Philipp L. Müller

Quantitative Fundus Autofluorescence in Early and Intermediate Age-Related Macular Degeneration

IMPORTANCE Increased lipofuscin accumulation is assumed to be an important factor in the pathogenesis of age-related macular degeneration (AMD), although direct evidence for this hypothesis is missing. OBJECTIVE To quantitatively investigate lipofuscin-associated fundus autofluorescence (AF) in patients with early and intermediate AMD. DESIGN, SETTING, AND PARTICIPANTS A prospective, single-center, case-control study was conducted from August 1, 2014, to October 31, 2015, at a university referral center. Participants included 40 patients aged 65 years or younger and 108 individuals without eye disease serving as controls. All participants underwent quantitative fundus AF (qAF) imaging with a modified scanning laser ophthalmoscope equipped with an internal fluorescent reference. Mean qAF values of an 8-segment circular ring centered on the fovea (qAF8) were measured and compared between patients and controls. For subgroup analysis, drusen were categorized as soft drusen, cuticular drusen, and/or reticular pseudodrusen (RPD). MAIN OUTCOMES AND MEASURES The qAF8 levels. RESULTS In the 40 patients with AMD, mean (SD) age was 54.8 (5.6) years, and 32 (80%) were women. None of the investigated patients had qAF8 values above the 95% prediction interval (PI) of the 108 controls. In the soft drusen (28 [70%]) and cuticular drusen (8 [20%]) groups, qAF8 levels within the 95% PI were noted in 22 patients (79%; 95% CI, 60% to 90%) and 7 patients (88%; 95% CI, 51% to 99%) respectively. The qAF8 values in the RPD group (4 [10%]) were below the 95% PI in 3 patients (75%; 95% CI, 29% to 97%). Compared with the controls, statistical analysis revealed lower qAF8 values in the overall AMD cohort after adjusting for age (difference, -19.9% [95% CI, -25.6% to -12.7%], P < .001) as well as in all subgroups (soft drusen, -17.1% [95% CI, -24.1% to -9.5%], P < .001; cuticular drusen, -19.6% [95% CI, -30.3% to -7.2%], P = .003; and RPD, -34.5% [95% CI, -47.1% to -21.3%]; P < .001). CONCLUSIONS AND RELEVANCE The qAF8 measurements in this sample showed no increased lipofuscin-related fundus AF in patients with early and intermediate AMD. Lower qAF levels in certain subgroups may point to subnormal lipofuscin levels in the retinal pigment epithelium or, alternatively, limitations to detection of true retinal pigment epithelial lipofuscin content. The results of this study might expand the understanding of the pathogenesis of AMD and may have an effect on upcoming treatment trials that aim to modify lipofuscin accumulation.

Reticular Pseudodrusen in Sorsby Fundus Dystrophy

PURPOSE To investigate the association of reticular pseudodrusen (RPD) with Sorsby fundus dystrophy (SFD). DESIGN Prospective, monocenter, cross-sectional case series. SUBJECTS Sixteen patients of 4 unrelated families with SFD caused by mutations in TIMP3. METHODS All subjects underwent multimodal imaging including near-infrared (NIR) reflectance and fundus autofluorescence with a confocal scanning laser ophthalmoscope and spectral-domain optical coherence tomography (SD OCT). MAIN OUTCOME MEASURES Prevalence, topographic distribution, and phenotype of RPD. RESULTS Mean age of the investigated patients was 56.8 years (range, 23-78 years). Reticular pseudodrusen were identified frequently in SFD patients in the sixth decade of life (5 of 7 [71%]) and were absent in younger (n = 3) or older (n = 6) patients. They were most abundant in the superior quadrant and spared the foveal region. Reticular pseudodrusen appeared as yellowish round to oval (dot subtype; n = 5) or confluent, wriggled (ribbon subtype; n = 3) lesions, sometimes forming irregular networks. Reticular pseudodrusen were hyporeflective on NIR reflectance and hypofluorescent on fundus autofluorescence imaging. They appeared as subretinal deposits on SD OCT imaging. Other lesions, such as peripheral pseudodrusen and soft drusen, were present less frequently. CONCLUSIONS Reticular pseudodrusen are a frequent finding in patients with SFD. Although SFD patients with RPD are younger, distribution and phenotype of RPD are similar to those observed in patients with age-related macular degeneration. The association of RPD with SFD implicates a role of Bruchs membrane, the Bruchs membrane-retinal pigment epithelium interface, or both in the pathogenesis of RPD.

