ISCEV extended protocol for the photopic negative response (PhNR) of the full-field electroretinogram

Frishman, Laura J.; Šuštar, Maja; Kremers, Jan; McAnany, J. Jason; Sarossy, Marc; Tzekov, Radouil; Viswanáthan, Suresh

doi:10.1007/s10633-018-9638-x

Cited by 131 publications

(119 citation statements)

References 22 publications

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“…The PhNR is a widely used protocol for assessing RGC and inner retinal function, 15 and was recently covered by ISCEV standards. 44 This study suggests that a loss in PhNR amplitude would depend on both the size and the location of the lesion, with peripheral lesions having a relatively greater impact than more central ones. This may explain the observation in other studies 9,10,45 that the full-field ERG is less sensitive to central lesions than peripheral ones.…”

Section: Discussionmentioning

confidence: 73%

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

Morny

Patel

Votruba

et al. 2019

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To assess the topographic relationship between the photopic negative response (PhNR) and retinal ganglion cell distribution in healthy individuals. METHOD. Data was recorded from 16 healthy participants. The amplitude of PhNRs obtained in response to focal long duration (250 ms) and brief flash (5 ms), red (660 nm) on blue (469 nm) stimuli of increasing size (58-full field) were measured. The number of retinal ganglion cell receptive fields (RGCf) in each stimulus area was established from the literature and regression analysis used to determine the relationships between: PhNR amplitude and number of RGCfs stimulated, PhNR density and the RGCf density and response per RGCf as a function of eccentricity. RESULTS. The overall amplitude of the PhNR increased with stimulus size and the response density declined from~0.1 lV/deg in the macular region to~0.003 lV/deg approximately 458 from the fovea. Contrary to expectations, the relationship between the PhNR and number of RGCf was nonlinear, the response from more eccentric neurons being about three times greater than those in the macular region. CONCLUSIONS. Although the amplitude of the PhNR broadly maps on to the topographic distribution of RGCf the increase in PhNR amplitude with increasing eccentricity is only partly explained by RGCf numbers. Increases in the PhNR amplitude may be due to topographic variations in the contributions from other non-RGC neurons, as well as eccentricity-related morphologic and physiologic differences in RGCs.

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Section: Discussionmentioning

confidence: 73%

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

Morny

Patel

Votruba

et al. 2019

Invest. Ophthalmol. Vis. Sci.

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“…10 It can be decreased in diseases that influence the inner retina, including glaucoma and different types of optic neuropathy. 11 Previous studies have reported a correlation between the amplitudes and latency of the PhNR with the mean RNFL thickness. This indicates that the RGC function is correlated to RNFL thickness.…”

Section: Introductionmentioning

confidence: 95%

“…The PhNR amplitude was identified as the difference between the baseline and the trough of the negative wave following the b-wave (Figure 1). 11 The implicit time was identified as the time interval from onset of the stimulus and the peak of the negative wave.…”

Section: Ophthalmological Examinationmentioning

confidence: 99%

<p>Functional and Structural Changes of the Retinal Nerve Fiber Layer and Ganglion Cell Complex in Heavy Smokers</p>

Abdelshafy¹,

Abdelshafy²

2020

OPTH

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Purpose: To assess the functional and structural changes in the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCC) in heavy smokers using pattern electroretinogram (PERG), photopic negative response(PhNR) and spectral domain optical coherence tomography (SD-OCT). Patients and Methods: Sixty eyes of 30 heavy smokers (at least 15 cigarettes/day for 10 years) (study group) and 60 eyes of 30 age and gender-matched healthy non-smoker subjects (control group) were included. After full ophthalmologic examination (PERG), (PhNR) using RETI-port/scan 21 (Roland Consult, Brandenburg, Germany) and (SD-OCT using Topcon 3D OCT model 2000 FA version.8.30) were tested for all participants. Statistical analysis was performed to compare GCC, RNFL thicknesses, PERG and phNR values between groups. Results: The mean age was 36.67±4.13 years in the study group and 36.0±4.76 years in the control group. There were no statistical significant differences between the two groups regarding intraocular pressure (p=0.43), axial length (p=0.37), and central corneal thickness (p=0.86). There were significant differences of GCC thickness values between the study group (88.4±6.6 µm) and control group (94.83±5.25 µm) (p<0.001). The mean RNFL values of study and control groups were 97.87±5.88 and 106.43±6.59 µm, respectively (p<0.001). In the study group the superior and inferior quadrants of RNFL were significantly thinner, but there were no significant differences between the two groups in nasal and temporal quadrants. There were no significant differences of PERG-P50 amplitude (p=0.49) and latency (p=0.71); however, PERG-N95 amplitude and latency showed significant differences between the two groups (p<0.001).There were significant differences of phNR amplitude and latency between the two groups (p<0.001). Multiple regression analyses demonstrated that the PhNR, PERG amplitude and latency are the most important determinants for both RNFL and GCC thicknesses. Conclusion: In heavy smokers RNFL thickness was decreased, the PhNR, PERG-N95 amplitudes were diminished and the implicit times were prolonged compared to non-smokers. PhNR and PERG reflect both dysfunction and loss of ganglion cells and their axons.

