【In Press】 Extracting intraocular foreign body at or near the ciliary body with scleral indentation in direct visualization

Letter to the editor     

The point-spread function of the eye from 0° to 100° and the pattern electroretinogram

In studies on the pattern electroretinogram the quality of the retinal image is a major concern. The use of contact lens electrodes was rejected since a good pattern could not be recorded. This is believed to be due to blurring of the retinal image. As indicator of image quality the patient's visual acuity is often used. We wondered whether this is a sufficient criterion. The retinal image is the product of the whole optical point-spread function of the eye whereas visual acuity refers only to the central portion of this function. On the basis of existing reports it can be estimated that for the young normal eye the outer edges of this function (straylight) causes considerable loss of contrast. The strength of the straylight can be much greater in older eyes. We studied the relation between the point-spread function including straylight and the pattern electroretinogram in normal eyes and some pathological cases. The measurements proved to follow the calculated contrasts on the basis of a local luminance model, with the exception of enhancement (tuning) around 60 checksize for the young normal eye. Because of the considerable differences in straylight in an older population one has to take into account that loss of pattern electroretinogram can be suffered in patients with otherwise good visual acuity.     

Studies on the “vascular labeling” phenomenon in the iris and the ciliary body of the rat after intravenous injection of colloidal carbon

Summary The occurrence of carbon deposits after intravenous injection of colloidal carbon (vascular labeling phenomenon) in the iris and the ciliary body of the rat eye was studied by vital microscopy, unstained perfused mount preparations, and by electron microscopy. Generally in the untouched eye the vascular labeling phenomenon is either absent or appears only in the form of finest granular deposits in some capillaries and venules of the iris and the ciliary body. A decrease of intraocular pressure by paracentesis causes a certain blackening phenomenon, which prefers the capillaries and the venules of the iris and the capillaries in the ciliary processes. This effect is intensified by a further decrease of the intraocular pressure to -30 mm Hg. Predominantly the deposits are found stronger in the ciliary region than in the iris. Increase of the intraocular pressure of up to 30 mm Hg diminishes the blackening phenomenon. After administration of the vasodilator bencyclane into the anterior chamber the vascular labeling phenomenon shows a clear graduation of carbon affinity depending upon the concentration of the drug: The capillaries and venules are exclusively blackened at low concentrations, additionally the collecting venules and arterioles are influenced at medium and high doses. By electron microscopy an intraluminal as well as an intramural (subendothelial) deposition of carbon, partly accompanied with signs of hemoconcentration, can be seen. Extravascular position of carbon material is seldom observed and restricted to a state of abnormally high vascular permeability. The observations give evidence for a gradient of permeability between the different types of vessels of the terminal anterior uveal vascular system and also permit the assumption that the vessels of the ciliary processes are more permeable than those of the iris.

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Zusammenfassung Das Auftreten von Tuscheablagerungen nach intravenöser Injektion von Spezialtusche (vascular labeling phenomenon) im Gebiet der feinsten Gefäße der Iris und der Ziliarfortsätze des Rattenauges wurde sowohl vitalmikroskopisch am durchströmten Augenkreislauf als auch anhand ungefärbter, perfundierter Totalpräparate und elektronenmikroskopisch untersucht.An intakten Augen finden sich im allgemeinen keine oder nur sehr geringe kleinfleckige Tuscheablagerungen in einzelnen Kapillaren und Venulen der Iris bzw. an den Kapillaren der Ziliarfortsätze. Bei Druckentlastung des Auges durch Parazentese kommt es zu einer deutlichen Schwärzung der Venulen der Iris und der Kapillaren und der Ziliarfortsätze. Der Effekt läßt sich durch einen Saugdruck von -30 mm Hg steigern. Die Ablagerungen sind im Gebiet des Ziliarkörpers im allgemeinen stärker als in der Iris ausgeprägt. Erhöhung des Augeninnendruckes auf +30 mm Hg schwächt das Schwärzungsphänomen ab. Nach intrakammeraler Gabe von Bencyclan, einem Wirkstoff mit stark vasodilatatorischen Eigenschaften, zeigt das Schwärzungsphänomen deutliche, von der Konzentration abhängige Abstufungen. Bei niedriger Konzentration werden ausschließlich die Kapillaren und kleineren Venulen, bei mittelstarken und hohen Dosen zusätzlich die Sammelvenulen und die Arteriolen geschwärzt.Elektronenmikroskopisch werden intraluminale und intramurale Tuscheablagerungen gefunden, welche z.T. mit Zeichen der Hämokonzentration (Stase) vergesellschaftet sind. Eine extravasale Lage von Tuschematerial ist selten zu finden und auf den Zustand von abnormal hoher Vasopermeabilität beschränkt.Die Untersuchungen sprechen für das Vorliegen eines Permeabilitätsgradienten zwischen den verschiedenen Gefäßkategorien des vorderen Uveakreislaufes und geben auch einen Hinweis auf eine höhere Durchlässigkeit der Gefäße der Ziliarfortsätze gegenüber der der Irisgefäße.

