Combined hamartoma of the retina and retinal pigment epithelium - MRI features of a rare paediatric intraocular tumour.

Combined hamartoma of the retina and retinal pigment epithelium is a rare benign ocular tumour in children, composed of glial cells, vascular tissue, and sheets of pigmented epithelial cells. Although generally thought to be congenital, acquired cases are known to exist. It usually presents with reduced visual acuity and/or strabismus and it can be associated with several syndromes, including Neurofibromatosis Type 2. There is no consensus on the management of combined hamartoma of the retina and retinal pigment epithelium. We present a case, including MRI features, of a 4,5-years-old girl with a combined hamartoma of the retina and retinal pigment epithelium.

[Nishida Extraocular Muscle Transposition Surgery for Abducens Nerve Palsy]. / Augenmuskeltransposition nach Nishida bei Abduzensparese.

BACKGROUND: Surgical treatment of abducens nerve palsy depends on the remaining function of the lateral rectus muscle. Vertical rectus transposition surgery is indicated if the attempted maximal abduction effort does not rotate the eye beyond the midline. After the first description more than 100 years ago, a variety of muscle transposition modifications have been suggested. Nishida's minimally-invasive adaptation has attracted a great deal of attention in recent years. PATIENTS AND METHODS: Retrospective case series of four patients with abducens nerve palsy who were treated with Nishida muscle transposition surgery. Patients' characteristics with special emphasis on comparison between pre- and postoperative angle of deviation and ocular motility are reported. RESULTS: Four patients (2 females, 2 males) were included in this study. Unilateral transposition surgery was performed in a 7-year-old girl and a 37-year-old woman with a left abducens nerve palsy. In a 56-year-old male with a left sixth nerve palsy and in an 82-year-old male with a right sixth nerve palsy the transposition maneuver was combined with a recession of the medial rectus muscle in the same eye. In all patients, ocular motility was improved and the angle of deviation was reduced. CONCLUSIONS: Transposition of vertical rectus muscles is well established in the surgical treatment of abducens nerve palsy. Nishida's adaptation is a safe, effective and minimally-invasive treatment option. This vessel-sparing technique also allows for equilateral weakening of the medial rectus muscle.

[Prism-Induced Gaze Shift and Strabismus Treatment for Ocular Motility Disorders and Anomalous Head Posture]. / Prismen zur Blickverlagerung und Schielkorrektur bei Augenmotilitätsstörungen und Kopfzwangshaltung.

BACKGROUND: The therapeutic treatment of ocular motility disorders and anomalous head postures (AHP) is often challenging. We report our experience with prism use in these patients. PATIENTS AND METHODS: Retrospective case series of three patients with ocular motility disorders and associated AHP who were treated with prism correction. RESULTS: A 37-year-old male with a traumatic left oculomotor nerve palsy suffered from a residual minor depression deficit and a severe elevation palsy. With OS: 10^ base-up he was corrected for left hypotropia only in down gaze. Ten yoked prisms base-up shifted the field of binocular single vision in primary position. A 45-year-old male with traumatic Parinaud syndrome and upward gaze palsy suffered from neck pain due to his pronounced chin elevation. He also had a right amaurosis with secondary exotropia. With OS: 8^ base-up, his AHP was corrected and his neck pain was alleviated. A 69-year-old woman with a left abducens nerve palsy adopted a left turn of 20° to compensate for her deviation in extreme right gaze. With OS: 20^ base-out, her AHP was corrected and she experienced no double vision in primary position. CONCLUSIONS: Prisms are used to correct strabismic deviations but also can successfully shift images towards another gaze in different clinical scenarios. Reduction of AHP, therefore, can be obtained by a prism-induced gaze shift in the direction of the motility restriction.

Optic Disc Features in Familial Retinal Arteriolar Tortuosity.

PURPOSE: Describing optic disc appearance in familial retinal arteriolar tortuosity (fRAT) using multimodal imaging and raising awareness of peripapillary arterial changes due to this disorder. METHODS: A cross-sectional study was performed in four consecutive patients of two non-related families. Detailed ophthalmological examination was performed and supported by medical and family history and multimodal imaging. RESULTS: In all subjects, increased tortuosity of second- and third-order retinal arteries in superior and deeper vascular plexus was documented. Furthermore, tortuosity in the peripapillary circle of Zinn-Haller was found. In addition, retinal vessel oximetry confirmed tortuosity only of the arterial vessels. CONCLUSION: The present data suggests that a blurry bordered, hyperemic optic disc in the presence of abnormally tortuous arteriolar vessels and asymptomatically or oligosymptomatically spontaneously resolved hemorrhages could be associated with a fRAT. This finding could be linked to peripapillary arterial vessel tortuosity.

