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Journal Français d'Ophtalmologie
Volume 40, n° 4
pages 303-313 (avril 2017)
Doi : 10.1016/j.jfo.2016.11.009
Received : 13 September 2016 ;  accepted : 19 November 2016
Macular pigment density variation after supplementation of lutein and zeaxanthin using the Visucam® 200 pigment module: Impact of age-related macular degeneration and lens status
Densité optique du pigment maculaire après supplémentation en lutéine et zéaxanthine grâce au module pigment du Visucam® 200 : impact de l’état du cristallin et de la dégénérescence maculaire liée à l’âge
 

G. Azar a, , M. Quaranta-El Maftouhi b, J.-J. Masella c, M. Mauget-Faÿsse d
a Eye & ear university hospital, faculté de médecine, université Saint-Esprit de Kaslik, université Saint-Joseph, Beirut, Lebanon 
b Rabelais Eye Clinic Center, 16, rue Rabelais, 69003 Lyon, France 
c Ophthalmology center of Dauphiné, 6, boulevard Agutte-Sembat, 38000 Grenoble, France 
d Rothschild Foundation, 25, rue Manin, 75019 Paris, France 

Corresponding author. Eye & Ear Hospital, PO Box 70-933, Naccache, Lebanon.
Summary
Purpose

To assess the evolution of macular pigment optical density (MPOD) following supplementation with various macular formulations obtained with the Visucam® 200, and to study the factors affecting MPOD measurements.

Materials and methods

In this prospective, randomized, double-masked multicenter study, patients were divided into 2 groups: group A (patients without retinal pathology who underwent cataract surgery 1 month previously) and group B (patients with neovascular age-related macular degeneration [AMD] in one eye). In each group, half of the patients were randomly assigned to receive a food supplementation either with or without carotenoids (5mg of Lutein and 1mg of Zeaxanthin). Outcome measures included MPOD responses obtained with the Visucam® 200 for one year.

Results

In total, 126 subjects (52 men, 74 women) with a mean age of 75.3±7.61 years were enrolled. Mean MPOD values at the time of inclusion were statistically lower in group A (0.088 density unit [DU]) compared to group B (0.163 DU, P <0.05). No statistically significant increase in MPOD was noted in either group, even after discontinuation of the supplementation. By multiple regression analysis, age, female gender, lens status and the presence of AMD seemed to significantly affect MPOD measurements.

Conclusion

No significant improvement in MPOD seems to be detected with the Visucam® 200 after carotenoid supplementation. The MPOD measurement seems to be highly affected by cataract extraction and the presence of AMD.

The full text of this article is available in PDF format.
Résumé
Objectif

Étudier l’évolution de la densité optique du pigment maculaire (DOPM) après supplémentation par des formulations maculaires différentes grâce au module pigment maculaire du Visucam 200.

Matériels et méthodes

Il s’agit d’une étude prospective randomisée multicentrique à double insu, ayant inclus des patients également divisés en 2 groupes : groupe A (patients opérés de cataracte depuis 1 mois, sans pathologie rétinienne) et groupe B (patients atteints de dégénérescence maculaire liée à l’âge [DMLA] exsudative sur un œil). Dans chaque groupe, la moitié des patients ont reçu un supplément alimentaire contenant ou pas des caroténoïdes (5mg de Lutéine et 1mg de Zéaxanthine). Les paramètres mesurés étaient la DOPM obtenue grâce au Visucam pendant un an.

Résultats

Au total, 126 patients (52 hommes, 74 femmes) avec une moyenne d’âge±déviation standard (DS) de 76,8±7,61 ans ont été inclus. À l’inclusion, la valeur de la DOPM était significativement plus basse dans le groupe A (0,088 density unit [DU]) que dans le groupe B (0,163 DU, p <0,05). Aucune amélioration significative de la DOPM n’a été notée après supplémentation dans les deux groupes, même après arrêt de la supplémentation. Par analyse de régression multiple, l’âge, le sexe féminin, l’état du cristallin et la présence de DMLA paraissent affecter significativement les valeurs de la DOPM.

