Ocular Imaging Technologies Research Articles

Evidence-based guidelines for diagnosis and treatment of age-related macular degeneration in China (2023)

Age-related macular degeneration (AMD) is the main cause of low vision and even blindness in the elderly. With the aging of our population, the number of AMD patients will continue to rise. In the past decade, the rapid development of ocular fundus imaging technology has provided a new perspective and approach for the classification, diagnosis and follow-up of AMD. The advent of new drugs has provided more diverse intervention and treatment methods for AMD, especially for neovascular AMD, and the emphasis on accurate and individualized treatment has put forward higher requirements for retinal specialists. Therefore, based on the latest evidence-based medical information, combined with the international guidelines and the current situation of China's social and economic development, experts from the Chinese Vitreo-Retinal Society of Chinese Medical Association, the Fundus Disease Group of Chinese Ophthalmologist Association, and the National Clinical Research Center for Eye Diseases gave recommendations around eight clinical problems and formed China's guidelines for the clinical diagnosis and treatment of AMD. With the implementation of these guidelines, we can standardize the diagnosis, treatment, prevention and follow-up of AMD in China.

Myopic tilted disc: Mechanism, clinical significance, and public health implication.

Myopic tilted disc is a common structural change of myopic eyes. With advancing ocular imaging technology, the associated structural changes of the eye, particularly the optic nerve head, have been extensively studied. These structural changes may increase patients' susceptibility to axonal damage and the risk of developing serious optic neuropathies including glaucoma. They also lead to diagnostic difficulties of disease suspects and treatment dilemmas of patients, which implicate clinical practice and subsequently the health care system. In the context of the mounting prevalence of myopia worldwide and its implications to irreversible visual impairment and blindness, it is essential to gain a thorough understanding of the structural changes of myopia. Myopic tilted disc has been extensively investigated by different study groups. However, generalizing the knowledge could be difficult because of the variable definitions of myopic tilted disc utilized in these studies and the complexities of the changes. The current review aimed to clarify the concepts and discuss various aspects of myopic tilted disc, including the definitions, association with other myopia-related changes, mechanism of tilted disc development, structural and functional changes, and clinical implications.

Hotspots and trends in ophthalmology in recent 5 years: Bibliometric analysis in 2017-2021.

PurposeThe purpose of this study was to investigate the hotspots and research trends of ophthalmology research.MethodOphthalmology research literature published between 2017 and 2021 was obtained in the Web of Science Core Collection database. The bibliometric analysis and network visualization were performed with the VOSviewer and CiteSpace. Publication-related information, including publication volume, citation counts, countries, journals, keywords, subject categories, and publication time, was analyzed.ResultsA total of 10,469 included ophthalmology publications had been cited a total of 7,995 times during the past 5 years. The top countries and journals for the number of publications were the United States and the Ophthalmology. The top 25 global high-impact documents had been identified using the citation ranking. Keyword co-occurrence analysis showed that the hotspots in ophthalmology research were epidemiological characteristics and treatment modalities of ocular diseases, artificial intelligence and fundus imaging technology, COVID-19-related telemedicine, and screening and prevention of ocular diseases. Keyword burst analysis revealed that “neural network,” “pharmacokinetics,” “geographic atrophy,” “implementation,” “variability,” “adverse events,” “automated detection,” and “retinal images” were the research trends of research in the field of ophthalmology through 2021. The analysis of the subject categories demonstrated the close cooperation relationships that existed between different subject categories, and collaborations with non-ophthalmology-related subject categories were increasing over time in the field of ophthalmology research.ConclusionsThe hotspots in ophthalmology research were epidemiology, prevention, screening, and treatment of ocular diseases, as well as artificial intelligence and fundus imaging technology and telemedicine. Research trends in ophthalmology research were artificial intelligence, drug development, and fundus diseases. Knowledge from non-ophthalmology fields is likely to be more involved in ophthalmology research.

