Influence of macular oedema on the measurement of macular pigment optical density.

INTRODUCTION: The purpose of this study was to determine macular pigment optical density (MPOD) in patients with macular degeneration as well as in patients with non-proliferative diabetic retinopathy. METHODS: Fifty-one phakic patients with either age-related macular degeneration (60 eyes of 30 patients; average age, 70.9 years) or non-proliferative diabetic retinopathy (42 eyes of 21 patients; average age, 61.7 years) were included in this cross-sectional study. Within the groups, patients were divided into those suffering from macular oedema and those with no oedema. An intra-subject comparison between eyes was carried out in both groups. Data were investigated on the basis of the coefficient of determination (R (2)). Macular pigment optical density was measured by fundus reflectometry using the one-wavelength reflection method (Visucam 500; Carl Zeiss Meditec AG, Jena, Germany), in conformity with the method described by Schweitzer et al. (2010). We evaluated the maximum optical density in the measurement area (max OD) and the average optical density across the reference area in the measurement area (mean OD). Specifically, the influence of macular oedema on macular pigment optical density was examined. The subsequent measurement of retinal thickness was carried out by spectral-domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering GmbH, Heidelberg, Germany). RESULTS: The current study included two groups. The first group consisted of patients with non-proliferative diabetic retinopathy, as follows: no macular oedema on either side (max OD: R (2) = 43.2 %, p = 0.16; mean OD: R (2) = 68.7 %, p = 0.04); one-sided macular oedema (max OD: R(2) = 16 %, p = 0.60; mean OD: R(2) = 100 %, p = 0.04); or macular oedema in both eyes (max OD: R(2) = 79.7 %, p < 0.01; mean OD: R(2) = 81.4 %, p < 0.01). The second group comprised patients with age-related macular degeneration (AMD), as follows: non-exudative changes on both sides (max OD: R(2) = 64.0 %, p = 0.20; mean OD: R (2) = 16 %, p = 0.60); one-sided exudative macular changes (max OD: R (2) = 50.6 %, p < 0.01; mean OD: R (2) = 20.8 %, p = 0.04); or exudative macular degeneration on both sides (max OD: 3 R (2) = 6.0 %, p = 0.29; mean OD: R (2)= 81.0 %, p = 0.04). The data available presented a correlation of MPOD values of both eyes of an individual within the groups investigated. In this respect, the data of the partner eyes within the group of patients with diabetic retinopathy were more highly correlated with each other than the values of both eyes of patients suffering from age-related macular degeneration. CONCLUSIONS: The present study showed that macular oedema did not seem to have an influence on a valid measurement of MPOD by one-wavelength fundus reflectometry. Thus, meaningful data could also be obtained on patients with exudative retinal changes.

Biometry and visual function of a healthy cohort in Leipzig, Germany.

BACKGROUND: Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany. METHODS: Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies. RESULTS: The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL -0.19 (0.006), ACD -0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (-0.66 (< 0.001)), ACD (-0.52 (< 0.001)) and ACV (-0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = -0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF -0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age. CONCLUSION: Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research. TRIAL REGISTRATION: ClinicalTrials.gov # NCT01173614 July 28, 2010.

Macular pigment optical density measurements by one-wavelength reflection photometry--influence of cataract surgery on the measurement results.

