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Near-infrared autofluorescence (NIA) is a non-invasive retinal imaging technique for examination of the retinal pigment epithelium (RPE) based on the autofluorescence of melanin. Melanin has several functions within the RPE cells, in one of them it serves as a protective antioxidative factor within the RPE cells and is involved in the phagocytosis of photoreceptor outer segments. Disorders that affect the photoreceptor-RPE complex result in alterations of RPE cells which are detectable by alterations of NIA. Therefore, NIA allows to detect early alterations in inherited and acquired chorioretinal disorders, frequently prior to ophthalmoscopical visualisation and often prior to alterations in lipofuscin associated fundus autofluorescence (FAF) or optical coherence tomography (OCT). Although NIA and FAF relate to disorders affecting the RPE, findings between both imaging methods differ and the area involved has been demonstrated to be larger in NIA compared to FAF in several disorders (e.g., age-related macular degeneration, retinitis pigmentosa, ABCA4-gene associated Stargardt disease and cone-rod dystrophy, light damage), indicating that NIA detects earlier alterations compared to FAF. In addition, due to the absence of blue-light filtering which limits foveal visualisation in FAF, foveal alterations can be much better detected using NIA. A reduced subfoveal NIA intensity is the earliest sign of autosomal dominant BEST1-associated disease, when FAF and OCT are still normal. In other disorders, a normal subfoveal NIA intensity is associated with good visual acuity. This review summarizes the present knowledge on NIA and demonstrates biomarkers for various chorioretinal disorders.

Optoacoustic imaging (OAB) has developed steadily in recent years. By means of partly pulsed light, in a wide variety of wavelengths, different colour carriers (chromophores) are excited to form sound waves. These in turn are detected by the newly developed systems and converted into three-dimensional images by means of various algorithms. The technique is characterised by a good ratio between contrast and penetration depth and can create macro-, meso- and microscopic images due to its scalability. Optoacoustic macroscopy broadly irradiates the area to be examined with laser light. This can produce images with a high penetration depth, but only with a moderate resolution. Clinically interesting fields of application are for example the results of sentinel lymph nodes (SLNs) examined ex vivo using macroscopic optoacoustics. Due to the ability of OAB to visualise melanin, the detection rate of metastases was superior to previous methods, but not to histology. The ability to visualise dermal and epidermal structures, especially vessels, with good resolution makes optoacoustic mesoscopy useful in the examination of inflammatory skin diseases and could contribute to the verification of the success of therapy, e.g., with biologics for psoriasis vulgaris or atopic eczema (AE), in the future. Optoacoustic microscopy, which has so far been limited mainly to preclinical in vivo research, could be used in the future to detect even finer vascular structures and their changes. The clinical possibilities of OAB seem to be of great benefit and continue to be the subject of intensive research.Die optoakustische Bildgebung (OAB) hat sich in den letzten Jahren stetig weiterentwickelt. Mittels teils gepulsten Lichts in verschiedenen Wellenlängen werden unterschiedliche Farbträger (Chromophore) zur Bildung von Schallwellen angeregt. Diese werden von den neu entwickelten Systemen detektiert und mittels verschiedener Algorithmen in dreidimensionale Bilder umgewandelt. Die Technik zeichnet sich durch ein gutes Verhältnis von Kontrast und Eindringtiefe aus und kann aufgrund ihrer Skalierbarkeit makro-, meso- und mikroskopische Bilder erzeugen. Die optoakustische Makroskopie bestrahlt das zu untersuchende Areal breit mit Laserlicht. Hierdurch können Abbildungen mit hoher Eindringtiefe erzeugt werden, jedoch lediglich mit einer mittleren Auflösung. Klinisch interessante Anwendungsfelder sind z. B. die Ergebnisse von ex-vivo untersuchten Sentinellymphknoten mittels makroskopischer Optoakustik. Aufgrund der Fähigkeit der OAB Melanin darzustellen zeigte sich eine bisherigen bildgebenden Methoden, jedoch nicht der Histologie überlegene Detektionsrate für Metastasen. Die Fähigkeit, mit einer guten Auflösung dermale und epidermale Strukturen, besonders Gefäße, darzustellen, macht sich die optoakustische Mesoskopie bei der Untersuchung entzündlicher Hauterkrankungen zunutze und könnte künftig zur Überprüfung des Therapieerfolges, z. B. durch Biologika bei Psoriasis vulgaris oder dem atopischen Ekzem, beitragen. Die bisher v. a. auf präklinische In-vivo-Forschung beschränkte optoakustische Mikroskopie könnte künftig zur Detektion noch feinerer Gefäßstrukturen und deren Veränderungen verwendet werden. Die klinischen Möglichkeiten der OAB scheinen bisher sehr großen Nutzen bieten zu können und sind ein aktuell stark untersuchtes Forschungsfeld.