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“…The photopic negative (PhNR) and positive scotopic threshold responses are parameters of the electroretinogram (ERG) that are largely generated by RGCs in the inner retina. [26][27][28][29][30] RGC function has been shown to recover after acute and chronic IOP insults even after prolonged periods of functional loss. [31][32][33][34][35] Capacity for recovery is reduced with advancing age 36 and can be modified by interventions such as exercise and diet restriction.…”

Section: Main Textmentioning

confidence: 99%

Improvement in Inner Retinal Function in Glaucoma with Nicotinamide (Vitamin B₃) Supplementation: A Crossover Randomised Clinical Trial

Hui

Tang

Williams

et al. 2020

Preprint

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Importance: Retinal ganglion cells endure significant metabolic stress with ageing and glaucoma-related stressors. Injured cells require increased energy for repair but maintain capacity to recover function despite periods of functional loss. Nicotinamide, a precursor of redox co-factor and metabolite, NAD+, is low in serum of patients with primary open-angle glaucoma and its supplementation provides robust protection of retinal ganglion cells by targeting mitochondrial health in glaucoma models. However, the potential of nicotinamide to improve retinal ganglion cell function in humans with glaucoma is yet unknown. Objective: To determine whether nicotinamide supplementation taken in conjunction with conventional IOP-lowering therapy leads to early improvement in retinal ganglion cell function in people with glaucoma. Design: Crossover, double-masked, randomized clinical trial conducted between October 2017 to January 2019. Setting: Study participants recruited from two tertiary care centers in Melbourne, Australia. Participants: Adults diagnosed and treated for primary glaucoma. Ninety-four participants assessed for study eligibility. Intervention: Participants randomized to first receive oral placebo or nicotinamide and reviewed six-weekly. Accelerated dosing method utilized; participants commenced 6-week course of 1.5 grams/day followed by 6 weeks of 3.0 grams/day. After 12 weeks, participants crossed over to other intervention for 12 weeks without washout. At each visit, visual function measured using full-field flash electroretinography and white-on-white perimetry. Main outcome measures: Primary endpoint was change in inner retinal function determined a-priori as change in photopic negative response (PhNR) parameters: saturated PhNR amplitude (Vmax), ratio of PhNR/b-wave amplitude (Vmax ratio). Results: Fifty-seven participants (65.5±10.0 years, 39% female) enrolled. PhNR Vmax improved beyond 95% coefficient of repeatability (COR) in 23% of participants following 12 weeks of nicotinamide versus 9% on placebo. Conversely, PhNR Vmax deteriorated in 9% on placebo and 7% on nicotinamide. Overall, Vmax improved by 14.8% [95% CI: 2.8%, 26.9%], (p=0.02) on nicotinamide and 5.2% [-4.2%, 14.6%], (p=0.27) on placebo. Vmax ratio improved on average by 12.6% [5.0%, 20.2%], (p=0.002) following nicotinamide and 3.6% [-3.4%, 10.5%], (p=0.30) on placebo. A concomitant trend for improved visual field mean deviation was observed with 27% improving ≥1dB on nicotinamide and fewer deteriorating ≥1dB (4%) compared to placebo (p=0.02). Moderate correlation was observed between PhNR and visual field change with treatment. Participants demonstrated excellent treatment adherence rates (>94%) and nicotinamide was well tolerated with minimal side effects. Conclusions and Relevance: Nicotinamide supplementation can improve inner retinal function in patients receiving concurrent IOP-lowering glaucoma therapy. Further studies are underway to elucidate the effects of long-term nicotinamide supplementation on glaucoma progression.

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ISCEV extended protocol for the photopic negative response (PhNR) of the full-field electroretinogram

Cited by 131 publications

References 22 publications

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

<p>Functional and Structural Changes of the Retinal Nerve Fiber Layer and Ganglion Cell Complex in Heavy Smokers</p>

Improvement in Inner Retinal Function in Glaucoma with Nicotinamide (Vitamin B₃) Supplementation: A Crossover Randomised Clinical Trial

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ISCEV extended protocol for the photopic negative response (PhNR) of the full-field electroretinogram

Cited by 131 publications

References 22 publications

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

The Relationship Between the Photopic Negative Response and Retinal Ganglion Cell Topography

<p>Functional and Structural Changes of the Retinal Nerve Fiber Layer and Ganglion Cell Complex in Heavy Smokers</p>

Improvement in Inner Retinal Function in Glaucoma with Nicotinamide (Vitamin B3) Supplementation: A Crossover Randomised Clinical Trial

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Improvement in Inner Retinal Function in Glaucoma with Nicotinamide (Vitamin B₃) Supplementation: A Crossover Randomised Clinical Trial