Experimental Ophthalmology Research Articles

Инструментальная и морфологическая оценка изменений стромы роговицы мыши в динамике посттравматического восстановления

Relevance. Around the world, corneal blindness caused by impaired transparency is one of the leading causes of vision loss. Damage to the cornea can also lead to the development of opacities. The pathogenesis of corneal opacities is based on pathomorphological changes in the corneal stroma. To explore the therapeutic potential of biomedical products and develop new treatments, a standardized and reproducible in vivomodel of corneal stromal injury is needed. In experimental ophthalmology, mouse models of various corneal injuries are widely used, but the dynamics of posttraumatic restoration of the ultrastructural organization of the stroma have been little studied. Purpose. To evaluate structural and functional changes in the corneal stroma of mice in the dynamics of post-traumatic recovery. Material and methods. Injury to the corneal stroma was performed using a sharp 33G needle in the form of a tunnel defect in the thickness of the cornea of C57BL/6 mice. The presence of post-traumatic damage and the dynamics of corneal recovery were assessed using instrumental methods (biomicroscopy of the anterior segment of the eye with a fluorescein test, optical coherence tomography (OCT) before, immediately after the injury, and after 2 and 4 weeks after injury. Transmission electron microscopy was performed using a JEM 1400 electron microscope. Morphometry of digital images was performed using Image J software, calculating the minimum nearest interfibrillar distance, diameter and fibril density. Results. The formation of a corneal stromal wound was confirmed by the development of reactive edema according to OCT data and the accumulation of fluorescein in all damaged corneas. 2 weeks after the injury, complete epithelization of the wound surface was observed. According to OCT data, 2 weeks after the injury, an increase in corneal thickness by 34% and an increase in the opacity index by 1.5 times were recorded compared to a healthy cornea. By the 4th week of observation, the corneal thickness and opacity index remained at a high level in the injured cornea. After the formation of injury to the corneal stroma, a decrease in the diameter of collagen fibrils, an increase in fibril density and the shortest nearest interfibrillar distance were revealed throughout the observation period. onclusion. A mechanical model of corneal trauma performed using a sharp 33-gauge needle induces the formation of stable stromal opacities. Instrumental and morphological research methods did not reveal stromal restoration during the entire observation period (4 weeks). Key words: corneal trauma, optical coherence tomography, corneal thickness, corneal transparency, corneal morphology, corneal fibrils

Intraocular lens power calculation formulas: a scientometric analysis.

The most accurate method of intraocular lens (IOL) power calculation in cataract surgery has not been determined, and further studies are needed to reach a consensus. The aim of this study was to assess publications related to IOL power calculation formulas, mapping their yearly trends, most productive authors, top publishing countries and institutions, and areas of specialization for IOL power formulas. We conducted a comprehensive analysis of research articles published on the topic of IOL power calculation formulas. Using PubMed, we employed appropriate search terms and filtered the results for the period of January 1, 1946, to June 28, 2023. Data were analyzed using CiteSpace, VOSviewer, and Microsoft Excel programs. The visual representations of the collected data through the use of figures was provided to demonstrate the aspects of IOL power calculation research. We retrieved 5475 documents in the initial search. Analysis of these documents revealed an increase in the number of publications, from one publication in 1946 to 201 publications in 2023. The top three countries contributing to these publications were the United States, China, and Japan, collectively accounting for over 27% of the total articles. However, the two institutions with the highest contributions were located in the United Kingdom and Hungary, neither of which was among the top 10 countries in overall contributions. Overall 15 326 authors contributed to publications pertaining to IOL power calculation formulas. Among these authors, the most prolific contributors included Achim Langenbucher from Saarland University (Germany), Giacomo Savini from G.B. Bietti Foundation I.R.C.C.S. (Italy), and Kenneth J Hoffer from the University of California (United States). Saarland University emerged as the most productive institution, contributing equally to two distinct departments: the Dr. Rolf M. Schwiete Center for Limbal Stem Cell Research and Congenital Aniridia, as well as the Department of Experimental Ophthalmology. The School of Physical Science at the Open University in the United Kingdom engaged in partnership with various institutions including Eye & Laser Clinic Castrop Rauxel in Germany and Johannes Kepler University Linz in Austria. Among the top 10 keywords found in the publications were "cataract", "cataract surgery", and "intraocular lens". This study represents the first scientometric analysis of publications related to IOL power calculation formulas. The study offers valuable insights into the geographic distribution, contributing authors, and emphasis of research on the IOL power calculation formulas. Further cooperation is essential to pinpoint the most suitable formula and to address gaps in our current understanding.