Albinism can be divided into oculocutaneous albinism (OCA) and ocular albinism (OA). In the differential diagnostics these can be distinguished from rarer syndromes with partial albinism, which are frequently associated with susceptibility to infections and neurological symptoms. The OCA is an autosomal recessive inherited disease of melanin biosynthesis, which leads to complete or partial loss of melanin in the skin, hair follicles and eyes. Of the seven currently known subtypes (OCA 1-7), four are well-characterized (OCA 1-4). These are based on gene mutations, which code for tyrosinase, a key enzyme in melanin synthesis and for further proteins. These play an important role in the catalytic activity of tyrosinase and the structure and function of melanosomes. In the presence of these subtypes, the clinical symptoms and the course of the disease show a pronounced variability, especially in the type and extent of pigmentation of the skin and hair as well as the severity of eye involvement, which makes the phenotypic classification difficult. Treatment priorities are a consistent protection from UV light for prophylaxis against skin cancer and regular preventive investigations. The ocular alterations typical for albinism necessitate timely diagnostics and care by institutions specialized in ophthalmology. Novel strategies for systemic treatment of subtypes of albinism are in preclinical testing. The OA without skin involvement shows X‑linked inheritance, is much rarer and is characterized by reduced pigmentation of the retina and iris, nystagmus and macular hypoplasia, sometimes with substantial loss of visual acuity. The typical ocular symptoms of OA can be manifested to a varying extent in all forms of OCA.

Visualizing anatomical and functional features of hair follicle development in their unperturbed environment is key in understanding complex mechanisms of hair pathophysiology and in discovery of novel therapies. Of particular interest is in-vivo visualization of the intact pilosebaceous unit, vascularization of the hair bulb and evaluation of the hair cycle particularly in humans. Furthermore, non-invasive visualization of the sebaceous glands could offer crucial insight into pathophysiology of follicle-related diseases, dry or seborrhoic skin, in particular by combining in-vivo imaging with other phenotyping, genotyping and microbial analyses. The available imaging techniques are limited in their ability for deep tissue in-vivo imaging of hair follicles and lipid-rich sebaceous glands in their entirety without biopsy. We developed a non-invasive, painless and risk-free volumetric multispectral optoacoustic tomography (vMSOT) method for deep tissue three-dimensional visualization of whole hair follicles and surrounding structures with high spatial resolution below 70μm. Herein we demonstrate on-the-fly assessment of key morphometric parameters of follicles and lipid content as well as functional oxygenation parameters of the associated capillary bed. The ease of handheld operation and versatility of the newly-developed approach poise it as an indispensable tool for early diagnosis of disorders of the pilosebaceous unit and surrounding structures, and for monitoring the efficacy of cosmetic and therapeutic interventions.

Pseudoexfoliation (PEX) glaucoma is the most frequent and most important type of secondary glaucoma, accounting for approximately 25% of open angle glaucoma worldwide and currently representing the most common identifiable cause of glaucoma overall. Due to high intraocular pressure levels, marked diurnal pressure fluctuations and spikes, and rapid optic nerve damage and visual field loss, PEX glaucoma represents a relatively severe and progressive type of glaucoma. Therefore, hard and fast lowering of intraocular pressure is necessary. Fixed combinations in medical therapy and early glaucoma surgery are recommended. When considering a surgical procedure (e.g. selective laser trabeculoplasty, bleb-dependent or bleb-independent surgery) the timing of cataract surgery plays a major role. Pathogenesis, clinical characteristics and therapeutic aspects of PEX glaucoma are described in the following article.

