Resonance Raman measurement of macular carotenoids in retinal, choroidal, and macular dystrophies

Abstract

Background: It has been hypothesized that the macular carotenoid pigments lutein and zeaxanthin may protect against macular and retinal degenerations and dystrophies.

Objective: To test this hypothesis by objectively measuring lutein and zeaxanthin levels in a noninvasive manner in patients who have retinitis pigmentosa (RP), choroideremia (CHM), and Stargardt macular dystrophy and comparing them with an age-matched healthy control population.

Methods: Using resonance Raman spectroscopy, a novel objective noninvasive laser-optical technique, we measured macular carotenoid levels in 30 patients (54 eyes) who have RP, CHM, and Stargardt macular dystrophy and compared them with 76 age-matched subjects (129 eyes) who did not have macular pathologic conditions in a case-control study.

Results: As a group, patients with RP and CHM had the same macular carotenoid levels as age-matched healthy control subjects (P =.76, 2-way analysis of variance). Patients with Stargardt macular dystrophy tended to have levels of macular carotenoid pigments that, on average, were about 50% lower than healthy controls (P =.02,unpaired 2-tailed t test).

Conclusions: The patients with RP and CHM had normal levels of macular carotenoids, suggesting that nutritional supplementation with macular carotenoids such as lutein, zeaxanthin, or both will be unlikely to affect the clinical course of RP and CHM. Although the number of patients with Stargardt macular dystrophy examined was limited, their macular carotenoid levels were usually lower than those of subjects of a similar age with no macular pathologic condition.