Effect of Antioxidant Supplementation on Macular Pigment Optical Density and Visual Functions: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

Antioxidants are bioactive molecules that function to scavenge free radicals and balance oxidative stress. Although all antioxidants can act as reactive oxygen species scavengers, their efficacy on eye health may vary. Moreover, the comparative effectiveness and potential additive effect between groups of antioxidants, hitherto, have not been systematically studied. A systematic review and network meta-analysis were conducted to investigate the comparative or additive effect of dietary antioxidant supplements on eye health. Four databases (PubMed, Embase, CINAHL, and Cochrane) were searched, and relevant randomized controlled trials were identified. Out of 60 articles selected for systematic review, 38 were included in the network meta-analysis, categorized into 8 distinct antioxidant-supplemented groups and placebo. All groups significantly increased macular pigment optical density and contrast sensitivity at low spatial frequency, whereas only the antioxidant mixture + lutein (L) + fatty acid combination exhibited significant improvements in visual acuity (hazard ratio = -0.15; 95% confidence interval: -0.28, -0.02) and L + zeaxanthin combination for photostress recovery time (hazard ratio = -5.75; 95% confidence interval: -8.80, -1.70). Especially, the L + zeaxanthin + fatty acid combination was ranked best for macular pigment optical density (surface under the cumulative ranking: 99.3%) and second best for contrast sensitivity at low spatial frequency (67.7%). However, these findings should be interpreted with caution due to low quality of evidence, primarily influenced by indirectness and potential publication bias. Overall, antioxidant supplementation was estimated to improve eye health parameters, whereas different combinations of antioxidants may also have varying effects on improving visual health from multiple perspectives. This study was registered at PROSPERO as CRD42022369250.

Predictors of macular pigment and contrast threshold in Spanish healthy normolipemic subjects (45-65 years) with habitual food intake.

INTRODUCTION: The dietary carotenoids lutein (L) and zeaxanthin (Z) are transported in the bloodstream by lipoproteins, sequestered by adipose tissue, and eventually captured in the retina where they constitute macular pigment. There are no L&Z dietary intake recommendations nor desired blood/tissue concentrations for the Spanish general population. Our aim was to assess the correlation of L&Z habitual dietary intake (excluding food supplements), resulting serum concentrations and lipid profile with macular pigment optical density (MPOD) as well as the contrast sensitivity (CT), as visual outcome in normolipemic subjects (n = 101) aged 45-65. METHODS: MPOD was measured by heterochromatic flicker photometry, serum L&Z by HPLC, the dietary intake by a 3-day food records and CT using the CGT-1000-Contrast-Glaretester at six stimulus sizes, with and without glare. RESULTS: Lutein and zeaxanthin concentrations (median) in serum: 0.361 and 0.078 µmol/L, in dietary intake: 1.1 mg L+Z/day. MPOD: 0.34du. L+Z intake correlates with their serum concentrations (rho = 0.333, p = 0.001), which in turn correlates with MPOD (rho = 0.229, p = 0.000) and with fruit and vegetable consumption (rho = 0.202, p = 0.001), but not with lutein+zeaxanthin dietary intake. MPOD correlated with CT, with and without glare (rho ranges: -0.135, 0.160 and -0.121, -0.205, respectively). MPOD predictors: serum L+Z, L+Z/HDL-cholesterol (ß-coeficient: -0.91±0.2, 95%CI: -1.3,-0.5) and HDL-cholesterol (R2 = 15.9%). CT predictors: MPOD, mainly at medium and smaller visual angles (corresponding to spatial frequencies for which sensitivity declines with age) and gender (ß-coefficients ranges: -0.95,-0.39 and -0.13,-0.39, respectively). CONCLUSION: A higher MPOD is associated with a lower ratio of L+Z/HDL-cholesterol and with a lower CT (higher contrast sensitivity). The HDL-cholesterol would also act indirectly on the CT improving the visual function.

The Functional Vision Protection Effect of Danshensu via Dopamine D1 Receptors: In Vivo Study.