A 45-year-old woman presented with diffuse melanosis, icteric sclera and melanuria. Physical examination revealed a massive nodular melanoma with ulceration and satellite metastases on the back. Further investigation showed distant cutaneous and visceral metastasis. After palliative debulking along with postoperative multidrug chemotherapy, the patient has shown objective disease regression for more than 11 months. However, it remains to be seen if disease regression will translate into increased survival.

Skin pigmentation is highly determined by genetic factors and so far more than 150 genes have been identified that affect skin color either directly or indirectly. The production of eu- and pheomelanin in melanosomes results from the complex interaction between melanogenic regulators in melanocytes and factors derived from keratinocytes and fibroblasts. Besides genetic determination, pigmentation depends on environmental and endocrine factors that modulate the amount, type and distribution of melanins in the skin. Understanding the intrinsic mechanisms of melanogenesis is the basis for modifications of skin pigmentation which are of great interest pharmaceutically and cosmeceutically.

The accumulation of autofluorescent bodies in retinal pigment epithelium (RPE) cells has an impact on the pathogenesis of retinal diseases, including age-related macular degeneration. While current in vivo fluorescence microscopy allows a lateral resolution of fluorophores in a micrometer range, with ex vivo microscopy a lateral resolution down to 200 nm is possible. For the first time, we used structured illumination microscopy for ex vivo high-resolution fluorescence microscopy of RPE cells.Histological sections were prepared from a 68-year-old patient. With epifluorescence microscopy, fluorescent RPE cells were detectable. Structured illumination uses inhomogeneous illumination for resolution of previously nonresolvable structures, similar to the Moiré effect. Images were taken from RPE cells at different excitation wavelengths (488, 568, and 647 nm) and were reconstructed with special software. The different excitation patterns of the fluorescent granules in the RPE cells were colour-coded and analysed.With structured illumination microscopy, autofluorescence signals of RPE cells were detectable, and a lateral resolution of 110 nm could be achieved. Using varying wavelengths, different pigments were excitable. Lipofuscin gave the highest signals, at 488 and 568 nm. The improved resolution showed inhomogeneous intragranular fluorophore patterns.Structured illumination microscopy enabled us to generate images of fluorescent structures in RPE cells ex vivo with a lateral resolution of 110 nm. With the use of different excitation wavelengths, intracellular fluorescence patterns in single cell compartments are visible and allow further differentiation.

Alpha-melanocyte-stimulating hormone (alpha-MSH) is a tridecapeptide that is produced by the skin itself from the precursor proopiomelanocortin. It crucially mediates ultraviolet light-induced tanning after binding to melanocortin-1 receptors (MC-1R) expressed on the surface of epidermal melanocytes. The potent pigment-inducing and also cytoprotective actions of alpha-MSH are the rationale for the performance of first phase II clinical trials with Nle4-D-Phe7-alpha-MSH (NDP-alpha-MSH), a subcutaneously administered synthetic and superpotent alpha-MSH analogue, in patients with photodermatoses such as erythropoietic protoporphyria. Since alpha-MSH has shown promising anti-inflammatory and antifibrotic properties in numerous preclinical studies, it will be most interesting to evaluate these effects in further clinical pilot studies with NDP-alpha-MSH. In addition to alpha-MSH analogues, truncated tripeptides such as KDPT which do not bind to MC-1R but have sustained anti-inflammatory properties are currently emerging as another novel therapeutic strategy in dermatology.

Choroidal melanoma is the most frequent form of primary neoplasia among malignant ocular tumors. Since it is presumed that metastasis often occurs before the primary tumor is first diagnosed, early detection is exigent. The aim of the studies described in this report was to develop an objective, noninvasive method for the diagnosis of choroidal melanoma. The underlying new principle of fluorescence excitation is presented. This is based on the observation that melanin, due to its unique absorption characteristics, is selectively excited into fluorescence via stepwise absorption of two photons of a femtosecond laser emitting at 800 nm. In the experiment described, the fluorescence of excised tissue from healthy choroidal pigment epithelium was compared to that of excised choroidal melanoma. The fluorescence of choroidal melanomas exhibited a more reddish appearance and less intensity than that of healthy tissue. This implies that the configuration of melanin apparently changes during the process of malignant degeneration. The method described here could thus serve as an evidentiary objective diagnostic technique before initiating treatment for choroidal melanomas.