     

Primary position vertical nystagmus: ‘Directional preponderance’ of the pursuit system?

Summary The essential disturbance in five patients with vertical nystagmus was an inability to generate smooth pursuit eye movements in the direction of the quick phase of their nystagmus. As the cause of this behavior, the authors suggest an asymmetric impairment of the visual input to the pursuit system. This defect causes a directional preponderance of the pursuit system detectable as a continuous drift off target. The drift is interrupted by refoveating saccades, thus resulting in a vertical nystagmus.

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Zusammenfassung Fünf Patienten mit Vertikalnystagmus zeigten als wesentliche Störung eine Unfähigkeit, gleitende Folgebewegungen in Richtung der raschen Nystagmusphase auszuführen. Als Ursache dieser Störung nehmen Verff. eine asymmetrische Unterbrechung visueller Zuflüsse zum Folgesystem an. Durch diese Unterbrechung wird das normalerweise bestehende Gleichgewicht im Folgesystem gestört. Es entsteht ein Richtungsüberwiegen im Folgesystem, das sich in einem Abtreiben der Gesichtslinie vom ruhenden Fixierpunkt auswirkt. Dieses Abtreiben wird immer wieder durch Sakkaden korrigiert, so daß ein Nystagmus entsteht.

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Supported by the Deutsche Forschungsgemeinschaft, SFB 70, B 4     

Primary Wegener’s Granulomatosis of the Orbital Apex with Initial Optic Nerve Infiltration

Wegener’s granulomatosis can involve the orbit and sometimes the optic nerve. This usually occurs as a result of contiguous spread from affected sinuses or extraocular muscles, or from a vasculitic posterior optic neuropathy. However, we present an unusual case of isolated orbital apex infiltrative disease in a patient with known Wegener’s granulomatosis. This initially caused painless optic neuropathy and progressed to painful ophthalmoplegia and blindness. Optic nerve biopsy, performed to exclude methotrexate-induced lymphoma, confirmed optic nerve infiltration. The condition was refractory to high-dose pulsed methylprednisolone but the patient gained symptomatic relief from rituximab. Wegener’s granulomatosis should be considered in cases of isolated posterior optic neuropathy, and close attention should be placed on imaging the orbital apex.     

Long-term results of 360A° scleral buckling and vitrectomy with silicone oil tamponade for management of gunshot-perforating ocular injury

Purpose

This is a retrospective consecutive study to assess the long-term results of combined scleral buckling and pars plana vitrectomy (PPV) with silicone oil for the management of perforating ocular injury caused by gunshots.

Methods

Data were gathered from medical records of patients who underwent scleral buckling and PPV with silicone oil 2 weeks after primary repair elsewhere, in Magrabi eye center (Tanta, Egypt), from June 2005 to May 2010.

Results

The evaluated group consisted of 49 cases, out of which 26 cases presented with gunshot injury. Twenty-two were male (84.62%) and four were female (15.38%), with a mean age of 27.19+12.7 years. The follow-up ranged from 12 to 72 months, with a mean period of 32.04+8.9 months. The t-test was used to determine the visual outcome and main prognostic factors. Visual acuity improved in 22 of 26 eyes (76.92%), was unchanged in 4 eyes (15.38%), and worsened in 2 eyes (6.69%). Ten eyes (38.46%) achieved visual acuity between (20/40) and (20/100), and eight eyes (30.76%) had visual acuity between (20/200) and (20/400). The 18 eyes (69.23%) with visual acuity better than counting fingers (CF) had an attached retina with no signs of active proliferation after removal of the silicone oil.

Conclusion

POI due to gunshot is usually a terminal event for the eye. Eyes with perforating injury can be saved and may attain useful vision after performance of combined scleral buckling and PPV with silicone oil tamponade. The final visual outcome depends on the macular or the optic nerve involvement and the final retinal stability, and phthisis bulbi can also be prevented.     

Post-intravitreal injection endophthalmitis pattern during the COVID-19 pandemic with implementation of patients’ masking

Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the role of patient facial masks on the occurrence of post-intravitreal injection (IVI) endophthalmitis in a real-word...     