PURPOSE: The main objective of the present study was the investigation of possible influence of lens opacification on macular pigment optical density (MPOD) measurements. METHODS: Eighty-six eyes of 64 patients (mean age 73.4 ± 8.3 years) were included in the study. MPOD was prospectively measured using the one-wavelength reflection method (Visucam500, Carl Zeiss Meditec AG) before and after cataract extraction, with implantation of a blue-light filtering intraocular lens (AlconSN60WF). The median of the maximum optical density (MaxOD) and the median of the mean optical density (MeanOD) measurements of macular pigment across the subject group were evaluated. RESULTS: Statistically significant differences were noticed between pre-operative and post-operative measurements, the absolute values were generally lower after cataract extraction. The following median (lower/upper quartile) differences across the group were determined: MaxOD -33.8 % (-46.2 to -19.1 %), MeanOD -44.0 % (-54.6 to -26.6 %). Larger changes were observed in elderly patients [<70 years of age (n = 25 eyes): MaxOD -13.4 % (-20.5 to 3.6 %), MeanOD -23.6 % (-30.5 to -15.3 %) versus patients ≥70 years (n = 61 eyes) MaxOD -40.5 % (-53.2 to -30.1 %), MeanOD -47.2 % (-57.8 to -40.1 %)] and in patients with progressed stage of cataract. MaxOD for lens opacification grade 1 (n = 9 eyes): -27.4 % (-42.1 to -19.6 %), grade 2 (n = 26 eyes): -35.0 % (-44.2 to -25.3 %), grade 3 (n = 21 eyes): -34.4 % (-45.4 to -11.4 %), grade 4 (n = 25 eyes): -32.6 % (-53.2 to -6.4 %), and grade 5 (n = 5 eyes): -53.5 % (-61.7 to -38.7 %) and MeanOD for cataract stage 1 (n = 9 eyes): -42.6 % (-46.0 to -26.0 %), stage 2 (n = 26 eyes): -44.1 % (-51.8 to -26.2 %), stage 3 (n = 21 eyes): -45.7 % (-54.7 to -24.7 %), stage 4 (n = 25 eyes): -39.5 % (-59.4 to -26.1 %), and stage 5 (n = 5 eyes): -57.0 % (-66.1 to -51.4 %). CONCLUSIONS: As established by comparison of pre- to post-operative measurements, cataract presented a strong effect on MPOD measured by one-wavelength reflection method. Particular care should therefore be taken when evaluating MPOD using this method in elderly patients with progressed stage of cataract. Future optimization of correcting parameters of scattered light and consideration of cataract influence may allow more precise evaluation of MPOD.

Long term effects of lutein, zeaxanthin and omega-3-LCPUFAs supplementation on optical density of macular pigment in AMD patients: the LUTEGA study.

BACKGROUND: The primary objective of LUTEGA is to determine the long-term effect of a supplementation with fixed combination of lutein, zeaxanthin, omega-3-longchain-polyunsaturated-fatty-acids (O-3-LCPUFAs) and antioxidants on macular pigment optical density (MPOD) in patients with non-exudative age-related macular degeneration (AMD). METHODS: The LUTEGA study is a double-blind, placebo-controlled clinical trial. 172 patients with non-exudative AMD were enrolled and randomized to three treatment arms. Supplementation included either once (dosage D1) or twice daily (dosage D2) of 10 mg L / 1 mg Z/ O-3-LCPUFAs (thereof 100 mg DHA, 30 mg EPA)/ antioxidants, or placebo (P). After best-corrected visual acuity (BCVA) test, blood sample was collected and MPOD was measured using the 1-wavelength-reflection method and recording reflection images at 480 nm (modified Visucam(NM/FA), Carl Zeiss Meditec, Germany). During 1 year of intervention, AMD patients were followed up after 1, 3, 6 and 12 months. 145 AMD patients (D1 = 50, D2 = 55, P = 40) completed the study. RESULTS: After 12 months of intervention, the MPOD parameters (volume, area, maxOD, meanOD) increased significantly in treatment arms D1 and D2 (p < 0.001). Volume of MPOD showed the highest within-group difference and increased significantly in D1 and D2, and decreased significantly in P (p = 0.041). Between-group comparison of absolute changes of all MPOD parameters were significantly different between D1 and P as well as D2 and P with p < 0.001 at end point (t = 12). BCVA, measured in log MAR, improved in D1 and in D2 (p < 0.001). After 12 months of intervention, the mean improvement in BCVA was significant in D2 (p = 0.006) and D1 (p = 0.038) compared to P. CONCLUSIONS: The supplementation of L, Z, O-3-LCPUFAs and antioxidants resulted in considerable increase in MPOD. There was no difference in accumulation of MPOD between both dosages. Thus, we believe that the used supplementation with L and Z seems to reach a saturation level in retinal cell structure. Additionally, the constant supplementation of L, Z, O-3-LCPUFAs and antioxidants in AMD patients seems to be useful, because MPOD reduces without supplementation. We conclude that the supplementation caused an increase of MPOD, which results in an improvement and stabilization in BCVA in AMD patients. Thus, a protective effect on the macula in AMD patients is assumed.

Photodynamic properties of vital dyes for vitreoretinal surgery.