Patients with idiopathic Parkinson's disease display a 60% degeneration of the nigrostriatal neurons before motor symptoms have progressed enough to allow clinical diagnosis. It is clear that any neuroprotective therapy starting at such a late stage can have no substantial effect on the disease progression. Therefore, earlier diagnosis must be the goal of future research,when at most mild motor or non-motor symptoms are present or when only risk factors can be identified. Evidence of various gene mutations associated with idiopathic Parkinsonism raise the hope that these or other biological markers will allow earlier identification of patients at risk. A possibly significant vulnerability factor for developing Parkinson's disease can also be demonstrated by means of transcranial sonography. Since the individual tests are not sufficiently specific or sensitive, a gradual, precise, and inexpensive battery of tests needs to be developed for the successful identification of a risk group for this disease. The extent of damage to the dopaminergic system in these patients can be quantified using nuclear techniques.

A 72 year old bedridden, disoriented man presented with a continuously increasing number of blue nodules on his abdomen and both thighs. In addition, he had a melanoma on his left forearm (SSM, Clark level III, Breslow 0.75 mm), which lead to the clinical diagnosis of melanoma metastases. Biopsy of one of the blue nodules showed CD68 positive histiocytic cells loaded with brownish pigment granules and a lymphocytic infiltrate within the deep dermis and upper subcutis. The pigment reacted histochemically similarly to melanin. Melanocytes were absent at these sites. Because of the unexplained clinical and histopathological picture, the patient's history was reassessed and it was learned that the patient had received subcutaneous infusions of apomorphine for the past 10 years for the treatment of Parkinson's disease. By oxidation, apomorphine may be converted into tetrahydroisoquinoline-melanin, which apparently is the cause for the accumulation of pigment within the deep dermis.

Pathologic processes of the caruncle are relatively rare with a predominance of papillomas, pyogenic granulomas and nevi.A 22 year old Caucasian male patient presented with bilateral hyperpigmentations of the caruncle. They had first been observed at an age of seven and showed slight progression in size and colour with time. Examination revealed hyperpigmentation with clear pseudocystic spaces. The tarsal or bulbar conjunctiva was not involved. An excision of both processes was performed.Light microscopy revealed nests of nevus cells with melanin granules and round basophilic nuclei as well as gland ducts and sebaceous glands, beneath and within the multilayered keratinizing and nonkeratinizing squamous epithelium. The sections revealed a bilateral melanocytic compound nevus of the caruncle.To our knowledge, there is no report on bilateral nevi of the caruncle among the Caucasian population. The possibility of a common precursor cell during the embryologic development causing the bilaterality is discussed.

To study the role of macrophages in experimental melanin-induced uveitis (EMIU), we used the method of intravital microscopy to analyse changes in leukocyte adhesion to iris venules of live rats with EMIU after pretreatment with liposomal clodronate.EMIU was induced in Lewis rats (n = 48) by intraperitoneal immunisation with bovine crude melanosomes emulsified in complete Freund's adjuvant (CFA) and pertussis toxin (PTX). Control animals received CFA and PTX only (n = 12) or no injection (n = 6). Animals were treated with liposomal clodronate (DMDP-lip) or empty liposomes on days -2, +1, 4, 6 and 8. Using IVM, postcapillary iris venules of rats were examined to quantify leukocyte rolling and firm adhesion to the vascular endothelium.Depletion of macrophages caused a decreased percentage of rolling leukocytes on day 8 (2 +/- 1.1% vs 15.2 +/- 1.6%, DMDP-lip vs EMIU, mean +/- SEM, ANOVA, p0.05) and day 10 (2.6 +/- 0.3% vs 14.2 +/- 1.6%). A significant decline in the number of firmly adherent leukocytes was detected on days 8 and 10 (88 +/- 13/mm2 vs 175 +/- 18/mm2 and 129 +/- 13/mm2 vs 372 +/- 31/mm2, DMDP-lip vs EMIU). Treatment with empty liposomes showed no changes in leukocyte firm adhesion.Elimination of macrophages prevents the induction of EMIU. In autoimmune-mediated uveitis, macrophages play a crucial role in the initiation of leukocyte-endothelium interaction.