Assessment of reading behavior with an infrared eye tracker after 360° macular translocation for age-related macular degeneration

PURPOSE. Macular translocation (MT360) is complex surgery used to restore reading in exudative age-related macular degeneration (AMD). MT360 involves retinal rotation and subsequent oculomotor globe counterrotation and is not without significant surgical risk. This study attempts to gauge the optimal potential of MT360 in restoring reading ability and describe the quality and extent of recovery. METHODS. The six best outcomes were examined from a consecutive series of 23 MT360 cases. Reading behavior and fixation characteristics were examined with an infrared eye tracker. Results were compared to age-matched normal subjects and patients with untreated exudative and nonexudative AMD. Retinal sensitivity was examined with microperimetry to establish threshold visual function. RESULTS. MT360 produced significant improvements in visual function over untreated disease and approximated normal function for reading speed and fixation quality. Relative to the comparative groups, eye tracking revealed the MT360 cohort generated a greater number of horizontal and vertical saccades, of longer latency and reduced velocity. In contrast, saccadic behavior when reading (forward and regressive saccades) closely matched normal function. Microperimetry revealed a reduction in the central scotoma with three patients recovering normal foveal sensitivity. CONCLUSIONS. Near normal reading function is recovered despite profound surgical disruption to the anatomy (retinal/oculomotor). MT360 restores foveal function sufficient to produce a single stable locus of fixation, with marked reduction of the central scotoma. Despite the limitations on saccadic function, the quality of reading saccadic behavior is maintained with good reading ability. Oculomotor surgery appears not to limit reading ability, and the results of retinal surgery approximate normal macular function.     

Primary neuroendocrine carcinoma (“Merkel cell tumor”) of the eyelid: a report of two cases

BACKGROUND . Merkel cell tumor is an uncommon, aggressive neoplasm of the skin, now regarded as a neuroendocrine carcinoma. Eyelids are among the sites where it can develop, often mimicking a benign process. The purpose of this report is to describe two new cases and to discuss briefly the problems of diagnosis and treatment. METHODS . Two patients with Merkel cell tumor of the eyelids are described. In both cases, the original clinical diagnosis was chalazion. Progressive growth of the lesion identified it as a tumor some 2-7 months after it was first noticed. The patients were treated by surgical excision of the tumor tissue, and only one by a course of local radiotherapy. The visual acuity was measured with Snellen fractions. The dose of local radiotherapy is given in cGy. RESULTS . Histopathological and immunohistochemical studies identified the lesion as a neuroendocrine carcinoma, consistent with Merkel cell tumor. The natural history was marked by aggressive behavior in one case, and by a delayed recurrence in the other, requiring different therapeutic approaches. CONCLUSION . Merkel cell carcinoma of the eyelid is a tumor that ophthalmogists should be aware of, as early diagnosis is a prerequisite for successful treatment. Rapid recurrence of any chalazion in a middle-aged or elderly patient should therefore prompt its histological examination to exclude the possibility of a malignant tumor.     

Pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP) in the early stages of Alzheimer’s disease

Alzheimer’s disease (AD) is one of the most common causes of dementia in the world. Patients with AD frequently complain of vision disturbances that do not manifest as changes in routine ophthalmological examination findings. The main causes of these disturbances are neuropathological changes in the visual cortex, although abnormalities in the retina and optic nerve cannot be excluded. Pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP) tests are commonly used in ophthalmology to estimate bioelectrical function of the retina and optic nerve. The aim of this study was to determine whether retinal and optic nerve function, measured by PERG and PVEP tests, is changed in individuals in the early stages of AD with normal routine ophthalmological examination results. Standard PERG and PVEP tests were performed in 30 eyes of 30 patients with the early stages of AD. The results were compared to 30 eyes of 30 normal healthy controls. PERG and PVEP tests were recorded in accordance with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. Additionally, neural conduction was measured using retinocortical time (RCT)—the difference between P100-wave latency in PVEP and P50-wave implicit time in PERG. In PERG test, PVEP test, and RCT, statistically significant changes were detected. In PERG examination, increased implicit time of P50-wave (P < 0.03) and amplitudes reductions in P50- and N95-waves (P < 0.0001) were observed. In PVEP examination, increased latency of P100-wave (P < 0.0001) was found. A significant increase in RCT (P < 0.0001) was observed. The most prevalent features were amplitude reduction in N95-wave and increased latency of P100-wave which were seen in 56.7% (17/30) of the AD eyes. In patients with the early stages of AD and normal routine ophthalmological examination results, dysfunction of the retinal ganglion cells as well as of the optic nerve is present, as detected by PERG and PVEP tests. These dysfunctions, at least partially, explain the cause of visual disturbances observed in patients with the early stages of AD.     