Conclusion

Aucune amélioration significative de la DOPM ne paraît détectable par le Visucam® 200 après supplémentation en caroténoïdes. La mesure de la DOPM paraît quant à elle très affectée par l’extraction de la cataracte et la présence de DMLA.

The full text of this article is available in PDF format.

Keywords : Age-related macular degeneration, Macular pigment optical density, Lutein and zeaxanthin supplementation, Visucam® 200

Mots clés : Dégénérescence maculaire liée à l’âge, Densité optique du pigment maculaire, Lutéine, Zéaxanthine, Visucam® 200


Introduction

Age-related macular degeneration (AMD) is the leading cause of blindness and visual impairment in industrialized countries [1, 2]. Macular pigment (MP), which comprises three carotenoids (Lutein [L], Zeaxanthin [Z] and Meso-zeaxanthin [MZ]) [3, 4, 5, 6, 7], is concentrated in the center of the retina (macula lutea). It is known to act as antioxidant [8] and blue-light filter [9] protecting the macula and retinal pigment epithelium (RPE) from light-initiated oxidative and destructive processes by quenching oxygen radicals [10, 11], which may be consequently beneficial in patients with AMD [12, 13].

Whether the supplementation of MP is associated with a lower risk of AMD development is of an extreme controversy. While some studies proved that MP intake might lower the risk of AMD [14, 15], other studies came up with opposite conclusions [16, 17].

To determine such relationship, many investigators tried to measure the macular pigment optical density (MPOD) by several clinical methods such as heterochromatic flickering photometry [18], fundus reflectance spectroscopy [19], motion-detection photometry [20], Raman spectrometry [21] and autofluorescence spectrometry [22], but none of those techniques have yet been fully validated [23].

The Visucam® 200 (Carl Zeiss Meditec AG, Jena, Germany) is a new technique that has been suggested to measure the MPOD. It is based on reflectometry, and measures the MPOD through reflectance of a single 460-nm wavelength fundus. Until now, very few reports studied the reliability of this technique [18, 24, 25, 26]. Moreover, some recent studies did not find any agreement when comparing the concordance of MPOD measurement obtained by Visucam® 200 with other techniques such as the heterochromic flicker photometry [18] and the modified Heidelberg Retina Angiograph [27]. On the other hand, no data exists concerning whether MPOD measurement with this method is affected by MP supplementation, and whether the cataract extraction and the type of intraocular lens (IOL) have an effect on the accuracy of this measurement.

Therefore, a prospective, randomized clinical trial was performed to analyze the density and evolution of the MPOD after MP supplementation and 4 months after its withdrawal using the Visucam® 200 technique. Factors that may affect this MPOD variation are also studied.

Methods
Study design

This is a 24-months randomized, double-masked, comparative, multicenter trial. Patients were enrolled based on a prestudy screening including physical, ophthalmological examinations and fundus photography. Information including lifestyle habits, demographic characteristics, hair color and ethnicity, iris photos and eye color classification according to Mackey classification [28], blood pressure and heart rate, measurement of height and weight, other medical history and use of medications was collected. Dietary intake was assessed with a validated 120-item food frequency questionnaire. Approvals from the Ethics Committee of the University of Lyon were obtained. The study was performed in compliance with the tenets of the Declaration of Helsinki and registered with :NCT0140845. The protocol and the possible consequences of the study were clearly explained to patients, and a written informed consent was obtained from all subjects.

Inclusion criteria

One hundred and twenty six consecutive patients were recruited from Rabelais Ophthalmology Center and Ophthalmology Center of Dauphiné during one year. Subjects were divided into two groups, based on the first prestudy visit examination: group A – patients without any retinal pathology who underwent cataract surgery 1 month previously; and group B – patients with stage 4 exudative AMD in only one eye, according to the Age-Related Eye Disease Study (AREDS) [29].