Melanin granules in the retinal pigment epithelium (RPE) have many important functions which are not yet completely understood. Melanin in the RPE protects the cell from damage caused by oxidative stress. This pigment acts as a free radical sink and diminishes cytotoxic lipid peroxidation. Thus, melanin protects against light toxicity and against cytotoxic effects caused by ocular inflammation. Many enzymes, e.g. superoxide dismutase or carboanhydrase, are only activated in the presence of zinc. Melanin can store zinc and release it when required. The absence of melanin in patients with oculocutaneous albinism is accompanied by photophobia, poor visual acuity and nystagmus. Furthermore melanin is said to protect against damaging lipofuscin accumulation in the RPE. Melanosomes are involved in the lysosomal degradation pathways and possibly take part in the degradation of rod outer segments (ROS) in the RPE.

Melanin has been shown to act as antioxidant in lipid peroxidation studies. We have now investigated lipid peroxidation in dependence on stromal pigmentation in isolated porcine irises.The same number of lightly pigmented and heavily pigmented porcine irises (visual selection) were homogenized in buffer (50 mmol/l Na2HPO4, 50 mmol/l NaH2PO4 and 4 mmol/l sodium azide; 1:20 w/v). 500 microliters homogenate were incubated at 37 degrees C for 5, 10, 20 and 40 min in absence and presence of Fe2+ as inducer of lipid peroxidation. Lipid peroxidation was assayed by the thiobarbituric acid (TBA) test. Results are expressed as nmol of TBA reactive material produced (TBAR) per mg protein. Fe2+ concentration of the supernatant was determined spectrophotometrically with phenanthroline.70 mumol/l, 180 mumol/l and 360 mumol/l Fe2+ induced lipid peroxidation. A plateau region was reached after 20 min. Lipid peroxidation differed in dependence on stromal pigmentation in porcine irises by a factor of 2.8. 180 mumol/l Fe2+ induced 1.373 +/- 0.138 nmol TBAR/mg protein in lightly pigmented irises compared to 0.491 +/- 0.125 nmol TBAR/mg protein in heavily pigmented irises after 10 min incubation (p0.0001, n = 4). On the other hand, the content of Fe2+ in the supernatant was the same within error.There was a stronger induction of lipid peroxidation in lightly pigmented porcine irises compared to heavily pigmented porcine irises. This effect may be related to the difference in stromal melanin content and its antioxidant activity.

Wir berichten uber eine 37jahrige Frau, bei der sich seit ca. eineinhalb Jahren im Gesicht und am oberen Rumpf scharf abgegrenzte hypopigmentierte Maculae entwickeln. Die weitere korperliche Untersuchung sowie die Anamnese waren unauffallig. Histologisch zeigte sich im Zentrum der betroffenen Areale ein reduzierter Melaningehalt der basalen Keratinozyten und Melanozyten. Immunhistochemisch und elektronenmikroskopisch fand sich eine unverminderte Anzahl von Melanozyten mit Zeichen der Degeneration und verkurzten Dendriten, so das die Diagnose einer Hypomelanosis guttata idiopathica gestellt werden konnte. Anhand des vorgestellten Falles werden das klinische Bild, die Atiologie und Behandlungsmoglichkeiten dieser relativ haufigen, jedoch selten diagnostizierten Hauterkrankung diskutiert.

Diffuse hyperpigmentation of the skin may develop without preceding inflammatory skin disease or be associated with various inflammatory disorders. The differential diagnosis of the diffuse hyperpigmentation is complex and difficult. We present a 36-year-old woman with diffuse hyperpigmentation caused by adrenal insufficiency, with special reference to the diagnosis and differential diagnosis of hyperpigmentation associated with endocrine disorders. In addition, metabolic, toxic, nutritional and internal factors and the skin-associated diseases leading to hyperpigmentation are categorized. A classification of diffuse hyperpigmentation is presented.

A 49-year-old male patient is presented, who developed hyperpigmented macules on the face. An exact classification of the disorder was not possible on the basis of anamnestic data, histology and electron microscopy. An attempt was made to differentiate it from other known dyschromias of the face.