The purpose of this study was to evaluate photodynamic properties of indocyanine green (ICG), brilliant blue G (BBG) and trypan blue (TB) as currently used vital dyes for chromovitrectomy. Under consideration of intraoperative illumination intensities and dye concentrations, a simulative in vitro investigation was set up. Therefore, standardized dilutions of original ICG, BBG and TB vials were irradiated at a wavelength of 366 nm with an intensity of 14 µW/cm2 between 0 and 48 h. After this, all samples were measured spectroscopically in a 220- to 750-nm bandwidth. Analyzing the vital dyes over the time course, an exponential photolysis was observed for ICG, whereas BBG and TB presented photostable properties. Regarding ICG, 5% of the concentration was degraded to toxic metabolites every 20 min. For this reason, our study provides evidence that intraocular dye concentrations and modern endoillumination systems alone cannot fully prevent ICG photodegradation.

Determination of absolute size of fundus objects.

BACKGROUND: Creating multiple beam interference fringes on the retina using the "retina fringe projector" (RFP) provides us with a scale which can be used to determine the absolute size of objects at the fundus. METHODS: The procedure is tested on an model eye, the optical parameters of which are varied in order to simulate different refraction conditions. The RFP was used to determine the size of a known object at the model fundus; the result was then checked against the real value of the object. In a second series of measurements, the RFP fringes were included in fundus photos of 52 patients with varying levels of ametropia, taken at the University Eye Clinic in Jena using the FF450 fundus camera (manufacturer: Carl Zeiss Meditec AG) for diagnostic purposes. The distance between the fringes was determined using both the RFP and the Littmann method. RESULTS: The differences to the real value of the fundus size of a known object deviated on average by 1 to 2%, and always remained under 3% in the model eye. A very good correlation between RFP and Littmann methods results could be found in the clinical part of the study. The resulting deviations are below 2.5%. CONCLUSION: Integration of a RFP in a fundus camera permits measurement of absolute values of the retina, regardless of the type of observation or documentation. Knowing the real size of fundus objects holds a potential in many clinical classification scales of fundus objects such as drusen or vessels, or in optimizing photodynamic therapy spot size measurement.

Ultrastructure of the membrana limitans interna after dye-assisted membrane peeling.

The purpose of this study was to investigate the ultrastructure of the membrana limitans interna (internal limiting membrane, ILM) and to evaluate alterations to the retinal cell layers after membrane peeling with vital dyes. Twenty-five patients (25 eyes) who underwent macular hole surgery were included, whereby 12 indocyanine green (ICG)- and 13 brilliant blue G (BBG)-stained ILM were analyzed using light, transmission electron and scanning electron microscopy. Retinal cell fragments on the ILM were identified in both groups using immunohistochemistry. Comparing ICG- and BBG-stained membranes, larger cellular fragments were observed at a higher frequency in the BBG group. Thereby, the findings indicate that ICG permits an enhanced separation of the ILM from the underlying retina with less mechanical destruction. A possible explanation might be seen in the known photosensitivity of ICG, which induces a stiffening and shrinkage of the ILM but also generates retinal toxic metabolites.

Diabetic patients with retinopathy show increased retinal venous oxygen saturation.

BACKGROUND: Longstanding diabetes mellitus results in a disturbed microcirculation. A new imaging oximeter was used to investigate the effect of this disturbance on retinal vessel oxygen saturation. METHODS: The haemoglobin oxygen saturation was measured in the retinal arterioles and venules of 41 diabetic patients (65 +/- 12.3 years) with mild non-proliferative through proliferative diabetic retinopathy (DR). Twelve individuals (61.3 +/- 6.2 years, mean +/- standard deviation) without systemic or ocular disease were investigated as controls. Measurements were taken by an imaging oximeter (oxygen module by Imedos GmbH, Jena). This technique is based on the proportionality of the oxygen saturation and ratio of the optical density of the vessel at two wavelengths (548 nm and 610 nm). RESULTS: Whereas there were no significant differences in the arterial oxygen saturation between controls and diabetic retinopathy at any stage, the venous oxygen saturation increased in diabetic patients with the severity of the retinopathy: controls 63 +/- 5%, mild non-proliferative DR 69 +/- 7%, moderate non-proliferative DR 70 +/- 5%, severe non-proliferative DR, 75 +/- 5%, and proliferative DR 75 +/- 8%. CONCLUSIONS: The increase of retinal vessel oxygen saturation in diabetic retinopathy points to a diabetic microvascular alteration. This may be due to occlusions and obliterations in the capillary bead and the formation of arterio-venous shunt vessels. On the other hand, hyperglycaemia-induced endothelial dysfunction, with subsequent suppression of the endothelial NO-synthase and disturbance of the vascular auto-regulation, may contribute to retinal tissue hypoxia.