Sorsby Fundus Dystrophy: Novel Mutations, Novel Phenotypic Characteristics, and Treatment Outcomes

PURPOSE To report novel TIMP3 mutations, and to characterize the ocular phenotype of Sorsby fundus dystrophy (SFD), including a novel early sign for the disease and to report the effect of anti-VEGF therapy. METHODS Twenty-one probands of three unrelated families with SFD were investigated using wide-field imaging, confocal laser scanning ophthalmoscopy with autofluorescence imaging, optical coherence tomography (OCT), indocyanine green-angiography (ICG-A), and molecular diagnostic for causative mutations. RESULTS Molecular genetic analysis revealed two novel (p.Tyr174Cys, p.Tyr177Cys) and one previously described (p.Tyr182Cys) missense mutations in TIMP3. In families with p.Tyr177Cys and p.Tyr182Cys, metamorphopsia and/or decrease in visual acuity were the initial symptoms occurring at approximately the sixth decade of life. The p.Tyr174Cys mutation carriers had first symptoms at approximately the third decade with dark adaptation problems and visual field defects. The ocular phenotype included drusen-like deposits, rapidly progressive geographic atrophy, choroidal neovascularization (CNV), and polypoidal choroidal neovascularization (PCV). Late disease manifestations were uniform with widespread chorioretinal atrophy, fibrosis, and choroidal thinning. Three asymptomatic young carriers of a TIMP3 mutation with otherwise normal findings on funduscopy and retinal imaging showed a characteristically reduced fluorescence on late-phase ICG-A images. This phenotypic sign was more pronounced and widespread in later disease stages. Patients with CNV or PCV showed a favorable response to therapy with intravitreally injected bevacizumab. CONCLUSIONS This study expands the spectrum of mutations in the TIMP3 gene and associated phenotypic findings. Imaging using late-phase ICG-A may be useful for early identification of individuals at risk for developing SFD. Intravitreal anti-VEGF therapy if initiated timely is effective in SFD patients with CNV.

Monoallelic ABCA4 Mutations Appear Insufficient to Cause Retinopathy: A Quantitative Autofluorescence Study

PURPOSE To investigate the effect of ABCA4 mutation status on lipofuscin-related quantitative autofluorescence (qAF) in humans and on bisretinoid accumulation in mice. METHODS Genotyped parents (n = 26; age 37-64 years) of patients with biallelic ABCA4-related retinopathy underwent in-depth retinal phenotyping including qAF imaging as a surrogate measure for RPE lipofuscin accumulation. In addition, bisretinoids as the main components of autofluorescent lipofuscin at the ocular fundus were quantified in Abca4-/-, Abca4+/-, and wild-type mice. RESULTS Index patients showed a retinal phenotype characteristic for ABCA4-related retinopathy, including increased qAF levels. In contrast, qAF measures in carriers of only one ABCA4 mutation were not different from age-matched controls in this sample, and there was no difference between truncating and missense mutations. Also, none of these carriers presented an abnormal phenotype on conventional imaging. One parent with ABCA4-related retinopathy and increased qAF carried an additional ABCA4 mutation, explaining the phenotype under a recessive disease model (pseudodominance). Biochemical analysis in the mouse model revealed direct downstream products (A2PE-H2, at-RALdimer-PE) of the ABCA4 substrate N-Ret-PE to be similar in wild-type and Abca4+/- mice. Both bisretinoids were 12- to 18-fold increased in Abca4-/- mice. Levels of A2E and A2PE in Abca4+/- mice were in between those measured in wild-type and Abca4-/- mice. CONCLUSIONS This study indicates that carriers of monoallelic ABCA4 mutations are phenotypically normal. However, biochemical analysis in the Abca4-deficient mouse model suggests detectable effects of one mutation in ABCA4 on the molecular level. The findings may have implications for therapeutic approaches such as gene replacement therapy.

Technical principles of OCT angiography

ZusammenfassungHintergrundDie OCT-Angiographie (OCT-A) ist eine neue klinische Untersuchungsmethode, die eine nichtinvasive dreidimensionale Darstellung der vaskulären Strukturen der Netzhaut und Aderhaut erlaubt. Technisch handelt es sich bei der OCT-A um eine Weiterentwicklung der optischen Kohärenztomographie (OCT). Durch leistungsfähigere Soft- und Hardware ermöglicht die OCT-A neben morphologischen Analysen auch eine dreidimensionale retinale und choroidale Perfusionsanalyse. Wir erläutern die Grundlagen sowie die Anwendung der OCT-A im Vergleich mit anderen nichtinvasiven Untersuchungsverfahren der retinalen und choroidalen Blutzirkulation.MethodenDer Arbeit liegen eine selektive Literaturrecherche und die Auswertung eigener Daten zugrunde.ErgebnisseVorteile der OCT-A bestehen in der einfachen Anwendung, die keiner Mydriasis oder intravenösen Fluoreszenzfarbstoffverabreichung bedarf. Sie gestattet eine exakte tiefensensitive Lokalisation vaskulärer Veränderungen. Bei retinalen Pathologien können Diskrepanzen zwischen softwareassistierter automatischer Segmentierung und realen Netzhautschichten bestehen, die bei der klinischen Interpretation zu beachten sind.SchlussfolgerungDie OCT-A ist von allen nichtinvasiven Perfusionsanalysen die einzige, die bereits in den klinischen Alltag implementiert werden kann. Mit diesem neuen bildgebenden Untersuchungsverfahren können vaskuläre retinale und choroidale Veränderungen tiefenselektiv und ohne Maskierungseffekt durch Pooling- oder Stainingphänomene detektiert werden.AbstractBackgroundOptical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation.MethodsThis article is based on a selective literature review and analyses of own data.ResultsThe advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation.ConclusionOf all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.BACKGROUND Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. METHODS This article is based on a selective literature review and analyses of own data. RESULTS The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. CONCLUSION Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.