Exclusion criteria

Subjects were excluded if they had any intolerance or were already taking any supplementation similar to the tested product, were allergic to mydriatic agents, or if they manifested AMD for which existing medical or surgical options were available. Other exclusion criteria for ophthalmological reasons were the presence of ocular diseases or conditions that might interfere with the MPOD measurement (e.g. dense cataract, diabetic retinopathy, macular telangiectasia, optic atrophy, myopia>6.5 Diopters). Patients presenting any other severe organic conditions such as acute/chronic liver disease, endocrine, neoplastic or hematological disorders, infectious diseases, severe psychiatric disorders, significant cardiovascular abnormalities, and/or any other aggravating factors or structural defect considered as being inconsistent with the study, were also excluded. Additional disqualifying criteria included inability of the patient to understand the study procedures and to give informed consent, patients not covered by the social security scheme and pregnancy.

Nutritional supplementation

In each group (group A and group B), patients were randomly assigned to take 1 of 2 dietary supplement treatment arms for 8 months (Table 1): either 2 tablets daily of a nutritional supplement containing 560mg of docosahexaenoic acid (DHA), 420mg of gamma linolenic acid (GLA), 80mg of vitamin C, 10mg of vitamin E, 2mg of vitamin B6, 200μg of Vitamin B9, 1μg of vitamin B12, 10mg of Zinc and carotenoids (5mg of L and 1mg of Z) (“Intervention group”, n =64), or 2 tablets daily of another nutritional supplement that has the same composition but without carotenoids (“Placebo group”, n =62). Both participants and ophthalmologists were blinded as to which subgroup was taking which supplement. Both tablets, manufactured by the same laboratory (Laboratorios Thea, Barcelona, Spain), presented with the same look, packaging, taste and smell. The importance of compliance was emphasized to patients at the day of inclusion, during each visit and in the subject information leaflet. Adherence to treatment was evaluated during each visit by capsule counts. All patients were requested to maintain their usual diet and to abstain from taking any other nutritional supplementation.

Outcome measures

On the day of inclusion (visit 0), a complete ophthalmological exam including Amsler grid testing, best-corrected visual acuity (BCVA), intraocular pressure (IOP) measurement using the Goldman tonometer, fundus exams and fundus photographs centered on the macula were performed. Central macular thickness and the presence of subretinal fluid were also assessed using Spectral-Domain Optical Coherence Tomography (SD-OCT; Cirrus HD-OCT, Spectralis Heidelberg Engineering, Germany). Baseline measurements of MPOD (in Density Units [DU]) using the Visucam® 200 were also performed on the same day. This device uses a narrow-band wavelength (480–500nm) reflectance for measuring MPOD. Determination is done by comparing the reflectance at the macula with the reflectance at the parafoveal reference area, with a fixed analysis area of 3.5° eccentricity. All subjects started the supplementations on the morning of the next day. The same exams were then performed again at week 8±10 days (visit 1), week 16±10 days (visit 2), week 24±10 days (visit 3) and week 32±10 days (visit 4, which corresponds to the end of supplementation in all subgroups). MPOD was then taken again after supplementation withdrawal at week 40±10 days (visit 5, follow-up visit) and week 48±10 days (visit 6, end of study visit). At every MPOD measurement, the pupils were sufficiently dilated using 1% tropicamide. Subject head alignment was obtained in front of the fundus camera, and patients were instructed to fixate straight ahead at a green light star. Four MPOD parameters were taken at every measurement: area (area where macular pigments could be detected), maximum OD (maximum value of OD in the area), mean OD (mean value of OD in the area) and volume (sum of all OD in the area) (Figure 1). In the group A, MPOD measurement was done on the recently operated eye, while in the group B the measurement interested the non-exudative eye.



Figure 1


Figure 1. 

Baseline macular pigment optical density (MPOD) pattern as measured with the Visucam® 200 in a pseudophakic patient at the time of inclusion. Four MPOD parameters were taken at every measurement: volume (sum of all OD in the area), area (area where macular pigments could be detected), max OD (maximum value of OD in the area) and mean OD (mean value of OD in the area).

