Daniel Pauleikhoff

Correlation between Biochemical Composition and Fluorescein Binding of Deposits in Bruch's Membrane

PURPOSE The fluorescence of drusen during fluorescein angiography is believed to have important prognostic and pathogenetic implications in age-related maculopathy. It is believed that deposits containing predominantly neutral lipids would be hydrophobic, resulting in hypofluorescence on fluorescein angiography, while the presence of polar phospholipids would be indicated clinically by hyperfluorescence because of its hydrophilic properties. To identify the potential determinants of fluorescence of drusen and Bruchs membrane, a series of macular specimens from human donors older than 60 years of age was examined. No clinical information was available concerning any previous eye disease. METHODS In vitro fluorescein binding was recorded microscopically, and the presence of fibronectin was sought by immunohistochemistry. The results were correlated with the proportions of phospholipids to neutral lipids identified by histochemical and biochemical studies. RESULTS It was found that high content of neutral fats was associated with lack of both fluorescein binding and fibronectin, and, conversely, in those specimens with high proportions of phospholipids, fluorescein binding was strong and fibronectin was present. CONCLUSIONS These observations support the central hypothesis concerning biophysical changes in Bruchs membrane with age and the potential importance of fluorescein angiography in the characterization of Bruchs membrane deposits.

Pigment epithelial detachment in the elderly. Clinical differentiation, natural course and pathogenetic implications.

AbstractBackground. A prospective analysis was performed to characterize the angiographic appearance, natural course and prognosis of serous pigment epithelial detachments (PEDs) in elderly patients. The aim was to differentiate PEDs according to their angiographic characteristics and to analyze the specific clinical, visual and morphologic course of the different PEDs. Methods. Fluorescein and indocyanine green angiography were performed in 101 consecutive patients (53–87 years; 63 female, 38 male) with clinical signs of serous PED and drusen. Results. Different types of serous PED were identified: polypoidal choroidal vasculopathy (PCV)-associated PED in 14 patients (13.9%), vascular PED in 72 (71.2%), and avascular PED in 15 (14.9%). All PEDs resulted initially in similar visual loss. Avascular PEDs were smaller than vascular PEDs, and the latter were smaller than PCV-PEDs. During follow-up these differences were always present, but all PEDs enlarged initially followed by regression. This course was associated in all PEDs with progressive visual loss, accompanied by the development of RPE atrophy in avascular PEDs or disciform scars or RPE tears in the two other types. Conclusion. Despite different associations, all PEDs have a similar clinical course with respect to visual loss and enlargement or regression. This is compatible with the proposed common pathogenetic background with a hydrophobic barrier in Bruchs membrane causing fluid resulting from RPE pumping activity to accumulate between the pigment epithelium and Bruchs membrane.

Classification of abnormal fundus autofluorescence patterns in the junctional zone of geographic atrophy in patients with age related macular degeneration

Aim: To describe and classify patterns of abnormal fundus autofluorescence (FAF) in the junctional zone of geographic atrophy (GA) in patients with age related macular degeneration. Methods: Digital FAF images were recorded in 164 eyes of 107 patients using a confocal scanning laser ophthalmoscope (cSLO; excitation 488 nm, detection above 500 nm) as part of a prospective multicentre natural history study (FAM Study). FAF images were obtained in accordance with a standardised protocol for digital image acquisition and generation of mean images after automated alignment. Results: Image quality was sufficient for classification of FAF patterns in 149 eyes (90.9%) with lens opacities being the most common reason for insufficient image quality. Abnormal FAF outside GA in 149 eyes was classified into four patterns: focal (12.1%), banded (12.8%), patchy (2.0%), and diffuse (57.0%), whereby 12.1% had normal background FAF in the junctional zone. In 4% there was no predominant pattern. The diffuse pattern was subdivided into four groups including reticular (4.7%), branching (27.5%), fine granular (18.1%), and fine granular with peripheral punctate spots (6.7%). Conclusions: Different phenotypic patterns of abnormal FAF in the junctional zone of GA can be identified with cSLO FAF imaging. These distinct patterns may reflect heterogeneity at a cellular and molecular level in contrast with a non-specific ageing process. A refined phenotypic classification may be helpful to identify prognostic determinants for the spread of atrophy and visual loss, for identification of genetic risk factors as well as for the design of future interventional trials.

Correlation between Lipids Extracted from Bruch's Membrane and Age

BACKGROUND There is increasing circumstantial evidence that the chemical composition of the deposits in Bruchs membrane influences the clinical outcome in age-related macular disease. In particular, it has been postulated that deposition of neutral lipids in Bruchs membrane may cause hydrophobicity and predispose to detachment of the retinal pigment epithelium and cause functional loss. METHODS Analysis of the lipid extracted from Bruchs membrane of eye bank eyes from donors of different ages has been undertaken using thin layer and gas chromatography. No clinical information was available concerning any previous eye disease. RESULTS It is shown that the lipid extracted increases with the age of the donor, and that the total quantity and ratio of neutral fats to phospholipids varies widely from one specimen to another from donors older than 60 years of age. The ratios of the different phospholipids imply that they are not derived from blood. CONCLUSION The results are compatible with the concept of hydrophobicity developing with age in Bruchs membrane.

