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Melanin concentration in normal human retinal pigment epithelium. Regional variation and age-related reduction
Abstract:
Melanin concentrations were analyzed in the pigment epithelium of 61 postmortem normal human eyes from donors 14-97 yr of age. The content of soluble melanin in the pigment epithelium declined with age from the highest values of 95 micrograms/mg in the 14-50 yr age group to the lowest values of 22 micrograms/mg dry weight in the over 70 yr age group. In 16 of these eyes, regional measurements revealed that melanin concentrations were lowest in the macula-perimacular area (a region 5-8 mm in diameter centered on the fovea), were higher in the mid-periphery, and were highest in the far periphery. In the macular region, melanin concentrations were similarly low at all ages, whereas, in the mid- and far-peripheral regions, melanin concentrations decreased with age. These studies demonstrate age-related reductions and regional variations in melanin concentrations in the pigment epithelium of postmortem normal human eyes, and establish a baseline for future comparison with donor eyes from patients with hereditary retinal degenerations.
Insights
Melanin pigment in the human eye
Area of Science:
- Ophthalmology
- Cell Biology
- Gerontology
Background:
- Melanin pigment epithelium is crucial for retinal health.
- Age-related changes in ocular tissues are not fully understood.
Purpose of the Study:
- To quantify age-related and regional variations in melanin concentrations within the human retinal pigment epithelium.
- To establish a baseline for studies on retinal degenerations.
Main Methods:
- Analysis of soluble melanin concentrations in postmortem human eyes (n=61).
- Age groups ranged from 14 to 97 years.
- Regional melanin measurements in macular, mid-peripheral, and far-peripheral areas.
Main Results:
- Soluble melanin content in the pigment epithelium significantly declined with age.
- Melanin concentrations were lowest in the macula and increased towards the periphery.
- Age-related decreases were more pronounced in peripheral regions compared to the macula.
Conclusions:
- Human retinal pigment epithelium melanin concentrations decrease with age and vary regionally.
- These findings provide essential normative data for understanding age-related ocular changes and retinal diseases.