Investigation of local expression of NLRP3 inflammasome complex genes in modeling retinal degeneration <i>in vivo</i>

Neurodegenerative ophthalmopathology is one of the main causes of irreversible blindness and disability in the world. In the pathogenesis of diseases of this group, more and more attention has recently been paid to the role of local inflammation caused by the activation of innate immunity and the mechanisms of its genetic regulation. In recent years, works have appeared in the field of experimental ophthalmology that have demonstrated the possibility of NLRP1, NLRP3 inflammasome complexes assembling when exposed to hyperglycemia, oxygen deprivation of retinal cells, as well as modeling compressive stress similar to that in glaucoma [15]. However, the mechanism of inflammasome involvement in the development of neurodegenerative eye diseases remains unclear. The aim of the study was to investigate the local expression of genes encoding proteins of the NLRP3 inflammasome complex (NLRP3, CASP-1) in an experimental model of retinal degeneration in rabbits. The studies were performed on samples of tissue complex (TC) of the retina/retinal pigment epithelium (RPE) (retina/RPE TC), isolated from the eyes of 14 New Zealand albino rabbits, in which degenerative retinal lesion was modeled by a single subretinal injection of 0.01 mL of 0.9% sodium chloride solution, and 7 healthy rabbits without eye damage. The formation of retinal degeneration was judged on the basis of changes in morphofunctional parameters obtained during specialized ophthalmological research methods (optical coherence tomography, fundus autofluorescence, electroretinography) at follow-up periods of 1, 3 and 6 months. The level of expression of NLRP3 and CASP-1 genes in the retina/RPE TC was evaluated by reverse transcription polymerase chain reaction (RT-PCR). According to the results of the study, a statistically significant increase in NLRP3 gene expression (p < 0.001) was noted in the retina/RPE TC of experimental animals, which may indicate the involvement of NLRP-3 inflammasome components in the development of neurodegenerative retinal lesions. At the same time, the expression of the gene encoding CASP-1 was detected only in the retina/RPE TC of experimental eyes and is probably due to local inflammatory mechanisms in the retinal tissue. The high level of NLRP3, CASP-1 mRNA, detected in all retina/RPE TC samples of experimental eyes at late stages of the experiment (3 and 6 months), allows us to assume the formation of mechanisms (for example, activated glial phenotype) that support inflammation in retinal tissue. This should be taken into account in actively developing transplantation methods for the treatment of retinal degeneration.

The Chick Embryo and Its Structures as a Model System for Experimental Ophthalmology

The possibilities of using the chick embryo and its individual structures as a model system in experimental ophthalmology are considered. Cultures of the retina and spinal ganglia from chick embryos are used in the development of new methods for the treatment of glaucomatous optic neuropathy and ischemic optic neuropathy. The chorioallantoic membrane is used for modelling vascular pathologies of the eye, screening of anti-VEGF drugs, and assessing biocompatibility of implants. Co-culturing of chick embryo nervous tissue and human corneal cells makes it possible to study the processes of corneal reinnervation. The use of chick embryo cells and tissues in the "organ-on-a-chip" system opens up wide opportunities for fundamental and applied ophthalmological studies.