Danshensu, a traditional herb-based active component (Salvia miltiorrhiza Bunge), has garnered attention, due to its safety, nutritional value, and antioxidant effects, along with cardiovascular-protective and neuroprotective abilities; however, its effect on the retinal tissues and functional vision has not been fully studied. The objective of this study was to analyze the protective effect of danshensu on retinal tissues and functional vision in vivo in a mouse model of light-induced retinal degeneration. High energy light-evoked visual damage was confirmed by the loss in structural tissue integrity in the retina accompanied by a decline in visual acuity and visual contrast sensitivity function (VCSF), whereas the retina tissue exhibited severe Müller cell gliosis. Although danshensu treatment did not particularly reduce light-evoked damage to the photoreceptors, it significantly prevented Müller cell gliosis. Danshensu exerted protective effects against light-evoked deterioration on low spatial frequency-based VCSF as determined by the behavioral optomotor reflex method. Additionally, the protective effect of danshensu on VCSF can be reversed and blocked by the injection of a dopamine D1 receptor antagonist (SCH 23390). This study demonstrated that the major functional vision promotional effect of danshensu in vivo was through the dopamine D1 receptors enhancement pathway, rather than the structural protection of the retinas.

Effects of Citicoline, Homotaurine, and Vitamin E on Contrast Sensitivity and Visual-Related Quality of Life in Patients with Primary Open-Angle Glaucoma: A Preliminary Study.

The aim of the present study was to evaluate the effects of supplementation with a fixed combination of citicoline 500 mg, homotaurine 50 mg, and vitamin E 12 mg (CIT/HOMO/VITE) on contrast sensitivity and visual-related quality of life in patients with primary open-angle glaucoma (POAG) in mild stage. This was a multicenter, observational, cross-over, short-term, pilot study on POAG patients with stable controlled intraocular pressure (IOP). Patients were randomly assigned to Group 1 (current topical therapy for 4 months and then current topical therapy plus CIT/HOMO/VITE for 4 months) or Group 2 (CIT/HOMO/VITE in addition to current topical therapy for 4 months and then topical therapy alone for 4 months). Best-corrected visual acuity, IOP, visual field, and the Spaeth/Richman contrast sensitivity (SPARCS) test score were recorded at baseline and after 4 and 8 months. The Glaucoma Quality of Life-15 (GQL-15) questionnaire was administered at each check time. Forty-four patients were assigned to Group 1 and 65 to Group 2. Over the follow-up period, there were no significant changes in IOP or visual field findings, whereas SPARCS and GQL-15 findings significantly varied from baseline, both being improved in subjects treated with CIT/HOMO/VITE fixed combination. These results demonstrate that a daily intake of a fixed combination of citicoline, homotaurine, and vitamin E in addition to the topical medical treatment significantly increased the total score of the contrast sensitivity test and the quality of life in patients with POAG.

Clinical Effects of Dietary Supplementation of Lutein with High Bio-Accessibility on Macular Pigment Optical Density and Contrast Sensitivity: A Randomized Double-Blind Placebo-Controlled Parallel-Group Comparison Trial.

Improvements in macular pigment optical density (MPOD) and contrast sensitivity after administration of 12 mg lutein alone and the timing at which efficacy is observed remain unknown. Therefore, lutein (12 mg), a crystalline formulation, was used in this study, considering its bioaccessibility. This study aimed to determine the effects of lutein administration for 16 weeks on MPOD, contrast sensitivity, and glare sensitivity, and changes in serum lutein levels were determined. The study subjects comprised 59 healthy male and female adults aged 20-69 years. The study diet included a placebo (placebo group) or a diet supplemented with 12 mg of lutein (lutein group). Each study diet was continuously administered for 16 weeks. At weeks 8 and 16, MPOD, contrast sensitivity, glare sensitivity, and serum lutein levels were evaluated. Compared with the placebo group, the lutein group showed significantly improved MPOD, contrast sensitivity, and glare sensitivity at week 16 and significantly increased serum lutein levels at weeks 8 and 16. Continuous administration of lutein for 16 weeks, considering its bioaccessibility, increased MPOD; it made the outlines of visible objects clearer and was effective in inhibiting decreases in visual function caused by glare from light.