[Ocular Motor Nerve Palsies Caused by Paragliding Accidents]. / Augenmuskelparesen nach Gleitschirmunfällen.

BACKGROUND: Paragliding is a risk-taking adventure sport. It can be performed either individually or accompanied by a pilot in tandem formation. Paragliding, as well as other types of "extreme" sport, have gained popularity over the past few years. Injuries predominantly involve the lower extremities and the spinal column. Head injuries occur only rarely. PATIENTS AND METHODS: Retrospective case series of three patients with ocular motor nerve palsies caused by paragliding accidents. Patients' characteristics with special emphasis on treatment strategies are reported. RESULTS: Two men (41 and 56 years of age) suffered from open head injuries and one 56-year-old male from a closed head injury as part of polytrauma caused by paragliding accidents. All patients complained of double vision. The first patient showed a right abducens nerve palsy and elevation deficit due to a complex orbital fracture. Patient 2 had a traumatic right six nerve palsy. The third patient had a complex motility disorder with a bilateral abducens and trochlear nerve palsy. In all three cases, eye muscle surgery improved ocular motility. Two patients regained binocular single vision. CONCLUSIONS: Characteristics of injuries caused by paragliding accidents depend on the trauma scenario. Injury pattern might differ widely. Ocular motor nerve palsies often accompany head trauma. Treatment is guided by common strategies for incomitant strabismus. These ocular motility disorders are often complex and require an individually tailored approach.

First Clinical Experience with Anti-myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis.

BACKGROUND: Antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have been consistently found in a range of demyelinating disorders. In this context, MOG-IgG-associated optic neuritis (ON) has been suggested as a new subset of optic neuropathy. However, clinical manifestations and distinctive characteristics have only rarely been described. PATIENTS AND METHODS: A retrospective case series of three patients with MOG-IgG-associated ON. Clinical morphological features using imaging techniques are presented. RESULTS: Three patients (8-year-old boy, 28-year-old female, 48-year-old male) were included. An 8-year-old boy suffered from a bilateral ON with severe visual loss. The best-corrected visual acuity (BCVA) was 0.05 in the right eye and finger counting in the left eye. The patient had a previous episode of acute disseminated encephalomyelitis (ADEM) with a right abducens nerve palsy. Visual acuity recovered after repeated cycles of intravenous methylprednisolone pulse therapy and 10 cycles of plasma exchange. During the last follow-up, BCVA was 0.9 in the right eye and 0.8 in the left eye. A 28-year-old female presented with a bilateral ON. Her BCVA was 0.5 in the right eye and 0.8 in the left eye. She fully recovered with pulse methylprednisolone therapy (1000 mg/d) with tapering after the second cycle and had a BCVA of 1.0 during the last follow-up visit. A 48-year-old male suffered from a relapsing bilateral ON. At first presentation, BCVA was 0.1 in the right eye and finger counting in the left eye. BCVA fully recovered after each pulse therapy with intravenous methylprednisolone (two cycles). Since the first relapse, the patient has been receiving long-term immunosuppression with rituximab. Despite rituximab and low-dose oral prednisone, the patient had another relapse with a left ON. After a third cycle with intravenous methylprednisolone, he partially recovered. BCVA at last follow-up was 1.0 in the right and 0.8 in the left eye. CONCLUSIONS: MOG-IgG antibodies have been identified in different acquired demyelinating syndromes. The patients reported had an ADEM followed by bilateral ON, an isolated bilateral ON, and a relapsing bilateral ON. Individual treatment strategies led to substantial visual recovery in all patients. We recommend inclusion of MOG-IgG antibodies in the diagnostic workup at least after the first recurrence of ON since they can serve as a diagnostic and potential prognostic tool and might lead to specific therapeutic recommendations.

[Acute Macular Neuroretinopathy]. / Akute makuläre Neuroretinopathie.

