Purpose
Albinism represents a spectrum of disorders with diminished to absent amounts of melanin pigmentation including the posterior segment of the eye. The role of melanin in visual development is not completely understood, but a correlation was found between the amount of fundus pigmentation and visual function in albinos.<br /> Macular pigment (MP) consists of two main carotenoids, lutein and zeaxanthin, concentrated in the macula. MP serves as blue light absorbent, antioxidant, and is believed to reduce chromatic aberration and glare.<br /> It remains unclear if albinos have detectable MP. An increase of MP deposition in the macula may allow improving visual performance by reducing light scatter and glare. Our purpose was to investigate the distribution of MP in albino patients with psychophysical and imaging techniques.
Methods
4 albino patients were enrolled in the study and multimodal ophthalmic imaging was performed. Macular pigment was measured either by heterochromatic flicker perimetry (QuantifEye; MPS 9000 series: Tinsley Precision Instruments Ltd., Croydon, Essex, UK) or by scanning laser ophthalmoscopy (MPOD module, MultiColor Spectralis®, Heidelberg Engineering). The study followed the tenets of the Declaration of Helsinki and was approved by the local Ethics Review Board. Informed written consent was obtained from each patient.
Results
3 patients had genetically confirmed oculo-cutaneous albinism. Visual acuity ranged from 20/32 to 20/125, significant nystagmus was present in 2 patients, and all 4 patients showed typical foveal hypoplasia on fundus exam and optical coherence tomography. Fundus autofluorescence (FAF) demonstrated various degrees of central FAF signal attenuation (Fig. 1). Measurable amounts of MP were detected in all 4 patients and ranged from 0.05 to 0.24.
Conclusions
MP can be demonstrated and measured in albinos. Further studies are needed to investigate MP accumulation following supplementation and its consequences for visual performance in albino patients. This is currently being investigated in The Effects of Lutein and Zeaxanthin Supplementation on Vision in Patients with Albinism (LUVIA) Study (ClinicalTrials.gov Identifier: NCT02200263).