Contrast Sensitivity and Lateral Inhibition Are Enhanced With Macular Carotenoid Supplementation.

Purpose: Once deposited in the retina, the so-called macular carotenoids lutein (L), zeaxanthin (Z), and mesozeaxanthin (MZ) have been shown to enhance visual performance. The purpose of our study was to investigate whether increasing macular pigment optical density (MPOD) could enhance lateral inhibitory processes, and thereby improve contrast sensitivity (CS). Methods: A total of 59 young (18-25 years), healthy individuals participated in this 1-year, double-masked, placebo-controlled study. MPOD was assessed via heterochromatic flicker photometry. Lateral inhibition sensitivity (LIS) was determined with a computer-based, user-adjustable Hermann grid. CS (at 8 cycles/degree) was determined with a two-alternative, forced-choice procedure. Subjects received either the placebo (n = 10), 12 mg total macular carotenoids (n = 24), or 24 mg total macular carotenoids (n = 25). Results: MPOD, LIS, and CS increased significantly in treatment groups between baseline and 6 months, and between 6 and 12 months (P < 0.05 for all) versus placebo. The relationships between changes in MPOD and both LIS and CS were significant at 6 and 12 months (P < 0.05 for both). Changes in CS and LIS over the 12-month study period were found to be significantly related (r = 0.41; P = 0.0014). Conclusions: Increases in MPOD led to enhanced lateral inhibitory processes, which correspond to improved CS. Because optical filtering has the same net effect on dark versus light bars, it cannot explain these improvements. Improvement in CS with increases in MPOD therefore appears to involve enhancement of the fundamental physiological systems that give rise to edge detection.

Enrichment of Macular Pigment Enhances Contrast Sensitivity in Subjects Free of Retinal Disease: Central Retinal Enrichment Supplementation Trials - Report 1.

PURPOSE: The high-performance visual function associated with central vision is mediated by the macula (the central retina), which accumulates three diet-derived pigments (the carotenoids lutein [L], zeaxanthin [Z], and meso-zeaxanthin [MZ]). Our study sought to investigate the impact on visual function, including contrast sensitivity (CS), of supplementation with these naturally occurring carotenoids, in individuals with low retinal concentrations. METHODS: Subjects consumed daily a formulation containing 10 mg L, 2 mg Z, and 10 mg MZ (active group; n = 53) or placebo (n = 52) for a period of 12 months. Study visits were at baseline, 3, 6, and 12 months. Contrast sensitivity at 6 cycles per degree (cpd) was the primary outcome measure (POM). Secondary outcome measures included CS at other spatial frequencies, best-corrected visual acuity (BCVA), glare disability, photostress recovery, and light scatter. Macular pigment optical density (MPOD) was measured using dual-wavelength autofluorescence, and serum carotenoid concentrations were analyzed using high performance liquid chromatography (HPLC). RESULTS: Compared to placebo, statistically significant improvements from baseline CS were detected at 6 (P = 0.002) and 1.2 (P = 0.004) cpd in the active group. Additionally, improvements in CS were commensurate with the observed increases in retinal concentrations of these carotenoids (r = 0.342, P = 0.002 at 6 cpd). CONCLUSIONS: These results indicate that dietary fortification with the macular carotenoids can have meaningful effects on visual function.

Sustained supplementation and monitored response with differing carotenoid formulations in early age-related macular degeneration.

