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Method Article

Workflows for the Photopic Negative Response and the Baby Vision Test

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DOI:

10.3791/72062

August 7th, 2026

In This Article

Summary

This article presents standardized workflows for the photopic negative response (PhNR) and the Baby Vision Test, two underutilized but clinically valuable electrophysiological modalities, to reduce procedural variability and enhance their diagnostic utility in glaucoma and pediatric visual disorders.

Abstract

Visual electrophysiological tests are noninvasive, objective tools widely used in clinical ophthalmology. However, two promising modalities, the photopic negative response (PhNR), which assesses inner retinal and retinal ganglion cell function, and the dynamic target-based Baby Vision Test, remain underutilized in clinical practice despite their ability to provide valuable objective functional data. Limited adoption is primarily due to procedural variability, numerous confounding factors, and challenges in result interpretation. To address these barriers, clear and standardized operational protocols are essential for maximizing their diagnostic potential. Here, a standardized 6E workflow is proposed, encompassing Environment, Equipment, Examinee, Electrode, Examination, and Exit, designed to improve the clinical feasibility and implementation of these tests. In a retrospective analysis, implementation of the 6E protocol significantly increased the proportion of infants who successfully completed testing. Specifically, the PhNR test success rate increased from 61.54% to 86.45% (p < 0.05), while the average duration of the Baby Vision Test decreased from 17.44 ± 9.89 min to 13.28 ± 9.24 min (p < 0.05). These findings demonstrate that the 6E workflow enhances the clinical utility and efficiency of PhNR and Baby Vision testing, supporting their broader application in the diagnosis and management of glaucoma and pediatric visual disorders.

Introduction

Visual electrophysiology provides an objective, quantitative means of assessing visual pathway function from the retina to the cortex1,2. Conventional tests such as full‑field electroretinography (ERG) and visual evoked potentials (VEPs) are widely used in clinical ophthalmology3,4. However, several specialized techniques with proven clinical value remain underutilized in routine practice.

Two such techniques are the photopic negative response (PhNR), a negative wave that follows the b-wave of the light-adapted electro....

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Protocol

The procedures described here focus on the photopic negative response (PhNR) and the Baby Vision Test. All procedures were approved by the Institutional Review Board (IRB) of the Eye Hospital, Wenzhou Medical University (IRB approval no. H2025-071-K59 for the retrospective analysis). The requirement for informed consent was waived because of the retrospective nature of the study. This protocol is based on the 6E examination framework, which comprises Environment, Equipment, Examinee, Electrode, Examination, and Exit (Figure 1).

1. Workflow for the photopic negative response (PhNR)

  1. E....

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Results

The clinical utility of the 6E workflow was evaluated by comparing examination outcomes before and after its implementation. Specifically, PhNR data were analyzed during the one-year period before and the one-year period after adoption of the 6E protocol (Figure 8), as well as Baby Vision Test data collected during the two-year periods before and after implementation (Figure 9).

Following implementation of the 6E protocol, the number .......

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Discussion

While the photopic negative response (PhNR) and automated eye-tracking–based grating acuity assessments offer substantial promise for the objective evaluation of inner retinal function and infant visual acuity (VA), with the PhNR requiring neither refractive correction nor fixation monitoring5 and eye-tracking methods providing reliable acuity measurements without verbal responses7, both techniques remain underutilized in many clinical settings.

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Disclosures

The authors have no conflicts of interest to disclose.

Acknowledgements

The authors would like to express gratitude to all the participants and the people working on these workflows.

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Materials

List of materials used in this article
NameCompanyCatalog NumberComments
Compound tropicamide eye dropsKingyork Group Hebei Univision Pharmaceutical,Tianjin, China8327304Fixed combination ophthalmic solution containing 0.5% tropicamide and 0.5% phenylephrine hydrochloride. Used for pupillary dilation and cycloplegia. 
Durapore3M Deutschland GmbH,Neuss,Germany108099995High strength, non stretch silk like cloth medical tape.
GT20 Conductive PasteGREENTEK, Wuhan, China20142072064Water soluble conductive paste for non adhesive electrodes in electrophysiological examination
GT5 Conductive GelGREENTEK, Wuhan, China20152072150Combined skin prep and conductive gel for electrophysiological recordings
MonpackOne instrumentMetrovision, Perenchies, France20162160840,K211643Integrated electrodiagnostic system for visual electrophysiology. Supports full field flash ERG, pattern ERG, multifocal ERG, VEP, multifocal VEP, and sensory EOG et al. Used in hospitals and clinics by trained ophthalmologists and medical professionals.
Vision Monitor SoftwareMetrovision, Perenchies, FranceMon2018F,K211643Integrated software platform for visual electrophysiology. Controls stimulus generation (flash, pattern, multifocal), acquires bioelectrical signals via up to 5 channels, and processes raw data using spatial filtering and artifact rejection algorithms. Produces digitized ERG, VEP, EOG waveforms et al. 

References

  1. Robson AG et al. ISCEV standard for full-field clinical electroretinography (2022 update). Documenta Ophthalmologica. 2022;144(3):165-177.
  2. Robson AG et al. ISCEV guide to visual electrodiagnostic procedures. Documenta Ophthalmologica. 2018;136(1):1-26.
  3. McCulloch DL et al. ISCEV guidelines for calibration and verification of stimuli and recording instruments (2023 update). Documenta Ophthalmologica. 2023;146(3):199-210.
  4. Thompson DA et al. ISCEV standard for clinical pattern electroretinography (2024 update). Documenta Ophthalmologica. 2024;148(2):75-85.
  5. Prencipe M, Perossini T, Brancoli G, Perossini M. The photopic negative response (PhNR): Me....

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Tags

Visual ElectrophysiologyRetinal Ganglion CellsInner Retinal FunctionPediatric Vision Testing6E WorkflowGlaucoma DiagnosisStandardized ProtocolsClinical Ophthalmology
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