Epiluminescent microscopy is now used frequently for the differential diagnosis of pigmented skin lesions. In order to improve the distinction between benign and malignant melanocytic tumours it seemed advisable to develop a standardized pathway of epiluminescent microscopical analysis and to determine the frequency of structures recognizable with the microscope. A total of 600 melanocytic lesions were examined by epiluminescent microscopy, photographed and classified histologically after excision, revealing 426 naevocellular naevi and 174 melanoma. The experience achieved during the course of the investigation was used as the basis of a procedure for stepwise analysis of keratin layer, pigment structures and blood vessels. The most important findings are described and referred to malignancy. The photographs were analysed for the frequency of occurrence of various pigment structures in different types of lesions. The results differ in several aspects from previous findings.

In MRI choroidal melanoma shows a very short relaxation time (T2), shorter than that of any other intraocular tumor. This short T2 time is referred to the high concentration of paramagnetic melanine in this tumor. Therefore, it is of interest to measure the relaxation time in an amelanotic melanoma and compare it with the histological analysis. The duration of T2 for the amelanotic melanoma examined ranged from 130 to 160 ms. The small concentration of melanine is not a sufficient explanation, but it is possible that there are some precursors of melanine with paramagnetic characteristics.

The conditions for an optimal ophthalmic coagulating system are derived from the absorption spectra of xanthophyll, melanin and hemoglobin. Coagulation is effected by a dye laser with two dyes. The continuously tunable range of 570 nm to 680 nm opens up new horizons in photocoagulation of the retina.

Regarding the rare phenomenon of diffuse melanosis of the skin secondary to widespread melanoma, the possibility of a circumscribed melanosis in melanoma patients is hypothetically discussed on the basis of a personal observation. Microscopically, such a circumscribed melanosis appears as clusters of melanin-laden macrophages.

This is the first report on the occurrence of giant melanosomes in normal human epidermis and in moles. Due to their characteristic ultrastructural features these large pigment organelles are of special interest for the research in melanin pigmentation. The diferentiation of giant malanosomes from other types of large melanin granules is discussed.

652 Spitz' nevi have been histologically analysed and separated into epidermal and dermal changes. There are similarities between Spitz' nevus and melanocytic nevus. 44.9% of the examined Spitz' nevi consist of spindle cells only, 34% of spindle as well as epithelioid cells, and 21% of epithelioid cells only. We are going to discuss the difficulties in histological examination; more or less important signs are differentiated in detail. In some cases, Spitz' nevus will remain a somewhat dubious and disturbing tumor.

In 19 patients with malignant melanoma of the choroid and 11 controls 20 different metabolic parameters of melanin and melatonin metabolism in urine were examined by high-pressure liquid chromatography (HPLC). Significant differences were found in DOPA, DOPAC, MHPG, alpha-keto-glutaric acid, pseudo-uridine, serotonin, OH-tryptophan and homovanillic acid.

The pigment present in melanosis cerebelli where it is deposited in the dentate nucleus and within the cerebellar granular layer is similar to that of S. nigra as judged from the typical infrared absorption bands near wave numbers 3.450 cm-1 and 1.650 cm-1, respectively. According to electron microscopic findings, this type of melanin arises within the astrocytes of the dentate nucleus. The astrocytic melanosomes exhibit a relatively monotonous substructure reaching diameters of 30 mu and more, and they differ in this respect from the triadic neuronal melanosomes of S. nigra that are strongly reminiscent of lipofuscin granules. These differences may be due to additional components of melanosomes, apparently specific of a particular cell type, and they are in turn accounted for by the dissimilar cellular metabolic make-up of nigral cells and astrocytes, respectively. This does not dismiss the possibility, however, that the melanin pigments of either type of melanosomes are the same or closely related to each other as far as their basic chemical composition is concerned. The cause of the melanosis of the dentate nucleus is not known. Possibly involutional tissue changes governed by endocrine factors among others may play an important part.

A solid adenoma of the pigmented ciliary epithelium was removed by 9.0 X 6.0 mm "block-excision" (postoperative visual acuity 1.0). The black lesion with a velvety surface consists of very large cells packed with melanin granules of abnormal and variable density, structure and size. Striking intracellular vacuoles contain acid mucopolysaccharides, particularly sialomucins. The literature on tumors of the pigmented ciliary epithelium is reviewed. Criteria for the separation of adenomas for adeno- "carcinomas" (8 cases, all without metastases) from reactive hyperplasia (6 cases) are proposed. The histologic, histochemical and electronmicroscopic findings of our tumor show striking similarities to those of an adenoma of the retinal pigment epithelium.