Color vision defects in pigmentary retinal dystrophy

Area of Science:

• Ophthalmology
• Genetics
• Vision Science

Background:

• Primary pigmentary retina dystrophy is an inherited condition affecting photoreceptor cells.
• Color vision impairment is a known symptom, but its progression and specific mechanisms are not fully understood.

Purpose of the Study:

• To investigate the relationship between color vision defects and visual acuity/visual field in primary pigmentary retina dystrophy.
• To analyze the specific types of color vision defects and their prevalence at different stages of the disease.

Main Methods:

• Farnsworth Panel D-15 test administered to 72 patients with primary pigmentary retina dystrophy.
• Correlation analysis of color vision test results with visual acuity and visual field data.
• Stiles' two-color threshold technique used to assess blue and green cone mechanisms in a subset of patients.

Main Results:

• Color vision defects and their severity correlated with decreased visual acuity and visual field.
• Type III acquired blue-yellow defects were observed in 22% of patients with visual acuity >0.7 and 52% with visual acuity 0.4-0.6.
• Total achromatopsia occurred in 64% of patients with visual acuity ≤0.1.
• Elevated blue and green cone mechanism thresholds were found, with a more pronounced increase in the blue cone mechanism.

Conclusions:

• Color vision impairment progresses with primary pigmentary retina dystrophy.
• Early blue-yellow color vision defects are characteristic, potentially progressing to achromatopsia.
• While blue cone mechanisms may be more affected, the results do not definitively confirm preferential damage due to cone density differences.