Macular pigment density and distribution: Comparison of fundus autofluorescence with minimum motion photometry

Macular pigment (MP) distribution profiles were measured for 18 subjects using a Moreland anomaloscope modified for motion photometry. The total amount of MP within the central 7 degrees was estimated from the distribution profile by numerical integration. Fundus autofluorescence images were obtained for eight of these subjects using a scanning laser ophthalmoscope. Peak optical density of MP increased with the total amount present, but the correlation was weakened by inter-subject differences in MP distribution. The mean MP distribution derived from mean grey-scale profiles of fundus autofluorescence images correlated closely with that obtained psychophysically (r=0.96). Autofluorescence imaging provides a fast non-invasive method for assessing MP in vivo.

A portable instrument for measuring macular pigment with central fixation.

Purpose. To evaluate the reliability and validity of a portable instrument for measuring macular pigment optical density. Methods. The instrument is small, uses light emitting diodes as light sources and the principles of heterochromatic flicker photometry of comparing foveal and extra-foveal minimum flicker matches. It uses central fixation for the extra-foveal matches, which subjects found easier than eccentric fixation. Subjects with healthy eyes used the instrument to measure their pigment density in a number of eye clinics. Results. The mean pigment density in 124 eyes in 124 individuals was 0.41 ± 0.16 (mean ± SD), there was no significant change with age but the density was less in females, those with light irides, smokers, subjects on diets low in precursor carotenoids and in those exposed to several hours of daylight every day or who used sun beds. Conclusions. The portable instrument gave valid and reliable data that confirmed published values for macular pigment. It was convenient to use in the clinic and has potential as a screening tool.

Aging Changes in Bruch's Membrane

Using histochemical staining techniques and electron microscopy, the authors have examined the histochemical properties and ultrastructure of Bruchs membrane in 30 human eyes with an age range of 1 to 95 years. The results analyzed in three age groups (0-30 years, 31-60 years, and older than 60 years) show that there is a progressive accumulation of lipids in Bruchs membrane with relation to age. Differences were found in the specific types of lipids in individual eyes. Five eyes stained for neutral lipids alone, four stained predominantly for phospholipids, and nine stained intensely for both neutral lipids and phospholipids. The deposits were associated with the progressive destruction of the native architecture of Bruchs membrane but no correlation was identified between specific inclusions in Bruchs membrane with a particular lipid. These results are significant to age-related macular disease (ARMD), and the lipid rich barrier in Bruchs membrane is implicated as a cause of photoreceptor dysfunction and pigment epithelial detachment.

CFH, C3 and ARMS2 are significant risk loci for susceptibility but not for disease progression of geographic atrophy due to AMD

Background Age-related macular degeneration (AMD) is a prevalent cause of blindness in Western societies. Variants in the genes encoding complement factor H (CFH), complement component 3 (C3) and age-related maculopathy susceptibility 2 (ARMS2) have repeatedly been shown to confer significant risks for AMD; however, their role in disease progression and thus their potential relevance for interventional therapeutic approaches remains unknown. Methodology/Principal Findings Here, we analyzed association between variants in CFH, C3 and ARMS2 and disease progression of geographic atrophy (GA) due to AMD. A quantitative phenotype of disease progression was computed based on longitudinal observations by fundus autofluorescence imaging. In a subset of 99 cases with pure bilateral GA, variants in CFH (Y402H), C3 (R102G), and ARMS2 (A69S) are associated with disease (P = 1.6×10−9, 3.2×10−3, and P = 2.6×10−12, respectively) when compared to 612 unrelated healthy control individuals. In cases, median progression rate of GA over a mean follow-up period of 3.0 years was 1.61 mm2/year with high concordance between fellow eyes. No association between the progression rate and any of the genetic risk variants at the three loci was observed (P>0.13). Conclusions/Significance This study confirms that variants at CFH, C3, and ARMS2 confer significant risks for GA due to AMD. In contrast, our data indicate no association of these variants with disease progression which may have important implications for future treatment strategies. Other, as yet unknown susceptibilities may influence disease progression.