Comparison of Indocyanine Green Angiography and Fluorescein Angiography for Imaging of Central Serous Chorioretinopathy Patients as Candidates for Photodynamic Therapy

To compare fluorescein angiography (FA) and indocyanine green angiography (ICGA) for imaging of central serous chorioretinopathy (CSC) patients. The observational cross-sectional clinical study was conducted on 131 eyes of 131 patients with CSC who were candidates for photodynamic therapy (PDT). An experienced ophthalmologist marked the leakage sites and choroidal hyperpermeability sites that needed PDT. For each eye, simultaneous FA and ICGA imaging with the maximum leakage area was selected for comparison regarding the site and size. The mean±standard deviation age of patients was 44.53±9.03 years. Of 226 leakage points, 177 (78.32%) points were in the same site, and 168 (74.34%) points were in the same size on FA. No statistical difference was found between age (P=0.45), sex (P=0.32), and chronicity (P=0.11) of the disease in comparing the ICGA images to the FA images regarding leakage at the same site. A statistically significant difference was also found regarding size of leakage and chronicity (P<0.001). The current results suggested that FA could be considered an alternative ocular imaging technology as a guide for PDT in CSC patients.

BCLA CLEAR - Scleral lenses

Scleral lenses were the first type of contact lens, developed in the late nineteenth century to restore vision and protect the ocular surface. With the advent of rigid corneal lenses in the middle of the twentieth century and soft lenses in the 1970’s, the use of scleral lenses diminished; in recent times there has been a resurgence in their use driven by advances in manufacturing and ocular imaging technology. Scleral lenses are often the only viable form of contact lens wear across a range of clinical indications and can potentially delay the need for corneal surgery. This report provides a brief historical review of scleral lenses and a detailed account of contemporary scleral lens practice including common indications and recommended terminology. Recent research on ocular surface shape is presented, in addition to a comprehensive account of modern scleral lens fitting and on-eye evaluation. A range of optical and physiological challenges associated with scleral lenses are presented, including options for the clinical management of a range of ocular conditions. Future applications which take advantage of the stability of scleral lenses are also discussed. In summary, this report presents evidence-based recommendations to optimise patient outcomes in modern scleral lens practice.

Ocular Imaging for Enhancing the Understanding, Assessment, and Management of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is a progressive neuro-retinal disease and the leading cause of central vision loss among elderly individuals in the developed countries. Modern ocular imaging technologies constitute an essential component of the evaluation of these patients and have contributed extensively to our understanding of the disease. A challenge with any review of ocular imaging technologies is the rapid pace of progress and evolution of these instruments. Nonetheless, for proper and optimal use of these technologies, it is essential for the user to understand the technical principles underlying the imaging modality and their role in assessing the disease in various settings. Indeed, AMD, like many other retinal diseases, benefits from a multimodal imaging approach to optimally characterize the disease. In this chapter, we will review the various imaging technologies currently used in the assessment and management of AMD.

Objective Imaging Diagnostics for Dry Eye Disease.

Traditional diagnostic tests for dry eye disease (DED), such as fluorescein tear film break-up time and the Schirmer test, are often associated with poor reproducibility and reliability, which make the diagnosis, follow-up, and management of the disease challenging. Advances in ocular imaging technology enables objective and reproducible measurement of changes in the ocular surface, tear film, and optical quality associated with DED. In this review, the authors will discuss the application of various imaging techniques, such as, noninvasive tear break-up time, anterior segment optical coherence tomography, in vivo confocal microscopy, meibography, interferometry, aberrometry, thermometry, and tear film imager in DED. Many studies have shown these devices to correlate with clinical symptoms and signs of DED, suggesting the potential of these imaging modalities as alternative tests for diagnosis and monitoring of the condition.

Ocular blood flow as a clinical observation: Value, limitations and data analysis.

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.