Frequency, Phenotypic Characteristics and Progression of Atrophy Associated With a Diseased Bruch's Membrane in Pseudoxanthoma Elasticum.

PURPOSE To characterize atrophy of the outer retina and the retinal pigment epithelium in patients with pseudoxanthoma elasticum (PXE). METHODS In this retrospective cross-sectional study, the frequency and phenotypic characteristics of manifest atrophy were investigated in 276 eyes of 139 patients using color fundus photography, fundus autofluorescence (AF) imaging, and spectral domain optical coherence tomography. Progression rates of atrophy were quantified in eyes with longitudinal AF recordings. RESULTS Atrophy was present in 90 eyes (32%; mean age, 60; range, 32-88 years). In 19 eyes (7%; mean age, 56; range, 37-77 years) atrophy occurred without any signs for an active or fibrotic choroidal neovascularization (CNV). The frequency of both, atrophy and CNV, increased with age. In those > 60 years of age, atrophy and/or CNV were almost universally present but varied considerably in severity. Eyes with emerging pure atrophy (n = 13, no signs of CNV) showed pattern dystrophy-like changes (100%), reticular pseudodrusen (82%), and reduced choroidal thickness. Advanced atrophy was multifocal, reached beyond the arcades, and was present nasal to the optic disc. The average expansion rate of atrophy was 3.3 ± 1.3 and 1.6 ± 1.1 mm2/year (mean ± SD), in those without or with signs for CNV, respectively. CONCLUSIONS Atrophy of the outer retina and the retinal pigment epithelium is a common finding in PXE patients characterized by early onset and fast progression with subsequent visual loss independent from CNV. This suggests that atrophy is the natural endpoint of Bruchs membrane disease. Phenotypic similarities with multifactorial geographic atrophy in age-related macular degeneration suggest common pathogenic pathways at the level of Bruchs membrane.

Clinical and genetic characteristics of 251 consecutive patients with macular and cone/cone-rod dystrophy

Macular and cone/cone-rod dystrophies (MD/CCRD) demonstrate a broad genetic and phenotypic heterogeneity, with retinal alterations solely or predominantly involving the central retina. Targeted next-generation sequencing (NGS) is an efficient diagnostic tool for identifying mutations in patient with retinitis pigmentosa, which shows similar genetic heterogeneity. To detect the genetic causes of disease in patients with MD/CCRD, we implemented a two-tier procedure consisting of Sanger sequencing and targeted NGS including genes associated with clinically overlapping conditions. Disease-causing mutations were identified in 74% of 251 consecutive MD/CCRD patients (33% of the variants were novel). Mutations in ABCA4, PRPH2 and BEST1 accounted for 57% of disease cases. Further mutations were identified in CDHR1, GUCY2D, PROM1, CRX, GUCA1A, CERKL, MT-TL1, KIF11, RP1L1, MERTK, RDH5, CDH3, C1QTNF5, CRB1, JAG1, DRAM2, POC1B, NPHP1 and RPGR. We provide detailed illustrations of rare phenotypes, including autofluorescence and optical coherence tomography imaging. Targeted NGS also identified six potential novel genotype-phenotype correlations for FAM161A, INPP5E, MERTK, FBLN5, SEMA4A and IMPDH1. Clinical reassessment of genetically unsolved patients revealed subgroups with similar retinal phenotype, indicating a common molecular disease cause in each subgroup.