BACKGROUND: Acute macular neuroretinopathy (AMNR) is a rare unilateral or bilateral macular disorder. It typically occurs in young women presenting with sudden onset of central scotomas. They correspond to sharp reddish-brown areas in the macular region. The lesions often can only be observed with infrared reflectance imaging. These flat oval or wedge-shaped lesions are often grouped as a flower around the fovea. PATIENTS AND METHODS: Retrospective case series of 4 patients with AMNR. Clinical morphological features using different imaging techniques are presented. RESULTS: Four young women (26, 27, 28, 29 years of age) complained of seeing dark spots in the central visual field. In 3 patients, the scotomas occurred bilaterally. Three patients reported a history of preceding flu-like illness. In all 4 cases, visual acuity in both eyes was 1.0 with normal anterior and posterior segments. The corresponding retinal lesions were only noted in the infrared image of the optical coherence tomography (OCT). OCT images showed focal abnormalities in the photoreceptor outer segments. Follow-up periods varied between 9 and 36 months. In all patients, symptoms improved with at least partial recovery of the retinal architecture. CONCLUSIONS: Patients with AMNR suffer from acute onset of unilateral or bilateral central scotomas. Visual acuity is often only mildly affected. AMNR has a variable prognosis. In some cases, a self-limiting course with retinal recovery is observed while some patients have persistent reduction in visual acuity. Because there is no causative treatment for AMNR, an observational treatment approach is generally recommended.

Vision Screening in Children in the Canton of St. Gallen.

BACKGROUND: Pediatric vision screening has been shown to reduce the prevalence of amblyopia. To assess the current local situation in the Canton of St. Gallen, a survey study was performed. METHODS: A standardized questionnaire was sent to 191 general practitioners and school doctors to obtain information on the currently applied vision screening protocols for children. The questionnaire included 17 questions with multiple answers possible. RESULTS: Sixty-seven participants (35%) answered the survey. Overall, 61 (91%) of the repliers confirmed that some sort of vision screening exists. According to 45 (67%) repliers, a mandatory examination exists. As to the question about the person performing the examination, multiple answers were given; 39 (44%) answered that the secretary or the medical practical assistant performs the vision tests, 15 (17%) indicated the school doctor, and 25 (28%) indicated the general practitioner or the pediatrician. Most screening tests are performed in a general practitioner's practice (32; 40%), some are done in the kindergartens (17; 21%), and others are done in a pediatrician's practice (17; 21%). The majority of children are tested at the age of 5 - 6 years (58, 87%). Sixty-one (91%) of the repliers indicated that at least the children's visual acuity is measured. Acuity is assessed with different methods, mainly, with pictures (20; 30%), numbers (23; 34%), and Snellen optotypes (33; 49%). CONCLUSIONS: There are no consistent regulations regarding vision screening in the Canton of St. Gallen. Actually, rather different screening scenarios exist. Tests are performed by a variety of people in different locations with diverse testing procedures. A standardization of the applied screening procedures at cantonal and national levels seems reasonable.

[Assessment of Cyclofusion Capabilities of Normal Subjects with 3D Dynamic Random-Dot Stereograms]. / Messung der Zyklofusionskompetenz bei Normalprobanden mittels dynamischer 3-D-"Random-Dot"-Stereogramme.

BACKGROUND: Evaluation of a new method for cyclofusion measurement. PATIENTS AND METHODS: The maximal incyclofusion and excyclofusion tolerated of 20 normal subjects (15 females, mean age 36 ± 9.9 years) were measured by computer-generated dynamic random-dot stereograms (DRDS). Subjects had to detect the orientation of only binocularly visible Landolt C stimuli randomly presented with a 3-D monitor. Both eyes were separately stimulated with shutter glasses. The DRDS-pattern projected to the left and right eye were rotated in the opposite direction in 0.5° steps. In 10 subjects, cyclofusion measurements were repeated. RESULTS: Incylofusional amplitudes were between 2.5° and 6°, excyclofusional amplitudes measured between 3° and 5.5°. Mean incyclofusion was 3.71° (SD 0.82) and mean excyclofusion measured 4.24° (SD 0.73). Repeated measurements of incyclofusion and excyclofusion in the same subject demonstrated a difference of about 0.5° (0.55° for incyclofusion, 0.45° for excyclofusion). CONCLUSIONS: The DRDS Landolt C method provided a reliable assessment with good reproducibility of cyclofusion in healthy subjects with only binocularly perceivable objects. Our cyclofusional capabilities were slightly higher than those received with dissociating 2D measurements.