Retinal fluorescence lifetime imaging ophthalmoscopy measures depend on the severity of Alzheimer's disease.

PURPOSE: To determine alterations in the retina of patients with Alzheimer's disease (AD) by the newly developed technique of fluorescence lifetime imaging ophthalmoscopy (FLIO) in a pilot study. METHODS: FLIO set-up uses a scanning laser ophthalmoscope (HRA2, Heidelberg Engineering, Germany), which was modified by the use of an excitation pulse laser BLD440 (Becker&Hickl, Berlin, Germany) and detection of fluorescence lifetime by time-correlated single photon counting (TCSPC; Becker&Hickl) in two spectral channels (channel 1: 490-560 nm, channel 2: 560-700 nm). Least square fit of three exponential functions was used for fluorescence decay analysis. That resulted in three fluorescent components with lifetimes τi , amplitudes αi and relative contributions Qi . 16 patients with AD (mean age 77.2 ± 7.0 years) were investigated. After regular ophthalmic investigation, FLIO examination and OCT examination were performed. Alzheimer-specific clinical data were collected (MMSE, cerebrospinal fluid (CSF) concentration of amyloid-ß (1-42), total-tau and phosphorylated tau181 (p-tau181) protein). RESULTS: The FLIO parameters of the second fluorescent component α2 and Q2 (channel 2) correlated significantly with MMSE score (Q2 , R = -0.757, p = 0.007; α2 , R = -0.618, p = 0.043) as well as p-tau181-protein concentration in CSF (Q2 , R = 0.919, p = 0.009; α2 , R = 0.881, p = 0.020) in patients with AD. OCT measurements of retinal nerve fibre layer thickness, optic disc excavation and macular thickness neither correlated with Alzheimer-specific CSF data nor MMSE score. CONCLUSIONS: Unlike conventional techniques, such as OCT, the new technique of FLIO revealed changes in the retina of patients with AD in relation to Alzheimer-specific markers in this pilot study.

Fluorescence lifetime imaging ophthalmoscopy in type 2 diabetic patients who have no signs of diabetic retinopathy.

The time-resolved autofluorescence of the eye is used for the detection of metabolic alteration in diabetic patients who have no signs of diabetic retinopathy. One eye from 37 phakic and 11 pseudophakic patients with type 2 diabetes, and one eye from 25 phakic and 23 pseudophakic healthy subjects were included n the study. After a three-exponential fit of the decay of autofluorescence, histograms of lifetimes τ(i), amplitudes α(i), and relative contributions Q(i) were statistically compared between corresponding groups in two spectral channels (490 < ch1 < 560 nm, 560 < ch2 < 700 nm). The change in single fluorophores was estimated by applying the Holm­Bonferroni method and by calculating differences in the sum histograms of lifetimes. Median and mean of the histograms of τ(2), τ(3), and α(3) in ch1 show the greatest differences between phakic diabetic patients and age-matched controls (p < 0.000004). The lack of pixels with a τ(2) of ∼360 ps, the increased number of pixels with τ(2) > 450 ps, and the shift of τ(3) from ∼3000 to 3700 ps in ch1 of diabetic patients when compared with healthy subjects indicate an increased production of free flavin adenine dinucleotide, accumulation of advanced glycation end products (AGE), and, probably, a change from free to protein-bound reduced nicotinamide adenine inucleotide at the fundus. AGE also accumulated in the crystalline lens.

Methylglyoxal-derived hydroimidazolone advanced glycation end-products of human lens proteins.