Differences between the neurogenic and proliferative abilities of Müller glia with stem cell characteristics and the ciliary epithelium from the adult human eye

Much controversy has arisen on the nature and sources of stem cells in the adult human retina. Whilst ciliary epithelium has been thought to constitute a source of neural stem cells, a population of Müller glia in the neural retina has also been shown to exhibit neurogenic characteristics. This study aimed to compare the neurogenic and proliferative abilities between these two major cell populations. It also examined whether differences exist between the pigmented and non-pigmented ciliary epithelium (CE) from the adult human eye. On this basis, Müller glia with stem cell characteristics and pigmented and non-pigmented CE were isolated from human neural retina and ciliary epithelium respectively. Expression of glial, epithelial and neural progenitor markers was examined in these cells following culture under adherent and non-adherent conditions and treatments to induce neural differentiation. Unlike pigmented CE which did not proliferate, non-pigmented CE cells exhibited limited proliferation in vitro, unless epidermal growth factor (EGF) was present in the culture medium to prolong their survival. In contrast, Müller glial stem cells (MSC) cultured as adherent monolayers reached confluence within a few weeks and continued to proliferative indefinitely in the absence of EGF. Both MSC and non-pigmented CE expressed markers of neural progenitors, including SOX2, PAX6, CHX10 and NOTCH. Nestin, a neural stem cell marker, was only expressed by MSC. Non-pigmented CE displayed epithelial morphology, limited photoreceptor gene expression and stained strongly for pigmented epithelial markers upon culture with neural differentiation factors. In contrast, MSC adopted neural morphology and expressed markers of retinal ganglion cells and photoreceptors when cultured under similar conditions.This study provides the first demonstration that pigmented CE possess different proliferative abilities from non-pigmented CE. It also showed that although non-pigmented CE express genes of retinal progenitors, they do not differentiate into neurons in vitro, as that seen with Müller glia that proliferate indefinitely in vitro and that acquire markers of retinal neurons in culture under neural differentiation protocols. From these observations it is possible to suggest that Müller glia that express markers of neural progenitors and become spontaneously immortalized in vitro constitute a potential source of retinal neurons for transplantation studies and fulfil the characteristics of true stem cells due to their proliferative and neurogenic ability.     

Dimensions of the ciliary muscles of Brücke,Müller and Iwanoff and their associations with axial length and glaucoma

Graefe's Archive for Clinical and Experimental Ophthalmology - To assess the dimensions of Brücke’s muscle, as the longitudinal portion, and of Müller’s muscle and...     

Further evidence for the fusional nature of the compensation (or ‘eating up’) of prisms in concomitant strabismus

The fusional nature of the phenomenon of prism compensation in strabismus was studied. At first a general survey was performed on the characteristics of anomalous fusional movements (a.f.m.). The influence of different kinds of stimuli (foveal and peripheral fusionable targets, non-fusionable targets) on a.f.m. was considered, and finally the effect of a sensorial obstacle to fusion was investigated. It is concluded that eating up the prisms is definitely a phenomenon of fusional nature, although it has special features which are interpreted as a consequence of the initial pathological condition. In this way the puzzling prism compensation also in subjects with normal retinal correspondence may be explained.     

Primary Ewing’s sarcoma of the orbit with intracranial extension abutting the temporal lobe: a rare case report

International Ophthalmology - Ewing’s sarcoma is a small, blue, round-cell tumor of mesenchymal origin which typically presents itself during the first and the second decades of life....     

Efficacy of bimatoprost 0.03% in reducing intraocular pressure in patients with 360° synechial angle-closure glaucoma: a preliminary study

Context:

Peripheral anterior synechiae (PAS; synechiae anterior to functional trabecular meshwork) formation in primary angle-closure glaucoma (PACG) hampers access to uveoscleral outflow. Thus, the role of bimatoprost in such patients with 360° synechiae was evaluated.

Aims:

To assess efficacy and safety profile of bimatoprost 0.03% in lowering intraocular pressure (IOP) in 360° synechial angle-closure glaucoma patients.

Settings and Design:

This was a prospective, non-randomized, non-comparative, selective analysis, single-center pilot study.

Materials and Methods:

A total of 23 eyes of 20 Indian chronic angle-closure glaucoma (CACG) patients with IOP greater than 21 mmHg, 360° PAS and no visual potential in the study eye underwent detailed eye examination. Baseline IOP was measured and YAG peripheral iridotomy was performed for complete angle-closure reconfirmation. Bimatoprost 0.03% was administered for 8 weeks as once-daily evening dose. IOP reduction within treatment group was determined with “paired t-test”.

Results:

The mean reduction in IOP from baseline to 8 weeks of bimatoprost therapy was 15.3 ± 9.5 mmHg (P < 0.001). The most commonly observed adverse event was conjunctival hyperemia (35%). Bimatoprost was well tolerated in the study.

Conclusions:

In this study, exclusively involving patients with 360° synechial angle-closure glaucoma and no visual potential, bimatoprost 0.03% treatment demonstrated a statistically significant IOP reduction. Hence, it can be inferred that bimatoprost 0.03% is an efficacious treatment modality in this subgroup of patients for reducing IOP.