[Congenital Simple Hamartoma of the Retinal Pigment Epithelium]. / Kongenitales einfaches Hamartom des retinalen Pigmentepithels.

BACKGROUND: Congenital simple hamartoma of the retinal pigment epithelium (CSHRPE) is an uncommon benign lesion with characteristic clinical features. Ophthalmoscopically it appears as a small localized, well circumscribed, pigmented tumor in the foveal region. In contrast to the more common flat congenital hypertrophy of the RPE the CSHRPE has an elevated nodular appearance. PATIENTS AND METHODS: Retrospective case series of three patients with CSHRPE. Clinical morphological features using different imaging techniques are presented. RESULTS: A typical dark lesion was incidentally noted in the macula of two patients. Optical coherence tomography (OCT) demonstrated a nodular preretinal hyperreflectivity with shadowing of deeper structures. In one patient the CSHRPE was hypofluorescent throughout the angiogram. The third patient presented with a reduced visual acuity of 0.3. A characteristic lesion was found at the foveal center. OCT revealed a hyperreflective preretinal lesion with associated moderate disruption of the foveal architecture. Amblyopia treatment slightly improved visual acuity in this case. The lesions remained stationary in two patients (follow-up 8 - 14 months). CONCLUSIONS: CSHRPE are usually detected as an incidental finding. Given its benign character and typically asymptomatic presentation an observational treatment approach is generally recommended. The lesions generally remain stationary and are not known to grow. In cases with visual impairment due to foveal involvement amblyopia treatment should be initiated.

Directed Two-Photon Absorption in CdSe Nanoplatelets Revealed by k-Space Spectroscopy.

We show that two-photon absorption (TPA) is highly anisotropic in CdSe nanoplatelets, thus promoting them as a new class of directional two-photon absorbers with large cross sections. Comparing two-dimensional k-space spectroscopic measurements of the one-photon and two-photon excitation of an oriented monolayer of platelets, it is revealed that TPA into the continuum is a directional phenomenon. This is in contrast to one-photon absorption. The observed directional TPA is shown to be related to fundamental band anisotropies of zincblende CdSe and the ultrastrong anisotropic confinement. We recover the internal transition dipole distribution and find that this directionality arises from the intrinsic directionality of the underlying Bloch and envelope functions of the states involved. We note that the photoemission from the CdSe platelets is highly anisotropic following either one- or two-photon excitation. Given the directionality and high TPA cross-section of these platelets, they may, for example, find employment as efficient logic AND elements in integrated photonic devices, or directional photon converters.

Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure.

Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters.

Variability of panretinal photocoagulation lesions across physicians and patients. Quantification of diameter and intensity variation.

BACKGROUND: Photocoagulation lesion intensity relies on the judgement of retinal blanching. Lesions turn out variable due to observer-dependent judgement and time dependency of blanching. We investigated lesion variability per patient and per physician in clinical routine treatments. METHODS: In this observational clinical trial, different physicians performed panretinal photocoagulation for diabetic retinopathy. Study eyes received 20-30 study lesions at 20 ms (three physicians, nine eyes) and 200 ms (four physicians, 12 eyes) irradiation time (532 nm continuous wave photocoagulator, 300 µm spot size). Lesions were imaged after 1 hour with photography and optical coherence tomography (OCT). We measured lesion diameters in fundus and OCT images, and graded intensities according to a previously published six-step classifier. RESULTS: 200-ms lesions were larger and more severe (568, 474-625 µm [median, IQR], predominantly class 6) than 20-ms lesions (397, 347-459 µm, predominantly classes 3-4). The impact of laser power was small compared to other factors. Lesion intensities and diameters in fundus and OCT images varied significantly between patients and between physicians. Median photographic lesion diameters varied by up to a factor of 1.61 (20 ms) or 1.5 (200 ms) respectively. CONCLUSIONS: In this study, the treated area of retina varied by up to a factor of 1.612 = 2.59 for a given spot number. As clinical efficacy depends on the treated area, which is a function of lesion number by area per lesion, our results implicate poor control of the overall treatment effect if treatments are administered according to lesion number or spacing alone. Better ways of laser effect control should be sought.