Macular pigment: quantitative analysis on autofluorescence images

BackgroundMacular pigment (MP) reduces oxidative damage in the central retina and can be quantified by flicker-photometric analysis (HFP) of MP optical density. These analyses demonstrate a very good correlation with central absorption by MP on autofluorescence (AF) images. With these techniques different types of MP-distribution have been described. In the present study a quantification analysis of MP in AF images was developed to verify these MP types and to compare MP distribution patterns between healthy individuals and those with age-related macular degeneration (AMD).MethodsAF images (HRA) were analysed with respect to the area of central and paracentral absorption in 400 eyes with a computerised analysis program of MP optical density. The patients were between 41 and 90 years old (mean 67.2 years); 168 were male and 232 female, and 253 had early AMD and 147 showed no AMD characteristics. The central MP concentrations (peak) were measured, the amount of MP values within the first 8-pixel radius (“C”), the total amount of MP within a 120-pixel radius (“T”) were calculated as the volume of the MP values over the regarded radius and the C/T ratio was registered.ResultsFour types of MP distribution (type 1, intense central and paracentral MP; type 2, less intense central and paracentral MP; type 3, only central MP; type 4, only paracentral MP) were identified. The differences in MP distribution were confirmed and clearly characterised by quantitative analyses of peak, total MP (“T”), central MP (“C”) and C/T ratio: mean peak in type 1, 0.65; type 2, 0.42; type 3, 0.42; type 4, 0.29; mean total amount of MP in 120-pixel radius (“T”) in type 1, 5829.0; type 2, 4412.5; type 3, 2709; type 4, 4302.8. MP types with lower levels of MP were significantly more often observed in the AMD group (AMD: type 1, 120=47.4%; types 2–4, 133=52.6%; healthy eyes: type 1, 112=76.2%; types 2–4, 35=23.8%) (P<0.0001)ConclusionsAnalysis of MP on AF images is a quantitative method for investigation of MP. With this method a wide variation in concentration and distribution of MP could be seen in the population. Four different types of MP distribution could be characterised and quantitatively distinguished. Reduced levels of MP seem to be associated with a higher risk of development of AMD as they were significantly more often observed in the AMD group. This strategy of quantitative MP analysis on AF images is easily practicable and may be used in further studies to investigate the role of MP as a potential risk factor for AMD.

Economic Burden of Bilateral Neovascular Age-Related Macular Degeneration : Multi-Country Observational Study

BackgroundThere is limited previous research examining the healthcare costs of neovascular age-related macular degeneration (NV-AMD), which constrains our understanding of the economic impact of this condition. With aging populations, this leading cause of rapid vision loss in Western countries is expected to become a pressing health predicament, requiring decision makers to evaluate alternative treatment strategies for AMD.ObjectiveTo document the economic burden of bilateral NV-AMD, the late stage of AMD, in elderly patients, from a societal perspective.Study design, setting and participants: A cross-sectional, observational study surveyed 401 patients with bilateral NV-AMD and 471 non-AMD subjects in Canada, France, Germany, Spain and the UK. Physicians’ records and subjects’ standardized telephone interviews were used to record medical resource utilization, assistance with daily living and social benefits. Annual bilateral NV-AMDrelated socioeconomic costs were calculated in €, year 2005 values. Main outcome measures: Societal costs including direct vision-related medical costs (e.g. treatment of AMD and vision-related equipment), direct non-vision-related medical costs (e.g. medications) and direct non-medical-related costs (e.g. home healthcare and social services) were the main outcome measures.ResultsThe demographic profile of NV-AMD patients was similar across countries; however, co-morbid condition profiles varied. NV-AMD patients reported substantial health-related problems and associated health resource utilization (HRU). In the previous 12 months, 12–22% of patients fell, and half of these patients required medical treatments. More than 20% (range 21–59%) of patients were prescribed vision-enhancing equipment. More than half of the patients (54–81%) were living with a spouse or family member and 19–41% reported receiving assistance for activities of daily living.The average annual societal cost per bilateral NV-AMD patient treated was estimated to be €7879 in Canada, €7349 in France, €12 445 in Germany, €5732 in Spain and €5300 in the UK, and direct vision-related medical costs accounted for 23–63% of the total cost. Half of the patients were diagnosed with bilateral NV-AMD for <1 year, with an average length of 5 months; there were no statistically significant differences in total annual costs per patient between these patients and those who were diagnosed with bilateral disease for ≥1 year. Estimated annual societal costs of bilateral NV-AMD patients in these countries ranged from €268 to €1311 million. Estimated annual societal costs of all NV-AMD patients in these countries ranged from €671 to €3278 million.ConclusionsBilateral NV-AMD imposes significant functional impairment on patients, leading to increased HRU and a high societal cost burden. Differences in national healthcare systems and NV-AMD treatment patterns were reflected in the wide variation of NV-AMD costs across the five surveyed countries. Even though the prevalence rates and per-patient costs varied by country, the societal costs of NV-AMD patients were substantial in each country. Earlier intervention with effective therapies is expected to reduce disease burden and disability associated with NV-AMD and, thus, decrease the overall societal cost.