Serum and Macular Carotenoids in Relation to Retinal Vessel Caliber Fifteen Years Later, in the Second Carotenoids in Age-Related Eye Disease Study

Low Macular Pigment Optical Density Is Associated with Manifest Primary Open-Angle Glaucoma in Older Women

Background

Lower density of carotenoids lutein and zeaxanthin (L/Z) in the macula (i.e., macular pigment) has been linked to greater risk for age-related eye disease.

Objectives

We evaluated whether macular pigment optical density (MPOD) was associated with manifest primary open-angle glaucoma (POAG) among older women in the Carotenoids in Age-Related Eye Disease Study 2 (CAREDS2).

Methods

MPOD was measured with customized heterochromatic flicker photometry in women who attended CAREDS2 (2016-2019) and CAREDS1 (2001-2004) study visits. Manifest POAG at CAREDS2 was assessed using visual fields, disc photos, optical coherence tomography, and medical records. Age-adjusted linear and logistic regression models were used to investigate the cross-sectional association between POAG and MPOD at CAREDS2, and MPOD measured 15 years earlier at CAREDS1.

Results

Among 426 CAREDS2 participants (mean age: 80 y; range: 69-98 y), 26 eyes with manifest POAG from 26 participants were identified. Glaucomatous eyes had 25% lower MPOD compared to nonglaucomatous eyes [mean (SE): 0.40 (0.05) compared with 0.53 (0.01)] optical density units (ODU), respectively (P = 0.01). Compared with MPOD quartile 1, odds for POAG were lower for women in quartiles 2-4 (P-trend = 0.01). After excluding eyes with age-related macular degeneration, associations were similar but not statistically significant (P-trend = 0.16). Results were similar for MPOD measured at CAREDS1.

Conclusions

Our results add to growing evidence that low MPOD may be a novel glaucoma risk factor and support further studies to assess the utility of dietary interventions for glaucoma prevention.

Blue Light Filtration in Intraocular Lenses: Effects on Visual Function and Systemic Health

Blue light-filtering (BLF) intraocular lenses (IOLs) are designed to mimic the healthy natural adult crystalline lens. Studies that evaluated the relative merit of ultraviolet-only IOL design (ie, blocking wavelengths <400 nm) versus BLF IOL design (ie, filtering wavelengths ~400-475 nm in addition to blocking wavelengths <400 nm) on protection and function of the visual system suggest that neither design had a deleterious impact on visual acuity or contrast sensitivity. A BLF design may reduce some aspects of glare, such as veiling and photostress. BLF has been shown in many contexts to improve visual performance under conditions that are stressed by blue light, such as distance vision impaired by short-wave dominant haze. Furthermore, some data (mostly inferential) support the notion that BLF IOLs reduce actinic stress. Biomimetic BLF IOLs represent a conservative approach to IOL design that provides no harm for visual acuity, contrast sensitivity, or color vision while improving vision under certain circumstances (eg, glare).

A Narrative Review: The Effect and Importance of Carotenoids on Aging and Aging-Related Diseases

Aging is generally defined as a time-dependent functional decline that affects most living organisms. The positive increase in life expectancy has brought along aging-related diseases. Oxidative stress caused by the imbalance between pro-oxidants and antioxidants can be given as one of the causes of aging. At the same time, the increase in oxidative stress and reactive oxygen species (ROS) is main reason for the increase in aging-related diseases such as cardiovascular, neurodegenerative, liver, skin, and eye diseases and diabetes. Carotenoids, a natural compound, can be used to change the course of aging and aging-related diseases, thanks to their highly effective oxygen-quenching and ROS-scavenging properties. Therefore, in this narrative review, conducted using the PubMed, ScienceDirect, and Google Scholar databases and complying with the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines, the effects of carotenoids on aging and aging-related diseases were analyzed. Carotenoids are fat-soluble, highly unsaturated pigments that occur naturally in plants, fungi, algae, and photosynthetic bacteria. A large number of works have been conducted on carotenoids in relation to aging and aging-related diseases. Animal and human studies have found that carotenoids can significantly reduce obesity and fatty liver, lower blood sugar, and improve liver fibrosis in cirrhosis, as well as reduce the risk of cardiovascular disease and erythema formation, while also lowering glycated hemoglobin and fasting plasma glucose levels. Carotenoid supplementation may be effective in preventing and delaying aging and aging-related diseases, preventing and treating eye fatigue and dry eye disease, and improving macular function. These pigments can be used to stop, delay, or treat aging-related diseases due to their powerful antioxidant, restorative, anti-proliferative, anti-inflammatory, and anti-aging properties. As an increasingly aging population emerges globally, this review could provide an important prospective contribution to public health.

Effect of macular pigment carotenoids on cognitive functions: A systematic review

Lutein and zeaxanthin-xanthophyll carotenoids with antioxidant and anti-inflammatory characteristics-are present in the retina and the brain. High concentrations of these carotenoids have been positively related to cognitive performance. Therefore, this systematic review analyses the relationship between macular pigment density and cognitive functions. Most relevant databases were scoured for studies on healthy people relating cognitive functions to macular pigment optical density (MPOD). There were no age, sex, or race limitations. PROSPERO registration: CRD42021254833. Nineteen studies were included, seven randomized controlled trials (RCT) and eleven observational studies. The general aim of the studies was to examine the association between carotenoids (lutein, meso‑zeaxanthin and zeaxanthin) and cognitive function. Most observational studies correlates MPOD levels with cognitive function or brain activity. Besides, RCTs compared the cognitive function and/or brain activity after increasing lutein and zeaxanthin intake though dietary supplementation or avocado consumption. Dietary lutein and zeaxanthin intake increased MPOD in six of the seven clinical trials and significantly improved most of the cognitive functions studied. A wide variety of test and methodologies for measuring cognitive functions were observed. Memory, processing speed, attention and reasoning were the cognitive function significantly related to MPOD levels in adults. Brain activity also was related to MPOD, but the results were inconsistent. Only four of the eleven observational studies were based on young people and all studies showed a significant relationship between MPOD and cognitive functions. This systematic review showed a direct relationship among cognitive functions, macular pigment and the intake of lutein and zeaxanthin.

Arterial Hypertension and the Hidden Disease of the Eye: Diagnostic Tools and Therapeutic Strategies

Hypertension is a major cardiovascular risk factor that is responsible for a heavy burden of morbidity and mortality worldwide. A critical aspect of cardiovascular risk estimation in hypertensive patients depends on the assessment of hypertension-mediated organ damage (HMOD), namely the generalized structural and functional changes in major organs induced by persistently elevated blood pressure values. The vasculature of the eye shares several common structural, functional, and embryological features with that of the heart, brain, and kidney. Since retinal microcirculation offers the unique advantage of being directly accessible to non-invasive and relatively simple investigation tools, there has been considerable interest in the development and modernization of techniques that allow the assessment of the retinal vessels’ structural and functional features in health and disease. With the advent of artificial intelligence and the application of sophisticated physics technologies to human sciences, consistent steps forward have been made in the study of the ocular fundus as a privileged site for diagnostic and prognostic assessment of diverse disease conditions. In this narrative review, we will recapitulate the main ocular imaging techniques that are currently relevant from a clinical and/or research standpoint, with reference to their pathophysiological basis and their possible diagnostic and prognostic relevance. A possible non pharmacological approach to prevent the onset and progression of retinopathy in the presence of hypertension and related cardiovascular risk factors and diseases will also be discussed.