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: Between 2011 and 2013, two large-scale cohort epidemiology studies were launched in Shanghai: the SCALE study, which aimed to provide ocular public health services to cover the entire youth population in Shanghai, and the SCES, which was based on sample surveys and aimed to provide information on the prevalence and incidence of visual impairment and different types of refractive errors. A total of 910,245 children and adolescents were finally enrolled in the SCALE study; three possible methods for monitoring refractive error without mydriasis were tested, and the agreement between the refractive outcomes of three commonly used autorefractors were examined to ensure the accuracy of the results of the SCALE study. A total of 8,627 children were enrolled in the SCES, and the baseline prevalence of different refractive errors, different behaviors associated with 1 year myopic shifts, and the different patterns of 2-year myopia progression between internal migrant and local resident school children have been analyzed. In some subset samples of the SCALE study and the SCES, several refraction components such as choroidal thickness (ChT) and crystalline lens power were also measured, to further elucidate the relationships between the refraction components and myopia as well as the mechanism of myopia incidence and development. The three methods used in Shanghai to prevent and intervene with childhood myopia: increasing outdoor time, low concentration atropine, and use of orthokeratology lens are also addressed in this review.
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.
Abstract: The article discusses the early abandonment of mechanical theories about eye enlargement in degenerative myopia at the turn of the 20th century. At that time, the number of theories about myopia grew unrestricted, but with scant support from the experimental field. The mechanical theories vanished as a new wave of metabolism-based theories appeared, propelled by the huge advances in molecular biology. Modern techniques allow reconsidering those theories and to put them to test with higher confidence.
Background: Understanding the neurophysiological mechanisms of Amblyopia, a neurodevelopmental disorder of the visual cortex, will bring us closer to full recovery. Past findings have been contradictory. Results have shown that despite having severe acuity impairment, amblyopes can nonetheless perceive sharp edges. In this study, we explore the representation of blur through a series of image blur-discrimination and matching tasks, to understand more about the amblyopes’ visual system.
Methods: Monocular image blur-discrimination thresholds were measured in a spatial two-alternative forced-choice procedure whereby subjects had to decide which image was the blurriest. Subjects also had to interocularly match pictures that were identical to those used for the image blur discrimination task. Ten amblyopes, as well as a group of ten controls were under study.
Results: Data on amblyopes and controls will be presented for both experiments. According to previous research that was done on blur-edge discrimination and matching, we predict that subjects’ performance will follow a dipper function, that is, all observers will be better at discriminating between both images when a small amount of blur is applied rather than when the image is either sharp or very blurry. We also predict that amblyopes’ blur discrimination will be noisier, but that they will paradoxically be able to match the sharpness of the images presented in the matching task.
Conclusions: This would confirm our hypothesis about amblyopes’ visual system, that they can represent blur levels defined by spatial frequencies that are beyond their resolution limit, and would also raise interesting questions about the visual system in general regarding the different perceptions driven by images versus edges.
Background: This infrastructure delivers biological material necessary for several research projects to Vision Health Research Network investigators (VHRN).
Methods: Héma-Québec is the organism in charge obtaining consent and retrieving donor eyes for patient treatment or for research. In Quebec City, donor eyes are sent to the eye bank of the “Centre Universitaire d’Ophtalmologie” (CUO) of Saint-Sacrement hospital. Technicians at the eye bank evaluate the quality of the tissues. Those unfit for graft are transferred to the infrastructure where the coordinator encodes samples prior to their distribution.
Results: Between 2013 and 2017, 27 fundamental investigators, clinical investigators and collaborators supported by 60 students, trainees and laboratory assistants used this infrastructure to move forward their projects. Since 2013, results from those projects generated 21 scientific publications and 232 presentations. The infrastructure helped VHRN investigators obtain near 4 million dollars in grants from many organisms (CIHR, NSERC, Foundations, etc.). These grants allowed recruitment and formation of highly qualified personnel. Last year (April 2016 to March 2017), 189 corneas and 23 eyes transited through the infrastructure.
Conclusions: This infrastructure is available for all investigators that are members of the VHRN. Many original projects have been elaborated thanks to the human ocular tissues provided by this infrastructure. These projects will advance our knowledge in vision health. A better understanding of eye functions will lead to new treatments for eye diseases.