PURPOSE: To compare the impact of sustained supplementation using different macular carotenoid formulations on macular pigment (MP) and visual function in early age-related macular degeneration (AMD). PATIENTS AND METHODS: Sixty-seven subjects with early AMD were randomly assigned to: Group 1 (20 mg per day lutein (L), 0.86 mg per day zeaxanthin (Z); Ultra Lutein), Group 2 (10 mg per day meso-zeaxanthin (MZ), 10 mg per day L, 2 mg per day Z; Macushield; Macuhealth), Group 3 (17 mg per day MZ, 3 mg per day L, 2 mg per day Z). MP was measured using customised heterochromatic flicker photometry and visual function was assessed by measuring contrast sensitivity (CS) and best-corrected visual acuity (BCVA). AMD was graded using the Wisconsin Age-Related Maculopathy Grading System (AREDS 11-step severity scale). RESULTS: At 3 years, a significant increase in MP from baseline was observed in all groups at each eccentricity (P<0.05), except at 1.75° in Group 1 (P=0.160). Between 24 and 36 months, significant increases in MP at each eccentricity were seen in Group 3 (P<0.05 for all), and at 0.50° in Group 2 (P<0.05), whereas no significant increases were seen in Group 1 (P>0.05 for all). At 36 months, compared with baseline, the following significant improvements (P<0.05) in CS were observed: Group 2-1.2, 6, and 9.6 cycles per degree (c.p.d.); Group 1-15.15 c.p.d.; and Group 3-6, 9.6, and 15.15 c.p.d. No significant changes in BCVA, or progression to advanced AMD, were observed. CONCLUSION: In early AMD, MP can be augmented with a variety of supplements, although the inclusion of MZ may confer benefits in terms of panprofile augmentation and in terms of CS enhancement.

Effect of oral omega-3 Fatty Acid supplementation on contrast sensitivity in patients with moderate meibomian gland dysfunction: a prospective placebo-controlled study.

PURPOSE: To evaluate the effect of oral supplementation with omega-3 (ω-3) fatty acids (FAs) in improving contrast sensitivity (CS) of patients with moderate meibomian gland dysfunction (MGD). METHODS: In this prospective study, 60 patients with moderate MGD were allocated alternately to treatment and control groups. Both groups received warm compresses, lid massage, and artificial tear substitutes. The treatment group also received oral supplements of 1.2 g ω-3 FAs per day. All parameters were recorded at baseline and at 12 weeks and included Ocular Surface Disease Index scores, CS testing at 3, 6, 12, and 18 cycles per degree (cpd), tear break-up time, Schirmer test I without anesthesia, corneal and conjunctival staining scores, and meibum quality and expressibility. RESULTS: At the end of 12 weeks, significant improvement in CS was seen in the treatment group in 7 of the 8 testing conditions (3, 6, 12, and 18 cpd photopic and 6, 12, and 18 cpd mesopic), whereas in the placebo group, significant improvement was seen only in 3 of the 8 testing conditions (3 cpd photopic, 6 and 18 cpd mesopic). Ocular Surface Disease Index, tear break-up time, ocular surface staining, and meibum quality and expressibility improved significantly in both groups, but more so in the treatment group. Schirmer scores showed no significant improvement in either group. CONCLUSIONS: Oral supplementation with ω-3 FAs significantly improved CS under both photopic and mesopic testing conditions in patients with moderate MGD. Tear film stability also improved significantly, whereas no effect was seen on aqueous tear production.

Effect of supplemental lutein and zeaxanthin on serum, macular pigmentation, and visual performance in patients with early age-related macular degeneration.

PURPOSE: To compare the 2-year effect of multiple doses of lutein/zeaxanthin on serum, macular pigmentation, and visual performance on patients with early age-related macular degeneration (AMD). METHODS: In this randomized, double-blinded, and placebo-controlled trial, 112 early AMD patients randomly received either 10 mg lutein, 20 mg lutein, a combination of lutein (10 mg) and zeaxanthin (10 mg), or placebo daily for 2 years. Serum concentration of lutein/zeaxanthin, macular pigment optical density (MPOD), visual functions including best-spectacle corrected visual acuity (BCVA), contrast sensitivity (CS), flash recovery time (FRT), and vision-related quality of life (VFQ25) was quantified. RESULTS: Serum lutein concentration and MPOD significantly increased in all the active treatment groups. Supplementation with 20 mg lutein was the most effective in increasing MPOD and CS at 3 cycles/degree for the first 48 weeks. However, they both significantly increased to the same peak value following supplementation with either 10 mg or 20 mg lutein during the intervention. No statistical changes of BCVA or FRT were observed during the trial. CONCLUSIONS: Long-term lutein supplementation could increase serum lutein concentration, MPOD, and visual sensitivities of early AMD patients. 10 mg lutein daily might be an advisable long-term dosage for early AMD treatment.