Superporous Poly(ethylene glycol) Diacrylate Cryogel with a Defined Elastic Modulus for Prostate Cancer Cell Research.

The physical and mechanical properties of the tumor microenvironment are crucial for the growth, differentiation and migration of cancer cells. However, such microenvironment is not found in the geometric constraints of 2D cell culture systems used in many cancer studies. Prostate cancer research, in particular, suffers from the lack of suitable in vitro models. Here a 3D superporous scaffold is described with thick pore walls in a mechanically stable and robust architecture to support prostate tumor growth. This scaffold is generated from the cryogelation of poly(ethylene glycol) diacrylate to produce a defined elastic modulus for prostate tumor growth. Lymph node carcinoma of the prostate (LNCaP) cells show a linear growth over 21 d as multicellular tumor spheroids in such a scaffold with points of attachments to the walls of the scaffold. These LNCaP cells respond to the growth promoting effects of androgens and demonstrate a characteristic cytoplasmic-nuclear translocation of the androgen receptor and androgen-dependent gene expression. Compared to 2D cell culture, the expression or androgen response of prostate cancer specific genes is greatly enhanced in the LNCaP cells in this system. This scaffold is therefore a powerful tool for prostate cancer studies with unique advantages over 2D cell culture systems.

Long-term, therapy-related visual outcome of 49 cases with retinal arterial macroaneurysm: a case series and literature review.

PURPOSE: Retinal arterial macroaneurysms (RAMAs) are acquired dilations of branches of the central retinal artery. Treatment depends on vision-limiting complications. We compare the long-term visual acuity (VA) in three groups according to treatment. METHODS: 49 charts of patients with RAMA were reviewed. 16 remained untreated, 15 received photocoagulation and 18 vitrectomy. Patients underwent full ophthalmological examinations and up-to-date imaging. We evaluated chosen therapy, complications and final VA at the last visit. RESULTS: 65% of the cohort was female, aged 75±11 years (mean±SD). Follow-up was 34±23 months. These parameters did not differ significantly between the three groups. In the observed group, initial VA was 0.48 (mean log MAR) vs 0.35 at the final visit, in the photocoagulation group 0.55 vs 0.59, and in the vitrectomy group 1.8 vs 0.77. VA was significantly worse at enrolment in the vitrectomy group, while all other VA differences were not significant. CONCLUSIONS: The overall visual prognosis of RAMA was good, even after macular complications. VA remained unchanged in the observed and the laser groups and was comparable in all groups after 3 years. Based on an individual treatment decision, all therapies were effective and efficient. If subfoveal haemorrhage caused a macular hole, the VA outcome was limited.

The dual annihilation of a surface plasmon and a photon by virtue of a three-wave mixing interaction.

The enhanced nonlinear interactions that are driven by surface-plasmon resonances have readily been exploited for the purpose of optical frequency conversion in metallic structures. As of yet, however, little attention has been payed to the exact particulate nature of the conversion process. We show evidence that a surface plasmon and photon can annihilate simultaneously to generate a photon having the sum frequency. The signature for this nonlinear interaction is revealed by probing the condition for momentum conservation using a two-beam k-space spectroscopic method that is applied to a gold film in the Kretschmann geometry. The inverse of the observed nonlinear interaction-an exotic form of parametric down-conversion-would act as a source of surface plasmons in the near-field that are quantum correlated with photons in the far-field.

Nonlinear plasmon-photon interaction resolved by k-space spectroscopy.

Metallic nanostructures support extreme localization and enhancement of optical fields via surface-plasmon (SP) resonances. Although SP are associated with giant enhancements of nonlinear phenomena such as second-harmonic generation (SHG), the role of SP in the process, whether as a field-enhancing catalyst or as a quasiparticle converted in the interaction, has remained experimentally elusive. We demonstrate how k-space spectroscopy can distinguish between the plasmonic and photonic SHG processes that occur in a metal nanofilm when it is optically driven via the Kretschmann geometry. The results revealed a nonlinear interaction where two SP annihilate to create a second-harmonic photon. This knowledge has implications for realizing the inverse process, plasmonic parametric down-conversion, which could act as a coherent source of entangled SP pairs.