Comparison of chorioretinal layers in rhesus macaques using spectral-domain optical coherence tomography and high-resolution histological sections

Nonhuman primates are important preclinical models of retinal diseases because they uniquely possess a macula similar to humans. Ocular imaging technologies such as spectral-domain optical coherence tomography (SD-OCT) allow noninvasive, in vivo measurements of chorioretinal layers with near-histological resolution. However, the boundaries are based on differences in reflectivity, and detailed correlations with histological tissue layers have not been explored in rhesus macaques, which are widely used for biomedical research. Here, we compare the macular anatomy and thickness measurements of chorioretinal layers in rhesus macaque eyes using SD-OCT and high-resolution histological sections. Images were obtained from methylmethacrylate-embedded histological sections of 6 healthy adult rhesus macaques, and compared with SD-OCT images from 6 age-matched animals. Thicknesses of chorioretinal layers were measured across the central 3 mm macular region using custom semi-automated or manual software segmentation, and compared between the two modalities. We found that histological sections provide better distinction between the ganglion cell layer (GCL) and inner plexiform layer (IPL) than SD-OCT imaging. The first hyperreflective band between the external limiting membrane (ELM) and retinal pigment epithelium (RPE) appears wider on SD-OCT than the junction between photoreceptor inner and outer segments seen on histology. SD-OCT poorly distinguishes Henle nerve fibers from the outer nuclear layer (ONL), while histology correctly identifies these fibers as part of the outer plexiform layer (OPL). Overall, the GCL, inner nuclear layer (INL), and OPL are significantly thicker on histology, especially at the fovea; while the ONL, choriocapillaris (CC), and outer choroid (OC) are thicker on SD-OCT. Our results show that both SD-OCT and high-resolution histological sections allow reliable measurements of chorioretinal layers in rhesus macaques, with distinct advantages for different sublayers. These findings demonstrate the effects of tissue processing on chorioretinal anatomy, and provide normative values for chorioretinal thickness measurements on SD-OCT for future studies of disease models in these nonhuman primates.

The advantages of intermediate-tier, inter-optometric referral of low risk pigmented lesions.

PurposePigmented ocular lesions are commonly encountered by eye‐care professionals, and range from benign to sight or life‐threatening. After identifying a lesion, the primary care professional must establish the likely diagnosis and decide either to reassure, to monitor or to refer. The increasing use of ocular imaging technologies has contributed to an increase in the detection rate of pigmented lesions and a higher number of referrals, which may challenge existing pathways of health‐care delivery. Specialist services may be over‐burdened by referring all patients with pigmented lesions for an opinion, while inter‐optometric referrals are underutilised. The aim of this study was to describe the referral patterns of pigmented lesions to an optometry led intermediate‐tier collaborative care clinic.MethodsWe performed a retrospective review of patient records using the list of patients examined at Centre for Eye Health (CFEH) for an initial or follow up pigmented lesion assessment between the 1/7/2013 and the 30/6/2016. Analysis was performed on: patient demographic characteristics, the referrer's tentative diagnosis, CFEH diagnosis and recommended management plan.ResultsAcross 182 patient records, the primary lesion prompting referral was usually located in the posterior segment: choroidal naevus (105/182, 58%), congenital hypertrophy of the retinal pigment epithelium (CHRPE; 11/182, 6%), chorioretinal scarring (10/182, 5%) or not specified (52/182, 29%). Referrals described a specific request for ocular imaging in 25 instances (14%). The number of cases with a non‐specific diagnosis was reduced after intermediate‐tier care assessment (from 29% to 10%), while the number of diagnoses with less common conditions rose (from 2% to 21%). There was a 2% false positive referral rate to intermediate‐tier care and a first visit discharge rate of 35%. A minority required on‐referral to an ophthalmologist (22/182, 12%), either for unrelated incidental ocular findings, or suspicious choroidal naevi. Conditions most amenable to optometric follow up included: 1) chorioretinal scarring, 2) choroidal naevus, and 3) CHRPE.ConclusionsIntermediate‐tier optometric eye‐care in pigmented lesions (following opportunistic primary care screening) has the potential to reduce the number of cases with non‐specific diagnoses and to increase those with less common diagnoses. The majority of cases seen under this intermediate‐tier model required only ongoing optometric surveillance.