The impact of supplemental macular carotenoids in Alzheimer's disease: a randomized clinical trial.

BACKGROUND: Patients with Alzheimer's disease (AD) exhibit significantly less macular pigment (MP) and poorer vision when compared to control subjects. OBJECTIVE: To investigate supplementation with the macular carotenoids on MP, vision, and cognitive function in patients with AD versus controls. METHODS: A randomized, double-blind clinical trial with placebo and active arms. 31 AD patients and 31 age-similar control subjects were supplemented for six months with either Macushield (10 mg meso-zeaxanthin [MZ]; 10 mg lutein [L]; 2 mg zeaxanthin [Z]) or placebo (sunflower oil). MP was measured using dual-wavelength autofluorescence (Heidelberg Spectralis®). Serum L, Z, and MZ were quantified by high performance liquid chromatography. Visual function was assessed by best corrected visual acuity and contrast sensitivity (CS). Cognitive function was assessed using a battery of cognition tests, including the Cambridge Neuropsychological Test Automated Battery (CANTAB)). RESULTS: Subjects on the active supplement (for both AD and non-AD controls) exhibited statistically significant improvement in serum concentrations of L, Z, MZ, and MP (p < 0.001, for all) and also CS at (p = 0.039). Also, for subjects on the active supplement, paired samples t-tests exhibited four significant results (from five spatial frequencies tested) in the AD group, and two for the non-AD group, and all indicating improvements in CS. We found no significant changes in any of the cognitive function outcome variables measured (p > 0.05, for all). CONCLUSION: Supplementation with the macular carotenoids (MZ, Z, and L) benefits patients with AD, in terms of clinically meaningful improvements in visual function and in terms of MP augmentation.

A randomized placebo-controlled study on the effects of lutein and zeaxanthin on visual processing speed in young healthy subjects.

Speed of processing is a particularly important characteristic of the visual system. Often a behavioral reaction to a visual stimulus must be faster than the conscious perception of that stimulus, as is the case with many sports (e.g., baseball). Visual psychophysics provides a relatively simple and precise means of measuring visual processing speed called the temporal contrast sensitivity function (tCSF). Past study has shown that macular pigment (a collection of xanthophylls, lutein (L), meso-zeaxanthin (MZ) and zeaxanthin (Z), found in the retina) optical density (MPOD) is positively correlated with the tCSF. In this study, we found similar correlations when testing 102 young healthy subjects. As a follow-up, we randomized 69 subjects to receive a placebo (n=15) or one of two L and Z supplements (n=54). MPOD and tCSF were measured psychophysically at baseline and 4months. Neither MPOD nor tCSF changed for the placebo condition, but both improved significantly as a result of supplementation. These results show that an intervention with L and Z can increase processing speed even in young healthy subjects.

Oral Lutein Supplementation Enhances Macular Pigment Density and Contrast Sensitivity but Not in Combination With Polyunsaturated Fatty Acids.

PURPOSE: It has been shown that lutein and zeaxanthin accumulate in the macula where they enhance contrast sensitivity and may reduce the risk of progression to advanced age-related macular degeneration (AMD). Furthermore, omega-3 long-chain polyunsaturated fatty acids (PUFA) might further reduce this risk. However, controversy exists regarding whether PUFA may reduce the bioavailability of lutein. METHODS: This was a prospective 12-month, randomized, open label study evaluating the effect of supplementation with lutein, other antioxidants, and minerals on contrast sensitivity (CS) and macular pigment optical density (MPOD) in patients with age-related maculopathy. A total of 79 patients were randomized to either lutein (10 mg) and antioxidant supplement or lutein and antioxidant supplement in combination with PUFA. Patients received supplementation for a period of 6 months and were followed for a total of 12 months. RESULTS: Serum lutein and zeaxanthin increased significantly by the first follow-up visit at 1 month, and remained elevated throughout the intervention period of 6 months in the lutein-only group but not in the lutein+PUFA group. Macular pigment optical density and CS increased significantly in the lutein-only group (P < 0.005) but not in the lutein+PUFA group (P = 0.059) compared to baseline. Best-corrected visual acuity remained unchanged during the entire study period in both groups. CONCLUSIONS: Addition of PUFA may reduce the bioavailability of lutein and therefore lessen the beneficial effect on macular pigment and CS. This needs to be considered when prescribing lutein supplements to patients with low lutein levels. (ClinicalTrials.gov number, NCT00563979.).