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Sample size calculations and statistical analysis

A statistical power was computed once enough data were available, assuming an alpha error risk of 0.05 (type I error). Baseline characteristics among groups were compared using t -test or Chi-square test depending on the nature of variables, as appropriate. Values are reported as mean±standard deviation (SD) unless otherwise noted. At baseline time point, an analysis of covariance of MPOD using age as covariate was performed to assess phakic–pseudophakic groups’ differences. Changes in MPOD over time were assessed through a linear mixed model taking into account correlation across time points. The following covariates were included in the modeling process: patients (random effect), gender, age, time points, treatment (“intervention group” vs. “placebo group”), iris color, smoking, lens status, body mass index (BMI) and earlier supplementation. Backward variable selection was then performed using the Bayesian Backward Criterion (BIC) and either maximum likelihood or restricted maximum likelihood (REML). Analysis was performed using the computer program SPSS software version 15.0 (SPSS, Inc., Chicago, IL, USA). A P -value of less than 0.05 was considered significant.

Results
Baseline findings

One hundred and twenty six consecutive patients were enrolled. In total, 74 (58.7%) were women and 52 (41.3%) were men. Mean age±SD was 75.3±7.61 years, and mean BMI±SD was 25.69±4.68kg/m2. Fourteen patients (11.1%) were smokers and 21 (16.7%) were former smokers. Demographics variables and baseline characteristics are shown on Table 2. As previously mentioned, patients were categorized into two groups: group A – 47 patients without any retinal pathology who underwent cataract surgery 1 month previously; and group B – 79 patients with stage 4 exudative AMD in only one eye, 22 of which were pseudophakics, the MPOD measurement being done in the non-exudative eye. Except for age that was statistically lower in the group A compared to the group B (72.7 years and 76.8 years respectively, P =0.003), there were no statistical differences between both groups in any of the other demographic characteristics. In each group, as cited above, patients were assigned to take either a nutritional supplement containing carotenoids (“Intervention group”) or another supplement without carotenoids (“Placebo group”). All patients completed 32 weeks of treatment. No serious adverse event related to the supplements occurred across treatment. Pill compliance, defined as taking at least 90% of pills, was 100% in all subgroups. Based on a 120-item food frequency questionnaire that was done during each visit, no changes in dietary habits were found among subgroups during follow-up.

Macular pigment optical density (MPOD) Profile

The mean MPOD levels at the baseline visit as measured with the Visucam® 200 was significantly lower in group A comparing to group B (0.088 DU and 0.163 DU respectively, P <0.05). Figure 2 shows a graph of the mean MPOD levels measured at the time of inclusion, during 8 months of supplementation and 4 months after withdrawal. All measurements were done on the basis of 2 months follow-up for 1 year. In the group A, the mean MPOD levels were respectively 0.089 DU at baseline, 0.089 DU at visit 1, 0.093 DU at visit 2, 0.090 DU at visit 3, 0.088 DU at visit 4, 0.077 DU at visit 5 and 0.082 DU at visit 6 for the “Intervention group”, and respectively 0.086 DU at baseline, 0.090 DU at visit 1, 0.089 DU at visit 2, 0.093 DU at visit 3, 0.088 DU at visit 4, 0.093 DU at visit 5 and 0.085 DU at visit 6 for the “Placebo group”. Concerning the group B, those levels were respectively 0.168 DU at baseline, 0.169 DU at visit 1, 0.172 DU at visit 2, 0.172 DU at visit 3, 0.172 DU at visit 4, 0.169 DU at visit 5 and 0.166 DU at visit 6 for the “intervention group”, and respectively 0.158 DU at baseline, 0.154 DU at visit 1, 0.158 DU at visit 2, 0.158 DU at visit 3, 0.159 DU at visit 4, 0.158 DU at visit 5 and 0.154 DU at visit 6 for the “Placebo group”. No significant differences in changes in MPOD levels were found at any time point in all subgroups. During follow-up, only the group B supplemented with carotenoids had a non-significant tendency to increase mean MPOD levels from baseline (0.168 DU) to the end of supplementation (0.172 DU), with a decrease of those levels 2 months after withdrawal (0.166 DU). Moreover, as also noted in Figure 2, no significant differences in changes in MPOD were found among the 4 subgroups when comparing them at any time point, even at the last visit. However, when a further stratification was done in the group B according to the lens status, “phakic patients of Group B” tended to have a significantly higher MPOD compared to “pseudophakic patients of Group B” at visit 0 (0.186 DU and 0.107 DU respectively; P <0.001) and at visit 4 (0.184 DU and 0.115 DU respectively; P <0.001), which corresponds to the end of the supplementation. These two tendencies of MPOD are shown in Figure 3 for both visit 0 (Figure 3A) and visit 4 (Figure 3B).