Benefits and new features of modern international internet data‐base “IOLCon” for updated and optimized IOL constants

AbstractPurposeBy inventing optical biometry about 20 years ago cataract surgery has changed fundamentally. Today, by establishing the most modern up‐to‐date internationally available database for IOL constants, “IOLCon” meets nowadays standards and requirements of a WEB based database for intraocular lens specifications and constants and provides essential data for successful cataract surgery. Biometer manufacturers are implementing the open XML interface to integrate IOLCon into their devices.MethodsClose cooperation with Institute of Experimental Ophthalmology, University Homburg/Saar (Germany).ResultsHaigis´ ULIB (User Group for Laser Interference Biometry) was the first database of its time to set a milestone in providing optimized constants for cataract surgery. From today's perspective, it no longer meets modern requirements. By launching IOLCon in 2017 a modern data base is worldwide available today which is open to all IOL and biometer manufacturers. By its self‐explanatory functionality it is providing its users all relevant lens parameters. IOLCon fulfills the requirements of a modern biometry database and established itself as an indispensable tool for cataract surgeons by today.ConclusionsSince its launch, IOLCon has grown steadily: As of February 2021, IOLCon offers data on approximately 489 IOL models from 29 manufacturers with almost 21.000 clinical data and optimizations for 121 IOL models. Thus, by implementing IOLCon a biometry database is now available, which will also meet the future demands of ongoing developing ophthalmo‐surgery. Today, IOLCon is a globally available internet‐based database which meets all requirements of modern ophthalmic surgery, it can be accessed at: https://iolcon.org.

Characteristics of the least-cited and most-cited articles in ophthalmology journals: A pilot study.

Limited research has examined differences between uncited papers and their most-cited counterparts. By comparing characteristics of each cohort, it is possible to better determine factors associated with increased citation count in the ophthalmology literature. We initially identified all research articles published in six popular general ophthalmology journals (Ophthalmology, JAMA Ophthalmology, Investigative Ophthalmology and Visual Sciences, American Journal of Ophthalmology, British Journal of Ophthalmology, and Graefe's Archive for Clinical and Experimental Ophthalmology) between 2001 and 2011. Forty-nine articles were identified as having accrued zero citations as of March 2021 and were compared with an equivalent number of articles with the highest number of citations published in the same journals and time period. Significance (p < 0.05) for comparisons was determined using the Mann-Whitney U test and Fisher's exact test. Compared to the least-cited articles, the most-cited articles were significantly more likely to be clinical, multi-institutional, and multi-national in scope, report a statistically significant result, have a conflict of interest, state a funding source, and have higher sample sizes. These publications had significantly more words in the abstract and manuscript and more references. Overall, the first authors of the most-cited articles were significantly more likely to be female and report greater prior research productivity, as assessed by the relative citation ratio (RCR). Considering a small number of articles were uncited at least a decade after publication, it appears most research is useful for future investigations. However, there remain distinct differences between uncited articles and their most-cited equivalents in ophthalmology.

Emerging imaging developments in experimental vision sciences and ophthalmology.

Emerging imaging developments in experimental vision sciences and ophthalmology.

Edward S Perkins, MD, PhD (1919-2015): In the vanguard of ophthalmic physician-scientists.

British-American ophthalmologist Edward Perkins, MD, PhD (1919-2015) held wide-ranging research interests during his career at the Institute of Ophthalmology in London, the University of Iowa, and as a military doctor stationed in Kenya. With his PhD and a medical degree, Perkins was in the vanguard of clinician-scientists who possessed such dual credentials, enabling him to perform noteworthy experimental and clinical research. Perkins' glaucoma research included early work on acetazolamide and prostaglandins, laser iridotomy, and large-scale glaucoma surveys such as the Bedford Glaucoma Survey. In 1957, Perkins earned a PhD with a thesis on cranial nerve influences on rabbit intraocular pressure. Perkins also invented a handheld applanation tonometer; wrote an entire volume on uveitis for Duke-Elder's system of Ophthalmology; co-founded the Association for Eye Research (the European Association for Vision and Eye Research forerunner); and was a charter member of the Glaucoma Research Society. In 1961, Perkins became the first Professor of Experimental Ophthalmology at the Institute of Ophthalmology in London. In 1979, Perkins and his family emigrated to the United States, where he became a Professor of Ophthalmology at the University of Iowa. Perkins' understated personality masked a legacy of extensive contributions to the field of ophthalmology.

COVID-19 and ophthalmology: A scientometric analysis.