PURPOSE: To determine the concentrations of methylglyoxal-derived advanced glycation end-products (AGEs), the hydroimidazolones MG-H1 and -H2, in soluble human lens proteins and compare them with the concentrations of other methylglyoxal-derived AGEs and pentosidine. METHODS: Lens protein samples were hydrolyzed enzymatically. AGEs were assayed without derivatization by HPLC with tandem mass spectrometry; the fluorescent AGEs argpyrimidine and pentosidine were assayed by fluorometric detection. MG-H1 and -H2 were resolved and assayed by fluorometric detection after derivatization with 6-aminoquinolyl-N-hydroxysuccimidylcarbamate (AQC). RESULTS: The methylglyoxal-derived hydroimidazolones MG-H1 and -H2 were detected and quantified in human lens proteins. AGE concentrations (mean +/- SEM) were: MG-H1 4609 +/- 411 pmol/mg protein, MG-H2 3085 +/- 328 pmol/mg protein, argpyrimidine 205 +/- 19 pmol/mg protein, and pentosidine 0.693 +/- 0.104 pmol/mg protein. The concentration of MG-H1 in human lens protein correlated positively with donor age (correlation coefficient = 0.28, P < 0.05), the concentration of MG-H2 (correlation coefficient = 0.78, P < 0.001) and argpyrimidine (correlation coefficient = 0.42, P < 0.01). The concentrations of AGEs were increased in cataractous lenses in comparison with noncataractous lenses: the increases were MG-H1 85%, MG-H2 122%, argpyrimidine 255%, and pentosidine 183% (P < 0.001). Multiple logistic regression analysis showed a significant link of cataract to donor age (regression coefficient beta = 0.094, P = 0.026) and argpyrimidine (beta = 0.022, P = 0.002). CONCLUSIONS: Methylglyoxal hydroimidazolones are quantitatively major AGEs of human lens proteins. These substantial modifications of lens proteins may stimulate further glycation, oxidation, and protein aggregation leading to the formation of cataract.

Advanced glycation end-products in anterior chamber aqueous of cataractous patients.

PURPOSE: To investigate whether the advanced glycation end-products (AGEs) pentosidine, N( epsilon )-(carboxymethyl)lysine (CML), and imidazolone are present in the aqueous of cataract patients and how AGE levels correlate to cataract type or the diabetic condition of the patient. SETTING: Departments of Ophthalmology and Internal Medicine, University of Jena, Jena, Germany. METHODS: Aqueous and serum samples from 77 cataractous patients (33 nondiabetics, 44 diabetics; 14 with dense posterior, 63 with nuclear cataracts) were investigated. The mean age of the patients was 69 years +/- 14 (SD). The aqueous protein concentration was examined using a laser flare-cell meter. In the samples, pentosidine was measured by high-performance liquid chromatography and CML using a competitive enzyme-linked immunosorbent assay. Western blot analysis was used to detect imidazolone, pentosidine, and CML in the aqueous. RESULTS: The aqueous samples contained CML, pentosidine, or imidazolone. These AGEs occurred mainly bound to albumin. Significant correlations existed between serum pentosidine and aqueous CML and flare levels as well as between serum and aqueous CML. Patients with nuclear cataract had insignificantly higher pentosidine and CML levels than patients with posterior cataract, whereas the flare was significantly higher. No significant differences were found between the aqueous AGE levels in nondiabetic and diabetic patients. CONCLUSIONS: The aqueous of cataractous eyes contained the AGEs CML, pentosidine, and imidazolone. All 3 AGEs occurred mainly albumin-bound, providing evidence they may originate from the blood. Further investigation is needed to determine the relevance of aqueous AGEs in cataractogenesis.

Increased levels of advanced glycation end products in human cataractous lenses.

PURPOSE: To investigate the occurrence of advanced glycation end products (AGEs) formed oxidatively (pentosidine and N(epsilon)-carboxymethyl lysine [CML]) or nonoxidatively (imidazolone) in human lenses and the relation of AGEs to lens coloration, cataract type, and patients' diabetic state. SETTING: Departments of Ophthalmology and Internal Medicine III, University of Jena, Jena, Germany. METHODS: Pentosidine, CML, and imidazolone concentrations were measured in the water-soluble protein fraction of 44 cataractous lenses (from 24 nondiabetic and 20 diabetic donors) and 6 noncataractous control lenses. RESULTS: Pentosidine, CML, and imidazolone were higher in cataractous lenses than in control lenses (pentosidine, 3.7 pmol/mg +/- 5.3 (SD) and 1.9 +/- 1.7 pmol/mg, respectively; CML, 3.0 +/- 2.2 nmol/mg and 1.3 +/- 0.7 nmol/mg, respectively; imidazoline, 80.4 +/- 93.3 AU/mg and 19.6 +/- 18.5 AU/mg, respectively). Among the cataractous lenses, the highest AGE concentrations were found in mature cataracts, with a statistically significant increase in CML. The AGE content increased relative to the intensity of brown coloration of the lens; the brown coloration also indicated the highest rise of imidazolone compared to pentosidine and CML. Lenses from diabetic donors had generally similar pentosidine values and elevated CML and imidazolone levels compared to lenses from nondiabetic donors. The pentosidine, CML, and imidazolone levels in the lenses correlated significantly with one another but not with patient age. CONCLUSION: Advanced glycation end products formed oxidatively and nonoxidatively occurred to a higher degree in cataractous lenses than in noncataractous lenses. The strong relationship between the lenses' AGE content, color/opacity, and the state of the cataract may indicate that advanced glycation plays a pivotal role in cataract formation.

