uncommon among visual disorders, such observations have been reported in patients with cone dystrophies 37,51,52 , early diabetic retinopathy 53 , central retinal vein occlusion (CRVO) 54,55 and in animal disease models, e.g., Ant1-deficient mice 56 , a rabbit model of retinal degeneration 57 , and a rat traumatic brain injury model 58 . In normal porcine retina, intravitreal injection of AR13503 alone did not cause increased scotopic ERG responses after 7 days (n = 3 animals, unpublished data).…”

“…However, work in patients is encouraging. Miyata et al 55 suggested that after anti-VEGF treatment of non-ischemic CRVO, eyes with supernormal ERGs had a better prognosis after 1 year than non-ischemic CRVO eyes without supernormal ERG amplitudes.…”

Aquaporin 4 Suppresses Neural Hyperactivity and Synaptic Fatigue and Fine-Tunes Neurotransmission to Regulate Visual Function in the Mouse Retina

“…In humans, hyperactivity in ERG responses is observed in central retinal vein occlusion [63], and the estimated mechanism involves ischemia-related increase in the local levels of inflammatory cytokines [64]. Given that AQP4 is important for water diffusion allowing bidirectional water transport across the plasma membrane [3, 12], the fine-tuning of diffusible factor concentrations, besides glutamate and potassium, at the neuron-glial site could be also involved in its role in preserving neuron-microenvironment homeostasis.…”

Effects of Intravitreal Aflibercept on Retinal Function and Improvement of Macular Edema Associated With Diabetic Retinopathy

“…Full-field flicker ERGs were recorded with the RETeval system as described. 35 After full mydriasis with topical 0.5% tropicamide and 0.5% phenylephrine HCl, (Mydrin-P; Santen Pharmaceutical Co., Ltd., Osaka, Japan), the flicker ERGs were recorded. A special skin electrode array (Sensor Strip; LKC Technologies, Inc., Gaithersburg, MD, USA) was placed 2 mm from the margin of the lower eyelid.…”