Workflows for the Photopic Negative Response and the Baby Vision Test

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 cortex^1,2. Conventional tests such as full‑field electroretinography (ERG) and visual evoked potentials (VEPs) are widely used in clinical ophthalmology^3,4. 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....

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....

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 .......

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.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Compound tropicamide eye drops	Kingyork Group Hebei Univision Pharmaceutical,Tianjin, China	8327304	Fixed combination ophthalmic solution containing 0.5% tropicamide and 0.5% phenylephrine hydrochloride. Used for pupillary dilation and cycloplegia.
Durapore	3M Deutschland GmbH,Neuss,Germany	108099995	High strength, non stretch silk like cloth medical tape.
GT20 Conductive Paste	GREENTEK, Wuhan, China	20142072064	Water soluble conductive paste for non adhesive electrodes in electrophysiological examination
GT5 Conductive Gel	GREENTEK, Wuhan, China	20152072150	Combined skin prep and conductive gel for electrophysiological recordings
MonpackOne instrument	Metrovision, Perenchies, France	20162160840,K211643	Integrated 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 Software	Metrovision, Perenchies, France	Mon2018F,K211643	Integrated 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.