Abstract: This submission will briefly review the anatomy and physiology of the optic nerve, and highlight various ischemic optic neuropathies including anterior ischemic optic neuropathies (non-arteritis and arteritic), diabetic papillopathy, posterior ischemic optic neuropathies, and ischemic optic neuropathies in the setting of hemodynamic compromise.
Abstract: Acute retinal arterial ischemia, which includes transient monocular vision loss (TMVL), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and ophthalmic artery occlusion (OAO), is most commonly the consequence of an embolic phenomenon from the ipsilateral carotid artery, heart or aortic arch, leading to partial or complete occlusion of the central retinal artery (CRA) or its branches. Acute retinal arterial ischemia is the ocular equivalent of acute cerebral ischemia and is an ophthalmic and medical emergency. Patients with acute retinal arterial ischemia are at a high risk of having further vascular events, such as subsequent strokes and myocardial infarctions (MIs). Therefore, prompt diagnosis and urgent referral to appropriate specialists and centers is necessary for further work-up (such as brain magnetic resonance imaging with diffusion weighted imaging, vascular imaging, and cardiac monitoring and imaging) and potential treatment of an urgent etiology (e.g., carotid dissection or critical carotid artery stenosis). Since there are no proven, effective treatments to improve visual outcome following permanent retinal arterial ischemia (central or branch retinal artery occlusion), treatment must focus on secondary prevention measures to decrease the likelihood of subsequent ischemic events.
Abstract: Optical coherence tomography (OCT) is an ocular imaging technique that can complement the neuro-ophthalmic assessment, and inform our understanding regarding functional consequences of neuroaxonal injury in the afferent visual pathway. Indeed, OCT has emerged as a surrogate end-point in the diagnosis and follow up of several demyelinating syndromes of the central nervous system (CNS), including optic neuritis (ON) associated with: multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies. Recent advancements in enhanced depth imaging (EDI) OCT have distinguished this technique as a new gold standard in the diagnosis of optic disc drusen (ODD). Moreover, OCT may enhance our ability to distinguish cases of papilledema from pseudopapilledema caused by ODD. In the setting of idiopathic intracranial hypertension (IIH), OCT has shown benefit in tracking responses to treatment, with respect to reduced retinal nerve fiber layer (RNFL) measures and morphological changes in the angling of Bruch’s membrane. Longitudinal follow up of OCT measured ganglion cell-inner plexiform layer thickness may be of particular value in managing IIH patients who have secondary optic atrophy. Causes of compressive optic neuropathies may be readily diagnosed with OCT, even in the absence of overt visual field defects. Furthermore, OCT values may offer some prognostic value in predicting post-operative outcomes in these patients. Finally, OCT can be indispensable in differentiating optic neuropathies from retinal diseases in patients presenting with vision loss, and an unrevealing fundus examination. In this review, our over-arching goal is to highlight the potential role of OCT, as an ancillary investigation, in the diagnosis and management of various optic nerve disorders.
Background: To present a surgical technique using a rigid intraocular lens as endocapsular supporting device in manual small incision cataract surgery (MSICS) for treating mild-moderate subluxated cataracts.
Methods: In our technique, a single-piece rigid polymethyl methacrylate (PMMA) lens was implanted in the bag following the nucleus removal, with its axis vertical to the zonular dialysis. This endocapsular-implanted IOL stretched the bag and provided sufficient stability and lens centration. This technique was performed in 19 eyes with subluxated cataracts, with zonulysis of ≤120 degree and nuclear sclerosis of grade ≤3. Mean follow-up time was 9.8 months.
Results: All eyes had endocapsular IOL implantation during surgery. Intraoperative extension of the dialysis did not occur in any eye. The IOL was placed in the bag in all but 1 case, in which dislocation of the IOL haptic into the vitreous occurred. Though the IOL was slightly decentered in 3 cases, it kept stable. All patients were asymptomatic.
Conclusions: This approach provides a simplified and practical strategy for surgically managing subluxation with mild-moderate zonular loss.
Abstract: Myasthenia gravis (MG) is an autoimmune antibody-mediated disorder which causes fluctuating weakness in ocular, bulbar and limb skeletal muscles. There are two major clinical types of MG. Ocular MG (OMG) affects extra ocular muscles associated with eye movement and eyelid function and generalized MG results in muscle weakness throughout the body. Patients with OMG have painless fluctuating extra ocular muscles weakness, diplopia and ptosis accompanied by normal visual acuity and pupillary function. Frequently, patients with OMG develop generalized MG over 24 months. Pure OMG is more often earlier in onset (<45 years) than generalized MG. It can also occur as part of an immune-genetic disorder or paraneoplastic syndrome related to thymus tumors. Diagnosis is based on clinical manifestations, laboratory findings, electrophysiological evaluation and pharmacologic tests. Therapeutic strategies for MG consist of symptom relieving medications (e.g., acetylcholine esterase inhibitors), immunosuppressive agents, and surgical intervention (e.g., thymectomy).
Background: To compare objective electrophysiological contrast sensitivity function (CSF) in patients implanted with either multifocal intraocular lenses (MIOLs) or monofocal intraocular lenses (IOLs) by pattern reversal visual evoked potentials (prVEP) measurements.