Age-related macular degeneration: Effects of a short-term intervention with an oleaginous kale extract--a pilot study.

OBJECTIVE: Age-related macular degeneration (AMD) is a multifactorial degenerative disease of the retina, which accounts for slowly progressive visual impairment in the elderly. An increased dietary intake of xanthophylls is suggested to be inversely related to the risk of macular disease. METHODS: The present study was designed as a randomized, double-blind, placebo-controlled, parallel trial examining the influence of a short-term intervention with an oleaginous extract of Brassica oleracea var. sabellica L. (kale) on plasma xanthophyll concentrations and the optical density of the macular pigment xanthophylls (MPOD). Twenty patients with non-exudative AMD were recruited for a 10-wk study period (2-wk run-in, 4-wk intervention, 4-wk washout). All participants received 50 mL of a beverage containing either an oleaginous extract of kale (kale) or refined rapeseed oil (placebo). The verum product provides 10 mg lutein and 3 mg zeaxanthin per day. RESULTS: The concentrations of the xanthophylls in plasma and the MPOD increased significantly in the kale group after 4 wk of intervention. The successive washout period resulted in a significant decline of the values in plasma and macula. The values at the end of the study were still significantly higher than the initial values. Nevertheless, the improvements did not persist over 4 wk of washout. CONCLUSION: The distribution of the xanthophylls in the macula seems to be more dynamic than originally assumed.

Scanning electron microscopic characteristics of commercially available 1- and 3-piece intraocular lenses.

PURPOSE: To evaluate commercially available 1- and 3-piece intraocular lenses (IOLs) with scanning electron microscopy (SEM). SETTING: Department of Ophthalmology and Electron Microscopy Center, University Hospital Jena, Jena, Germany. DESIGN: Experimental study. METHODS: Seven +23.0 diopter IOLs of different design and material and from different manufacturers were chosen for a detailed assessment. Scanning electron microscopy was used at standardized magnifications to assess typical IOL characteristics. The particular focus was the optic edge, the optic surface, the haptic­optic junction, and the haptic. RESULTS: All square-edged IOLs had a curvature radius of less than 10 µm, while the mean optic edge thickness ranged between 216 µm and 382 µm. A 360-degree square-edged boundary was present in all 3-piece IOLs and in a single 1-piece model. Relevant production remnants on the optic edge were observed in 1 case. Regarding the haptic, 3-piece IOLs had uniformly shaped fibers with a mean thickness of 177 µm ± 51 (SD) (range 116 to 220 µm). Chemical adhesives were used to attach the haptic in 1 case, where alterations of the IOL material were observed. In another case, the haptic fiber was press-fitted into the optic, which resulted in bulging of the optic profile. Inspection of surface characteristics showed wavelike patterns in 2 IOLs. CONCLUSIONS: Taking clinical relevance into account, all IOLs were of high manufacturing quality. Certain attention was paid in creating a sharp optic edge. Surface irregularities of 2 IOLs were attributed to the manufacturing technique. Methods for implementing the haptic­optic junction were diverse.

Macular xanthophylls and ω-3 long-chain polyunsaturated fatty acids in age-related macular degeneration: a randomized trial.

