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Stephen Beatty

Publications and source records attributed to Stephen Beatty.

13 recordsLinked to original sources
PubMed2006

Risk factors for age-related maculopathy are associated with a relative lack of macular pigment.

Macular pigment (MP) is composed of the two dietary carotenoids lutein (L) and zeaxanthin (Z), and is believed to protect against age-related maculopathy (ARM). This study was undertaken to investigate MP optical density with respect to risk factors for ARM, in 828 healthy subjects from an Irish population. MP optical density was measured psychophysically using heterochromatic flicker photometry, serum L and Z were quantified by HPLC, and dietary intake of L and Z was assessed using a validated food-frequency questionnaire. Clinical and personal details were also recorded, with particular attention directed towards risk factors for ARM. We report a statistically significant age-related decline in MP optical density (r2=0.082, p<0.01). Current and past smokers had lower average MP optical density than never smokers and this difference was statistically significant (p<0.01). Subjects with a confirmed family history of ARM had significantly lower levels of MP optical density than subjects with no known family history of disease (p<0.01). For each of these established risk factors, their statistically significant negative association with MP persisted after controlling for the other two, and also after controlling for other potentially confounding variables such as sex, cholesterol, dietary and serum L (p<0.01). In the absence of retinal pathology, and in advance of disease onset, the relative lack of MP seen in association with increasing age, tobacco use and family history of ARM supports the hypothesis that the enhanced risk that these variables represent for ARM may be attributable, at least in part, to a parallel deficiency of macular carotenoids.

Adult↗
PubMed2006

Surgical and visual outcomes following exchange of opacified Hydroview intraocular lenses.

AIM: To report the clinical and surgical outcomes following exchange of opacified Hydroview intraocular lenses (IOLs), and to relate the final visual and anatomic results to clinical and surgical variables. METHODS: This is a prospective study of seventy-three eyes that underwent exchange of opacified Hydroview IOLs in Waterford Regional Hospital, Ireland. Preoperative, intraoperative and postoperative details were recorded. RESULTS: This study comprised 73 eyes of 71 consecutive patients undergoing IOL exchange, performed at mean (+/-SD) intervals of 36.64 (+/-9.9) months following the primary cataract surgery. The mean (+/-SE) follow-up following the exchange procedure was 13 (+/-1) months (range: 1-45 months). The secondary IOL was placed in the capsular bag, in the sulcus, and in the anterior chamber in 22 (30.1%), 24 (32.9%) and 27 (37%) cases, respectively. The IOL exchange procedure was uneventful in 36 eyes (49.3%), whereas intraoperative events such as posterior capsule rupture, vitreous loss and zonular dehiscence were seen in the remainder (50.7%). Following the IOL exchange procedure, a significant improvement in best corrected visual acuity (BCVA) was noted at one and at three months, and at the final visit (Wilcoxon signed ranks test: p<0.001, p = 0.006, and p<0.001, respectively). Following exclusion of eyes with visually consequential ocular comorbidity, a better final BCVA was noted among those eyes where the secondary IOL was placed in the capsular bag or in the sulcus when compared with placement of the secondary IOL in the anterior chamber (IOL in the bag or sulcus: 26 eyes (35.6%), median (IQR) final BCVA: 0.2 (0.10-0.40); IOL in the anterior chamber: 19 eyes (26.02%), median (IQR) final BCVA: 0.5 (0.20-0.60); Mann Whitney U Test: p = 0.004). CONCLUSION: IOL exchange is a technically challenging, but visually rewarding procedure. However, placement of the secondary IOL in the anterior chamber is associated with a poorer visual outcome when compared with placement of the secondary IOL in the sulcus or in the capsular bag.

Adult↗
PubMed2006

Macular pigment and ocular biometry.

This study is designed to investigate the relationship between macular pigment optical density (MPOD) and ocular biometric parameters. The following details were recorded for 180 healthy subjects: demographic profile; best-corrected visual acuity; refractive status; ocular biometric parameters [axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and vitreous chamber depth (VCD)]; ocular dominance; MPOD; serum lutein (L) and zeaxanthin (Z). The mean MPOD (+/-SD) was 0.307 (0.155) and 0.305 (0.149) in the right and left eyes, respectively. No demonstrable relationship was observed between MPOD and AL, ACD or VCD [AL: r=0.091, p=0.225; ACD: r=0.091, p=0.227; VCD: r=0.146, p=0.051]. There was a significant and inverse relationship between LT and MPOD (r=-0.204; p=0.008), which was attenuated to non-significance after correction for age and height (r=-0.058; p=0.466). This study fails to identify an association between MPOD and ocular biometric parameters. This is an important negative finding, which allows investigators to study MP, and its relationship with potentially important variables, without the need to correct for ocular biometric parameters.