Figure 2


Figure 2. 

Time course of macular pigment optical density (MPOD) at baseline (visit 0), during an 8-months supplementation either with () or without () carotenoids (visit 1 to 4), and after supplementation withdrawal (visit 5 and 6), expressed in Density Units (D.U.). Continuous lines: Group A (patients without any retinal pathology who underwent cataract surgery 1 month previously, followed on the operated eye). Dashed lines: Group B (patients with exudative age-related macular degeneration in only one eye, followed on the non-exudative eye).

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Figure 3


Figure 3. 

Distribution of macular pigment optical density (MPOD) in phakic and pseudophakic patients of Group B, at the visit of inclusion (V0 MPOD) (Figure 3A) and at visit 4 (V4 MPOD), which corresponds to the end of supplementation (Figure 3B). Phakic patients tended to have a significantly higher MPOD levels than pseudophakic patients at both visits (P <0.001).

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Multiple regression analysis of MPOD

To investigate the potential factors that might be associated with the MPOD measurements, a multiple regression analysis was performed. All factors considered to have some correlation with each other including age, gender, BMI, iris color, smoking, high blood pressure, diabetes, lens status and the presence of AMD were studied in both groups. At visit 0, as shown in Figure 4, the covariance analysis showed a strong positive correlation between mean baseline MPOD and age (P <0.001) in phakic patients. In fact, those patients tended to have a significantly higher level of MPOD measurement when they were older. Nevertheless, this correlation was not found in all other pseudophakic patients.



Figure 4


Figure 4. 

Scatterplots and regression lines depicting the correlations between baseline macular pigment optical density (MPOD) and age, in both phakic patients and all pseudophakic patients. A strong positive correlation was found between baseline MPOD and age in phakic patients (P <0.001), whereas no significant correlation was found in pseudophakic patients (P =0.3).

Zoom

On the other hand, to study the impact of AMD on MPOD evaluation, the MPOD profiles were compared between Group A (pseudophakic patients without any retinal pathology) and “pseudophakic patients of Group B” at visit 0 (Figure 5A) and visit 4 (Figure 5B). Surprisingly, MPOD levels were significantly lower in Group A compared to “pseudophakic patients of Group B” both at visit 0 (0.088 and 0.107 respectively; P <0.005) and at visit 4 (0.092 and 0.115 respectively; P <0.005).



Figure 5


Figure 5. 

Distribution of macular pigment optical density (MPOD) in Group A (pseudophakic patients without any retinal pathology) and in pseudophakic patients of Group B, at the visit of inclusion (V0 MPOD) (Figure 5A) and at visit 4 (V4 MPOD), which corresponds to the end of supplementation (Figure 5B). MPOD levels tended to be significantly lower in Group A compared to pseudophakic patients of Group B at both visits (P <0.05).

Zoom

Furthermore, as shown in Table 3, the time-dependent evolution of the mean MPOD was also studied using a mix linear model that also assessed all the above factors. In the “phakic patients of Group B”, age and female gender are two factors that were found to have a strong significant stimulating effect on the time-dependent MPOD evolution during supplementation (P <0.0001 and P =0.0025 respectively). Therefore, MPOD measurements were significantly higher in older phakic female patients who had an exudative AMD in the contralateral eye. The same longitudinal study for Group A and “pseudophakic patients of Group B” showed a strong positive stimulating effect on MPOD for female gender in both groups (P =0.015 and 0.010 respectively) and a negative effect for the presence of intraocular implant, suggesting that pseudophakics patients had lower MPOD levels than phakic patients, independently of the presence of AMD (P <0.0001 in both groups). None of all the other demographic factors (e.g. smoking, high blood pressure, diabetes mellitus, dyslipidemia) had direct influence on MPOD evolution during the longitudinal study in all subgroups.