IMPORTANCE: It has been shown that the functionality of the macula lutea depends on the nutritional uptake of lutein and zeaxanthin and that it is inversely associated with the risk of age-related macular degeneration (AMD). Additionally, ω-3 long-chain polyunsaturated fatty acids (LC-PUFAs) may also be protective. OBJECTIVE: To investigate the effect of a 12-month intervention with macular xanthophylls and ω-3 LC-PUFAs on xanthophylls and fatty acids in plasma, antioxidant capacity, and optical density of the macular pigment of patients with nonexudative AMD. DESIGN: The LUTEGA study was a randomized, double-blind, placebo-controlled, parallel clinical trial that was conducted for 12 months. SETTING: University Eye Hospital and Institute of Nutrition, Friedrich Schiller University Jena, Germany. PARTICIPANTS: A total of 172 individuals with nonexudative AMD. INTERVENTION: Individuals were enrolled and randomly divided as follows: placebo group, group 1 (a capsule containing 10 mg of lutein, 1 mg of zeaxanthin, 100 mg of docosahexaenoic acid, and 30 mg of eicosapentaenoic acid administered each day), and group 2 (same substances but twice the dose used in group 1). One hundred forty-five participants completed the study successfully. MAIN OUTCOME MEASURES: Plasma xanthophyll concentrations and fatty acid profiles, optical density of the macular pigment, and antioxidant capacity in plasma (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [Trolox] equivalent antioxidant capacity and photochemiluminescence). RESULTS: The concentrations of the administered carotenoids in plasma as well as the optical density of the macular pigment increased significantly in the groups randomized to receive supplementary macular xanthophylls and ω-3 LC-PUFAs after 1 month of intervention and remained at this level through the end of the study. Use of the double dose resulted in a beneficial alteration of the fatty acid profile in the plasma of patients with AMD in comparison with the dose in group 1. The lipophilic antioxidant capacity in plasma was significantly elevated with the intervention. CONCLUSIONS AND RELEVANCE: A supplement containing a fixed combination of lutein, zeaxanthin, and ω-3 LC-PUFAs during 12 months significantly improved plasma antioxidant capacity, circulating macular xanthophyll levels, and the optical density of the macular pigment. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00763659.

Optical coherence tomography as a diagnostic tool for retinal pathologies in avian ophthalmology.

PURPOSE: Optical coherence tomography (OCT) is an established diagnostic tool for retinal pathologies in human eyes and has been adapted to small animal models. However, there have been only a few attempts to use OCT for examination of avian eyes, and little is known about structural details of healthy or pathologically affected retinas in living birds. METHODS: We used SD-OCT (high-resolution spectral domain OCT) to investigate eyes of various avian species including birds of prey. The birds were anesthetized by isoflurane application during OCT examination. Eyes of a common buzzard (Buteo buteo) could be used for a comparative analysis of OCT images and histologic/immunohistochemical examinations. RESULTS: We investigated 45 wild and domestic birds (25 different species, 40 g-7.7 kg body mass) without and with diverse pathologic indications (e.g., body or head trauma). Animals were generally and ophthalmologically examined, and the diagnostic findings of direct ophthalmoscopy and OCT were compared. The OCT examination revealed an increased number of animals with clinical findings and allowed a detailed assessment of structural changes in retinal and choroidal tissue compared to simple direct ophthalmoscopy. Common findings were retinal and choroidal degeneration, retinal detachment, choroidal schisis, drusen, and drusenoid changes. Histologic and immunohistochemical analysis of retinal tissue confirmed the findings of the OCT examination. CONCLUSIONS: Spectral domain OCT of eyes in living birds is applicable and useful as a diagnostic tool in veterinary clinical practices and for vision research in general. Optical coherence tomography improves the quality of the common assessment methods in avian ophthalmology, and expands the diagnostic possibilities with respect to identification and prognosis of diseases. This will be particularly important for hereditary retinal defects, especially of precious breeding individuals, or estimation of treatment success in traumatized wild birds with the aim of release back into the wild.

Retinal vessel oxygen saturation under flicker light stimulation in patients with nonproliferative diabetic retinopathy.