Methods: Fourty-five cataract patients were randomly allocated to receive bilaterally: apodized diffractive-refractive Alcon Acrysof MIOL (A), full diffractive AMO Tecnis MIOL (B) or monofocal Alcon Acrysof IOL (C). Primary outcomes: 1-year differences in objective binocular CSF measured by prVEP with sinusoid grating stimuli of 6 decreasing contrast levels at 6 spatial frequencies. Secondary outcomes: psychophysical CSF measured with VCTS-6500, photopic uncorrected distance (UDVA), and mesopic and photopic uncorrected near and intermediate visual acuities (UNVA and UIVA respectively).
Results: Electrophysiological CSF curve had an inverted U-shaped morphology in all groups, with a biphasic pattern in Group B. Group A showed a lower CSF than group B at 4 and 8 cpd, and a lower value than group C at 8 cpd. Psychophysical CSF in group A exhibited a lower value at 12 cpd than group B. Mean photopic and mesopic UNVA and UIVA were worse in monofocal group compared to the multifocal groups. Mesopic UNVA and UIVA were better in group B.
Conclusions: Electrophysiological CSF behaves differently depending on the types of multifocal or monofocal IOLs. This may be related to the visual acuity under certain conditions or to IOL characteristics. This objective method might be a potential new tool to investigate on MIOL differences and on subjective device-related quality of vision.
Background: The purpose of this infrastructure is to provide to the Network researchers a database and diverse related tools for the anatomical and functional analysis of the normal, pathological and surgical cornea.
Methods: This database is composed of normal and pathological individuals, totaling more than 36,000 patients. It includes anatomical and functional imaging data, physiological optics data, psychometric and clinical data (medical history, surgical parameters, acuteness, etc.). Various corneal topography tools were added, giving the database a unique character: tools for analyzing individual maps, average map tools for the study and comparison of populations, 3D modeling and visualization tools, statistical tools, etc. There are also screening tools for detecting various corneal conditions (LASIK, PRK, RK, keratoconus) and for secure data exchange between colleagues.
Results: Several studies were made in recent years thanks to this common infrastructure. For example, this database has provided important information regarding the evolution of the 3D shape of the normal cornea with age and ametropia and has confirmed the mirror symmetry of corneas for the right and the left eyes (enantiomorphism). The different stages of Fuchs’ dystrophy were also characterized to provide essential knowledge for surgery of the posterior layer of the cornea. Our database also allowed studying the anatomy of the wounds and the shape of the cornea before and after a transfixing transplant or an endothelial transplant (DSAEK and DSEK). The data on the characterization of experimentally transplanted corneas with corneal equivalents generated by tissue engineering and the recent addition of clinical data on the replacement of a diseased cornea with a synthetic corneal equivalent (keratoprosthesis) also resulted in several publications. More recently, the database has allowed to develop innovative algorithms to determine the optimal shape of an implant according to the clinical parameters of the recipient. On the other hand, we also demonstrated that the 3D shape of the cornea can be used as a biometric characteristic (such as fingerprints) for identification of individuals for various applications ranging from forensics to secure border crossings. Consequently, a new multimodal database (cornea + iris + eventually retina) was created for the purpose of biometric identifications. This database provides a unique set of anatomical and functional tools for the analysis of the cornea. It is characterized by the scientific quality and large quantity of accumulated information on the cornea and the high-level tools to exploit its content.
Conclusions: The common infrastructure is easily accessible to all VHRN members on request. The database will also be accessible online in 2018 (see http://cvl.concordia.ca for more information).
Background: Understanding factors that contribute to posterior capsular opacification (PCO) development is a significant public concern as treatment can lead to complications. In order to prevent PCO, a better understanding of intraocular lens (IOL) characteristics, including design and material, and patient interaction is required. Herein, we performed a retrospective multivariable analysis to determine which factors (IOL and patient based) were least likely to result in PCO.
Methods: One hundred eighty post-mortem eyes with implanted IOLs were collected from the Minnesota Eye Bank, along with clinical history, including date of cataract surgery and IOL model number. The capsular bag (CB) with the IOL implant was removed from all eyes to obtain digital images. PCO outcome was quantified on CB images using an objective, automated custom image analyzer (Medical Parachute Automated Detector Opacification Software). The software measured intensity and area of the opacification within the IOL optic edge, intra-optic edge (IOE = intensity/area), and in Soemmering’s ring (SR = intensity/area). Epidemiologic analysis assessed which IOL characteristics and patient-related factors correlated with PCO. IOL factors included material, edge design, lens filter, company, IOL model, decentration and time from cataract surgery to death. Patient factors included sex, age and diabetes, among others.
Results: Multivariate analyses showed non-diabetic patients had less PCO (P=0.05). Individuals 50–80 years old compared to 80+ had lower SR PCO (P=0.04). Non-blue light filter IOLs had lower SR and IOE PCO compared to filter IOLs (P=0.03, 0.001). Square and frosted optic edge design had lower SR and IOE PCO rates compared to OptiEdge and round optic edge design (P=0.002, 0.02). The IOL model that had the least PCO was the ZA9003 model, but this was only significant for SR and not IOE PCO (P=0.04). Adjusting for patient-factors, IOL lens model was no longer a confounding factor for PCO. Patients with an IOL implanted for <7 years had lower SR PCO, whereas lower IOE PCO was only seen in implants <4 years old (P=0.0001, 0.04).
Conclusions: In order to generate a lens that does not develop PCO, it is critical to understand the IOL- and patient-related factors that lead to PCO development. Based on our data, the most susceptible patients are elderly and diabetic, and it may be preferable to implant a square and frosted edge lens without blue-light filtering in this cohort.