Novel Insights Into the Phenotypical Spectrum of KIF11-Associated Retinopathy, Including a New Form of Retinal Ciliopathy

Purpose This study sought to characterize the ophthalmic and extraocular phenotype in patients with known and novel KIF11 mutations. Methods Four patients (3, 5, 36, and 38 years of age, on father-daughter constellation) from three unrelated families were characterized by retinal examination including multimodal retinal imaging, investigation for syndromic disease manifestations, and targeted next-generation sequencing. The subcellular localization of Kif11 in the retina was analyzed by light and electron microcopy. Results There was considerable interindividual and intrafamilial phenotypic heterogeneity of KIF11-related retinopathy. Two patients presented with a progressive retinal dystrophy, one with chorioretinal dysplasia and one with familial exudative vitreoretinopathy (FEVR) in one eye and thinning of the photoreceptor layer in the fellow eye. Obvious syndromic disease manifestations were present only in the youngest patient, but minor signs (e.g. reduced head circumference) were present in the three other individuals. Immunohistochemistry results demonstrated Kif11 localization in the inner segment and ciliary compartments of photoreceptor cells and in the retinal pigment epithelium. Conclusions Progressive retinal degeneration in KIF11-related retinopathy indicates a role for KIF11 not only in ocular development but also in maintaining retinal morphology and function. The remarkable variability of the ocular phenotype suggests four different types of retinopathy which may overlap. KIF11 should be considered in the screening of patients with retinal dystrophies because other syndromic manifestations may be subtle. Evaluation of head circumference may be considered as a potential shortcut to the genetic diagnosis. The localization of Kif11 in photoreceptor cells indicates a retinal ciliopathy.

Perception of Haidinger Brushes in Macular Disease Depends on Macular Pigment Density and Visual Acuity

PURPOSE To optimize the perceptibility of Haidinger brushes (HB) and to investigate its association with visual acuity and macular pigment density. METHODS In this prospective cross-sectional study, each subject underwent best-corrected visual acuity (BCVA) testing, funduscopy, and assessment of macular pigment optical density (MPOD) using the two-wavelength fundus autofluorescence method. Haidinger brush visibility was tested with a rotating linear polarizer and a controllable three-color light-emitting diode (LED) panel as light source. A simple model of macular pigment absorption was used to predict HB visibility as a function of stimulus wavelength and MPOD. RESULTS All control eyes (n = 92) and 34% of the 198 eyes of subjects with macular disease (age-related macular degeneration, n = 40; macular telangiectasia type 2, n = 52; Stargardt disease, n = 58; other retinal dystrophies, n = 48) perceived HB when an optimized test setup (464-nm LED light) was applied. The degree of psychophysical perception and the dependency on different wavelengths were in accordance with the absorptance model. In eyes of subjects with macular disease, minimum thresholds of MPOD and BCVA required for HB perception were identified. Subjects with macular telangiectasia type 2 showed lowest values of MPOD and were mostly unable to perceive HB despite relatively preserved BCVA. CONCLUSIONS Macular pigment and a relatively preserved foveal function are necessary for the perception of HB. Haidinger brushes are usually not perceived by subjects with macular telangiectasia type 2, likely due to their characteristic foveal depletion of macular pigment.

Technische Grundlagen der OCT-Angiographie

ZusammenfassungHintergrundDie OCT-Angiographie (OCT-A) ist eine neue klinische Untersuchungsmethode, die eine nichtinvasive dreidimensionale Darstellung der vaskulären Strukturen der Netzhaut und Aderhaut erlaubt. Technisch handelt es sich bei der OCT-A um eine Weiterentwicklung der optischen Kohärenztomographie (OCT). Durch leistungsfähigere Soft- und Hardware ermöglicht die OCT-A neben morphologischen Analysen auch eine dreidimensionale retinale und choroidale Perfusionsanalyse. Wir erläutern die Grundlagen sowie die Anwendung der OCT-A im Vergleich mit anderen nichtinvasiven Untersuchungsverfahren der retinalen und choroidalen Blutzirkulation.MethodenDer Arbeit liegen eine selektive Literaturrecherche und die Auswertung eigener Daten zugrunde.ErgebnisseVorteile der OCT-A bestehen in der einfachen Anwendung, die keiner Mydriasis oder intravenösen Fluoreszenzfarbstoffverabreichung bedarf. Sie gestattet eine exakte tiefensensitive Lokalisation vaskulärer Veränderungen. Bei retinalen Pathologien können Diskrepanzen zwischen softwareassistierter automatischer Segmentierung und realen Netzhautschichten bestehen, die bei der klinischen Interpretation zu beachten sind.SchlussfolgerungDie OCT-A ist von allen nichtinvasiven Perfusionsanalysen die einzige, die bereits in den klinischen Alltag implementiert werden kann. Mit diesem neuen bildgebenden Untersuchungsverfahren können vaskuläre retinale und choroidale Veränderungen tiefenselektiv und ohne Maskierungseffekt durch Pooling- oder Stainingphänomene detektiert werden.AbstractBackgroundOptical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation.MethodsThis article is based on a selective literature review and analyses of own data.ResultsThe advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation.ConclusionOf all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.BACKGROUND Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. METHODS This article is based on a selective literature review and analyses of own data. RESULTS The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. CONCLUSION Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.