Effect of Protanopia on the Brightness Perception of Brake Lights (ProLight)

Investigation of the Effect of Protanopia ("Red Blindness") on the Brightness Perception of Brake Lights and Their Effect on Reaction Time

The aim of the offered project is to investigate the influence of protanopia (red blindness) or protanomaly (red vision weakness) on the recognizability of red brake lights with the help of a test person study. From this, estimates of the influence of protanopia or protanomaly on driving ability are to be derived.

If a relevant influence can be demonstrated in the study, recommendations for action for the legislator will be made.

Translated with www.DeepL.com/Translator

Study Overview

• Status: Completed
• Conditions: Reaction Time; Color Blindness, Red
• Intervention / Treatment: Diagnostic test: Anomaloscope (colour vision test)

Detailed Description

Protanopia is an x-chromosomal inherited cone pigment disorder that related to the red cone,i.e. the L-cone function completely fails. The prevalence of protanopia in the male population is 1%. An incomplete impairment of the L-cone is called protanomaly. The prevalence here is also in 1% of the male population.

In comparison to persons with normal vision red objects appear darker for persons with missing or functionally limited L-cones. This is particularly critical in road traffic, where red is used as a signal colour, for example in traffic lights or brake lights is used.

The scientific questions that need to be investigated are as follows:

1. At which contrast threshold (relative brightness) does a proband with protanopia recognize a brake light compared to a normal person?
2. If the luminance determined is above the contrast threshold, what influence does the excess of the contrast or the determined luminance have on the reaction time?
3. Are there differences with regard to the technology used in the brake light (incandescent lamp or LED)?

For this purpose, a representative set of combination rear lamps, focusing on stoplight, taillight (and of the elevated brake light) in a static situation is created. The test setup is based on a driving pursuit scenario. The test person is positioned at a relevant distance to the combination of rear lamps.

To determine the threshold contrast, an algorithm is developed to control the relative brightness of the brake lights and integrated into the test sequence control. In addition, a method for automated determining of the related reaction time is implemented.

Two taillight technologies (incandescent lamp and LED) are examined at both ambient brightness levels: (i) "bright", i.e. photopic luminance level (Lu >> 10 cd/m2) and (ii) "dark", i.e. mesopic luminance level (Lu < 10 cd/m2).

A comprehensive ophthalmological/optical examination (including visual acuity, ocular alignment, ocular motility, assessment of the leading eye, testing of the efferent and afferent pupillary system and biomicroscopic inspection of the anterior and posterior segments of the eye) is carried out. Comprehensive colour vision testing it performed with the HMC anomaloscope, Oculus Inc., Dutenhofen/FRG, including assessment of the loss of brightness sensation during anomaloscopic exam with max. red. stimulus . In addition, standardized semi-automated kinetic perimetry (SKP) along the horizontal meridian with an automated perimeter (Octopus 900, Haag-Streit Inc., Koeniz/CH) is performed. The ratio of the horizontal extent ("diameter") obtained with both, red vs. white stimuli, is measured and taken as a clinical parameter for quantifying the magnitude of the individual "protan colour vision deficiency".

To illustrate the worst-case scenario, this study is limited to protanopic patients. It is intended as a pure comparative study between a "protanopic" patient group and a "normal vision" control group. The protanopic test subjects and the control subjects are matched with regard to gender and age.

This study is carried out in a "within-subject design", i.e. all test persons go through all situations. In order to minimize sequence effects, the related test conditions are randomized.

• Study Type: Observational
• Enrollment (Actual): 16

Contacts and Locations

Study Locations

• Germany
  • Deutschland
    • Aalen, Deutschland, Germany, 73430
      • Ulrich SCHIEFER

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A
• Genders Eligible for Study: Male

• Sampling Method: Non-Probability Sample

Study Population

Ophthalmologically normal (male) subjects OR (male) subjects with (inherited) protanopia (red blindness)

Description

Inclusion Criteria:

• informed consent
• male
• age (greater or equal) 18 years

Exclusion Criteria:

• binocular (high contrast) distant visual acuity worse than 0.8 (16/20)
• spherical ametropia exceeding 8 dpt
• cylindrical ametropia exceeding 2.5 dpt
• manifest strabismus (squint) with diplopia
• relative afferent pupillary defect exceeding 0.3 log units
• anamnestic (patient history) OR morphological (slit lamp --> anterior segment, ophthalmoscope --> retina) clue/indicator for a ophthalmologically relevant affection of the eye OR the visual pathway
• S.p. severe ocular trauma
• Current OR s.p. severe intraocular inflammation
• S.p. intraocular surgery within the past three months

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Normal colour vision; Normal trichromopsia	Diagnostic test: Anomaloscope (colour vision test); The Heidelberg Multi Colour (HMC) Anolmaloscope (Oculus Inc., Dutenhofen/FRG) is used to differentiate between normal controls (normal trichromatopsia) and test subjects with protanopia ("inherited red colour blindness")
Inherited red blindness; Protanopia	Diagnostic test: Anomaloscope (colour vision test); The Heidelberg Multi Colour (HMC) Anolmaloscope (Oculus Inc., Dutenhofen/FRG) is used to differentiate between normal controls (normal trichromatopsia) and test subjects with protanopia ("inherited red colour blindness")

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Contrast sensitivity (I)	Contrast sensitivity between taillight and brake light under two luminance conditions	within one year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Reaction time	Time span within the onset of the brake light and the reaction of the tested subject	within one year
Contrast sensitivity (II)	taillight technology: incandescent lamp vs. light emitting diode (LED)	within one year
Reaction time (II)	taillight technology: incandescent lamp vs. light emitting diode (LED)	within one year
Perimetric extent of horizontal meridian	(Semi-autmated kinetic) perimetry with white vs. red stimuli	within one year
Loss of brightness sensation during anomaloscopic exam	Loss of brightness sensation during anomaloscopic exam with max. red. stimulus	within one year

Collaborators and Investigators

• Sponsor: Aalen University
• Collaborators: Karlsruhe Institute of Technology (KIT), Karlsruhe/FRG
• Investigators: Study Chair: Ulrich Schiefer, MD, Aalen University of Applied Sciences

Study record dates

Study Major Dates

• Study Start (Actual): January 7, 2020
• Primary Completion (Actual): March 15, 2020
• Study Completion (Actual): March 15, 2020

Study Registration Dates

• First Submitted: August 13, 2019
• First Submitted That Met QC Criteria: August 14, 2019
• First Posted (Actual): August 19, 2019

Study Record Updates

• Last Update Posted (Actual): March 31, 2020
• Last Update Submitted That Met QC Criteria: March 28, 2020
• Last Verified: June 1, 2019

More Information

Terms related to this study

• Keywords: perimetry; contrast sensitivity; reaction time; protanopia; taillight; brake light; differential luminance sensitivity; colour vision; colour vision defect; semi-automated kinetic perimetry; traffic; motorist
• Additional Relevant MeSH Terms: Nervous System Diseases; Eye Diseases; Neurologic Manifestations; Eye Diseases, Hereditary; Sensation Disorders; Vision Disorders; Cone Dystrophy; Blindness; Color Vision Defects
• Other Study ID Numbers: ProLight_I

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided
• IPD Plan Description: In case of a subsequent study, aiming at assessing the colour sensitivity of single cones, pseudonomized participant data will be shared with the involved researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No