Adult↗
PubMed2006

Monthly consistency of macular pigment optical density and serum concentrations of lutein and zeaxanthin.

PURPOSE: This study was undertaken to assess serial month-to-month consistency of macular pigment (MP) optical density and serum concentrations of lutein (L) and zeaxanthin (Z). Four healthy subjects aged between 23 and 51 years volunteered to participate in this study. METHODS: MP optical density (measured psychophysically using heterochromatic flicker photometry [HFP]), and serum concentrations of L and Z (quantified using high-performance liquid chromatography [HPLC]), were recorded every month for 24 consecutive months. RESULTS: Mean MP optical density (+/-SD) was 0.361 (0.086) and 0.369 (0.074) for right and left eyes, respectively. There was no statistically significant seasonal variation in MP optical density for the group (two-way ANOVA: p>0.05). Serum concentrations of L and Z demonstrated a statistically significant subject-season interaction effect (two-way ANOVA: p<0.01). Serial serum concentrations of L and Z were positively correlated within all four subjects (r=0.370 to 0.786), and significantly so for three subjects (p<0.05). There was no obvious relationship, synchronous or lagged, between serum concentrations of L (or Z) and MP optical density (r=-0.036 to 0.368). CONCLUSIONS: MP optical density was relatively stable for all subjects over the 24-month period. Fluctuations in serum concentrations of L and Z, in the absence of dietary modification or supplementation, are associated with stable MP optical density.

Adult↗
PubMed2005

Central retinal thickness is positively correlated with macular pigment optical density.

Macular pigment (MP) has been suggested to have a protective role in age-related macular degeneration by reducing the amount of oxidative stress on the retina. MP levels peak at the foveal center, where it is found predominantly in the receptor axon and inner plexiform layers of the retina. The purpose of this study was to investigate the relationship between central retinal thickness and macular pigment optical density in a group of healthy subjects. We report that macular pigment optical density (MPOD) has a significant and positive relationship with central retinal thickness as measured by optical coherence tomography. The strength of the observed relationship (r approximately 0.30) was independent of the technique used to measure MPOD, whether heterochromatic flicker photometry (HFP) or 2-wavelength autofluorescence (AF). Of note, there was no statistically demonstrable relationship between MPOD at an eccentricity of 1- or 2-degrees and central retinal thickness. This finding has important implications for future studies investigating MPOD, and its response to dietary modification/supplementation.

Adult↗
PubMed2005

Visual experiences during vitreous surgery under regional anesthesia: a multicenter study.

PURPOSE: To investigate patients' subjective intraoperative visual experiences during vitreous surgery performed under regional anesthesia, to ascertain if patients were frightened by their visual experiences, and to determine the risk factors associated with a frightening visual experience. DESIGN: Multicenter, prospective study. METHODS: Sixty-five patients who had vitreous surgery under regional (retrobulbar or peribulbar) anesthesia in five centers in Ireland, Singapore, and Hong Kong were interviewed within 2 hours of their operation using a standardized questionnaire. RESULTS: Thirty patients (46.2%) perceived light perception throughout the entire operation, 19 patients (29.2%) experienced transient loss of light perception, and 16 patients (24.6%) experienced no light perception throughout the entire duration of the surgery. Nine patients (13.8%) were frightened by their intraoperative visual experiences. Patients who were frightened by their visual experiences were more likely to see color (100%) than those who were not frightened (55.4%) (P = .010). The mean age of the patients who were frightened was lower (51.8 years) compared with those who were not frightened (64.6 years) (P = .003). The mean duration of surgery was longer for patients who were frightened (118.9 minutes) compared with those who were not frightened (91.2 minutes) (P = .047). CONCLUSIONS: Most patients undergoing vitreous surgery under regional anesthesia retained at least light perception intraoperatively. Importantly, 13.8% of patients were frightened by their visual experiences. A younger age, longer duration of surgery, and perception of color were risk factors for a frightening visual experience.