Intraoperative Optical Coherence Tomography - an Overview of Current Clinical Data for the Application in the Anterior and Posterior Segments

Intraoperative optical coherence tomography (iOCT) represents another milestone in ocular imaging technologies. Now, for the first time, high resolution OCT images are available not only pre- or postoperatively, but also intraoperatively. In recent years, there have been significant advances in iOCT technology - from hand-held probes and mounted systems towards iOCT systems which are fully integrated into the surgical microscope and which provide seamless integration into the workflow. These systems offer high-resolution, intraoperative OCT scans in real-time and provide additional information on microstructures of the retina or the cornea. These findings may even lead to a modification of surgical strategies. Like any other new technology, iOCT technology still has some limitations, such as shadowing from instruments and the lack of eye tracking systems. Therefore, the current state of iOCT technology still requires some skill to track surgical maneuvers in real time. Further research and development will help to solve these limitations in the future. However, even if not required for all surgical procedures, iOCT imaging can already improve safety and control in many surgical procedures on the anterior and posterior segments. This has already been shown in several studies and case series. Particularly in the surgery of vitreomacular traction, peeling of epiretinal membranes (ERM peeling) and macular hole surgery, iOCT offers significant added value. It improves the visualisation of transparent structures and helps to avoid the usage of dyes. In addition the success of the surgical maneuvers can be investigated intraoperatively. In lamellar keratoplasty and glaucoma surgery too, iOCT improves precision and safety. Moreover, iOCT technology may help to achieve further insight into ocular pathologies and a better understanding of the impact of surgical maneuvers on visual rehabilitation. Further prospective studies are however required to evaluate the usefulness of iOCT in various surgical procedures on both, the anterior and posterior segments.

Imaging of trabecular meshwork using Bessel–Gauss light sheet with fluorescence

Ocular imaging technology that holds promise for both fundamental investigation and clinical detection of glaucoma is still a challenging research area. A direct view of the trabecular meshwork (TM) with high resolution is not generally possible because the iridocorneal angle region is obstructed by the sclera overlap. The best approach to observe the aqueous outflow system (AOS) is therefore to view from the opposite angle. In this research work, we developed two imaging systems for the high resolution ex vivo studies of the AOS inside porcine eye, based on a Gaussian illuminated and a digitally scanned Bessel–Gauss beam light sheet fluorescence configurations. The digitally scanned Bessel–Gauss beam is able to overcome the trade-off between the length and thickness of the Gaussian light sheet to give better imaging performance. It has adequate spatial resolution to resolve critical anatomical structures such as the TM, thereby enabling objective information about the AOS. This non-contact and non-invasive imaging methodology with excellent safety profile is expected to be well received by vision researchers and clinicians in the evaluation and management of glaucoma.

Clinical Trials in Retinal Dystrophies.

Research development is burgeoning for genetic and cellular therapy for retinal dystrophies. These dystrophies are the focus of many research efforts due to the unique biology and accessibility of the eye, the transformative advances in ocular imaging technology that allows for in vivo monitoring, and the potential benefit people would gain from success in the field – the gift of renewed sight. Progress in the field has revealed the immense complexity of retinal dystrophies and the challenges faced by researchers in the development of this technology. This study reviews the current trials and advancements in genetic and cellular therapy in the treatment of retinal dystrophies and also discusses the current and potential future challenges.

Detection of retinal nerve fiber layer degeneration in patients with Alzheimer's disease using optical coherence tomography: searching new biomarkers