Purpose:Coronavirus disease pandemic has impacted global healthcare tremendously and ophthalmology is one of the high-hit specialties. An increasing number of research items are upcoming with COVID-19-related research in ophthalmology and this report aims at performing a scientometric analysis of all the available research pertaining to COVID-19 and ophthalmology.Methods:A Web of Science (https://webofknowledge.com) query TS = (“novel coronavirus 2019” OR “coronavirus 2019” OR “COVID 2019” OR “COVID 19” OR “nCOV” OR “SARS-CoV-2” OR “COVID-19”) AND WC = (“Ophthalmology”) was deployed on February 22, 2021, to retrieve all research items on the topics of interest. R software (v4.0.1) with Bibliometrix library was deployed to visualize metrics to quantify geographical distribution, source metrics, author metrics, document metrics, and keyword metrics.Results:A total of 616 research items appeared in our search results that were drafted by 2398 authors and published in 63 sources. India, USA, UK, and China had the greatest number of research items among others. Indian Journal of Ophthalmology, Eye, and Graefe’s Archive for Clinical and Experimental Ophthalmology were sources with greatest number of research items. Documents per author were 0.257 and authors per document were 3.89. The collaboration index was noted to be 4.28.Conclusion:Our scientometric analysis presents descriptive quantitative metrics for COVID-related research in the field of ophthalmology and provides evidence for the increased global collaboration that global researchers have fostered to fight this pandemic.

Contrast-enhanced plane-wave ultrasound imaging of the rat eye

Preclinical imaging, especially of rodent models, plays a major role in experimental ophthalmology. Our aim was to determine if ultrasound can be used to visualize and measure flow dynamics in the retrobulbar vessels supplying and draining the eye and the potential of contrast microbubbles to provide image and measurement enhancement. To accomplish this, we used a 128-element, 18 MHz linear array ultrasound probe and performed plane-wave imaging of the eyes of Sprague Dawley rats. Compound images were acquired by emitting unfocused wavefronts at multiple angles and combining echo data from all angles to form individual B-scans. Multiple imaging sequences were utilized, compounding up to six angles, with imaging rate of up to 3000 compound B-scans per second and sequence durations from 1.5 to 180 s. Data were acquired before and after intravenous introduction of contrast microbubbles. We found the total power of the Doppler signal in the image plane to increase approximately 20 fold after injection of contrast, followed by an exponential decay to baseline in about 90 s, The best-fit time constant of the decay averaged 41 s. While major vessels and the retinal/choroidal complex were evident pre-contrast, they were dramatically enhanced with contrast present, with details such as choroidal arterioles seen only with contrast. Ocular arteriovenous transit time determined from comparative enhancement curves in arteries and veins was approximately 0.2 s. In conclusion, plane wave ultrasound, especially with enhancement by contrast microbubbles, offers a means for the study of ocular hemodynamics using the rat eye as a model.

О научных итогах 17th International Conference on Clinical and Experimental Ophthalmology (1-3 октября 2018 г., Москва)

О научных итогах 17th International Conference on Clinical and Experimental Ophthalmology (1-3 октября 2018 г., Москва)

In Vivo Imaging of Cx3cr1gfp/gfp Reporter Mice with Spectral-domain Optical Coherence Tomography and Scanning Laser Ophthalmoscopy.

Spectral domain optical coherence tomography (SD-OCT) and scanning laser ophthalmoscopy (SLO) are extensively used in experimental ophthalmology. In the present protocol, mice expressing green fluorescent protein (gfp) under the promoter of Cx3cr1 (BALB/c-Cx3cr1gfp/gfp) were used to image microglia cells in vivo in the retina. Microglia are resident macrophages of the retina and have been implicated in several retinal diseases1,2,3,4,5,6. This protocol provides a detailed approach for generation of retinal B-scans, with SD-OCT, and imaging of microglia cell distribution in Cx3cr1gfp/gfp mice with SLO in vivo, using an ophthalmic imaging platform system. The protocol can be used in several reporter mouse lines. However, there are some limitations to the protocol presented here. First, both SLO and SD-OCT, when used in the high-resolution mode, collect data with high axial resolution but the lateral resolution is lower (3.5 µm and 6 µm, respectively). Moreover, the focus and saturation level in SLO is highly dependent on parameter selection and correct alignment of the eye. Additionally, using devices designed for human patients in mice is challenging due to the higher total optical power of the mouse eye compared to the human eye; this can lead to lateral magnification inaccuracies7, which are also dependent on the magnification by the mouse lens among others. However, despite that the axial scan position is dependent upon lateral magnification, the axial SD-OCT measurements are accurate8.