A double-blind, placebo-controlled study on the effects of lutein and zeaxanthin on photostress recovery, glare disability, and chromatic contrast.

PURPOSE: Past studies have shown that higher macular pigment optical density (MPOD) and lutein (L) and zeaxanthin (Z) supplementation are related to improvements in glare disability, photostress recovery, and chromatic contrast. This study assessed those links using a randomized, double-blind, placebo-controlled design. METHODS: The visual effects of 1 year of supplementing L (10 mg/d) and Z (2 mg/d) were investigated. One hundred fifteen young, healthy subjects were recruited and randomized into the study (58 received placebo, 57 L+Z). Several dependent measures were collected at baseline and then once every 3 months: serum L and Z measured by HPLC chromatography; MPOD measured using customized heterochromatic flicker photometry; photostress recovery assessed by measuring the time needed to recover visual acquisition of a grating target after 30 seconds of an intense xenon white flash exposure; glare disability evaluated as the energy in a surrounding annulus necessary to veil a central grating target; and chromatic contrast assessed by measuring thresholds for a yellow grating target superposed on a 460-nm background. RESULTS: Macular pigment optical density increased significantly versus placebo at all eccentricities (10, 30, 60, and 105 minutes from the center of the macula). Serum L and Z also increased significantly by the first follow-up visit (at 3 months), and remained elevated throughout the intervention period of 1 year. Chromatic contrast and photostress recovery time improved significantly versus placebo. Glare disability was correlated with macular pigment density throughout the study period but did not increase significantly in the treated group. CONCLUSIONS: Daily supplementation with L+Z resulted in significant increase in serum levels and MPOD and improvements in chromatic contrast and recovery from photostress. These results are consistent with past studies showing that increasing MPOD leads to improved visual performance. (ClinicalTrials.gov number, NCT00909090.).

Supplementation with three different macular carotenoid formulations in patients with early age-related macular degeneration.

PURPOSE: To investigate the impact of three different macular carotenoid formulations on macular pigment optical density and visual performance in subjects with early age-related macular degeneration. METHODS: Fifty-two subjects were supplemented and followed for 12 months, 17 of them were in intervention Group 1 (20 mg/day lutein and 2 mg/day zeaxanthin); 21 in Group 2 (10 mg/day meso-zeaxanthin, 10 mg/day lutein, and 2 mg/day zeaxanthin); and 14 in Group 3 (17 mg/day meso-zeaxanthin, 3 mg/day lutein, and 2 mg/day zeaxanthin). The macular pigment optical density was measured using customized heterochromatic flicker photometry, and visual function was assessed using corrected distance visual acuity and by letter contrast sensitivity. RESULTS: A statistically significant increase in the macular pigment optical density was observed at all measured eccentricities in Group 2 (P ≤ 0.005) and in Group 3 (P < 0.05, for all), but only at 1.75° in Group 1 (P = 0.018). Statistically significant (P < 0.05) improvements in letter contrast sensitivity were seen at all spatial frequencies (except 1.2 cycles per degree) in Group 3, and at low spatial frequencies in Groups 1 and 2. CONCLUSION: Augmentation of the macular pigment optical density across its spatial profile and enhancements in contrast sensitivity were best achieved after supplementation with a formulation containing high doses of meso-zeaxanthin in combination with lutein and zeaxanthin.

Central Retinal Enrichment Supplementation Trials (CREST): design and methodology of the CREST randomized controlled trials.