At the present time, researchers are searching for biomarkers and tools to detect the Alzheimer's disease (AD) in early phases, especially in high-risk families, and to monitor disease progression. Recent studies have revealed degenerative changes in optic nerve fibers, causing thinning of the retinal nerve fiber layer (RNFL) in patients with AD (Berisha et al. 2007; Kirbas et al. 2013). The RNFL comprises axons originating in retinal ganglion cells and can be measured using ocular imaging technologies such as optical coherence tomography (OCT), which provides non-invasive, rapid, objective and reproducible measurements. Retrograde loss of nerve fibers in the retina and optic nerve may be an early biomarker of neurodegeneration in AD, even prior to hippocampal damage, which impacts memory (Valenti 2007). Following this trend, we conducted a study in which we compared RNFL thickness in healthy and AD subjects using the two most commonly available spectral-domain (SD)-OCT machines [Cirrus OCT (Carl Zeiss Meditec, Inc., Dublin, Ireland) and Spectralis OCT (Heidelberg Engineering, Inc., Carlsbad, CA, USA)]. To carry out this prospective, cross-sectional study, 57 patients with mild or moderate AD and 57 healthy, age-matched control subjects were included. Inclusion criteria were: confirmed AD diagnosis; best-corrected visual acuity (BCVA) of 0.1 or higher; and intra-ocular pressure <21 mmHg. Exclusion criteria were: presence of significant refractive errors (>5 dioptres of spherical equivalent refraction or three dioptres of astigmatism); systemic conditions that could affect the visual system and history of ocular trauma or concomitant ocular diseases. Each eye was considered separately; one eye from each subject was randomly selected to be included in the analyses, except when one of the eyes was excluded (due to the presence of significant media opacity). All subjects underwent visual acuity, colour vision and OCT examinations using two SD-OCT devices. One hundred and fourteen eyes were evaluated: 57 eyes from patients with AD and 57 eyes from healthy subjects. To establish this cohort, we examined 65 patients with AD, but eight patients were not included in the study for the presence of unknown eye disease (two cases) or their inability to perform the full exploration protocol due to their functional status (six cases). Mean age was 75.29 ± 8.64 years in the AD group and 74.77 ± 9.24 years in the control group. Mean disease duration was 3.71 years (range, 1.46–5.96 years). Age, sex and intra-ocular pressure did not differ significantly between healthy controls and patients with AD (p > 0.05). RNFL thickness measured with the two OCT devices is shown in Table 1. Cirrus OCT revealed significant RNFL thinning in patients with AD especially in the superior and the inferior quadrant. The Spectralis OCT classic glaucoma application and the Nsite Axonal Analytics application revealed significant thinning in the inferior and inferotemporal RNFL in patients with AD compared with controls. There is histopathologic evidence of retinal ganglion cell loss and optic nerve degeneration in patients with AD (Blanks et al. 1996). Thus, we postulate that axonal loss secondary to other pathologic changes that occur in the brain can be detected by scanning the RNFL and the optic nerve, as these non-myelinated axons form the optical path that culminates in the occipital cortex. Although we believe the OCT could potentially provide a biomarker of AD, it should take into account a series of limitations: the relatively small sample size (despite being larger than that in previous studies) and the exclusion of subjects with mild cognitive impairment (preclinical stage of AD) or advanced dementia. Future prospective studies should attempt to segment the RNFL and macula to know which retinal layers are predominantly affected and should investigate Age Macular Disease-AD associations (by calculating amount of druse; measuring thickness of Bruch's membrane and auto-fluorescence of retina in AD cases, etc.) (Ohno-Matsui 2011). We think this is an interesting and promising research field in an unfortunately increasingly common dementing disorder in the elderly. Time will tell whether we are only measuring and comparing different parameters with the latest technologies or whether we are facing a new and accessible biomarker of disease.

Age-related macular degeneration: clinical findings, histopathology and imaging techniques.

Age-related macular degeneration (AMD) is the most common cause of blindness among people over age 55 years in industrialized countries. Known major risk factors for AMD include: age >55 years, history of smoking, white race, and mutations in various components of the complement system. Early AMD is characterized by the presence of drusen and pigmentary abnormalities. Late AMD is associated with central visual loss and is characterized by the presence of choroidal neovascularization and/or geographic atrophy. Early AMD is associated with a number of biochemical abnormalities including oxidative damage to retinal pigment epithelium (RPE) cells, complement deposition in the RPE-Bruch's membrane-choriocapillaris complex, lipidization of Bruch's membrane, and extracellular matrix abnormalities (e.g. collagen crosslinking, advanced glycation end product formation). Antiangiogenic drugs block the vascular leakage associated with choroidal new vessels, thus reducing retinal edema and stabilizing or restoring vision. At this time, there are no proven effective treatments for the nonexudative complications of AMD. Modern ocular imaging technologies (including spectral domain and phase variance optical coherence tomography, short- and long-wavelength fundus autofluorescence, adaptive optics-scanning laser ophthalmoscopy, and near-infrared reflectance) enable one to follow changes in the RPE, photoreceptors, and choriocapillaris quantitatively as the disease progresses. In addition, one can quantitatively assess the volume of drusen and areas of atrophy. These data, when correlated with the known histopathology of AMD, may provide useful measures of treatment efficacy that are likely to be more sensitive and reproducible than conventional end points such as visual acuity and rate of enlargement of geographic atrophy. As a result, these imaging technologies may be valuable in assessing the effects of cell-based therapy for patients with AMD.