New Therapeutic Approaches in Inflammatory Diseases of the Eye - Targeting Lymphangiogenesis and Cellular Immunity: Research Unit FOR 2240 Presents Itself

Background Ophthalmology, principally, is a very successful subdiscipline in medicine. Nonetheless, there are still unmet medical needs which necessitate translational research. Methods The funding instrument of a Research Unit (RU) of the German Research Foundation (DFG) is presented as exemplified by the RU 2240 at the Department of Ophthalmology at the University of Cologne. Results The Research Unit integrates different research groups working on pathologic ocular inflammation, macrophages/microglia and (lymph)angiogenesis to collaborate in a synergistic way. Rotation positions allow young clinicians to rotate into research labs for a defined period of time. A Research Unit is also a powerful strategic tool to strengthen clinical and experimental ophthalmology at individual medical faculties. Conclusions The funding instrument of a Research Unit is highly suitable for fostering translational research in a medical subdiscipline such as ophthalmology, supporting the next generation of (clinician) scientists in ophthalmology and finding new cures for our patients.

Genome Editing Tools and their Application in Experimental Ophthalmology

New genome editing tools in molecular biology are revolutionising precise genome surgery and have greatly influenced experimental ophthalmology too. Aside from the commonly used nuclease-based platforms, such as the zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN), CRISPR/Cas systems, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes, perform very efficiently in site-specific DNA cleavage within living cells. DNA double strand breaks (DSB) are repaired through two different conserved repair pathways: NHEJ (non-homologous end joining) and HDR (homology directed repair). By using the correct DNA templates, these repair pathways can be used to knock out defective genes or to repair mutations. Genome editing technology lays the ground for new strategies in basic science, biotechnology, and biomedical science, as well as clinical studies with genome editing. Therapeutic gene editing strategies are now concentrating on diseases in the retina, due to the comparatively easy accessibility of the eye and with local application in vivo.

Rabbit Models of Ocular Diseases: New Relevance for Classical Approaches

Over 100 million individuals are affected by irreversible visual impairments and blindness worldwide, while ocular diseases remain a challenging problem despite significant advances in modern ophthalmology. Development of novel drugs and drug delivery mechanisms, as well as advanced ophthalmological techniques requires experimental models including animals, capable of developing ocular diseases with similar etiology and pathology, suitable for future trials of new therapeutic approaches. Although experimental ophthalmology and visual research are traditionally performed on rodent models, these animals are often unsuitable for pre-clinical drug efficacy and safety studies, as well as for testing novel drug delivery approaches, e.g. controlled release of pharmaceuticals using intra-ocular implants. Therefore, rabbit models of ocular diseases are particularly useful in this context, since rabbits can be easily handled, while sharing more common anatomical and biochemical features with humans compared to rodents, including longer life span and larger eye size. This review provides a brief description of clinical, morphological and mechanistic aspects of the most common ocular diseases (dry eye syndrome, glaucoma, age-related macular degeneration, light-induced retinopathies, cataract and uveitis) and summarizes the diversity of current strategies for their experimental modeling in rabbits. Several applications of some of these models in ocular pharmacology and eye care strategies are also discussed.