Adult↗
PubMed2005

Measurement of macular pigment: Raman spectroscopy versus heterochromatic flicker photometry.

PURPOSE: There are several techniques for measuring macular pigment (MP) in vivo, of which Raman spectroscopy (RS) is a recently developed objective METHOD: This study reports the reproducibility, test-retest variability, and validity of RS MP readings, by comparing them with heterochromatic flicker photometry (HFP). METHODS: MP was measured with HFP and RS in 120 healthy subjects, and the latter technique was also used on two separate occasions in a sample of 20 subjects to investigate the intersessional variability of readings. Intrasessional reproducibility of RS MP measurements was also calculated. In addition, serum concentrations of lutein (L) and zeaxanthin (Z) were measured and correlated with both RS and HFP MP readings. RESULTS: Mean (+/-SD) MP in the right eye was 0.279 +/- 0.145 and 0.319 +/- 0.155 with RS and HFP, respectively. The differences between corresponding MP readings taken on RS and HFP lay within the Bland-Altman 95% limits of agreement for the two instruments in 93.6% and 94.4% of cases in the right and left eyes, respectively. Intrasessional reproducibility of RS readings, expressed as the coefficient of variation, was 8.42% +/- 7.12%. Ninety-five percent of MP readings taken with RS on two separate occasions lay within the 95% limits of agreement for the two sessions. A positive, but insignificant, relationship was observed between RS and HFP MP readings and serum concentrations of L and Z (RS, P = 0.356; HFP, P = 0.540). CONCLUSIONS: RS, an objective method of measuring MP levels in vivo, exhibits acceptable reproducibility and test-retest variability. The results demonstrated good correlation between RS and HFP measurements of MP, thus authenticating RS against a validated psychophysical technique of measuring MP. However, investigators should use only one of these instruments for the duration of any given study because of differences in the scientific rationale, and the factors that influence RS and HFP measurements of MP.

Adult↗
PubMed2005

Heritability of macular pigment: a twin study.

PURPOSE: Several studies have reported higher levels of macular pigment (MP) in association with reduced risk for age-related macular degeneration (ARMD), a disease to which there is a genetic predisposition. A classic twin study was performed to determine the heritability of MP in the healthy eye. METHODS: One hundred fifty twin pairs (76 monozygotic [MZ] and 74 dizygotic [DZ]), aged 18 to 50 years, participated. MP optical density was measured psychophysically with heterochromatic flicker photometry (HFP) and also with an imaging method involving fundus autofluorescence (AF). The covariance of MP within MZ and DZ twin pairs was compared, and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in MP. RESULTS: The mean MP optical density, measured using HFP, was 0.43 +/- 0.21. Using AF, the mean MP optical density, measured at 1 degrees eccentricity, was 0.28 +/- 0.11. MP optical densities correlated more highly in MZ twins than in DZ twins, according to both HFP (MZ: 0.65; DZ: 0.24) and AF (MZ: 0.83; DZ: 0.50). A model combining additive genetic and unique environmental effects provided the best fit and resulted in MP heritability estimates of 0.67 (95% CI, 0.52-0.77) and 0.85 (95% CI, 0.78-0.90) for HFP and AF readings, respectively. CONCLUSIONS: This classic twin study demonstrates that genetic background is an important determinant of MP optical density, reflected in heritability estimates of 0.67 and 0.85 for HFP and AF measures, respectively.

Adolescent↗
PubMed2004

Macular pigment optical density and its relationship with serum and dietary levels of lutein and zeaxanthin.

Observational evidence is accumulating that the onset of age-related maculopathy, the leading cause of legal blindness in the Western World, could be delayed, or even averted, with antioxidant supplements. Lutein (L) and zeaxanthin (Z) are two hydroxy-carotenoids with antioxidant activity which accumulate at the macula, where they are collectively known as macular pigment (MP). It has been shown that MP is entirely of dietary origin, and that L and Z levels in serum, diet, and retina correlate. However, the nature of the relationships between L and Z in foodstuffs, blood, and macula is confounded by many variables including processes which influence digestion, absorption, and transport of the compounds in question, and accumulation and stabilization of the carotenoids in the tissues. If macular pigment is protective for age-related maculopathy, a clear understanding of the mechanisms whereby L and Z arrive at the target tissue (retina) from their source (foodstuff) is essential. In this paper, we review the literature germane to this growing area of interest.