Glaucoma Diagnosis and Monitoring Using Advanced Imaging Technologies

Advanced ocular imaging technologies facilitate objective and reproducible quantification of change in glaucoma but at the same time, impose new challenges on scientists and clinicians for separating true structural change from imaging noise. This review examines time-domain and spectral-domain optical coherence tomography, confocal scanning laser ophthalmoscopy and scanning laser polarimetry technologies and discusses the diagnostic accuracy and the ability of each technique for evaluation of glaucomatous progression. A broad review of the current literature reveals that objective assessment of retinal nerve fiber layer, ganglion cell complex and optic nerve head topography may improve glaucoma monitoring when used as a complementary tool in conjunction with the clinical judgment of an expert.

Cataract Surgery and the LenSx® Femtosecond Laser System

The use of femtosecond laser systems in cataract surgery has been stated to be arguably the single biggest change to the procedure since phacoemulsification. The combination of a controllable high-frequency laser with increasingly advanced ocular imaging technology provides for a surgical precision that is difficult or impossible to duplicate manually. As a new technology, much clinical research is underway to identify best practices, and quantify the benefits of femtosecond cataract surgery. The main measures of interest are improvements in surgical precision, reduced complication rates and lower variability in clinical outcomes compared with manual procedures. The lower variability in outcomes would translate to a higher percentage of patients achieving their desired refractive target after surgery. This article provides an overview of the LenSx® femtosecond laser system, some of the ways in which it is being utilized in cataract surgery, and related surgical/ clinical results recently reported in the peer-reviewed literature.

New Technologies for Glaucoma Imaging

The evolution of imaging technologies over the past decade has reshaped our landscape in diagnosing and managing patients with glaucoma. Adopting technological advances and translating new information into clinical practice pose new challenges to both clinicians and research scientists. This special issue includes five papers covering some of the recent advances in ocular imaging and electrophysiology technologies and demonstrates how such advancement augments our understanding of glaucoma. Since its introduction in 2005, the spectral-domain optical coherence tomography (SD-OCT) has received considerable attention for retinal nerve fiber layer (RNFL) and optic disc imaging. With improved axial resolution to discern individual retinal layers, new parameters such as the ganglion cell complex (GCC) and the photoreceptor layer thicknesses can now be measured reliably with SD-OCT. S. T. Takagi and et al. demonstrate that macular GCC thickness could serve as a biomarker for early detection of glaucoma. With a high density of retinal ganglion cells in the macula, it is conceivable that measuring macular GCC thickness would be valuable for glaucoma assessment. By contrast, the outer retina would be expected to be unaffected. Unexpectedly, N. Fan et al. show that the outer nuclear layer is thicker in mild glaucomatous eyes than in normal eyes. This finding suggests glaucomatous damage may involve structural change in the photoreceptors. Full-field electroretinogram (ERG) has been considered less useful for glaucoma evaluation. S. Machida et al. show that a photopic negative response (PhNR) (a negative deflection following the photopic b-wave) obtained from a focal ERG system could indicate functional abnormality of retinal ganglion cells and has a high diagnostic performance to detect early glaucoma. While the potential of focal ERG PhNR for objective functional assessment appears promising, prospective longitudinal studies are needed to validate its use in glaucoma patients. Intraocular pressure (IOP) is a major risk factor for glaucoma progression. Yet, it has long been recognized that there are factors other than IOP that could modify the course of the disease. In a randomized double-masked study comparing dorzolamide/timolol and latanoprost/timolol fixed combination for treatment in glaucoma patients, I. Januleviciene et al. report that a number of hemodynamic parameters including blood pressure, ocular perfusion pressure, and ophthalmic and central retinal artery vascular resistance are associated with RNFL and/or visual field progression independent of IOP reduction. Although this study is limited by a small sample size (15 patients in each arm) and a high progression rate (40% and 47% of patients progressed, resp.), the result could stimulate more research investigating the roles of ocular and systemic hemodynamics in glaucoma progression. Multiphoton microscopy is a relatively new modality for ophthalmic imaging. E. A. Gibson et al. summarize the applications of multiphoton microscopy for retinal and transscleral imaging and demonstrate the feasibility to visualize the collagen fibers in human trabecular meshwork ex vivo. The exciting development of multiphoton imaging will undoubtedly provide new data for potential application in the clinic in the near future. The improvement in patient care depends upon continued research and development of new tools and new techniques to unfold the pathobiology of glaucoma for early diagnosis and treatment. It is sufficient to say that glaucoma imaging forms one of the cornerstones in the advancement of glaucoma care. Christopher K. S. Leung Felipe A. Medeiros David Garway-Heath David S. Greenfield Robert N. Weinreb