PURPOSE: The Central Retinal Enrichment Supplementation Trials (CREST) aim to investigate the potential impact of macular pigment (MP) enrichment, following supplementation with a formulation containing 10 mg lutein (L), 2 mg zeaxanthin (Z) and 10 mg meso-zeaxanthin (MZ), on visual function in normal subjects (Trial 1) and in subjects with early age-related macular degeneration (AMD; Trial 2). METHODS: CREST is a single center, double-blind, randomized clinical trial. Trial 1 (12-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ and 2 mg Z (n = 60) or placebo (n = 60). Trial 2 (24-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ, 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention A; n = 75) or 10 mg L and 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention B; n = 75). Contrast sensitivity (CS) at 6 cycles per degree represents the primary outcome measure in each trial. Secondary outcomes include: CS at other spatial frequencies, MP, best-corrected visual acuity, glare disability, photostress recovery, light scatter, cognitive function, foveal architecture, serum carotenoid concentrations, and subjective visual function. For Trial 2, AMD morphology, reading speed and reading acuity are also being recorded. CONCLUSIONS: CREST is the first study to investigate the impact of supplementation with all three macular carotenoids in the context of a large, double-blind, randomized clinical trial.

Effect of the administration of alpha-lipoic acid on contrast sensitivity in patients with type 1 and type 2 diabetes.

The aim of this study was to estimate the effects of oral supplementation of alpha-lipoic acid (ALA) on contrast sensitivity (CS) in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). The study included 12 patients with T1DM aged 43±12 years, 48 patients with T2DM aged 59±10 years, and 20 control subjects aged 33±8 years. Patients from each studied group, including the control group, were randomly assigned to receive 300 mg of ALA orally once daily for 3 months. CS was evaluated with the Functional Acuity Contrast Test (FACT, Stereo Optical). In the group of patients with T1DM receiving ALA for 3 months CS remained stable and improved in those with T2DM. Reduction of CS in both T1DM and T2DM patients without alpha-lipoic acid supplementation was observed. In the control group on alpha-lipoic acid supplementation, CS improvement was noticed at one spatial frequency. Changes in the CS were observed, despite stable visual acuity and eye fundus image in all studied subjects. Our study demonstrated that oral administration of alpha-lipoic acid had influence on CS in both T1DM and T2DM patients.

Effect of Ginkgo biloba on visual field and contrast sensitivity in Chinese patients with normal tension glaucoma: a randomized, crossover clinical trial.

PURPOSE: We evaluated the effect of ginkgo biloba extract on visual field defect and contrast sensitivity in a Chinese cohort with normal tension glaucoma. METHODS: In this prospective, randomized, placebo-controlled crossover study, patients newly diagnosed with normal tension glaucoma, either in a tertiary glaucoma clinic (n = 5) or in a cohort undergoing routine general physical examinations in a primary care clinic (n = 30), underwent two 4-week phases of treatment, separated by a washout period of 8 weeks. Randomization determined whether ginkgo biloba extract (40 mg, 3 times per day) or placebo (identical-appearing tablets) was received first. Primary outcomes were change in contrast sensitivity and mean deviation on 24-2 SITA standard visual field testing, while secondary outcomes included IOP and self-reported adverse events. RESULTS: A total of 35 patients with mean age 63.7 (6.5) years were randomized to the ginkgo biloba extract-placebo (n = 18) or the placebo-ginkgo biloba extract (n = 17) sequence. A total of 28 patients (80.0%, 14 in each group) who completed testing did not differ at baseline in age, sex, visual field mean deviation, contrast sensitivity, IOP, or blood pressure. Changes in visual field and contrast sensitivity did not differ by treatment received or sequence (P > 0.2 for all). Power to have detected a difference in mean defect as large as previously reported was 80%. CONCLUSIONS: In contrast to some previous reports, ginkgo biloba extract treatment had no effect on mean defect or contrast sensitivity in this group of normal tension glaucoma patients. (http://www.chictr.org number, ChiCTR-TRC-08000724).