Red color blindness
MONDO:0010565Protanopia is a severe type of color vision deficiency caused by the complete absence of red retinal photoreceptors. Protans have difficulties distinguishing between blue and green colors and also between red and green colors. It is a form of dichromatism in which the subject can only perceive light wavelengths from 400 to 650 nm, instead of the usual 700 nm. Pure reds cannot be seen, instead appearing black; purple colors cannot be distinguished from blues; more orange-tinted reds may appear as very dim yellows, and all orange-yellow-green shades of too long a wavelength to stimulate the blue receptors appear as a similar yellow hue. It is hereditary, sex-linked, and present in 1% of males.
Also known as: colorblindness, protan, partial achromatopsia, protan type, protan defect, protanopia, red color blindness, CBP, colorblindness, partial, protan series, protanomaly
13 clinical trials for this condition and its sub-types.
Follow this condition — get notified about new trialsBroader categories
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A clearer view: can training unlock reading for kids with low vision?
Symptom relief Recruiting nowThis program provides comprehensive low vision rehabilitation services to children aged 3 to 21 with vision impairment. Participants are prescribed optical devices and trained to use them, with the goal of improving their visual functioning and ability to read. The program aims t…
Sponsor: Vanderbilt University • Aim: Symptom relief
Last updated Aug 02, 2026 00:00 UTC
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Could a headset fix sleep problems in the blind? new trial tests Nerve-Stimulating device
Symptom relief Recruiting nowThis pilot study tests whether a non-invasive headset that delivers mild electrical stimulation to nerves behind the ear can safely improve sleep in adults who are blind or severely sight impaired. Sixty participants will use the device for 30 minutes a day, five times a week for…
Phase: NA • Sponsor: Neurovalens Ltd. • Aim: Symptom relief
Last updated Jun 27, 2026 12:07 UTC
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New app could let blind people pick the safest route before they walk
Knowledge-focused Recruiting nowThis study tests a smartphone-based tool called VisionWay that helps people with visual impairments choose the most accessible walking path before they start walking. Researchers will ask participants to walk different routes on a university campus and rate sidewalk features like…
Phase: NA • Sponsor: Ohio State University • Aim: Knowledge-focused
Last updated Jul 22, 2026 00:00 UTC
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Can your eyes trip you up? study watches how vision changes stepping over obstacles
Knowledge-focused Recruiting nowThis study looks at how older adults with and without vision problems step over obstacles of different heights and colors. Researchers want to understand how vision and eye movements affect walking to help prevent falls. About 200 adults who can walk on their own will take part.
Phase: NA • Sponsor: Indiana University • Aim: Knowledge-focused
Last updated Jun 27, 2026 07:57 UTC