PURPOSE: We investigated the response of retinal vessel diameters and oxygen saturation to flicker light stimulation of neuronal activity in patients with diabetic retinopathy. METHODS: We included 18 patients with nonproliferative diabetic retinopathy (mean age 62.2 ± 8.3 years, diabetes type 1 in 4 patients and type 2 in 14, hemoglobin A1c 7.7 ± 0.9%, duration of diabetes 24.1 ± 9.3 years) and 20 age-matched healthy controls (age 66.7 ± 10.3 years). Dual wavelength (548 and 610 nm) fundus images were taken before and during luminance flicker stimulation (12.5 Hz, modulation depth > 1:25) for 90 seconds. Diameters (central retinal arterial [CRAE] and venous [CRVE] equivalents) and oxygen saturation (SO(2)) were determined, and averaged for all arterioles and venules in an annular area centered at the optic disk. RESULTS: Flicker light increased CRAE, CRVE, and venous SO(2) by 0.6 ± 6.6%, 2.7 ± 6.1%, and 2.0 ± 2.4% (P < 0.05), respectively, in the patients as well as 4.7 ± 8.4% (P < 0.05), 8.7 ± 5.2% (P < 0.05), and 4.2 ± 3.5% (P < 0.05), respectively, in the controls. The arterial SO(2) remained unchanged in both groups. The increase of the venous SO2 correlated significantly (P = 0.027) with that of the CRAE. There was a trend (P = 0.06) for lower increase of the venous SO(2) with higher body mass index. CONCLUSIONS: Our results support the thesis of an impaired regulation of oxygen supply to the diabetic retina. Whereas in healthy subjects the stimulation of neuronal activity increases the vascular diameters and, subsequently, the oxygen supply, this increase is reduced in diabetic retinopathy. This may hint at the role of endothelial dysfunction in the etiology of the disease.

Retinal venous oxygen saturation increases by flicker light stimulation.

PURPOSE: Luminance flicker stimulation of the photoreceptors is known to increase retinal blood flow. Elevated blood velocity was determined using laser Doppler velocimetry, and increased vascular diameters during flicker were observed by measurements with a retinal vessel analyzer. Oxygen supply may be the target of the regulation of retinal blood flow. Thus, the oxygen saturation (SO(2)) in retinal arterioles and venules was investigated along with their diameters. METHODS: Dual-wavelength (548 nm and 610 nm) fundus images were taken in 19 healthy volunteers (mean age, 26 ± 2.5 years) before (baseline) and during luminance flicker stimulation (12.5 Hz; modulation depth, 1:25). Retinal vessel SO(2) (dual-wavelength optical oximetry) and diameters (central retinal arterial and venous equivalents [CRAE and CRVE]) were determined. RESULTS: CRAEs and CRVEs of 193 ± 20 µm and 228 ± 20 µm at baseline increased statistically significant to a maximum of 202 ± 19 µm (P < 0.0005) and 242 ± 17 µm (P < 0.0005), respectively, under flicker stimulation. Although the arterial SO(2) remained unchanged at 98%-99%, an increase of the venous saturation from 60% ± 5.7% to 64% ± 5.9% (P < 0.0005) was found. CONCLUSIONS: In agreement with earlier investigations, the vessel dilation found here indicates an elevation of retinal blood flow by luminance flicker stimulation. This increase of the flow should meet the enhanced metabolic need of the neural retina under a physiological stimulus. The augmentation of venous oxygenation may indicate a higher capillary oxygen concentration, necessary to provide a sufficient diffusion rate of oxygen from the capillaries to the inner retinal tissue.

Differential expression of tetraspanin CD9 in basal cell and squamous cell carcinomas of the skin and actinic keratosis.

Tetraspanins are potentially useful molecular markers that differentiate between tumour classes and subtypes, since members of this protein family were often found to be altered during malignant conversion and tumour progression. In this study, we analysed expression of the tetraspanin CD9 in the frequent cutaneous neoplasms basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and actinic keratosis (AK), which is considered a precursor lesion (carcinoma in situ) from which an invasive SCC can develop. A moderate to strong CD9-specific staining of the tumour cells' plasma membranes was uniquely observed in all BCCs, SCCs and AKs. All SCCs showed additional intracellular CD9 which was rarely (20%) seen in AKs. Semi-quantitative assessment of CD9 present in the plasma membranes of tumour cells of BCCs (mean staining intensity 1.91) and SCCs (3.64) reflected the different CD9 expression of normal precursor cells from which these tumours most likely originate. Although considered an intermediate stage in the development of SCCs, AKs did not show intense staining of the plasma membranes typical of normal keratinocytes or invasive SCCs (p=0.011) but only moderate intensity (mean 1.63). In BCCs, significantly (p=0.0005, n=56) stronger CD9-specific immunoreactivity was seen in the inner regions of the tumours than at their sites of expansion. In summary, our results point to an important role of CD9 at the front of tumour expansion in BCCs and SCCs, and in the pathogenesis of invasive SCCs.