Lanthony's new color test. IV. Neutral zone and neutral grays

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Accurate diagnosis of color vision defects is crucial for patient management.
• Anomaloscopic examination, while standard, may not always be accessible.
• Understanding spectral perception in different color vision deficiencies is key.

Purpose of the Study:

• To establish the utility of neutral gray classification in diagnosing color vision defects.
• To differentiate congenital and acquired color vision defects using spectral perception.
• To distinguish between optic nerve and retinal diseases based on gray scale perception.

Main Methods:

• Classification of neutral grays based on patient perception.
• Analysis of spectral perception in the PR-RP and BV-B regions.
• Correlation of perception shifts with congenital (protan, deutan) and acquired (blue-yellow) defects.
• Evaluation of the impact of lesion site and fixation mode on defect type.

Main Results:

• Congenital defects show distinct spectral perceptions: protan subjects see the PR-RP region as 'dark', deutan subjects as 'light'.
• Acquired defects commonly present as type III blue-yellow defects, influenced by lesion site and fixation.
• Neutral gray classification can differentiate optic nerve from retinal diseases by identifying rod-mediated sensitivity shifts.

Conclusions:

• Neutral gray classification offers a valuable diagnostic tool for color vision defects, particularly when anomaloscopy is unavailable.
• This method aids in differentiating between various types of congenital and acquired color vision impairments.
• The classification provides insights into the localization of visual pathway lesions, distinguishing optic nerve from retinal pathologies.