Influencia del tratamiento en la pérdida de fibras nerviosas de la retina en pacientes con esclerosis múltiple

Objective To evaluate the effect of pathogenic treatments in the reduction of the retinal nerve fibre layer (RNFL) in patients with Multiple Sclerosis (MS) by means of ocular imaging technologies. Material and methods A total 155 eyes of 79 patients with MS were enrolled in this study. All patients underwent a complete ophthalmic examination including best corrected visual acuity using Snellen chart, colour vision using Ishihara pseudoisochromatic plates, visual field examination, optical coherence tomography (OCT), scanning laser polarimetry (GDx) and visual evoked potentials. The patients were re-evaluated after a one year period and changes were assessed in order to detect differences between treatments using the Anova statistical test. The patients were divided into four groups: 1) Patients without treatment, 2) Patients treated with interferon beta-1a, 3) Subjects who received interferon beta-1b, 4) Patients treated using glatiramer acetate. Results There were no statistically significant differences between patients with or without treatment and between the four groups ( P > 0.05, t test), but functional and structural parameters showed greater loss in RNFL thickness in non-treated patients. Temporal quadrant RNFL thickness measured by OCT was the parameter with the highest variation (reduction of 4.97 μm in patients without treatment vs 1.08 μm in treated patients). Conclusions MS pathogenic treatment may be a protective factor in the RNFL loss that is associated to the disease progression. More studies are needed.

Effect of treatment in loss of retinal nerve fiber layer in multiple sclerosis patients

ObjectiveTo evaluate the effect of pathogenic treatments in the reduction of the retinal nerve fiber layer (RNFL) in patients with Multiple Sclerosis (MS) by means of ocular imaging technologies. Material and methodsA total 155 eyes of 79 patients with MS were enrolled in this study. All patients underwent a complete ophthalmic examination including best corrected visual acuity using Snellen chart, colour vision using Ishihara pseudoisochromatic plates, visual field examination, optical coherence tomography (OCT), scanning laser polarimetry (GDx) and visual evoked potentials. The patients were re-evaluated after a one year period and changes were assessed in order to detect differences between treatments using the Anova statistical test. The patients were divided into four groups: 1) Patients without treatment, 2) Patients treated with interferon beta-1a, 3) Subjects who received interferon beta-1b, 4) Patients treated using glatiramer acetate. ResultsThere were no statistically significant differences between patients with or without treatment and between the four groups (P>0.05, t test), but functional and structural parameters showed greater loss in RNFL thickness in non-treated patients. Temporal quadrant RNFL thickness measured by OCT was the parameter with the highest variation (reduction of 4.97μm in patients without treatment vs 1.08μm in treated patients). ConclusionsMS pathogenic treatment may be a protective factor in the RNFL loss that is associated to the disease progression. More studies are needed.