Andrei Szigiato

Université de Montréal | UdeM · Department of Ophthalmology

Purpose: To analyze the efficacy of induced macular detachment for the treatment of persistent or recurrent idiopathic macular holes after treatment with one or more standard pars plana vitrectomies (PPVs) with internal limiting membrane peeling. Methods: This study is a retrospective consecutive case series of 10 patients who underwent a PPV wi...

Importance Although screening examinations for retinopathy of prematurity (ROP) prevent blindness, they are physiologically stressful for infants. Photosensitivity during mydriasis may contribute to postexamination stress, and reducing light stimulation may make infants more comfortable. Objective To determine the effect of a phototherapy mask wor...

Background/aims To evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure. Methods Single surgeon retrospective cohort study including 85 eyes of 74 patients who underwent KPro implantation to treat severe ocular surface disease, including limbal stem cell deficiency, postin...

Purpose: A subset of patients with neovascular age related macular degeneration (nAMD) experience treatment burden and suboptimal response with anti-vascular endothelial growth factor (anti-VEGF) therapy. The aim of this study was to investigate the effect of switching to a novel bi-specific agent, faricimab, in patients with nAMD currently treate...

Background To evaluate the rate and risk factors of epiretinal membrane (ERM) formation and need for ERM peeling after pars plana vitrectomy (PPV) for uncomplicated primary rhegmatogenous retinal detachment (RRD). Methods Retrospective, single-center, cohort study of 119 consecutive patients (119 eyes) that underwent RRD repair using PPV. The prim...

Background/aims This study assesses the proficiency of Generative Pre-trained Transformer (GPT)-4 in answering questions about complex clinical ophthalmology cases. Methods We tested GPT-4 on 422 Journal of the American Medical Association Ophthalmology Clinical Challenges, and prompted the model to determine the diagnosis (open-ended question) an...

Aim: To report the efficacy of the revision of failed ab interno canaloplasty with micro-invasive suture trabeculotomy (MIST) over a follow-up period of 24 months. Materials and methods: A retrospective analysis was performed on 23 eyes with open-angle glaucoma (OAG), on whom an ab interno canaloplasty revision with MIST was performed for glauco...

Objective: To evaluate the outcomes of ab interno gelatin microstent implantation alone and in combination with phacoemulsification for the reduction of intraocular pressure (IOP). Design: Retrospective cohort study. Methods: A total of 141 eyes of 141 patients with any glaucoma subtype, including refractory glaucoma, who received ab interno m...

Background/aims To compare long-term outcomes of primary versus secondary (postgraft failure) Boston keratoprosthesis type 1 (KPro) implantation. Methods Medical records of patients at the Centre hospitalier de l’Université de Montréal having undergone KPro implantation between 2008 and 2017 were reviewed and included if they had a preoperative Sn...

Purpose: To determine the incidence and recurrence of Boston type I keratoprosthesis (KPro)-associated endophthalmitis, and its microbiological profile, risk factors, and outcomes. Methods: This is a retrospective study of 158 consecutive KPro procedures with a median follow-up of 78.4 months. Medical charts were reviewed for ocular history, con...

Background/aims To evaluate the non-invasive measurement of ocular rigidity (OR), an important biomechanical property of the eye, as a predictor of intraocular pressure (IOP) elevation after anti-vascular endothelial growth factor (anti-VEGF) intravitreal injection (IVI). Methods Subjects requiring IVI of anti-VEGF for a pre-existing retinal condi...

Purpose: To assess the efficacy of the prestorage corneal swab (PCS) culture to screen for corneal graft contamination after storage in Optisol-GS. Methods: A retrospective analysis of all PCS cultures was performed at the Eye Bank of Québec in Hôpital Maisonneuve-Rosemont from September 2013 to June 2016. Whole corneal culture was performed on...

Objective: To review the trends in adult strabismus procedures in Ontario from 2000-2013. Design: Population-based, retrospective data analysis. Participants: All patients 18 years or older who underwent a strabismus related procedure in Ontario and all ophthalmologists who performed these procedures from 2000-2013. Methods: Ontario Health I...

Repair of forceps-induced Descemet’s rupture with Descemet’s Membrane Endothelial Keratoplasty (DMEK). (A) Pre-operative photographs (top) and corneal optic coherence tomography (OCT) (bottom) of three oblique, curvilinear Descemet’s tears (black arrows) in a 69 year old pseudophakic man. His best corrected visual acuity (BCVA) was 20/150 with a co...

BACKGROUND Retinopathy of prematurity (ROP) is a disorder of retinal development in the low birthweight preterm infant. Eye screening is routinely performed for infants at risk of developing this disorder. While these examinations help prevent blindness, they can be physiologically stressful for infants, with changes in oxygen saturation, blood pre...