Prospects to regain the ability to accommodate

Over one billion people around the world are affected by presbyopia [1]. A major factor causing presbyopia is stiffening of the crystalline lens. Elasticity, as a material property of the crystalline lens matrix, is often expressed by the Young’s modulus, a unit for stiffness named after Thomas Young. Interestingly, Thomas Young also studied accommodation and developed an instrument to measure objectively the accommodative amplitude. In 1801 he concluded that Bin general, I have reason to think that the faculty diminishes to some degree as persons advance in life^ [2]. This phenomenon has been confirmed in later years by measuring the accommodative amplitude of thousands of subjects, and it was soon suggested that the decline in accommodative amplitude with age should be attributed to stiffening of the crystalline lens [3]. Traditionally, presbyopia is treated with reading spectacles or contact lenses, using bifocal contact lenses or some sort of monovision. More recently, laser refractive surgery has gained popularity as the procedure has options of using multifocality and monovision for treating presbyopia. Another and more invasive alternative is to perform clear lens extraction, in which the natural crystalline lens is replaced by a multifocal or accommodating intraocular lens or a by lens that extends the range of vision. Scleral approaches are also being explored [4]. A less invasive way to combat presbyopia, proposed in 1998 by Myers and Krueger, is to alter the properties of the crystalline lens by photoablation or photodisruption in the crystalline lens by a laser [5]. While mechanical changes in the lens material as a result of laser treatment were already foreseen [6], Krueger and co-workers demonstrated a change in pliability of the lens as a whole, suggesting that presbyopia may be alleviated or reversed [7]. So far, only moderate changes in pliability have been observed. A factor influencing the effect of the procedure is the geometrical pattern inside the lens that is treated by the laser. Studies have concentrated on cutting inside the lens, generating gliding planes along which internal deformations can take place [8]. The search for the optimal gliding planes that maximize lens pliability is the subject of the paper BFinite element modelling of radial lentotomy cuts to improve the accommodation performance of the human lens^ by Burd & Wilde in the current issue of in Graefe’s Archive for Clinical and Experimental Ophthalmology. Instead of experimental studies, e.g. using cadaver eyes, the authors use computational methods to compare the effects of different cutting geometries. Computational methods avoid issues with measurement uncertainties, as well as variance between test specimen and post mortem degradation of cadaver lenses. On the down side, the validity of computational outcomes depends heavily on the validity of the input parameters of the model: geometry, material properties, and boundary conditions. It has been well demonstrated by the same authors in previous studies that the way that the behavior of ocular tissues is modeled has a significant effect on the outcomes [9, 10]. In the current paper the authors demonstrate this once again, by modeling the behavior of the lens matrix in two different ways. First, they model the lens matrix as an incompressible material that is initially linear elastic, but becomes non-linear due to large deformations. This approach of modelling the mechanical behavior of the crystalline lens is most often used in current literature. Then, as an alternative, they introduce a poroelastic material model, which represents the lens matrix as a two-phase mixture of an incompressible fluid and a compressible hyperelastic solid matrix. Whether this is a more realistic * Henk A. Weeber henk.weeber@abbott.com

Ghost-image analysis in phakic intraocular lenses with central hole as a potential cause of dysphotopsia

To analyse the optical effect of an artificial hole in the optic centre of posterior chamber phakic intraocular lenses. Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany. Experimental simulation study. Four eye models with an ametropia of -4 D, -8 D, +4 D, and +8 D were created in the ray tracing software ASAP. Refractive correction of these models was implemented with a model of an Implantable Collamer Lens (ICL). Each eye was set up twice with 1 eye receiving a conventional ICL without a central hole and the second an ICL with a central hole. Ray bundles were traced for lateral visual field angles from 0 to 60 degrees in steps of 1 degree. Ray propagation and retinal illumination were then compared between the 2 ICL models. All eye models showed ghost images originating from the anterior surface of the ICL. Eye models with the ICL with central hole showed additional light spots in the peripheral areas of the retina originating from reflections at the cylindrical wall of the central hole in the ICL. The average intensity of ghost images in the temporal retinal hemisphere was between 30 and 40 dB less than the maximum intensity of the primary image. A central hole within a posterior chamber phakic intraocular lens may cause stray light and ghost images (positive dysphotopsia) although the on-axis visual quality of the eye with the ICL is mostly unaffected. The authors have no financial interest in any of the material presented in this paper.

