Related Experiment Video
Updated: May 14, 2026
08:38
Transretinal ERG Recordings from Mouse Retina: Rod and Cone Photoresponses
Published on: March 14, 2012
Applications of Photopic Negative Response: A Narrative Review.
Minzhong Yu1,2,3, Nara Shakaki4, Anas Bakdalieh4
1Department of Ophthalmology and Visual Sciences, University Hospitals Eye Institute, Case Western Reserve University, Cleveland, OH 44106, USA.
Journal of Clinical Medicine
|May 13, 2026
Summary
The photopic negative response (PhNR) is a functional biomarker for retinal ganglion cells. It offers insights into glaucoma and systemic diseases, complementing structural imaging when needed.
Area of Science:
- Ophthalmology
- Neuroscience
- Biomarker Discovery
Background:
- The photopic negative response (PhNR) is a functional signal from retinal ganglion cells, proposed as a clinical biomarker.
- Its exact clinical utility and added value across various diseases are still under investigation.
Purpose of the Study:
- To review human studies on PhNR, focusing on its physiological basis, recording methods, and clinical applications.
- To evaluate PhNR's role in providing additional functional insights in different disease contexts.
Main Methods:
- Narrative review of key human studies concerning the photopic negative response.
- Emphasis on physiological underpinnings, standardized recording techniques, and clinical utility.
Main Results:
- PhNR objectively measures retinal ganglion cell dysfunction in glaucoma, correlating with OCT and visual field data but showing variability.
- PhNR is valuable for early glaucoma detection, functional assessment, and monitoring short-term changes post-treatment, less so for progression.
- PhNR detects inner retinal dysfunction in systemic diseases like idiopathic intracranial hypertension and diabetes, reflecting broader health issues.
Conclusions:
- PhNR serves as a complementary functional biomarker, not a standalone diagnostic tool.
- It provides objective insights when structural or psychophysical tests are limited or conflicting.
- PhNR reflects the retina's role in mirroring systemic and genetic diseases, requiring standardized recordings and cautious interpretation.
Related Concept Videos
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...