Discussion

Many studies investigated the role of L and Z intake on the profiles of MP and visual performance, and reported an increase in MPOD after supplementation. Those MPs have been proved to play a vital role against oxidative stress damage and inflammation within the retina [30]. However, there are several controversies concerning these findings, as many other studies did not show any increase after intake [31, 32, 33, 34], hence the importance of a device that objectively measures reproducibly the MPOD. Furthermore, factors affecting those MPOD measurements are not yet clearly elucidated.

Several devices that claim to measure accurately MPOD have been studied in the literature, but till this date, there is not yet a gold standard technique available for this kind of measurement. The Visucam® 200 is a new technique that uses one wavelength (a narrow-band wavelength of 480–500nm) and is based on reflectance. It is a quick method for MPOD measurement that minimally requires patient involvement. While some reports found a significant increase in MPOD measurement using this method [26], Dennison et al. [18] and Creuzot-Garcher et al. [27] found no correlation between HRA and Visucam® 200, hence their conclusion that this device is not yet ready to be suitable for clinical and research setting. Similarly to their findings, our results show no difference in MPOD measurement after carotenoids supplementation in all subgroups when using the Visucam® 200.

To study the influence of the different factors on MPOD measurements, a multivariate analysis was performed. At baseline, a strangely strong positive correlation was found between age and MPOD measurement, but only in the phakic group. Unlikely to be expected, this MPOD tended to be higher in older patients. Moreover, when MPOD profiles were compared between Group A (pseudophakics without AMD) and pseudophakic patients of Group B (patients with AMD) during supplementation, MPOD levels were curiously lower in the former group. Many theoretical factors might explain those findings. First, the oxidative stress effect of free radical agents is known to be higher in older patients and patients having AMD. Thus, these patients might need metabolically more antioxidant agents to thwart this effect, and could consequently fixate more avidly the MP. However, the rationale of being able to integrate it biochemically – even after fixation – in convenient cascades in order to optimize its usefulness remains unclear and is object of further biochemical and metabolical studies. Second, some dietician factors may also explain those MPOD findings in older patients and patients presenting with AMD. In fact, our baseline assessment of dietary and lifestyle habits in the prestudy screening revealed a more balanced diet in those patients that tended to eat more frequently green vegetables. This tendency can be explained by the presence of a focused awareness and educational programs for seniors concerning the necessity of a healthier dietary habit in order to prevent the progression of AMD. Female gender seemed to have a strong positive effect in all subgroups on MPOD measurements, which may suggest a stronger dietary intake of carotenoids when compared to men.

On the other hand, when stratifying our patients according to their lens status, the tendency of higher MPOD findings with age was not seen in the pseudophakic groups, highlighting the role of the lens status in the measurement of MPOD levels. This may be partially explained by IOL absorption of the reflected light, which cannot be estimated and controlled, as the Visucam ® 200 uses only a one-wavelength reflectance. Unlike Nolan et al. [35] who state that increased light absorption across the IOL is found after cataract surgery, we think that the difference of measurement between phakic patients and pseudophakic patients found with the Visucam® 200, which seemed to be independent of the presence of AMD, is rather due to a filter found in the IOL, which blocks both incidence and reflectance of the beam, giving an underestimated MPOD values.

To conclude, despite the fact to be considered protective against the progression of AMD through their antioxidative properties, optical density of MP may be subject to individually determined distribution pattern and is not constantly and equally increased after supplement intake. Among the factors that seem to play an important role in this determination are age, sex, baseline dietary habits, lens status and the presence of AMD. However, additional larger cohorts that evaluate the long-term effects of L and Z on MPOD measurements, and accurately estimate the duration and quality of the dietary intake for each patient during follow-up will still be needed to fully validate our findings.

Finally, care should be taken when evaluating this variation of MPOD pattern using the Visucam® 200. Further studies are still required to understand the measurements done with this machine before considering it a gold standard in MPOD measurement. Taking into account lens status, and especially the type of IOLs in pseudophakic patients would be of a great interest, as each type of IOLs may absorb a predefined quantity of reflected light depending on its wavelength reflectance, which can consequently affect MPOD measurement.

Funding

Funding was received from Thea Laboratories in support of this study as the form of supplementations provision.

Disclosure of interest

The authors declare that they have no competing interest.

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