Objective: To evaluate and compare the surgeon's learning experience with an ab-interno gelatin microstent (XEN-45, Allergan) to other glaucoma surgeries. Design: Cross-sectional survey study. Methods: All surgeons in Canada who used the gelatin microstent were identified and given an anonymous online survey (FluidSurveys, Survey Monkey) desig...

Purpose To determine the incidence and trends in intraocular lens (IOL) repositioning, exchange, and explantation. Setting Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada. Design Population-based retrospective data analysis. Methods Service claims from 2000 to 2013 were analyzed for the total year...

A woman in her 60s presented with 2 years of slowly worsening binocular oblique diplopia. She underwent strabismus surgery 20 years prior to correct a hypotropic left globe, but had no imaging at the time. Examination revealed partial left ptosis, a nonreactive mydriatic left pupil, and limited adduction, elevation, and depression of the left globe...

Objective: The rate of strabismus surgery was previously reported to be decreasing in the United Kingdom and Ontario. Data on the influence of government funding on surgical trends and recent population trends for surgery in pediatric patients in Canada are limited. This study aims to analyze the trend in pediatric strabismus procedures in Ontario...

A woman in her 50s with advanced primary open-angle glaucoma presented 1 year post insertion of an ab interno gelatin microstent (Xen; Allergan) with mitomycin C (MMC). On examination, her intraocular pressure (IOP) was 21mmHg while taking 3 glaucoma medications. Her microstent was patent in the anterior chamber. Her bleb was flat and fibrosed. Aft...

Introduction: New modalities for providing sustained drug delivery in glaucoma continue to be developed and aim to improve on the limitations inherent to topical eye drops. This article provides an update on recently published studies and clinical trials of topical, injectable, and other targeted drug delivery systems used to manage glaucoma and bl...

Objective: To review cataract surgery trends and wait times in Ontario. Design: Retrospective analysis of health records. Methods: Ontario Health Insurance Plan billing service claims between 2000 and 2012 were analyzed for the yearly number of cataract surgeries, alone and in combination with other procedures. The number of Ontarians with cat...

Objective: To analyze trends in bilateral, same-day laser iridotomies, and trabeculoplasties in Ontario over the last decade. Methods: Ontario Health Insurance Plan billing service claims between 2000 and 2013 were analyzed for the yearly number of glaucoma laser procedures. The annual number of Ontarians with primary open-angle glaucoma (POAG)...

Objective: To analyze trends in the surgical management of glaucoma in Ontario over the past 2 decades. Design: Retrospective analysis of health records. Methods: Ontario Health Insurance Plan billing service claims between 1992 and 2012 were analyzed for the yearly number of glaucoma laser and incisional surgical procedures. The yearly number...

Purpose: To document the diagnosis and repair of bilateral retinal detachments in a child with spondyloepimetaphyseal dysplasia-Strudwick type, a rare autosomal dominant genetic disorder involving abnormal production of Type II collagen. Methods: Case report. Results: A 13-year-old patient diagnosed with spondyloepimetaphyseal dysplasia-Strudw...

The angiostatic nature of pharmacological doses of glucocorticoid steroids is well known. However, the consequences of pathophysiological elevation of endogenous glucocorticoids are not well established. In the current study, we hypothesized that the angiostatic effect of corticosterone, an endogenous glucocorticoid in rodents, occurs through multi...

Corticosterone inhibits MMP-2 production via glucocorticoid receptor activation. Endothelial cells (1.0×106 cells) were plated in 35 mm2 dishes coated with type I collagen and treated with 600 nM corticosterone for 24 and 48 hours. Total (Ai) and percent active (Aii) MMP-2 levels in whole cell lysates were measured by gelatin zymography (*p = 0.02...

Corticosterone does not cause apoptosis or necrosis of endothelial cells. Skeletal muscle endothelial cell spheroids were suspended in a 3-dimensional type I collagen culture (A, B). Spheroids were treated for 48 hours with 600 nM corticosterone, prior to immunostaining for cleaved caspase-3 (red) and actin (green). Endothelial cells were either re...

Chronically elevated glucocorticoids (GCs) and a high-fat diet (HFD) independently induce insulin resistance, abdominal obesity, and nonalcoholic fatty liver disease (NAFLD). GCs have been linked to increased food intake, particularly energy-dense "comfort" foods. Thus we examined the synergistic actions of GCs and HFD on hepatic disease developmen...

Poorly controlled type 1 diabetes mellitus can cause reduced skeletal muscle mass and weakness during adolescence, which may affect long-term management of the disease. The aim of this study was to determine whether regular voluntary physical activity and leucine feeding restore rates of protein synthesis and deficits in skeletal muscle mass in a y...