Flavonoids and glaucoma: revisiting therapies from the past

Flavonoids are a large family of phytonutrient compounds found in various plants (berries, tea, citrus fruits) as well as in chocolate and red wine. More than 5000 flavonoid compounds are currently known, grouped into five main categories (flavonols, flavan-3-ols, flavones, flavanones, and anthocyanidins). Flavonoids constitute 25 % of the Ginkgo biloba extract (GBE), processed from the leaves of one of the oldest living tree species, a Bliving fossil^, having survived since the Permian more than 250 million years ago. TheGinkgo biloba tree, which is found in the wild only in China, has been used for its therapeutic effects for more than 5000 years, both in China and worldwide. Today, the tree is cultivated across the world, and continues to be offered as alternative treatments for ailments associated with aging, such as neurodegenerative disorders, cognitive decline, vascular insufficiency and glaucoma, often with controversial results.Gingko biloba is the most common (50 %) herbal supplement used by elderly patients, often as an over-the-counter compound [1]. Due to their perceived antioxidant, anti-inflammatory and neuroprotective benefits, various flavonoids (and in particular GBE) have been proposed for the treatment of non-pressuredependent risk factors associated with glaucoma [2]. This interest has been propelled by the fact that classic glaucoma treatments, based on reduction of the intraocular pressure (IOP), may not always prevent glaucoma progression. This may be particularly true in patients with progressive primary open-angle glaucoma (POAG) despite IOP normalization, or in POAG patients with the normal-tension glaucoma (NTG) subtype. The use of flavonoids in glaucoma has been supported bymany in vitro and in vivo studies, suggesting their active role in neuroprotection, reduction of mitochondrial oxidative stress and improvement of ocular blood flow [3]. Since impaired ocular blood flow can be more pronounced in NTG than in POAG, or in progressive versus stable forms of POAG, it has been suggested that GBE—and more generally, flavonoids—could represent a promising adjuvant therapy in these two settings [4]. The high safety profile of flavonoids also contributes to its current popularity and its large over-thecounter consumption [5]. Despite numerous attempts to evaluate the efficacy of flavonoids and GBE in the treatment of glaucoma, only a few randomized comparative studies have been published so far, with conflicting results [6, 7]. Many of these studies have individually suggested a beneficial role in glaucoma, especially in NTG, but the small number of included patients and the heterogeneity of the study design make it difficult to draw a firm conclusion. In the current issue of Graefe’s Archive for Clinical and Experimental Ophthalmology, Patel et al. evaluate the efficacy of flavonoids in glaucoma and ocular hypertension, performing a review and a meta-analysis of the currently published data, including only randomized controlled trials [8]. The number of included studies was surprisingly small: among the initially 16,840 screened articles, only six trials encompassing a total of 214 participants could be included, based on the inclusion criteria. Despite a rigorous effort to avoid risks of bias at each step of the study, the authors chose to include patient populations with a large variety of conditions (ocular hypertension, POAG, NTG, chronic angle* Tin Aung aung.tin@snec.com.sg

Influence of stereoscopic vision on task performance with an operating microscope

To determine the extent to which stereoscopic depth perception influences the performance of tasks executed under an operating microscope. Laboratory of Experimental Ophthalmology, University Medical Center Groningen, the Netherlands. Experimental study. Medical students were assigned (on the basis of their stereoacuity) to a stereo-sufficient group (depth perception ≤240 seconds of arc [arcsec]) or stereo-deficient group (≥480 arcsec). They performed a bead-stringing task (a mockup surgical test) under an operating microscope or a task on a cataract surgery simulator. The stereo-sufficient subjects also performed the bead-stringing task under artificial stereo-deficient conditions (binocular and monocular viewing). The study comprised 77 medical students. The stereo-sufficient subjects performed both tasks faster than the stereo-deficient subjects and artificially stereo-deficient subjects (P ≤ .024). In addition, a within-group analysis established that the stereo-sufficient subjects were faster at the bead-stringing task with stereoscopic viewing than under artificial stereo-deficient conditions with binocular viewing (P ≤ .011). Having stereovision resulted in better initial performance on certain tasks involving the use of an operating microscope or cataract surgery simulator. However, this study did not show that stereo deficiency necessarily results in an inability to perform such tasks properly. Hence, it was not evident that for admission to an ophthalmology residency program, stereovision should be judged more stringently than other traits. No author has a financial or proprietary interest in any material or method mentioned.