Animals↗
PubMed2004

Plasma and macular responses to lutein supplement in subjects with and without age-related maculopathy: a pilot study.

There is a growing body of evidence which suggests that macular pigment (MP), which is entirely of dietary origin, protects against age-related maculopathy. We evaluated the effect of a daily 20 mg lutein ester (equivalent of 10 mg/day free lutein) supplement in patients with early age-related maculopathy (ARM), in terms of macular pigment optical density (MPOD) and plasma concentrations of lutein. MPOD was measured using a flicker photometric technique in seven ARM sufferers and six age-matched controls over a period of supplementation which lasted 18-20 weeks. Plasma lutein increased from a mean (SD) baseline concentration of 182 (127)ng ml(-1) to a peak of 1077 (165)ng ml(-1) in ARM patients, and from 152 (57) to 1110 (605)ng ml(-1) in control subjects. Mean MPOD had increased significantly from baseline of 0.24 to a peak of 0.31 in ARM sufferers. This mean increment of 0.07 was the same for the age-matched controls (baseline: 0.20; peak: 0.27). The augmentation of MP, and plasma concentrations of lutein, following supplementation in subjects with ARM provides the first evidence the disease is not associated with intestinal malabsorption of the relevant macular carotenoids, and that a diseased macula can accumulate and stabilise lutein and/or zeaxanthin. Furthermore, these results suggest that the beneficial effects of lutein supplementation, if any, may be extended to subjects with established ARM.

Aged↗
PubMed2004

Risk factors for endothelial cell loss after phacoemulsification surgery by a junior resident.

PURPOSE: To assess the risk factors for endothelial cell loss after phacoemulsification cataract surgery performed by a junior resident. SETTING: Ophthalmic teaching hospital, Dublin, Ireland. METHODS: This prospective study included 40 eyes having divide-and-conquer phacoemulsification cataract surgery by a junior resident under the supervision of an experienced surgeon. Nine variables were examined to assess the risk for corneal endothelial cell loss postoperatively. RESULTS: The mean overall endothelial cell loss was 11.6%. Longer surgery time, longer absolute and effective phaco time, higher mean ultrasound power, and higher cataract density were significantly associated with endothelial cell loss on univariate analysis. Multivariate analysis identified a grade 3 nucleus (severely dense) and long absolute phaco time as independent predictors for endothelial cell loss, with longer absolute phaco time the stronger predictor. CONCLUSIONS: Divide-and-conquer phacoemulsification cataract surgery was a safe technique in the hands of an ophthalmic trainee. This study supports advice to junior surgeons to choose cases with less dense cataracts as this will help reduce the absolute phaco time and thus minimize endothelial cell loss.

Adult↗
PubMed2004

Macular pigment and percentage of body fat.

PURPOSE: To investigate the relationship between percentage of body fat and macular pigment (MP) optical density. METHODS: One hundred healthy subjects of ages between 22 and 60 years volunteered to participate in this study. MP optical density was measured psychophysically, serum lutein and zeaxanthin were quantified by HPLC, and dietary intake of lutein and zeaxanthin was assessed using a validated food frequency questionnaire. Body fat was measured by dual energy x-ray absorptiometry (DEXA); body mass index (BMI) was also calculated for each subject. Clinical and personal details were recorded, with particular attention directed toward putative risk factors for AMD. RESULTS: There was a significant inverse relationship between the percentage of body fat and MP optical density in males (r=-0.392, P <0.01), and after correcting for age and dietary lutein and zeaxanthin, this inverse relationship remained significant (r=-0.290, P <0.05). The relationship between MP optical density and percentage of body fat in females was inverse, but not significant (r=-0.197, P=0.149). A significant and inverse relationship between serum zeaxanthin and percentage of body fat was observed for females only (r=-0.354, P <0.01). Dietary intake of fat was inversely related to serum lutein and zeaxanthin, and significantly so for lutein (r=-0.256, P <0.05). However, dietary fat was unrelated to MP optical density (r=0.041, P=0.688). CONCLUSIONS: A relative lack of MP is associated with adiposity in men, and may underlie the association between body fat and risk for AMD progression in males. Further, the processes governing accumulation and/or stabilization of lutein and zeaxanthin in fat tissue appear to differ for males and females.

Absorptiometry, Photon↗