Editorial introductions

Current Opinion in Ophthalmology was launched in 1990. It is one of a successful series of review journals whose unique format is designed to provide a systematic and critical assessment of the literature as presented in the many primary journals. The field of Ophthalmology is divided into nine sections that are reviewed once a year. Each section is assigned a Section Editor, a leading authority in the area, who identifies the most important topics at that time. Here we are pleased to introduce the Editor for the journal and the Section Editor for this issue. EDITOR Allen C. HoAllen C. HoDr Allen C. Ho is an Attending Surgeon of the Retina Service and Director of Retina Research of Wills Eye Hospital, USA. He is Professor of Ophthalmology at Thomas Jefferson University School of Medicine, USA. Dr Ho is a founding member of Mid Atlantic Retina, USA. He is author of multiple textbooks including Age Related Macular Degeneration Diagnosis and Treatment, The Wills Eye Hospital Color Atlas and Synopsis of Retinal Disease and is Editor-in-Chief of Current Opinion in Ophthalmology and Chief Medical Editor of Retina Today, a global publication that features new therapies for retinal disease. He is a member of the Scientific Editorial Boards of Retina Cases and Brief Reports, Ophthalmic Surgery, Lasers and Imaging, Retinal Physician, and Ocular Surgery News. Dr Ho has been an invited lecturer at numerous national and international ophthalmic meetings around the world. He is a recipient of multiple clinical research grants investigating new treatments for macular diseases sponsored by the National Eye Institute and received the American Academy of Ophthalmology's Achievement Award and Senior Achievement Award and the American Society of Retina Specialists Crystal Apple Award. Dr Ho is Principal Investigator at Wills Eye Institute of several collaborative clinical trials evaluating new treatments for age-related macular degeneration, surgical retina and diabetic retinopathy. He maintains special interests in macular diseases, diabetic retinopathy, surgical retinal diseases and clinical trials investigating new treatments for vitreoretinal diseases. SECTION EDITOR Natalie A. AfshariNatalie A. AfshariNatalie A. Afshari; MD, FACS, is Chief of Cornea and Refractive Surgery and Professor of Ophthalmology at Shiley Eye Center, University of California San Deigo, USA. Previous to this she was Professor of Ophthalmology and Cornea Fellowship Program Director at the Duke Eye Center, USA. She received her medical degree from Stanford University, USA and her residency training at Harvard University, Massachusetts Eye and Ear Infirmary, USA. She then completed a two year fellowship in cornea and refractive surgery at Harvard University, Massachusetts Eye and Ear Infirmary, USA. Dr Afshari has been recognized by her peers in several of the “best doctors” lists, including “The Best Doctors in America” in each listing for the past decade. She is also the recipient of the inaugural Top Ten Women in Medicine Award by Triangle News. Furthermore, Dr Afshari was awarded the Achievement Award and the Secretariat Award by the American Academy of Ophthalmology. Dr Afshari has published extensively in both medical journals and textbooks. She is the co-editor of a new two volume Cornea Book: Principles and Practice of Cornea and she has served on the editorial board of Clinical and Experimental Ophthalmology and EyeNet. She is also a reviewer for a number of scientific journals. Her research has won her honors, including Research to Prevent Blindness (RPB) award and the Heed Foundation Ophthalmic Award. Dr Afshari has received the Teacher of the Year award at Duke University Eye Center. She also has been invited to lecture nationally and internationally. Dr Afshari's peers also elected her to the cornea program committee and Awards committee of the Association for Research in Vision and Ophthalmology (ARVO). She is also the Chief Judge for the scientific posters of American Society of Cataract and Refractive Surgery. When not researching or practicing, Afshari donates her time and surgical expertise as an international volunteer. She has travelled to West Africa, Central America, and Mexico to help patients who might otherwise go untreated.